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Mater. Proc., 2021, CMDWC 2021

The 1st Corrosion and Materials Degradation Web Conference

Online | 17–19 May 2021

Volume Editors:
Raman Singh, Monash University, Australia
Digby Macdonald, University of Berkeley, USA
Rhys Jones, Monash University, Australia

Number of Papers: 35
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Cover Story (view full-size image): The 1st Corrosion and Materials Degradation Web Conference (CMDWC 2021), which is organized by the MDPI open access journals Corrosion and Materials Degradation (CMD) and Materials, was [...] Read more.
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156 KiB  
Abstract
Corrosion Behavior of Al7Cu0.2Si0.2Zn0.2Mg0.1 Complex Concentrated Alloy, in 3wt% and 5wt% Na Cl Solution
by Dumitru Mitrica, Denisa Vonica, Marian Burada, Mihai Tudor Olaru, Beatrice Adriana Serban, Ioana Cristina Badea and Ioana Anasiei
Mater. Proc. 2021, 6(1), 1; https://doi.org/10.3390/CMDWC2021-09953 - 08 May 2021
Cited by 1 | Viewed by 550
Abstract
Complex concentrated alloys (CCAs) are new types of materials, where the equimolar rule proposed by high entropy alloys (HEAs) is modified in relation to the potential of the obtained structures. CCAs expend the compositional space of the conventional alloys, revealing new pathways for [...] Read more.
Complex concentrated alloys (CCAs) are new types of materials, where the equimolar rule proposed by high entropy alloys (HEAs) is modified in relation to the potential of the obtained structures. CCAs expend the compositional space of the conventional alloys, revealing new pathways for material design. The Al7Cu0.2Si0.2Zn0.2Mg0.1 alloy was prepared in an induction furnace, in controlled atmosphere and was cast in a copper ingot mold. The resulting samples of Al7Cu0.2Si0.2Zn0.2Mg0.1 were analysed by chemical, structural, and corrosion resistance. Furthermore, the alloy has been subjected to mechanical tests of hardness, elongation and tensile strength. The corrosion immersion tests were performed in 3wt% and 5wt% NaClsolution, and corrosion indices were measured periodically. The obtained corrosion film was analized by SEM-EDS to determine the composition and structural behaviour. Depending on the adhesion level, the corrosion film remained stable or partially broken and separated in the solution. The sample weight loss presented large variations between the various experimental conditions, but the general tendency was the decrease in the weight of the samples during the corrosion tests. The formation of oxide and chloride layers, during the corrosion process, determined only the dealloying in Al. Other elements remained in initial concentrations. Overall, the resistance of the alloy in saline environment seems to be promising, with significant improvement over the comparable compositions of 2000 and 7000 series aluminium alloys. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
154 KiB  
Abstract
Hydrothermal Degradation of Biobased Poly(butylene succinate)/Nanofibrillated Cellulose Composites
by Olesja Starkova, Oskars Platnieks, Alisa Sabalina and Sergejs Gaidukovs
Mater. Proc. 2021, 6(1), 2; https://doi.org/10.3390/CMDWC2021-09981 - 08 May 2021
Viewed by 571
Abstract
Biobased polymers and composites have gained increased global attention due to their abundance, renewability, and biodegradability. Natural fillers such as cellulose-based fillers improve the mechanical properties of biopolymers, extending their application range, while maintaining the eco-friendly characteristics of the materials. Mowing towards engineering [...] Read more.
Biobased polymers and composites have gained increased global attention due to their abundance, renewability, and biodegradability. Natural fillers such as cellulose-based fillers improve the mechanical properties of biopolymers, extending their application range, while maintaining the eco-friendly characteristics of the materials. Mowing towards engineering applications, requirements imposed on materials’ durability with regard to their environmental impact and high performance is necessary. Variations of ambient humidity and temperature could essentially reduce the service lifetime of biobased polymer composites. This study is focused on the hydrothermal degradation of poly(butylene succinate) (PBS) filled with nanofibrillated cellulose (NFC) by up to 50 wt.% aimed at identifying the most efficient PBS/NFC composition, while maintaining a reasonable balance between the reinforcement effect and accelerated degradation that is inherent for most natural fillers. Water absorption and its effect on the structure, thermal, mechanical, and thermomechanical properties were studied. High reinforcement and adhesion efficiency is obtained for PBS/NFC composites and their properties are reasonably retained after hydrothermal ageing. Their water absorption capacity and diffusivity increased significantly with the NFC content in PBS. The degradation of the mechanical properties occurs to a greater extent with an increased NFC content in the polymer matrix. PBS, filled with 20 wt.% of NFC, is identified as the most efficient composition, for which the negative environmental degradation effects are counterbalanced by the positive reinforcement effect. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
160 KiB  
Abstract
Corrosion Properties of Biodegradable AZ31 and ZK60 Magnesium Alloys: In Situ Study
by Evgeniy Merson, Vitaliy Poluyanov, Dmitry Merson and Pavel Myagkikh
Mater. Proc. 2021, 6(1), 3; https://doi.org/10.3390/CMDWC2021-09959 - 08 May 2021
Cited by 1 | Viewed by 468
Abstract
Biodegradable magnesium alloys are promising materials for application in medicine. The corrosion rate and type of corrosion are among the most important properties for this kind of materials. The fine-grained biodegradable alloys AZ31 (hot-rolled) and ZK60 (extruded) were studied in the present work [...] Read more.
Biodegradable magnesium alloys are promising materials for application in medicine. The corrosion rate and type of corrosion are among the most important properties for this kind of materials. The fine-grained biodegradable alloys AZ31 (hot-rolled) and ZK60 (extruded) were studied in the present work with the use of in situ methods including the hydrogen evolution corrosion rate measurement and real-time surface observation as well as ex situ methods such as the weight loss assessment and the post-mortem examination by confocal laser scanning microscopy. The experimental methods included immersion test in SBF (0.9% NaCl aqueous solution) during 120 h with 37 °C with recirculating corrosion media. The hydrogen evolution was measured with a burette with a constant time interval of 1 hour. The real-time surface observation was carried out with a high-resolution camera. The measurement of pH level was done twice a day. Corrosion rate curves, 3D morphology of corroded morphology and video recordings showing evolution of corrosion damage have been obtained. As a result, ZK60 was found to be less corrosion-resistant and addicted to pitting corrosion, whereas AZ31 showed pronounced susceptibility to filiform corrosion. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
153 KiB  
Abstract
Modelling of Time-Dependent Behaviour of Corroded Reinforced Concrete Elements
by Francesca Vecchi, Lorenzo Franceschini and Beatrice Belletti
Mater. Proc. 2021, 6(1), 4; https://doi.org/10.3390/CMDWC2021-09957 - 08 May 2021
Viewed by 457
Abstract
Nowadays, the durability of reinforced concrete (RC) elements affected by corrosion has become a worldwide research topic, especially after some catastrophic failures that have involved corroded structures and infrastructures. One of the main purposes related to durability reduction is the evaluation of the [...] Read more.
Nowadays, the durability of reinforced concrete (RC) elements affected by corrosion has become a worldwide research topic, especially after some catastrophic failures that have involved corroded structures and infrastructures. One of the main purposes related to durability reduction is the evaluation of the maintenance of adequate safety and residual capacity throughout the life of the structure. Generally, the corrosion deterioration induces cross-sectional area reduction and degradation of mechanical properties of steel and concrete. Furthermore, referring to long-term prediction, creep and shrinkage play a fundamental role on the overall response of RC structures. For this reason, a nonlinear finite element approach, called PARC_CL 2.1 crack model, has been used to investigate the behavior of reinforced concrete elements characterized by corrosion of reinforcements. The PARC_CL 2.1 model is a fixed crack model based on multi-layer shell elements, developed at the University of Parma and implemented in a user subroutine UMAT for ABAQUS. The paper focuses on the modelling description and the comparison between the results of the analysis with the experimental data available in the literature. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
181 KiB  
Abstract
Effect of Sandblasting on the Long-Term Corrosion Resistance of Ti G4 in Artificial Saliva
by Patrycja Osak, Maciej Zubko, Julian Kubisztal, Joanna Maszybrocka and Bożena Łosiewicz
Mater. Proc. 2021, 6(1), 5; https://doi.org/10.3390/CMDWC2021-09985 - 08 May 2021
Viewed by 482
Abstract
Titanium Grade 4 (G4) is the most commonly used material for dental implants due to its excellent biocompatibility and mechanical properties. However, titanium implants require a rough surface that can increase the biomechanical potential of implant–bone contact and affect protein adsorption speed. In [...] Read more.
