Editorial

3 pages, 174 KiB

Open AccessEditorial

Advanced Surface Treatment Technologies for Metallic Alloys

by Petrica Vizureanu

Materials 2022, 15(4), 1464; https://doi.org/10.3390/ma15041464 - 16 Feb 2022

Cited by 2 | Viewed by 1153

The main objective of this Special Issue was to publish outstanding papers presenting cutting-edge research in the field of surface treatment technologies for metallic alloys and their understanding [...] Full article

(This article belongs to the Special Issue Advanced Surface Treatment Technologies for Metallic Alloys)

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14 pages, 3829 KiB

Open AccessArticle

Effect of Electric Pulse Treatment on Hot-Dip Aluminizing Coating of Ductile Iron

by Jie Dong, Shouqian Yuan, Yongtao Sun, Shuangping Yang, Xiangdong Xing and Xiaomei He

Materials 2021, 14(23), 7219; https://doi.org/10.3390/ma14237219 - 26 Nov 2021

Cited by 1 | Viewed by 1212

Abstract

In this paper, hot-dip aluminizing of ferrite nodular cast iron was carried out after treating liquid aluminum with different electrical pulse parameters. Compared with that of conventional hot-dip aluminizing, the coating structure of the treated sample did not change, the surface was smooth [...] Read more.

In this paper, hot-dip aluminizing of ferrite nodular cast iron was carried out after treating liquid aluminum with different electrical pulse parameters. Compared with that of conventional hot-dip aluminizing, the coating structure of the treated sample did not change, the surface was smooth and continuous, and the solidification structure was more uniform. When high voltage and large capacitance were used to treat the liquid aluminum, the thickness and compactness of the coating surface layer increased. The thickness of the alloy layer decreased, and, the compactness and the micro hardness increased, so the electric pulse had a certain inhibition on the formation of the alloy layer. The growth kinetics of the alloy layer showed that the rate-time index decreased from 0.60 for the conventional sample to 0.38 for the electric pulse treated sample. The growth of the alloy layer was controlled by diffusion and interface reaction, but only by diffusion. The AC impedance and polarization curves of the coating showed that the corrosion resistance of hot-dip coating on nodular cast iron was improved by electric pulse treatment. Full article

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18 pages, 5013 KiB

Open AccessArticle

The Effect of Sandblasting on Properties and Structures of the DC03/1.0347, DC04/1.0338, DC05/1.0312, and DD14/1.0389 Steels for Deep Drawing

by Janusz Krawczyk, Michał Bembenek, Łukasz Frocisz, Tomasz Śleboda and Marek Paćko

Materials 2021, 14(13), 3540; https://doi.org/10.3390/ma14133540 - 25 Jun 2021

Cited by 11 | Viewed by 2032

Abstract

The erosion phenomenon has a significant influence on many metallic materials used in numerous industrial sectors. In this paper, we present the results of an analysis of the influence of abrasive impact erosion on surface and properties of DC03/1.0347, DC04/1.0338, DC05/1.0312, and DD14/1.0389 [...] Read more.

The erosion phenomenon has a significant influence on many metallic materials used in numerous industrial sectors. In this paper, we present the results of an analysis of the influence of abrasive impact erosion on surface and properties of DC03/1.0347, DC04/1.0338, DC05/1.0312, and DD14/1.0389 deep drawing steels. The chemical composition, static tensile tests, hardness tests, drawability tests, erosion tests, microstructure analysis, surface roughness, and hardness of the plates were investigated. The wear mechanisms and wear behavior of the investigated steels were also discussed. The results obtained in this study allowed the assessment of the microstructural changes in deep drawing steels under the influence of intense erosive impact. The obtained results indicate that the erosive impact may cause a significant grain refinement of the microstructure of the surfaces of the investigated materials. Moreover, large amounts of heat released during erosive impact may cause the material phase changes. This research expands the knowledge on specific mechanisms taking place during sandblasting and their influence on the properties of deep drawing steels and their wear behavior. Full article

