Coatings

18 pages, 7556 KiB

Open AccessArticle

Thermal Case Study of Cilia Actuated Transport of Radiated Blood-Based Ternary Nanofluid under the Action of Tilted Magnetic Field

by Najma Saleem, Tahreem Ashraf, Ibtisam Daqqa, Sufian Munawar, Nazeran Idrees, Farkhanda Afzal and Deeba Afzal

Coatings 2022, 12(6), 873; https://doi.org/10.3390/coatings12060873 - 20 Jun 2022

Cited by 12 | Viewed by 1895

Abstract

Micro/nanoscale fabricated devices have widely been used in modern technology and bioengineering as they offer excellent heat transfer. Removal of excess heat, coolant selection, rapid mixing, and handling proportion of colloidal metallic nanogranules in the base fluid are the main challenges in micro/nanofluidic [...] Read more.

Micro/nanoscale fabricated devices have widely been used in modern technology and bioengineering as they offer excellent heat transfer. Removal of excess heat, coolant selection, rapid mixing, and handling proportion of colloidal metallic nanogranules in the base fluid are the main challenges in micro/nanofluidic systems. To address these problems, the primary motivation of the intended mathematical flow problem is to investigate the thermal and flow aspects of blood-based ternary nanofluid in the presence of inclined magnetic field and thermal radiations through a microfluidic pump with elastic walls. Further, the pump inner surface is smeared with fabricated cilia. The embedded cilia blow in coordination to start metachronal travelling waves along the pump wall that assist homogenous mixing and manipulation. The entire analysis is conducted in moving frame and simplified under lubrication and Rosseland approximations. Numerical solution of various flow and thermal entities are computed via the shooting method and plotted for different values of the parameters of interest. A comparative glimpse allows us to conclude that the trimetallic blood-based nanofluid exhibits elevated heat transfer rate by 12–18%, bi-metallic by about 11–12%, and mono nanofluid by about 6% compared to the conventional blood model. The study also determines that the prolonged cilia commence augmentation in flowrate and pressure-gradient around the pump deep portion. Furthermore, the radiated ternary liquid under fragile magnetic field effects may contribute to the cooling process by eliminating unnecessary heat from the system. It is also noticed that around the ciliated wall, the heat transfer irreversibility effects are appreciable over the fluid frictional irreversibility. Full article

(This article belongs to the Special Issue New Advances in Interfacial Mass Transfer)

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13 pages, 9549 KiB

Open AccessArticle

Bi Layer Properties in the Bi–FeNi GMR-Type Structures Probed by Spectroscopic Ellipsometry

by Natalia Kovaleva, Dagmar Chvostova, Ladislav Fekete and Alexandr Dejneka

Coatings 2022, 12(6), 872; https://doi.org/10.3390/coatings12060872 - 20 Jun 2022

Viewed by 1389

Abstract

Bismuth (Bi) having a large atomic number is characterized by a strong spin–orbit coupling (SOC) and is a parent compound of many 3D topological insulators (TIs). The ultrathin Bi films are supposed to be 2D TIs possessing a nontrivial topology, which opens the [...] Read more.

Bismuth (Bi) having a large atomic number is characterized by a strong spin–orbit coupling (SOC) and is a parent compound of many 3D topological insulators (TIs). The ultrathin Bi films are supposed to be 2D TIs possessing a nontrivial topology, which opens the possibility of developing new efficient technologies in the field of spintronics. Here we aimed at studying the dielectric function properties of ultrathin Bi/FeNi periodic structures using spectroscopic ellipsometry. The [Bi(d)–FeNi(1.8 nm)]

_{N}

GMR-type structures were grown by rf sputtering deposition on Sitall-glass (TiO

_{2}

) substrates. The ellipsometric angles

Ψ (ω)

and

Δ (ω)

were measured for the grown series (d = 0.6, 1.4, 2.0, and 2.5 nm, N = 16) of the multilayered film samples at room temperature for four angles of incidence of 60