Titanium Grade 4 (G4) is the most commonly used material for dental implants due to its excellent biocompatibility and mechanical properties. However, titanium implants require a rough surface that can increase the biomechanical potential of implant–bone contact and affect protein adsorption speed. In this work, the effect of sandblasting of the Ti G4 surface on the long-term corrosion resistance in artificial saliva of pH = 7.4 at 37 °C was studied. The X-ray diffraction (XRD) single-{hkl} sin2ψ method was used to measure the sandblasted Ti residual stress. In vitro corrosion resistance tests were conducted for 21 days using the open circuit potential method, polarization curves, and electrochemical impedance spectroscopy. Using the Kelvin scanning probe, the electron work function was determined. Analysis of the obtained results showed an improvement in the corrosion resistance of the sandblasted Ti G4 compared to Ti with the machine surface. The increase in corrosion resistance was related to the residual compressive stress of 324.7 MPa present in the sandblasted Ti surface. Sandblasting caused plastic deformation of the Ti surface, which resulted in the improvement in mechanical properties, as evidenced by the increase in the hardness of the sandblasted Ti compared to Ti with the machine surface. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
172 KiB  
Abstract
Electrochemical Response in Biological Media of Plasma Electrolytic Oxidation Treated Additively Manufactured Ti6Al4V Alloy
by Hugo Mora-Sanchez, Marta Mohedano, Raul Arrabal and Endzhe Matykina
Mater. Proc. 2021, 6(1), 6; https://doi.org/10.3390/CMDWC2021-10055 - 16 May 2021
Viewed by 516
Abstract
Innovative 3D metal additive manufacturing (AM) techniques are revolutionizing the biomedical industry, since they enable the production of porous structures and patient-customized parts of biomedical-grade materials, such as Ti alloys. Surface treatment via the plasma electrolytic oxidation (PEO) of conventionally manufactured Ti and [...] Read more.
Innovative 3D metal additive manufacturing (AM) techniques are revolutionizing the biomedical industry, since they enable the production of porous structures and patient-customized parts of biomedical-grade materials, such as Ti alloys. Surface treatment via the plasma electrolytic oxidation (PEO) of conventionally manufactured Ti and its alloys has been proved as an outstanding approach to promote the osseointegration of implants. Henceforth, it is of increasing interest to develop PEO treatments for AM Ti alloys. The objective of the present work was to fabricate Ca and P containing thin (~3–10 μm thickness) PEO coatings on a Ti6Al4V alloy manufactured via direct metal laser sintering (DMLS), a laser powder bed fusion AM technique, and to study the electrochemical behavior of the treated specimens in a modified α-MEM solution. The electrical response of the PEO process on the AM alloy was compared to that on wrought mill-annealed Ti6Al4V sheets. The electrochemical behavior of the PEO-treated AM alloy was evaluated via potendiodynamic polarization and electrochemical impedance spectroscopy (EIS) in comparison to the non-treated AM alloy and the PEO-treated conventional counterparts. The surface degradation morphologies were evaluated by electron-optical microscopy and optical profilometry. The effect of the AM microstructure on the PEO process and the microstructure and electrochemical response of the resultant coatings are discussed with the aim to define future research directions relevant to the improvement of the corrosion resistance of AM Ti6Al4V, particularly with regard to pitting corrosion. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
169 KiB  
Abstract
Unveiling the Self-Healing Effect of Cerium Ions in PMMA-Silica Coatings on AA7075: A Comparative Study of Ce(III) and Ce(IV)
by Andressa Trentin, Samarah V. Harb, Mayara C. Uvida and Peter Hammer
Mater. Proc. 2021, 6(1), 7; https://doi.org/10.3390/CMDWC2021-10049 - 14 May 2021
Viewed by 577
Abstract
Cerium salts in the form of ammonium cerium(IV) nitrate and cerium(III) nitrate hexahydrate are widely used as corrosion inhibitors due to their ability to provide active protection against corrosion. When incorporated into polymeric, ceramic or hybrid coatings, cerium ions modify their structure and [...] Read more.
Cerium salts in the form of ammonium cerium(IV) nitrate and cerium(III) nitrate hexahydrate are widely used as corrosion inhibitors due to their ability to provide active protection against corrosion. When incorporated into polymeric, ceramic or hybrid coatings, cerium ions modify their structure and impart beneficial or adverse effects on barrier features, depending on the concentration and type of salt added. In this study, we compare the effect of varying amounts of Ce(III) and Ce(IV) ions on the structure and anti-corrosion properties of poly(methyl methacrylate) (PMMA)-silica hybrid coatings deposited on AA7075 aluminum alloy. The PMMA-silica coatings provided for both additives a long-term protection of AA7075 due to the highly cross-linked structure and a less defective polymeric network; however, the self-healing ability as a key feature was achieved only by Ce(IV) ions. Electrochemical impedance spectroscopy essays combined with time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy revealed the corrosion inhibition mechanisms occurring in corrosion-induced and artificial defects. It was found that intermediate Ce(IV) loadings (500 and 1000 ppm) proved to be more effective in providing a high corrosion resistance with an active barrier property, extending the service time up to 720 days in 3.5% NaCl solution. The regenerative action of Ce(IV) can be associated with the faster formation of oxides and hydroxides mainly at intermetallic particle sites of AA7075 at pH ~ 3, compared to those from Ce(III) formed at pH ~ 9. These results link an optimized hybrid structure provided by cerium ions with their self-healing ability, making PMMA-silica-Ce(IV) hybrids very attractive as low-cost, high-performance and smart chromium-free coatings. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
151 KiB  
Abstract
Effect of Temperature on Curing Time of Single-Lap Adhesive Joints in Marine Applications
by Tiziana Alderucci, Chiara Borsellino, Guido Di Bella and Federica Favaloro
Mater. Proc. 2021, 6(1), 8; https://doi.org/10.3390/CMDWC2021-10002 - 10 May 2021
Viewed by 461
Abstract
In the industrial field, manufacturing time is one of the most important factors affecting production costs. Structural adhesives require long curing times (i.e., 3–4 weeks) before the joined components can be safely employed. The aim of the present work is to test the [...] Read more.
In the industrial field, manufacturing time is one of the most important factors affecting production costs. Structural adhesives require long curing times (i.e., 3–4 weeks) before the joined components can be safely employed. The aim of the present work is to test the effect of several thermal treatments on a commercial epoxy structural adhesive on the final resistance of single lap joints, trying to attain the possibility of a curing time reduction. Aluminum alloy 5083, typically employed in marine applications, is used as the substrate. Both the adhesive and the joints are treated at different temperatures/times, and then tensile tests are carried out to obtain the mechanical resistance and study the failure modes. A statistical analysis allows the evaluation of the effects of the thermal cycles on the mechanical performances of the joints and the comparison with those cured with the standard procedure. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
162 KiB  
Abstract
Microbial-Induced Corrosion of 3D-Printed Stainless Steels: A Surface Science Investigation
by Brianna L. Young, Jamie S. Quinton and Sarah L. Harmer
Mater. Proc. 2021, 6(1), 9; https://doi.org/10.3390/CMDWC2021-09973 - 08 May 2021
Viewed by 561
Abstract
Stainless steel is a material manufactured for its high corrosive resistance and is the first choice of material in a range of applications. Microbial-induced corrosion can cause significant damage to metals and is responsible for approximately 20% of corrosive damage. The corrosive resistance [...] Read more.