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14 pages, 4171 KiB

Open AccessArticle

Influence of Silver as a Catalyst on the Growth of β-Ga₂O₃ Nanowires on GaAs

by Badriyah Alhalaili, Howard Mao, Daniel M. Dryden, Hilal Cansizoglu, Ryan James Bunk, Ruxandra Vidu, Jerry Woodall and M. Saif Islam

Materials 2020, 13(23), 5377; https://doi.org/10.3390/ma13235377 - 26 Nov 2020

Cited by 8 | Viewed by 1879

Abstract

A simple and inexpensive thermal oxidation process was performed to synthesize gallium oxide (Ga₂O₃) nanowires using Ag thin film as a catalyst at 800 °C and 1000 °C to understand the effect of the silver catalyst on the nanowire [...] Read more.

A simple and inexpensive thermal oxidation process was performed to synthesize gallium oxide (Ga₂O₃) nanowires using Ag thin film as a catalyst at 800 °C and 1000 °C to understand the effect of the silver catalyst on the nanowire growth. The effect of doping and orientation of the substrates on the growth of Ga₂O₃ nanowires on single-crystal gallium arsenide (GaAs) wafers in atmosphere were investigated. A comprehensive study of the oxide film and nanowire growth was performed using various characterization techniques including XRD, SEM, EDS, focused ion beam (FIB), XPS and STEM. Based on the characterization results, we believe that Ag thin film produces Ag nanoparticles at high temperatures and enhances the reaction between oxygen and gallium, contributing to denser and longer Ga₂O₃ nanowires compared to those grown without silver catalyst. This process can be optimized for large-scale production of high-quality, dense, and long nanowires. Full article

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15 pages, 1573 KiB

Open AccessArticle

Phosphate Surface Treatment for Improving the Corrosion Resistance of the C45 Carbon Steel Used in Carabiners Manufacturing

by Diana-Petronela Burduhos-Nergis, Petrica Vizureanu, Andrei Victor Sandu and Costica Bejinariu

Materials 2020, 13(15), 3410; https://doi.org/10.3390/ma13153410 - 02 Aug 2020

Cited by 24 | Viewed by 2546

Abstract

This study approaches the issues which appear during carabiner use and analyses the possibility to eliminate them. Therefore, to improve the corrosion resistance of carbon steel, used in carabiners manufacturing, three different insoluble phosphate layers were deposited on the samples’ surface. The layers [...] Read more.

This study approaches the issues which appear during carabiner use and analyses the possibility to eliminate them. Therefore, to improve the corrosion resistance of carbon steel, used in carabiners manufacturing, three different insoluble phosphate layers were deposited on the samples’ surface. The layers were obtained by immersion in zinc-based phosphate solution, zinc/iron-based phosphate solution and manganese-based phosphate solution, Afterwards, to protect against mechanical shocks, a layer of elastomer-based paint was deposited. Furthermore, to reduce rope wear by decreasing the value of the coefficient of friction, the samples were impregnated in molybdenum disulfide-based lubricant. This study aims to analyse the corrosion behaviour of the layers deposited on the carbon steel surface in three of the most common corrosive environments (rainwater, seawater and fire extinguishing solution) by linear and cyclic polarisation. The overall results show that all types of deposited layers increase the corrosion resistance of C45 steel. The experimental results revealed that the samples coated with a phosphate layer obtained by immersion in the zinc-based phosphate solution possess the highest corrosion resistance among the phosphate samples. Full article

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16 pages, 3600 KiB

Open AccessArticle

Revealing the Influence of Microparticles on Geopolymers’ Synthesis and Porosity

by Dumitru Doru Burduhos Nergis, Petrica Vizureanu, Ioan Ardelean, Andrei Victor Sandu, Ofelia Cornelia Corbu and Ecaterina Matei

Materials 2020, 13(14), 3211; https://doi.org/10.3390/ma13143211 - 18 Jul 2020

Cited by 36 | Viewed by 3061

Abstract

Geopolymers are zeolites like structures based on hydrated aluminosilicates units of SiO₄ and AlO₄. These units, known as poly(sialate), poly(sialate)-siloxo or poly(sialate)-disiloxo are chemically balanced by the group I cations of K⁺, Li⁺, or Na⁺ [...] Read more.