^{\circ}

, 65

^{\circ}

, 70

^{\circ}

, and 75

^{\circ}

in a wide photon energy range of 0.5–6.5 eV. The measured ellipsometric angles,

Ψ (ω)

and

Δ (ω)

, were simulated in the framework of the corresponding multilayer model. The complex (pseudo)dielectric function spectra of the Bi layer were extracted. The GMR effects relevant for the studied Bi–FeNi MLF systems were estimated from the optical conductivity zero-limit (optical GMR effect). The obtained results demonstrated that the Bi layer possessed the surface metallic conductivity induced by the SOC effects, which was strongly enhanced on vanishing the semimetallic-like phase contribution on decreasing the layer thickness, indicating its nontrivial 2D topology properties. Full article

(This article belongs to the Special Issue Recent Advances in the Growth and Characterizations of Thin Films)

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11 pages, 3088 KiB

Open AccessEditor’s ChoiceArticle

Effects of Substrate Temperature on Nanomechanical Properties of Pulsed Laser Deposited Bi₂Te₃ Films

by Hui-Ping Cheng, Phuoc Huu Le, Le Thi Cam Tuyen, Sheng-Rui Jian, Yu-Chen Chung, I-Ju Teng, Chih-Ming Lin and Jenh-Yih Juang

Coatings 2022, 12(6), 871; https://doi.org/10.3390/coatings12060871 - 20 Jun 2022

Cited by 4 | Viewed by 1851

Abstract

The correlations among microstructure, surface morphology, hardness, and elastic modulus of Bi₂Te₃ thin films deposited on c-plane sapphire substrates by pulsed laser deposition are investigated. X-ray diffraction (XRD) and transmission electron microscopy are used to characterize the microstructures of [...] Read more.

The correlations among microstructure, surface morphology, hardness, and elastic modulus of Bi₂Te₃ thin films deposited on c-plane sapphire substrates by pulsed laser deposition are investigated. X-ray diffraction (XRD) and transmission electron microscopy are used to characterize the microstructures of the Bi₂Te₃ thin films. The XRD analyses revealed that the Bi₂Te₃ thin films were highly (00l)-oriented and exhibited progressively improved crystallinity when the substrate temperature (T_S) increased. The hardness and elastic modulus of the Bi₂Te₃ thin films determined by nanoindentation operated with the continuous contact stiffness measurement (CSM) mode are both substantially larger than those reported for bulk samples, albeit both decrease monotonically with increasing crystallite size and follow the Hall—Petch relation closely. Moreover, the Berkovich nanoindentation-induced crack exhibited trans-granular cracking behaviors for all films investigated. The fracture toughness was significantly higher for films deposited at the lower T_S; meanwhile, the fracture energy was almost the same when the crystallite size was suppressed, which indicated a prominent role of grain boundary in governing the deformation characteristics of the present Bi₂Te₃ films. Full article

(This article belongs to the Special Issue Recent Advances in the Growth and Characterizations of Thin Films)

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16 pages, 5141 KiB

Open AccessArticle

Mechanical and Self-Healing Performance of Yellow River Alluvial Silt Treated with Composite Flexible Curing Agent

by Zhiyi Sai, Lin Wang, Hongchao Han, Wenjuan Wu, Zhaoyun Sun, Jincheng Wei, Lei Zhang, Guiling Hu and Hao Wu

Coatings 2022, 12(6), 870; https://doi.org/10.3390/coatings12060870 - 20 Jun 2022

Cited by 2 | Viewed by 1366

Abstract

The silt in the Yellow River alluvial plain has low clay content, low cohesion and poor structure. Its stability has always been a difficult problem in the engineering field. In order to improve the engineering properties of the silt in the alluvial plain [...] Read more.