Stainless steel is a material manufactured for its high corrosive resistance and is the first choice of material in a range of applications. Microbial-induced corrosion can cause significant damage to metals and is responsible for approximately 20% of corrosive damage. The corrosive resistance of stainless steel is reduced during manufacturing processes, including welding or joining methods, as the connection points prevent the metal from reforming its passivation layer. Additive manufacturing processes allow for intricate designs to be produced without the need for welding or bolts. However, it is unknown how the layering method of additive manufacturing (AM) will affect stainless steel’s passivation layer and, in turn, its corrosive resistance. This research compares the corrosive resistance of 316L stainless steel produced using laser metal deposition and traditionally manufactured AISI 316 stainless steel to determine how the layering manufacturing method affects the corrosive resistance of the material. Samples are incubated over a 21-day period with Acidithiobacillus ferrooxidans (A.f) and Leptospirillum ferooxidans (L.f) in a modified HH medium with an approximate pH of 1.8 and kept at a constant temperature of 30 °C. Scanning electron microscopy and Auger electron spectroscopy surface analysis techniques are used to identify any corrosive processes on the surface of the samples. This research is an introductory analysis of the corrosive resistance of AM 316 stainless steel using the laser metal deposition technique. The results show how stainless steel produced using laser metal deposition will react in acidic environments and are used to determine if it could be used in conjunction with other materials in underground pipes for acidic soils. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
192 KiB  
Abstract
Influence of Waste Glass Powder Addition in the Microstructure and Durability of Mortars in the Very Long Term
by Rosa María Tremiño, Teresa Real-Herraiz, Viviana Letelier and José Marcos Ortega
Mater. Proc. 2021, 6(1), 10; https://doi.org/10.3390/CMDWC2021-10056 - 16 May 2021
Viewed by 473
Abstract
At present, the cement industry still constitutes an important pollutant in the industrial sector. As such, strategies to reduce its environmental impact are a popular research topic. One of these strategies consists of partially replacing clinker with other materials, such as waste glass [...] Read more.
At present, the cement industry still constitutes an important pollutant in the industrial sector. As such, strategies to reduce its environmental impact are a popular research topic. One of these strategies consists of partially replacing clinker with other materials, such as waste glass powder. Here, the effects of the addition of glass powder on the microstructure and durability properties of mortars that incorporate 10% and 20% of this addition as a clinker replacement after 1500 hardening days were analyzed. Reference mortars prepared with ordinary Portland cement without additions were also studied. The mortars were kept in optimum conditions (20 °C and 100% relative humidity) until the testing age. Their microstructure was characterized using mercury intrusion porosimetry and impedance spectroscopy. The steady-state chloride diffusion coefficient and the absorption after immersion were determined as durability parameters. According to the results obtained in the present study, the mortars with the added glass powder showed similar porosities and more refined microstructure compared to the reference mortars. Furthermore, the durability properties of the mortars that incorporate glass powder were similar or even better than those noted for the reference mortars without any additions after 1500 hardening days, especially regarding the resistance against chloride ingress, with the added value of contributing to sustainability. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
174 KiB  
Abstract
Predicting Environmental Ageing of Composites: Modular Approach and Multiscale Modelling
by Andrey E. Krauklis
Mater. Proc. 2021, 6(1), 11; https://doi.org/10.3390/CMDWC2021-09890 - 06 May 2021
Viewed by 557
Abstract
Fibre-reinforced composite materials are used in structural applications in marine, offshore, and oil and gas industries due to their light weight and excellent mechanical properties. However, the exposure of such materials to water leads to environmental ageing, weakening the composite over time. A [...] Read more.
Fibre-reinforced composite materials are used in structural applications in marine, offshore, and oil and gas industries due to their light weight and excellent mechanical properties. However, the exposure of such materials to water leads to environmental ageing, weakening the composite over time. A typical design lifetime of offshore composite structures, being in direct contact with water and humid air, spans 25 years or more. Thus, the prediction and modelling of environmental ageing phenomena has become highly important, especially for predicting long-term environmental durability. In this study, a systematic and modular approach for quantitatively modelling such phenomena is provided. The modular methodology presented in this work can, and should, be further expanded—it is multiscale and scalable. A state-of-the-art degradation framework is not yet complete; however, it is a systematic step towards the multiscale modelling paradigm for composite materials. The topic of the environmental durability of composite materials is being actively developed and is expected to continue growing in the future. There are three constituents in a composite: matrix, fibres, and an interphase. Each constituent degrades differently and may also affect the degradation behaviour of each other. Therefore, a modular multiscale approach is preferred. The modules are based on the physics and chemistry of individual constituents’ interaction with the environment, including the diffusion, molecular mechanisms, and kinetics of environmental ageing [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]. The methodology is seen as a useful approach for both industry and academia, including such use cases as accelerated testing, prediction of the lifetime of composite materials and structures, as well as improving the understanding of environmental ageing effects and the time-dependent properties of composites due to environmental ageing. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
169 KiB  
Abstract
Aluminum in Dental Implants: How to Reduce a Potential Risk to Patient’s Health?
by Željka Petrović, Ankica Šarić, Ines Despotović, Jozefina Katić and Marin Petković
Mater. Proc. 2021, 6(1), 12; https://doi.org/10.3390/CMDWC2021-09933 - 08 May 2021
Viewed by 832
Abstract
Some commercial dental implants contain aluminum, which represents a potential risk to health, since aluminum is associated with neurodegenerative diseases such as Alzheimer’s disease. Therefore, control of the chemical composition as well as the surface characteristics of implants is necessary, and one approach [...] Read more.
Some commercial dental implants contain aluminum, which represents a potential risk to health, since aluminum is associated with neurodegenerative diseases such as Alzheimer’s disease. Therefore, control of the chemical composition as well as the surface characteristics of implants is necessary, and one approach is functionalization of the implant’s surface by bio(organic) molecules. Hydrolyzed collagen molecules were self-assembled on the titanium implant containing aluminum. Density Functional Theory calculation results indicated an exergonic reaction (ΔG*INT = −6.45 kcal mol−1) between the implant surface and the chosen hydrolyzed collagen molecules, while electrochemical impedance spectroscopy results pointed to improved anti-corrosion properties of the modified implant surface (protective effectiveness, η = 98.5%) compared to the unmodified implant surface. During immersion in an artificial saliva (7 days), the hydrolyzed collagen-modified implant remained stable, which is crucial for minimizing the possible negative biological effects on patient’s health. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
154 KiB  
Abstract
The Corrosion Behavior of 316L Stainless Steel Additively Manufactured by Direct Energy Deposition Process
by Tomer Ron, Avi Leon, Amnon Shirizly and Eli Aghion
Mater. Proc. 2021, 6(1), 13; https://doi.org/10.3390/CMDWC2021-10053 - 16 May 2021
Cited by 1 | Viewed by 523
Abstract
Traditional additive manufacturing (AM) technologies tend to focus on powder bed fusion (PBF) methods, such as SLM (selective laser melting) and EBM (electron beam melting), that are attractive for the rapid production of complex components. However, their inherent drawbacks include the high cost [...] Read more.