Geopolymers are zeolites like structures based on hydrated aluminosilicates units of SiO₄ and AlO₄. These units, known as poly(sialate), poly(sialate)-siloxo or poly(sialate)-disiloxo are chemically balanced by the group I cations of K⁺, Li⁺, or Na⁺. Simultaneously, the chemical reaction of formation, known as geopolymerization, governs the orientation of the unit, generating mesoporous structures. Multiple methods can be used for pore structure and porosity characterization. Among them, nuclear magnetic resonance (NMR) relaxometry allows the detection of the porous structure in a completely nonperturbative manner. NMR relaxometry may be used to monitor the relaxation of protons belonging to the liquid molecules confined inside the porous structure and, thus, to get access to the pore size distribution. This monitoring can take place even during the polymerization process. The present study implements transverse relaxation measurements to monitor the influence introduced by the curing time on the residual liquid phase of geopolymers prepared with two different types of reinforcing particles. According to our results, the obtained geopolymers contain three types of pores formed by the arrangement of the OH⁻ and Si groups (Si-OH), Si-O-Si groups, Si-O-Al groups, and Si-O rings. After 48 days, the samples cured for 8 h show a high percentage of all three types of pores, however, by increasing the curing time and the percentage of reinforcing particle, the percent of pores decrease, especially, the gel pores. Full article

(This article belongs to the Special Issue Advanced Surface Treatment Technologies for Metallic Alloys)

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25 pages, 17424 KiB

Open AccessArticle

Properties of Cu-xFe₃O₄ Nanocomposites for Electrical Application

by Andra Mihaela Predescu, Ruxandra Vidu, Petrică Vizureanu, Andrei Predescu, Ecaterina Matei and Cristian Predescu

Materials 2020, 13(14), 3086; https://doi.org/10.3390/ma13143086 - 10 Jul 2020

Cited by 3 | Viewed by 1830

Abstract

Copper matrix nanocomposites reinforced with magnetite nanoparticles were developed using powder metallurgy. Various processing parameters were taken into consideration, such as magnetite content, compaction pressure, sintering time and temperature. The nanopowder blends were compacted using various uniaxial pressures and sintered at 650 and [...] Read more.

Copper matrix nanocomposites reinforced with magnetite nanoparticles were developed using powder metallurgy. Various processing parameters were taken into consideration, such as magnetite content, compaction pressure, sintering time and temperature. The nanopowder blends were compacted using various uniaxial pressures and sintered at 650 and 800 °C in order to study the influence of processing parameters on morphology, structure, thermal, magnetic and mechanical properties. The structure and morphology of the nanocomposites analyzed by X-ray diffraction (XRD), bright field transmission electron microscopy (TEMBF) and scanning electron microscopy (SEM) showed that sintered composites retained the nanoscale characteristics of the initial Fe₃O₄ and Cu nanopowders. These nanocomposites have good cold-rolling deformability and Vickers micro-hardness. The Cu-xFe₃O₄ nanocomposites have thermal and magnetic properties that make them suitable for electronical applications. Full article

(This article belongs to the Special Issue Advanced Surface Treatment Technologies for Metallic Alloys)

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17 pages, 10496 KiB

Open AccessArticle

The Effects of Micro-Segregation on Isothermal Transformed Nano Bainitic Microstructure and Mechanical Properties in Laser Cladded Coatings

by Yanbing Guo, Zhuguo Li, Liqun Li and Kai Feng

Materials 2020, 13(13), 3017; https://doi.org/10.3390/ma13133017 - 06 Jul 2020

Cited by 3 | Viewed by 2022

Abstract

The design of metastable retained austenite is the key issue to obtain nano bainitic steel with high strength and toughness. In this study, nanostructured Fe-based bainitic coatings were fabricated using laser cladding and following isothermal heat treatment. The microstructures and mechanical properties of [...] Read more.