The silt in the Yellow River alluvial plain has low clay content, low cohesion and poor structure. Its stability has always been a difficult problem in the engineering field. In order to improve the engineering properties of the silt in the alluvial plain of the Yellow River, a new type of silt composite flexible curing agent was prepared by using sintered red mud and matrix asphalt as the main materials to comprehensively stabilize the silt. The aim of this study was to investigate the effects of sintered red mud-asphalt composite flexible curing agent on aged mechanical properties of treated silt, in which the replacement levels of the flexible curing agent below 10% by weight are compared. Apart from the compressive strength, the drying shrinkage, low temperature freeze-thaw and high temperature self-healing ability are measured. The test results show that the flexible curing agent has a positive effect on improving the mechanical properties of stabilized silt. The flexible curing agent series exhibit higher compressive strength, better water stability, resistance to freeze-thaw and high temperature self-healing ability, and lower drying shrinkage compared to silt and cement stabilized silt. The preferred dosage 4%~6% of the flexible curing agent is obtained by mechanical property analysis. The SEM images show that the incorporation of the flexible curing agent helps the silt form dense cementation and non-connected microporous structure, that is beneficial to the improvement of water stability and frost resistance. The asphalt component in the flexible curing agent can reorganize and diffuse in the soil, fill the internal pores and micro cracks, and realize the repair of soil damage and structural reinforcement. Full article

(This article belongs to the Special Issue Asphalt Pavement Materials and Surface)

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16 pages, 6453 KiB

Open AccessArticle

Poly(2-Methoxyethyl Acrylate) (PMEA)-Coated Anti-Platelet Adhesive Surfaces to Mimic Native Blood Vessels through HUVECs Attachment, Migration, and Monolayer Formation

by Md Azizul Haque, Daiki Murakami, Takahisa Anada and Masaru Tanaka

Coatings 2022, 12(6), 869; https://doi.org/10.3390/coatings12060869 - 20 Jun 2022

Viewed by 3058

Abstract

Confluent monolayers of human umbilical vein endothelial cells (HUVECs) on a poly(2-methoxyethyl acrylate) (PMEA) antithrombogenic surface play a major role in mimicking the inner surface of native blood vessels. In this study, we extensively investigated the behavior of cell–polymer and cell–cell interactions by [...] Read more.

Confluent monolayers of human umbilical vein endothelial cells (HUVECs) on a poly(2-methoxyethyl acrylate) (PMEA) antithrombogenic surface play a major role in mimicking the inner surface of native blood vessels. In this study, we extensively investigated the behavior of cell–polymer and cell–cell interactions by measuring adhesion strength using single-cell force spectroscopy. In addition, the attachment and migration of HUVECs on PMEA-analogous substrates were detected, and the migration rate was estimated. Moreover, the bilateral migration of HUVECs between two adjacent surfaces was observed. Furthermore, the outer surface of HUVEC was examined using frequency-modulation atomic force microscopy (FM-AFM). Hydration was found to be an indication of a healthy glycocalyx layer. The results were compared with the hydration states of individual PMEA-analogous polymers to understand the adhesion mechanism between the cells and substrates in the interface region. HUVECs could attach and spread on the PMEA surface with stronger adhesion strength than self-adhesion strength, and migration occurred over the surface of analogue polymers. We confirmed that platelets could not adhere to HUVEC monolayers cultured on the PMEA surface. FM-AFM images revealed a hydration layer on the HUVEC surfaces, indicating the presence of components of the glycocalyx layer in the presence of intermediate water. Our findings show that PMEA can mimic original blood vessels through an antithrombogenic HUVEC monolayer and is thus suitable for the construction of artificial small-diameter blood vessels. Full article

(This article belongs to the Special Issue Bioactive Coatings for Implantable Devices)

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Graphical abstract

14 pages, 3118 KiB

Open AccessArticle

The Single-Step Fabrication of a Poly (Sodium Vinylsulfonate)-Grafted Polyetheretherketone Surface to Ameliorate Its Osteogenic Activity

by Lvhua Liu, Jun Dong, Weifang Zhang, Chanjuan He, Ying Liu and Yanyan Zheng

Coatings 2022, 12(6), 868; https://doi.org/10.3390/coatings12060868 - 20 Jun 2022

Cited by 4 | Viewed by 1697

Abstract

Polyetheretherketone (PEEK) is considered a potential material for replacing traditional biomedical metals used in orthopedic implants because of its similar elastic modulus to human bone. However, the poor osteogenic activity of PEEK itself hinders its clinical application. In this study, a PEEK surface [...] Read more.