Traditional additive manufacturing (AM) technologies tend to focus on powder bed fusion (PBF) methods, such as SLM (selective laser melting) and EBM (electron beam melting), that are attractive for the rapid production of complex components. However, their inherent drawbacks include the high cost of powders, high energy consumption and size limitation. Hence, more affordable and flexible direct energy deposition processes, such as wire arc additive manufacturing (WAAM), are gaining increased interest. This study aims to evaluate the corrosion behavior, including the stress corrosion resistance of 316L stainless steel, produced by the WAAM process. Experimental samples in the form of cylindrical rods were produced by WAAM process using 316L stainless steel wires and compared with their counterpart AISI 316L alloy. The corrosion resistance was evaluated using potentiodynamic polarization, impedance spectroscopy and slow strain rate testing (SSRT). Despite the differences between the microstructures of printed WAAM 316L alloy and its counterpart AISI 316L, the corrosion performance of both alloys in 3.5% NaCl solution was quite similar. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
154 KiB  
Abstract
Nanocharacterization of Dental Materials by Atomic Force Microscopy and Their Thermal Degradation Evaluation
by Marius Pustan, Corina Birleanu and Sanda Mirela Pop
Mater. Proc. 2021, 6(1), 14; https://doi.org/10.3390/CMDWC2021-09942 - 08 May 2021
Viewed by 404
Abstract
Restorative dental materials must be produced with special characteristics because they are operating in a medium environment with different humidity and temperature. These day-to-day factors play an important role in the lifetime of such dental restorative materials. Resin composites have been by far [...] Read more.
Restorative dental materials must be produced with special characteristics because they are operating in a medium environment with different humidity and temperature. These day-to-day factors play an important role in the lifetime of such dental restorative materials. Resin composites have been by far the most successful in dental applications by meeting several stringent design requirements that are difficult to achieve with homogeneous materials, such as ceramics and metal alloys. The mechanical and tribological properties of direct restorative filling materials are crucial not only to serve and allow similarity to human enamel and dentine, but also to compare composites between them and determine the objective criteria for their selection. The objective of this research is to investigate the mechanical and tribological properties of some commercial restorative materials using the atomic force microscopy technique as a function of the operating temperature. Therefore, restorative materials are expected to replace and perform as natural tooth materials. The demand is so great that most of the time, restorative filling materials replace enamel and dentin, which have very different mechanical properties, namely hardness and elastic modulus. The scope is to estimate the lifetime of such materials starting from their nano-behaviors under nano-wear, nano-friction, nano-mechanical tests. To conclude, nanoindentation is an attractive method for measuring the mechanical behavior of small specimen volumes in dental hard materials. Using this technique, the mechanical and tribological properties of nanocomposite resins were investigated. This technique only evaluates the tribo-mechanical properties of a very shallow surface region of a specimen that may have undergone damage associated with mechanical preparation that is required to achieve a satisfactory flat sample for testing. Experimental study has been carried out with several normal loads and time-duration tests, i.e., representing several steps of severity conditions for materials under investigation. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
168 KiB  
Abstract
Nano Topography Evaluation of NiTi Alloy Exposed to Artificial Saliva and Different Mouthwashes
by Zoran Bobić, Bojan Petrović, Sanja Kojić, Vladimir Terek, Branko Škorić, Lazar Kovačević and Pal Terek
Mater. Proc. 2021, 6(1), 15; https://doi.org/10.3390/CMDWC2021-09948 - 08 May 2021
Viewed by 460
Abstract
Evaluation of NiTi alloy corrosion behavior in conditions that exist in the oral cavity still remains a great characterization challenge. Such characterization is commonly simplified by avoiding the use of non-accelerated corrosion tests. Accordingly, difficulties in the characterization of material changes on a [...] Read more.
Evaluation of NiTi alloy corrosion behavior in conditions that exist in the oral cavity still remains a great characterization challenge. Such characterization is commonly simplified by avoiding the use of non-accelerated corrosion tests. Accordingly, difficulties in the characterization of material changes on a nano level are avoided, and results do not sufficiently resemble the real situation. Therefore, the motivation of this work was to perform a non-accelerated corrosion test to characterize the nano-topographic changes, and to evaluate the obtained results by statistical methods. In this study, we examined the behavior of NiTi alloy (50% Ni, 50% Ti) archwires exposed for 21 days to different corrosive mediums: artificial saliva, Eludril®, Aquafresh® and Listerine®. The corrosion was characterized by means of changes in surface topography. This was conducted by contact mode atomic force microscopy on all samples at five locations of 10 µm × 10 µm areas before and after the corrosion tests. Image analysis software was used for the analysis of topographic images and the calculation of surface roughness parameters Sa and S10z. The changes to the roughness parameters were statistically analyzed by ANOVA. Sa and S10z parameters displayed changes with a trend for all treatments. However, the confidence interval for all cases was overlapped. Statistically analyzed data revealed that all samples exposed to mouthwashes displayed significant changes in parameter S10z, while only samples exposed to Aquafresh® and Eludril® displayed significant changes in parameter Sa. On the other side, samples exposed to artificial saliva did not display significant changes in any parameter. As such, it is implied that mouthwashes have a significantly higher effect on surface topography. Differences in the confidence interval of the Sa parameter indicate that changes in roughness parameters caused by corrosion do not depend on the initial surface roughness. In this study, statistical analysis methods have been proven as a useful tool in the characterization of nano-topographic changes caused by corrosion in real conditions. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
478 KiB  
Abstract
Electrochemical and Morphological Characterization of Fe-28Mn-6Si-5Cr Shape Memory Steel
by Carmen Mariño-Martínez, Antonio Collazo, Xosé Ramón Nóvoa and Carmen Pérez
Mater. Proc. 2021, 6(1), 16; https://doi.org/10.3390/CMDWC2021-10063 - 17 May 2021
Viewed by 386
Abstract
In this paper, the Shape Memory Steel (SMS), a new kind of ferrous SMA of the Mn family and complemented with Cr additions, is introduced as a very interesting smart material, able to be used in fitting and reshaping applications, and with the [...] Read more.
In this paper, the Shape Memory Steel (SMS), a new kind of ferrous SMA of the Mn family and complemented with Cr additions, is introduced as a very interesting smart material, able to be used in fitting and reshaping applications, and with the potential of being used in structural reinforcement applications [...] Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
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154 KiB  
Abstract
Throwing Power of Embedded Anodes for the Galvanic Cathodic Protection of Steel in Concrete
by Bjorn Van Belleghem, Tim Soetens and Mathias Maes
Mater. Proc. 2021, 6(1), 17; https://doi.org/10.3390/CMDWC2021-09898 - 06 May 2021
Viewed by 589
Abstract
The chloride-induced corrosion of steel reinforcement is one of the main causes of deterioration of reinforced concrete structures. Cathodic protection (CP) of steel in concrete is a widely accepted repair technique to reduce, or completely stop, reinforcement corrosion. One possible method of cathodic [...] Read more.
The chloride-induced corrosion of steel reinforcement is one of the main causes of deterioration of reinforced concrete structures. Cathodic protection (CP) of steel in concrete is a widely accepted repair technique to reduce, or completely stop, reinforcement corrosion. One possible method of cathodic protection is through the use of embedded galvanic (sacrificial) anodes, consisting of a zinc metal core surrounded by a precast alkali-activated cementitious mortar. The design of a CP system based on embedded galvanic anodes is based on the required amount of zinc material and the throwing power of the anode (i.e., radius around the anode in which the steel achieves sufficient protection). In this research, the protection of steel reinforcement in concrete surrounding an embedded galvanic anode was evaluated through depolarisation measurements with internal and external reference electrodes. Based on these measurements, the throwing power of the galvanic anode was determined, taking into account the 100 mV depolarisation criterium (cf. EN ISO 12696:2016). Additionally, the influence of the degree of chloride contamination of the concrete and relative humidity and temperature of the environment on the throwing power was evaluated. The results show a strong influence of chloride contamination on the throwing power of the galvanic anodes, in the sense that a higher chloride concentration in the concrete matrix leads to a reduction in the throwing power. This reduction can be related to the more negative potential of corroding steel reinforcement compared to passive steel, thus leading to a lower driving potential for the galvanic reaction. Especially when the chloride concentration is higher than 1 m% vs. cement mass, the throwing power is greatly reduced. Additionally, it was found that a higher relative humidity (RH) of the environment (and consequently, a higher RH of the concrete) resulted in a higher throwing power. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
161 KiB  
Abstract
Study of the Iron Behavior in Acid Rain Water Solution by Application of Two Green Corrosion Inhibitors
by Meryem Zouarhi, Said Abbout, Hind Hammouch, Mohamed Chellouli, Hamid Erramli, Hassane Said Omar Said, Naima Bettach and Najat Hajjaji
Mater. Proc. 2021, 6(1), 19; https://doi.org/10.3390/CMDWC2021-10039 - 13 May 2021
Viewed by 504
Abstract
The corrosion of iron in an acidic medium similar to acid rainwater (pH = 3.6) at various rotation speeds was investigated. The investigation included the inhibiting effect of two new green formulations containing oils extracted from the seeds of Jatropha curcas (labeled JAC) [...] Read more.