The design of metastable retained austenite is the key issue to obtain nano bainitic steel with high strength and toughness. In this study, nanostructured Fe-based bainitic coatings were fabricated using laser cladding and following isothermal heat treatment. The microstructures and mechanical properties of the laser cladded coating were investigated. The results show that the Mn, Cr, Co, and Al segregated at the solidified prior grain boundaries. The micro-segregation of the solutes strongly influenced the stability of the austenite. As the isothermal temperature decreases, the interface of the bainite and blocky retained austenite approach to the prior interdendritic regions with the decreasing isothermal temperature, and the final volume fraction also decreases. The volume fractions of each phase and microstructure morphology of the coatings were determined by the interdendritic micro-segregation and isothermal temperatures. The stability of the blocky retained austenite distributed at the interdendritic area was lower than that of film and island-like morphology. This phenomenon contributed to the ductile and tough nano bainitic coatings with tunable mechanical properties. Full article

(This article belongs to the Special Issue Advanced Surface Treatment Technologies for Metallic Alloys)

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17 pages, 10285 KiB

Open AccessArticle

Effect of Al Content in Magnesium Alloy on Microstructure and Mechanical Properties of Laser-Welded Mg/Ti Dissimilar Joints

by Wen Dong, Rongrong Huang, Hongyun Zhao, Xiangtao Gong, Bo Chen and Caiwang Tan

Materials 2020, 13(12), 2743; https://doi.org/10.3390/ma13122743 - 17 Jun 2020

Cited by 5 | Viewed by 2011

Abstract

Laser penetration welding of magnesium alloys and pure titanium TA2 with unequal thickness was performed. Mg base metal with different Al content (AZ31B, AZ61A, AZ91D) was used to investigate the influence of Al element in microstructure and mechanical properties of Mg/Ti dissimilar joints. [...] Read more.

Laser penetration welding of magnesium alloys and pure titanium TA2 with unequal thickness was performed. Mg base metal with different Al content (AZ31B, AZ61A, AZ91D) was used to investigate the influence of Al element in microstructure and mechanical properties of Mg/Ti dissimilar joints. The results revealed that the change of Mg base metal did not influence the weld appearance of the joints. Three kinds of joint all presented the best mechanical property when the laser power was 3500 W. With the increase content of Al elements in Mg base metal, a reaction layer was observed which was identified as Ti₃Al. The highest enrichment of Al element was obtained and its fraction reached 19.31 at% at the AZ91/TA2 interface. The chemical potential gradient of Al from AZ91 to Ti alloy was higher than that from the other two base metals based on thermodynamic calculation. The maximum fracture load reached 3597 N when AZ61 was employed as the base metal and the fracture position was the Ti base metal. AZ31/TA2 joints failed at the weld seam without necking due to the rapid propagation of cracks at the Mg/Ti interface. The AZ91/TA2 joint failed inside the Mg fusion zone with necking at the middle area of the weld, which resulted from the precipitation of brittle phases such as Mg–Al, Ti–Al phases in the fusion zone of Mg alloys. Full article

(This article belongs to the Special Issue Advanced Surface Treatment Technologies for Metallic Alloys)

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13 pages, 10298 KiB

Open AccessFeature PaperArticle

Effects of Mn, Zn Additions and Cooling Rate on Mechanical and Corrosion Properties of Al-4.6Mg Casting Alloys

by Chih-Ting Wu, Sheng-Long Lee, Ye-Feng Chen, Hui-Yun Bor and Kung-Hui Liu

Materials 2020, 13(8), 1983; https://doi.org/10.3390/ma13081983 - 24 Apr 2020

Cited by 5 | Viewed by 2346

Abstract

The mechanical properties of the Al-Mg alloy can be enhanced by adding metallic elements, but a continuous distribution of precipitates at grain boundaries leads to intergranular corrosion during sensitization treatment. In the present work, Mn, Zn additions, water cooling and furnace cooling were [...] Read more.