The corrosion of iron in an acidic medium similar to acid rainwater (pH = 3.6) at various rotation speeds was investigated. The investigation included the inhibiting effect of two new green formulations containing oils extracted from the seeds of Jatropha curcas (labeled JAC) and Aleurite moluccana (labeled ALM). The inhibition efficiency was evaluated using electrochemical measurements, after performing an automatic ohmic drop compensation (ZIR). The results obtained show that an increase in the rotation speed leads an increase in the current density (from 75.57 µA/cm2 at 0 rpm to 99.09 µA/cm2 at 1500 rpm). This increase can be explained by the increase in the amount of dissolved oxygen at the electrode surface in the acidic rain solution (pH = 3.6). Also, the two environment-friendly corrosion inhibitors both act as mixed type inhibitors that protect iron against corrosion in the acidic solution. The inhibition efficiency increases with an increase in the inhibitor concentration to attain a maximum of 97% and 96% at 250 ppm of the ALM and the JAC, respectively. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
176 KiB  
Abstract
Characterization of Zinc Phosphate Coatings: Influence of pH and Temperature on Morphology and Corrosion Resistance
by Sheila Silva-Fernández, Belén Díaz and X. Ramón Nóvoa
Mater. Proc. 2021, 6(1), 20; https://doi.org/10.3390/CMDWC2021-10051 - 14 May 2021
Viewed by 668
Abstract
Zinc phosphate coatings are commonly used to protect high-strength steel rods and improve the corrosion protection ability. The temperature and the pH of the phosphating bath are important parameters that affect to the film’s appearance, porosity, and composition. In this work, some variations [...] Read more.
Zinc phosphate coatings are commonly used to protect high-strength steel rods and improve the corrosion protection ability. The temperature and the pH of the phosphating bath are important parameters that affect to the film’s appearance, porosity, and composition. In this work, some variations in the phosphating solution have been analysed. In particular, the temperatures were modified in the range of 50–75 °C and the pH values were fixed at 2.4, 2.8 and 3. Phosphate coatings were investigated via scanning electron microscopy (SEM) and energy dispersive X-ray (EDX), which allow a complete surface analysis, including of both the morphology and the composition. The coating’s mass was also determined by the gravimetric method. For the corrosion resistance of the film, the linear polarization curves obtained in Na2SO4 0.1 M were analyzed. The results show that the phosphating baths at 60–65 °C and pH at 2.44 produce a thicker film, with the highest amount of Zn and improved corrosion resistance. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
157 KiB  
Abstract
Effect of Carbon Nanotubes (CNTs) on Chloride Penetration Resistance and Physical-Mechanical Properties of Cementitious Materials
by Nikolaos Chousidis, Aggeliki Zacharopoulou, George Batis and Christos Zeris
Mater. Proc. 2021, 6(1), 21; https://doi.org/10.3390/CMDWC2021-09934 - 08 May 2021
Cited by 2 | Viewed by 519
Abstract
According to currently enforced Eurocode 2 for the design of reinforced concrete structures, it is essential to protect steel reinforcements from corrosion and concrete from degradation under aggressive environmental conditions such as marine, urban, industrial environments and soils, to which these are normally [...] Read more.
According to currently enforced Eurocode 2 for the design of reinforced concrete structures, it is essential to protect steel reinforcements from corrosion and concrete from degradation under aggressive environmental conditions such as marine, urban, industrial environments and soils, to which these are normally exposed. In this context, this experimental study investigates the enhancement of the physico-mechanical properties of common cement-based mortars and the electro-chemical properties of reinforcing steel, through the addition of nanomaterials in the mix. For the experimental set-up, cylindrical, prismatic, and cubic specimens of different dimensions were cast and were partially immersed in sodium chloride solution for eight months. To evaluate the corrosion of steel rebars, cylindrical cement mortar specimens were used in order to induce a constant cover between exposure and the reinforcement; the physical and the mechanical tests were carried out on standardized shape cubes and prisms, respectively. Two groups were considered: cement-based mortar composites with 0.5 wt.% CNTs addition and plain (reference) specimens without any addition of nanomaterials, for comparison. The influence of adding CNTs on chloride penetration resistance was subsequently evaluated using standardized and non-standardized testing techniques: tests such as flexural strength and porosity, mass loss of steel, electrochemical measurements (corrosion current, HCP) and total chloride content calculation. The test results showed that using CNTs as an addition in mortar production led to the protection of steel rebars against pitting corrosion; moreover, an improvement (almost 9% at 120 days) in flexural strength and reduced porosity of mortars was also observed compared to the reference specimens without CNTs. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
168 KiB  
Abstract
Localized Corrosion Degradation of Bioresorbable Mg Alloys Promising for Medicine
by Andrey S. Gnedenkov, Sviatlana V. Lamaka, Sergey L. Sinebryukhov, Valeriia S. Filonina, Mikhail L. Zheludkevich and Sergey V. Gnedenkov
Mater. Proc. 2021, 6(1), 22; https://doi.org/10.3390/CMDWC2021-09951 - 08 May 2021
Viewed by 533
Abstract
Magnesium is very light metal which possesses many useful properties, such as a high strength to weight ratio and good electrical and thermal conductivity. Magnesium and its alloys can be used in implant surgery as biodegradable materials. Taking into account the rapid degradation [...] Read more.
Magnesium is very light metal which possesses many useful properties, such as a high strength to weight ratio and good electrical and thermal conductivity. Magnesium and its alloys can be used in implant surgery as biodegradable materials. Taking into account the rapid degradation process of Mg alloys in chloride-containing solutions and the very complex composition of human body media, it is worthwhile to study the mechanism and kinetics of Mg alloy corrosion in solutions which closely resemble those of human body fluids. A comparative analysis of the corrosion activity of MA8 magnesium alloy (intended to be a bioresorbable material) in a medium for the cultivation of mammalian cells (minimum essential medium, MEM) and 0.83% NaCl solution was performed using the scanning vibrating electrode technique; local pH measurements; hydrogen evolution tests; and OCP, PDP, and EIS tests. Corrosion products formed on the alloy surface were characterized using XRD, SEM-EDX analysis and Raman spectroscopy. The hydrogen evolution rate was higher for samples in NaCl solution compared with MEM. The impedance modulus in the frequency range from 105 Hz down to 10−1 Hz for the sample immersed in MEM was higher than that for the sample immersed in NaCl. This indicates higher protective ability of the corrosion film formed in MEM compared to that formed during immersion in NaCl solution. Ca- and P-rich deposits were formed in the corrosion layer. The model of corrosion mechanism of MA8 magnesium alloy in MEM, which includes three stages of the development of corrosion product film, is hereby proposed. The corrosion product layer formation on the surface of the magnesium alloy sample in MEM), which included magnesium-substituted hydroxyapatite, stabilized the local pH below 9.0 and, along with the organic acids, did not allow the pH to increase during the corrosion of the Mg alloy. The obtained results indicate the prospect of using bioresorbable magnesium in implant surgery [1,2]. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
142 KiB  
Abstract
The Decoupling of Corrosion and Fatigue for Aircraft Service Life Management
by Loris Molent
Mater. Proc. 2021, 6(1), 23; https://doi.org/10.3390/CMDWC2021-09998 - 08 May 2021
Viewed by 446
Abstract
Metal fatigue management is generally well understood as reflected in the Aircraft Structural Integrity Management Plans, which, in some cases, consider environmental degradation prevention; however, limited provisions beyond find and fix exist for corrosion repair. Thus, the repair of corrosion can be a [...] Read more.
Metal fatigue management is generally well understood as reflected in the Aircraft Structural Integrity Management Plans, which, in some cases, consider environmental degradation prevention; however, limited provisions beyond find and fix exist for corrosion repair. Thus, the repair of corrosion can be a major undertaking, through life cost driver and an aircraft availability degrader. This find and fix approach exists largely because tools are too immature to accurately assess the structural significance of corrosion when it is detected. This presentation shows that fatigue and corrosion are decoupled for aircraft in general through the analysis of some in-service cracking cases. Corrosion occurs on the ground, whilst fatigue cycling occurs at altitude. This important observation allows fatigue and corrosion to be considered separately. This work aims to provide a crack growth basis for the justification of allowing detected pitting corrosion to remain in service for a limited period before repair. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
154 KiB  
Abstract
Corrosion Behavior of Fe-Based Amorphous/Nanocrystalline Composite Coating: Correlating the Influence of Porosity and Amorphicity
by Sapan K. Nayak, Anil Kumar, Kuntal Sarkar, Atanu Banerjee and Tapas Laha
Mater. Proc. 2021, 6(1), 24; https://doi.org/10.3390/CMDWC2021-10042 - 08 May 2021
Viewed by 591
Abstract
Recently, Fe-based amorphous coatings synthesized by different thermal spraying methods have been investigated as a potential candidate for long-term surface protection of various structures due to their outstanding wear and corrosion resistance. Defects such as porosity and crystallization are inevitable in the thermal-sprayed [...] Read more.
Recently, Fe-based amorphous coatings synthesized by different thermal spraying methods have been investigated as a potential candidate for long-term surface protection of various structures due to their outstanding wear and corrosion resistance. Defects such as porosity and crystallization are inevitable in the thermal-sprayed coatings, which are introduced during the synthesis process. The corrosion behavior of these coatings is adversely affected by the presence of such defects. However, identification of a microstructural feature among amorphous content and porosity that has a greater influence on the corrosion resistance of thermal-sprayed Fe-based amorphous/nanocrystalline coating has remained elusive so far. Thus, to address this problem, in situ amorphous/nanocrystalline composite coatings were synthesized via high-velocity oxy-fuel (HVOF) spraying, along with two melt-spun ribbons of different amorphous content (one fully amorphous, FA-Rib and the other with a similar level of amorphicity to the coatings, PA-Rib). Results obtained from electrochemical characterizations, Raman analysis and Auger electron spectroscopy revealed reduced amorphicity as the primary factor that affects the corrosion behavior of such coatings. A mechanism has been proposed to explain the role of amorphicity and porosity in the corrosion behavior of Fe-based amorphous/nanocrystalline coatings. This study will ultimately help to design new amorphous composite coatings with improved corrosion resistance. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
163 KiB  
Abstract
The Effect of pH and Fly Ash on the Electrochemical Performance of Stainless-Steel Concrete Reinforcement in Harsh Environments
by Sofia Tsouli, Christos Nikolaidis, Spyridon Kleftakis and Angeliki G. Lekatou
Mater. Proc. 2021, 6(1), 25; https://doi.org/10.3390/CMDWC2021-09976 - 08 May 2021
Viewed by 464
Abstract
The corrosion of steel reinforcement is the most significant factor responsible for the premature deterioration of the durability and seismic resistance of reinforced concrete structures. As such, the main objective of the present study is the investigation of the effect of fly ash [...] Read more.
The corrosion of steel reinforcement is the most significant factor responsible for the premature deterioration of the durability and seismic resistance of reinforced concrete structures. As such, the main objective of the present study is the investigation of the effect of fly ash (FA) as a corrosion inhibitor and pH on the electrochemical behavior of 316L and 304L concrete reinforcement in a simulating concrete pore solution exposed to aggressive environments, i.e., acid rain. The corrosion performance of 316L and 304L stainless steel rebars was examined by means of cyclic (reverse) polarization in order to evaluate the susceptibility of the rebars to localized corrosion. Two types of electrolyte were used. The first electrolyte was a highly alkaline solution simulating fresh concrete exposed to acid rain (pH ≈ 12), while the second electrolyte was a mildly alkaline solution simulating corroded concrete cover that exposed the reinforcement to direct acid rain attack (pH ≈ 8). Both solutions contained Ca(OH)2, an acid-rain-simulating solution, and FA (replacing 0–25 wt.% of Ca(OH)2) as a corrosion inhibitor. In both electrolytes, the beneficial effect of FA replacing up to 20 wt.% of Ca(OH)2 on the corrosion resistance of both 316L and 304L rebars was manifested. However, this trend was reversed at the 25 wt.% replacement of Ca(OH)2 due to the localized presence of agglomerates of FA on the surface of the steel. The above finding was confirmed by SEM/EDX examination of cross-sections after cyclic polarization. An important conclusion of this study was the feasibility of replacing 316L stainless steel with 304L (at pH ≈ 12) in critical applications, such as the restoration of ancient monuments, provided that FA is included in the concrete mixture, even at low contents (10 or 15 wt.% of cement). Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
169 KiB  
Abstract
Experimental Tests on Bond Performance between Corroded Steel Reinforcements and Concrete
by Armando Benenato, Barbara Ferracuti, Stefania Imperatore and Mahdi Kioumarsi
Mater. Proc. 2021, 6(1), 26; https://doi.org/10.3390/CMDWC2021-09972 - 08 May 2021
Cited by 1 | Viewed by 733
Abstract
The corrosion of steel bars in concrete is a dangerous and extremely costly problem that causes losses of serviceability and structural capacity in buildings and bridges. Once the depassivation occurs, because of concrete carbonation or chloride attack, the oxides occupy approximately 2–6 times [...] Read more.
The corrosion of steel bars in concrete is a dangerous and extremely costly problem that causes losses of serviceability and structural capacity in buildings and bridges. Once the depassivation occurs, because of concrete carbonation or chloride attack, the oxides occupy approximately 2–6 times the iron volume, causing a pressure at the steel–concrete interface, and consequently cracks and bond-slip degradation. In particular, the reinforcement-concrete bond degradation influences the deformability of the element and consequently its service behavior. The present study is a part of an extensive research project—CONSTIN, between Oslo Metropolitan University and Niccolò Cusano University—aiming to evaluate the steel-to-concrete interaction in the presence of corrosion and to establish a variation law for the bond strength as a function of the corrosion level. The research assess the influence of different levels of corrosion on the interaction between the concrete and the most typical steel reinforcement typologies (steel strands and smooth and ribbed bars), characterized by the same diameter (equivalent to 12 mm) and bonded length. The different level of corrosion is reached with a specific duration of exposition of the embedded reinforcements to the accelerated electrolytic corrosion process. Some details about the laboratory procedure, the duration of exposition and the current density are provided. The preliminary results of the experimental campaign are presented. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
206 KiB  
Abstract
Degradation Rate Control of MgxZnyCa Alloys by PEO Coatings
by Lara Moreno, Marta Mohedano, Raúl Arrabal and Endzhe Matykina
Mater. Proc. 2021, 6(1), 27; https://doi.org/10.3390/CMDWC2021-09936 - 08 May 2021
Viewed by 512
Abstract
Magnesium alloys are actively researched for biodegradable implants in order to avoid an implant-removal surgery after the healing process. However, the high degradation rate of Mg leads to hydrogen evolution and may increase the pH of the environment, causing an inflammatory response. In [...] Read more.