The mechanical properties of the Al-Mg alloy can be enhanced by adding metallic elements, but a continuous distribution of precipitates at grain boundaries leads to intergranular corrosion during sensitization treatment. In the present work, Mn, Zn additions, water cooling and furnace cooling were executed to investigate their effects on the mechanical and corrosion properties of the Al-4.6Mg alloy. Our results show that adding Mn to Al-4.6Mg alloys may produce grain refinement and dispersion strengthening, increasing tensile strength and hardness. The presence of Mn did not affect the corrosion resistance of Al-Mg alloys. Adding Zn to the Al-4.6Mg alloy increased tensile strength and hardness, but decreased corrosion resistance. Combined, the addition of Mn and Zn to the Al-4.6Mg alloy exhibited the highest tensile strength and hardness, but seriously reduced corrosion resistance. Furnace cooling substituted for water quenching could avoid intergranular corrosion, but slightly decreased the tensile strength and hardness by 7.0% and 6.8%, respectively. Full article

(This article belongs to the Special Issue Advanced Surface Treatment Technologies for Metallic Alloys)

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10 pages, 2180 KiB

Open AccessArticle

Effect of Magnetic Head Shape on Processing of Titanium Alloy Wire by Magnetic Abrasive Finishing

by Wenlong Li, Yan Chen, Miao Cheng and Yini Lv

Materials 2020, 13(6), 1401; https://doi.org/10.3390/ma13061401 - 19 Mar 2020

Cited by 11 | Viewed by 2317

Abstract

Titanium alloy wire is characterized by high specific strength, good corrosion resistance, high-temperature resistance and other excellent comprehensive performance. It has been widely used not only in aerospace, shipbuilding and other high-tech fields, but also increasingly in medical equipment, food safety and other [...] Read more.

Titanium alloy wire is characterized by high specific strength, good corrosion resistance, high-temperature resistance and other excellent comprehensive performance. It has been widely used not only in aerospace, shipbuilding and other high-tech fields, but also increasingly in medical equipment, food safety and other fields. Because titanium alloy wire is relatively difficult to process, it has a large deformation resistance, good elasticity, high flexion ratio and more serious rebound. During the processing, adhesion problems may occur, thus reducing the surface quality. The magnetic abrasive finishing (MAF) has good flexible machining characteristics. In this study, the rotating magnetic field was loaded on the titanium alloy wire, and the magnetic abrasive was absorbed by the magnetic field force to form a magnetic abrasive brush, so as to realize the precision processing of the titanium alloy wire. Under the same processing time, when the angle of the magnetic head was 37°, the surface roughness of titanium alloy wire was reduced to 0.28 μm by MAF, which improved the processing quality and efficiency of the titanium alloy wire. Full article

(This article belongs to the Special Issue Advanced Surface Treatment Technologies for Metallic Alloys)

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14 pages, 8921 KiB

Open AccessArticle

Investigation into the Effect of Thermal Treatment on the Obtaining of Magnetic Phases: Fe₅Y, Fe₂₃B₆, Y₂Fe₁₄B and αFe within the Amorphous Matrix of Rapidly-Quenched Fe_61+xCo_10−xW₁Y₈B₂₀ Alloys (Where x = 0, 1 or 2)

by Petrica Vizureanu, Marcin Nabiałek, Andrei Victor Sandu and Bartłomiej Jeż

Materials 2020, 13(4), 835; https://doi.org/10.3390/ma13040835 - 12 Feb 2020

Cited by 16 | Viewed by 1700

Abstract

The paper presents the results of research on the structure and magnetic properties of Fe_61+xCo_10−xW₁Y₈B₂₀ alloys (where x = 0, 1 or 2). The alloys were produced using two production methods with [...] Read more.