Magnesium alloys are actively researched for biodegradable implants in order to avoid an implant-removal surgery after the healing process. However, the high degradation rate of Mg leads to hydrogen evolution and may increase the pH of the environment, causing an inflammatory response. In the present work, bioactive plasma electrolytic oxidation (PEO) coatings on three MgxZnyCa alloys (two cast alloys and one extruded; x = 1, 3 or 0.5; y = 1 or 0.3), manufactured by Helmholtz-Zentrum Hereon, Geesthacht, were generated in order to enhance the corrosion resistance, bioactivity and cytocompatibility of the alloys. AC PEO process was carried out in two environmentally friendly alkaline electrolytes containing Ca, P and Si as bioactive elements. The electrolytes were a true solution and a particle suspension. F-free electrolyte design was employed to ensure cytocompatibility of the coatings with different types of cells. The materials were characterized by SEM, EDS, XRD and optical profilometry. The corrosion behavior was evaluated by EIS and hydrogen evolution measurements during 5 days of immersion in 0.9% NaCl and α-MEM solutions, a complete one and an inorganic part only, at 37 °C. PEO coatings (7–13 µm-thick, Sa = 1.85–4.19 µm) were constituted by MgO, Ca3(PO4)2, Ca5(PO4)3(OH) and Mg2SiO4 phases. Both PEO coatings decreased the degradation rate of Mg alloys; corrosion resistance of coated samples in inorganic α-MEM increased by more than an order of magnitude (|Z|10 mHz, Ω·cm2): MgZnCa = 746, MgZnCa/PEO = 8544…28,277). All materials exhibited considerably greater corrosion rates in 0.9% NaCl than in α-MEM, where phosphate-based additives acted as corrosion inhibitors. Corrosion rates were slightly greater in complete α-MEM than in inorganic α-MEM due to the presence of complexing aminoacids. The developed coatings are considered suitable candidates for the subsequent development of hybrid hierarchical ceramic/biodegradable polymer systems. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
174 KiB  
Abstract
The Impact of Post Processing Heat Treatments on Elemental Distribution and Corrosion Properties of Cold Spray Printed Al Alloys
by Ruby Alice Sims, Rebecca Adamson, Rebecca Murray and Jamie Scott Quinton
Mater. Proc. 2021, 6(1), 28; https://doi.org/10.3390/CMDWC2021-09926 - 08 May 2021
Viewed by 572
Abstract
In contrast to other additive manufacturing methods such as Wire Arc Additive Manufacturing or Laser Metal Deposition, the cold spray system designed by SPEE3D allows for structures to be printed at much lower temperatures. As a result, structures printed via cold spray often [...] Read more.
In contrast to other additive manufacturing methods such as Wire Arc Additive Manufacturing or Laser Metal Deposition, the cold spray system designed by SPEE3D allows for structures to be printed at much lower temperatures. As a result, structures printed via cold spray often undergo post processing heat treatments that potentially alter the distribution of trace elements throughout the sample. The distribution of elements within these structures may then have a direct impact on the corrosion properties of these materials. The impact of post processing heat treatment parameters on the microstructure and distribution of Mg and Si trace elements within an Al alloy was investigated using cross section analysis of samples by SEM-EDS. From an Al-powered feedstock, alloys were printed using SPEED3D’s LightSPEE3D printer utilising air as the carrier gas, at 30 Bar and 500 °C; various post processing heat and water quench treatments were then applied. The results revealed a reorganisation of Mg (which subsequently becomes oxidised) toward the edges of pores, regions that typically have a higher surface energy. This is in direct contrast to the largely homogenous distribution of Mg in the samples that did not undergo post printing heat treatments. The addition of charcoal during the heat treatment process also resulted in the redistribution of Si within the sample, and the creation of silicon carbide structures. The impact of the reorganisation of Mg within the sample as well as the creation of silicon carbide structures on the selective corrosion of these materials was then investigated using potentiodynamic corrosion testing and electrochemical impedance spectroscopy. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
159 KiB  
Abstract
Corrosion of Post-Tension Tendons Associated with Segregated Grout
by Samanbar Permeh and Kingsley Lau
Mater. Proc. 2021, 6(1), 29; https://doi.org/10.3390/CMDWC2021-10036 - 13 May 2021
Viewed by 589
Abstract
Post-tensioned (PT) construction incorporating bonded tendons with cementitious grouts has been used for highway bridges. The tendon duct and the encapsulating grout materials provide barrier corrosion protection for the embedded high-strength steel strand. Although generally used in good engineering practice, cases of PT [...] Read more.
Post-tensioned (PT) construction incorporating bonded tendons with cementitious grouts has been used for highway bridges. The tendon duct and the encapsulating grout materials provide barrier corrosion protection for the embedded high-strength steel strand. Although generally used in good engineering practice, cases of PT tendon corrosion have been documented relating to inadequate detailing for joints, development of grout bleed water, and, more recently in the past several years, segregation of thixotropic grouts. In the latter case, cases of thixotropic grouts (which have been developed to mitigate grout bleeding), developed physically and chemically deficient grout, have been characterized to have high moisture content and elevated sulfate ion concentrations. The early presence of elevated sulfate ion concentrations in the deficient grout was attributed to hindering stable steel passivation. Case studies of PT corrosion associated with grouts with elevated sulfate concentrations are presented followed by a review of electrochemical techniques and measurements used to identify the role of sulfates in steel corrosion in alkaline solutions such as polarization techniques, electrochemical impedance spectroscopy, and electrochemical noise. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
183 KiB  
Abstract
Experimental Test on Flexural Performance of Prestressed Concrete Beams Damaged by Corrosion
by Armando Benenato, Barbara Ferracuti, Stefania Imperatore, Mahdi Kioumarsi and Simone Spagnuolo
Mater. Proc. 2021, 6(1), 30; https://doi.org/10.3390/CMDWC2021-09974 - 07 May 2021
Viewed by 520
Abstract
Prestressed reinforced concrete beams are widely used in industrial and commercial buildings, which are commonly exposed to aggressive environments and damaged by corrosion. This precast construction technique has also been used for the last 50 years in most viaducts and bridges built in [...] Read more.
Prestressed reinforced concrete beams are widely used in industrial and commercial buildings, which are commonly exposed to aggressive environments and damaged by corrosion. This precast construction technique has also been used for the last 50 years in most viaducts and bridges built in many countries like Italy. According to previous literature results, the corrosion of prestressed concrete structures causes the size reduction of strands, degradation of mechanical properties of steel, cracking of the surrounding concrete and bond decay at the steel-to-concrete interface. The mixing of these effects strongly reduces the bearing-capacity of prestressed reinforced concrete members, changing the failure mechanism as well. In the framework of the OPTION research project between Niccolò Cusano University and Oslo Metropolitan University, an experimental campaign investigates the behavior of corroded prestressed beams. Four prestressed beams (cross section size 200 × 300; total length 3000 mm; clear span 2700 mm) were first subjected to artificial corrosion, to obtain different damage levels, and were then tested in four-point bending. The goal is to estimate the corrosion level that makes a deteriorated prestressed reinforced concrete beam less ductile while keeping the strength unchanged. In the present study, the first experimental results and some details about the laboratory procedure are presented. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
169 KiB  
Abstract
Corrosion Resistance of Aluminium against Salt Hydrates Used for Latent Heat Storage by Using Different Coating Materials
by Mayra Paulina Alferez Luna, Franziska Klünder and Stefan Gschwander
Mater. Proc. 2021, 6(1), 31; https://doi.org/10.3390/CMDWC2021-10045 - 14 May 2021
Viewed by 447
Abstract
Thermal energy storage (TES) is required when using energy sources that are intermittent in order to fill the gap between energy supply and energy demand. Latent heat storage systems are based on phase change materials (PCM) such as salt hydrates, which absorb and [...] Read more.