The paper presents the results of research on the structure and magnetic properties of Fe_61+xCo_10−xW₁Y₈B₂₀ alloys (where x = 0, 1 or 2). The alloys were produced using two production methods with similar cooling rates: Injection casting and suction casting. The alloy samples produced were subjected to isothermal annealing at 940 K for 10 min. The structure of the materials was examined using X-ray diffraction. Isothermal annealing has led to the formation of various crystallization products depending on the chemical composition of the alloy and the structure of the alloy in a solidified state. In two cases, the product of crystallization was the hard magnetic phase Y₂Fe₁₄B. However, the mechanism of this phase formation was different in both cases. The magnetic properties of alloys were tested using a vibrating sample magnetometer and a Faraday magnetic balance. It is found that the grain crystallite size of the crystalline phases have a decisive influence on the value of the coercive field (especially in the case of hard magnetic phases). It has been shown that privileged areas can already be created during the production process. Their presence determines the crystallization process. Full article

(This article belongs to the Special Issue Advanced Surface Treatment Technologies for Metallic Alloys)

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13 pages, 4349 KiB

Open AccessArticle

Effect of the Application of Different Surface Treatment Methods on the Strength of Titanium Alloy Sheet Adhesive Lap Joints

by Anna Rudawska, Kazimierz Zaleski, Izabela Miturska and Agnieszka Skoczylas

Materials 2019, 12(24), 4173; https://doi.org/10.3390/ma12244173 - 12 Dec 2019

Cited by 26 | Viewed by 2453

Abstract

This study investigated the effect of the different surface treatment methods on the strength of Ti6Al4V titanium alloy sheet adhesive joints. The following surface treatment methods were used: alkaline degreasing, anodizing, vibratory shot peening, and anodizing with vibrational shot peening. The following tests/measurements [...] Read more.

This study investigated the effect of the different surface treatment methods on the strength of Ti6Al4V titanium alloy sheet adhesive joints. The following surface treatment methods were used: alkaline degreasing, anodizing, vibratory shot peening, and anodizing with vibrational shot peening. The following tests/measurements were carried out during the experiment: surface roughness measurements; microhardness measurements (conducted by the Vickers hardness test method); and strength tests of single-lap adhesive joints fabricated with the use of two epoxy adhesives, rigid and flexible, both based on epoxy resin Epidian 5. It has been found that the application of anodizing followed by vibratory shot peening leads to increased strength of adhesive joints, irrespective of the type of applied epoxy adhesive. Full article

(This article belongs to the Special Issue Advanced Surface Treatment Technologies for Metallic Alloys)

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19 pages, 8066 KiB

Open AccessArticle

Promoted Anodizing Reaction and Enhanced Coating Performance of Al–11Si Alloy: The Role of an Equal-Channel-Angular-Pressed Substrate

by Zhikai Zhou, Dan Song, Ningning Liang, Haiyang Jiang, Bo Gao, Yuna Wu, Aibin Ma, Yanxin Qiao, Jiapeng Sun, Jinghua Jiang and Xiaolong Ma

Materials 2019, 12(19), 3255; https://doi.org/10.3390/ma12193255 - 05 Oct 2019

Cited by 9 | Viewed by 2709

Abstract

In this paper, the effect of the equal-channel-angular-pressed (ECAPed) substrate on the coating formation and anticorrosion performance of the anodized Al–11Si alloy was systematically investigated. The ECAP process dramatically refines both Al and Si phases of the alloy. The parallel anodizing circuit is [...] Read more.

In this paper, the effect of the equal-channel-angular-pressed (ECAPed) substrate on the coating formation and anticorrosion performance of the anodized Al–11Si alloy was systematically investigated. The ECAP process dramatically refines both Al and Si phases of the alloy. The parallel anodizing circuit is designed to enable a comparative study of anodizing process between the cast and the ECAPed alloys by tracking their respective anodizing current quota. The optimum coatings of both alloys were obtained after anodization for 30 min. The ECAPed alloy attained a thicker, more compact, and more uniform coating. Energetic crystal defects in the fine Al grains of the ECAPed substrate promote the anodizing reaction and lead to the thicker coating. Fragmented and uniformly distributed fine Si particles in the ECAPed alloy effectively suppress the coating cracks, enhancing the compactness of the coating. Overall, the ECAP-coated sample exhibits the best anticorrosion performance, which is evidenced by the concurrently enhanced prevention of coating and improved corrosion resistance of the substrate. Full article

(This article belongs to the Special Issue Advanced Surface Treatment Technologies for Metallic Alloys)

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