Thermal energy storage (TES) is required when using energy sources that are intermittent in order to fill the gap between energy supply and energy demand. Latent heat storage systems are based on phase change materials (PCM) such as salt hydrates, which absorb and release thermal energy with a change in its physical state. However, even though salt hydrates are widely used as PCM, they are potentially corrosive. Since PCM are normally encapsulated in containers, their compatibility with each other has to be assessed in order to create resistant containers. In this work, the corrosion resistance of aluminium against two different salt hydrates (SP24E and SP50) in a temperature range of 40 °C to 60 °C was tested. Furthermore, four coatings (anodized, electroless nickel-phosphorous, powder and KTL-cathodic dip) were used to enhance the aluminium corrosion protection. The method used was the immersion corrosion test. Signs of severe localized corrosion were found in uncoated and nickel–phosphorous-coated aluminium, while the anodized coated aluminium showed slight uniform corrosion. According to the calculated corrosion rates, uncoated aluminium is not recommended to be used for long-term applications when using SP24E as PCM, as well as nickel–phosphorous-coated aluminium when using either of the two tested salt hydrates. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
197 KiB  
Abstract
Data Science Framework to Select Corrosion Inhibitors
by Tiago L. P. Galvão, Gerard Novell-Leruth, Inês Ferreira, Alena Kuznetsova, José R. B. Gomes and João Tedim
Mater. Proc. 2021, 6(1), 32; https://doi.org/10.3390/CMDWC2021-09935 - 08 May 2021
Viewed by 709
Abstract
Organic corrosion inhibitors embedded in coatings play a crucial role in substituting for traditional anti-corrosion pigments, which can cause acute toxicity problems to human health and the environment [...] Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
175 KiB  
Abstract
Corrosivity of Different Natural Groundwaters from Repository Sites
by Mervi Somervuori, Elisa Isotahdon, Maija Nuppunen-Puputti, Malin Bomberg, Leena Carpén and Pauliina Rajala
Mater. Proc. 2021, 6(1), 33; https://doi.org/10.3390/CMDWC2021-10064 - 17 May 2021
Cited by 1 | Viewed by 383
Abstract
In Finland, the repositories for low- and intermediate-level waste (LLW and ILW) are situated in three different geographical locations in deep granite bedrock, where waste containers can be subjected to anoxic groundwater containing microbes. The composition of groundwater varies in terms of chemistry [...] Read more.
In Finland, the repositories for low- and intermediate-level waste (LLW and ILW) are situated in three different geographical locations in deep granite bedrock, where waste containers can be subjected to anoxic groundwater containing microbes. The composition of groundwater varies in terms of chemistry and microbial activity in different locations. In this study, groundwater from three repository areas was analyzed with regard to chemistry and microbial community. The corrosion tendency of three steel grades, carbon steel AISI/SAE 1005 and stainless steels AISI 304 and 316L, was studied in these groundwater environments using electrochemical methods. As a reference, measurements were also performed in simulated groundwater that did not contain microbes. The measurements show that the corrosivity of the water, and thus, the steels’ performance, differed depending on its location of origin. Additionally, the groundwater differed remarkably in their chemical composition as well as the abundance and diversity of the microbial community within them. Consequently, the local environment has to be considered when evaluating the long-term safety of the disposal of nuclear waste. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
203 KiB  
Abstract
Layered Double Hydroxide Coatings Loaded with Corrosion Inhibitors for Corrosion Protection of AZ31
by Borja Pillado, Marta Mohedano, Rubén del Olmo, Beatriz Mingo, Endzhe Matykina and Raúl Arrabal
Mater. Proc. 2021, 6(1), 34; https://doi.org/10.3390/CMDWC2021-10041 - 14 May 2021
Viewed by 301
Abstract
Layered double hydroxide (LDHs) coatings were developed for the corrosion protection of AZ31 Mg alloy. AZ31 is widely used in the transport industry due to its low mass density and good mechanical properties. LDH coatings were fabricated under co-precipitation conditions and applied under [...] Read more.
Layered double hydroxide (LDHs) coatings were developed for the corrosion protection of AZ31 Mg alloy. AZ31 is widely used in the transport industry due to its low mass density and good mechanical properties. LDH coatings were fabricated under co-precipitation conditions and applied under hydrothermal conditions. Two different systems Zn-Al LDH and Li-Al LDH were studied. Specimens were post-treated via immersion for 2 h at 45 °C in inhibitor aqueous baths. Na2WO4·H2O and LiNO3 inorganic inhibitors were used, respectively, to produce inhibitor-loaded systems: Zn-Al LDH(W) and Li-Al LDH(Li). The characterization of the coatings was carried out by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The corrosion process was studied by electrochemical impedance spectroscopy (EIS) and scanning vibrating electrode technique (SVET). The surface was also evaluated via the determination of water drop contact angle and the performance of a paint adhesion test using an epoxy primer. The characterization of the coating revealed two-layered coatings with a denser inner layer and a flaky outer layer. Both coatings improved the corrosion resistance of the AZ31 alloy. Loading with inhibitor further increased the corrosion resistance by one order of magnitude (bare substrate, Z10mHz~102 Ω cm2; LDH, Z10mHz~103–4 Ω cm2; LDH-inhibitor, Z10mHz~105 Ω cm2). Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
188 KiB  
Abstract
Corrosion Resistance of Electroless Nickel–Boron Coating in a Bath Exempt from Stabilizer
by Muslum Yunacti, Alexandre Megret, Alex Montagne and Véronique Vitry
Mater. Proc. 2021, 6(1), 35; https://doi.org/10.3390/CMDWC2021-10038 - 13 May 2021
Viewed by 319
Abstract
Electroless nickel–boron (ENB) coatings from borohydride-reduced baths have received wide acceptance thanks to their excellent hardness and superior wear resistance. Therefore, they have been considered as an alternative to hard chrome. However, the presence of a small amount of toxic heavy metals such [...] Read more.
Electroless nickel–boron (ENB) coatings from borohydride-reduced baths have received wide acceptance thanks to their excellent hardness and superior wear resistance. Therefore, they have been considered as an alternative to hard chrome. However, the presence of a small amount of toxic heavy metals such as Pb or Tl in the plating bath restricts their application. These metallic salts are used to stabilize the bath, which is necessary to avoid abrupt decomposition, and are harmful towards the environment. A new bath, exempt from stabilizer, was designed for ENB plating. In this bath, the bath stability is achieved through the optimization of the concentration of complexing agent, pH adjuster, and reducing agent. An ENB coating from the new bath presents promising properties, including modified surface morphology, excellent hardness, low friction coefficient, etc. Salt spray test (ASTM B117-07) and potentiodynamic polarization test results show that the new ENB coating has a significantly better corrosion resistance than the conventional ENB coatings stabilized by Pb or Tl salts. In conclusion, the present ENB coating is produced in an environmentally friendly bath, and the deposit presents properties close to those of the conventional ENB deposit. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)

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Proceeding Paper
Evaluation and Prevention of Hydrogen Embrittlement by NDT Methods: A Review
by Sujeet Choudhary, Manish Vishwakarma and Sandeep Kumar Dwivedi
Mater. Proc. 2021, 6(1), 18; https://doi.org/10.3390/CMDWC2021-10044 - 14 May 2021
Cited by 1 | Viewed by 2422
Abstract
This paper comprises of hydrogen embrittlement phenomena in material, factors responsible for the hydrogen embrittlement and non-destructive methods to evaluate the internal defect in machines or components when working in hydrogen atmosphere. Hydrogen embrittlement is responsible for sub-critical crack growth in materials, fracture [...] Read more.
This paper comprises of hydrogen embrittlement phenomena in material, factors responsible for the hydrogen embrittlement and non-destructive methods to evaluate the internal defect in machines or components when working in hydrogen atmosphere. Hydrogen embrittlement is responsible for sub-critical crack growth in materials, fracture and mechanical properties such as ductility, toughness, and consequently loss of strength. This hydrogen is induced into the material during electrochemical reactions and in a high-pressure hydrogen gas environment. The paper covers the review on the capabilities of non-destructive testing methods regarding advantages and disadvantages. Sometimes one non-destructive technique does not provide sufficient information about physical integrity and therefore a different combination of methods is required. Ultrasonic testing is very useful to detect internal defects. Full article
(This article belongs to the Proceedings of The 1st Corrosion and Materials Degradation Web Conference)
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