Polyetheretherketone (PEEK) is considered a potential material for replacing traditional biomedical metals used in orthopedic implants because of its similar elastic modulus to human bone. However, the poor osteogenic activity of PEEK itself hinders its clinical application. In this study, a PEEK surface was grafted with poly (sodium vinylsulfonate) through a single-step ultraviolet-initiated graft polymerization method to ameliorate its osteogenic activity. X-ray photoelectron spectroscopy and water contact angle measurements confirmed that different amounts of poly (sodium vinylsulfonate) were grafted onto the PEEK surface upon varying the ultraviolet irradiation time. Atomic force microscopy revealed that the surface topography and roughness of PEEK before and after surface grafting did not change significantly. The in vitro results showed that grafting with poly (sodium vinylsulfonate) rendered the PEEK surface with improved MC3T3-E1 osteoblast compatibility and osteogenic activity. Moreover, a PEEK surface with a higher grafting amount of poly (sodium vinylsulfonate) was observed to be more beneficial to the proliferation and osteogenic differentiation of MC3T3-E1 osteoblasts. Collectively, by employing this simple and one-step method, the osteogenic activity of PEEK can be enhanced, paving the way for the clinical application of PEEK in orthopedic implants. Full article

(This article belongs to the Special Issue Implants and Its Protection)

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12 pages, 2444 KiB

Open AccessArticle

Reproduction of Fine Details and Compatibility of Vinyl Polysiloxane Impression Materials

by Shahab Ud Din, Farooq Ahmad Chaudhary, Yasir Alyahya, Bilal Arjumand, Muhammad Qasim Javed, Ahmed Ali and Mangala Patel

Coatings 2022, 12(6), 867; https://doi.org/10.3390/coatings12060867 - 20 Jun 2022

Cited by 1 | Viewed by 1980

Abstract

The purpose of this study was to develop novel experimental (Exp) vinyl polysiloxane (VPS) impression materials (ab initio) and to evaluate their reproduction of fine details and compatibility with pouring materials. The Exp materials were compared with three commercial VPSs (Aquasil Ultra Monophase [...] Read more.

The purpose of this study was to develop novel experimental (Exp) vinyl polysiloxane (VPS) impression materials (ab initio) and to evaluate their reproduction of fine details and compatibility with pouring materials. The Exp materials were compared with three commercial VPSs (Aquasil Ultra Monophase (Aq M), Extrude Medium-Bodied (Extr M), Elite HD Monophase (Elt M)) under dry, moist and wet conditions. Five VPSs (Exp-I–V) were developed, out of which Exp-I and II were hydrophobic while Exp-III, IV and V were hydrophilic. In the current study, Exp-II is the control for Exp-III, IV and V. Exp-I was the control for Exp-II, in which tear strength of the VPS was improved by adding a novel cross-linking agent. This part of the study has already been published by the authors. Under dry conditions, all commercial and Exp materials reproduced the 20 µm line satisfactorily. Under moist conditions, all commercial and some of the Exp (III, IV and V) materials reproduced the 20 µm line satisfactorily, with the exception of Exp-I and II. Under wet conditions, Aq M, Extr M and Exp-IV and V reproduced the continuous line, while Elt M and Exp-I, II and III failed to produce the line. For compatibility, all commercial and Exp VPSs, under dry conditions, reproduced the 50 µm line on the cast. Under moist conditions, Elt M and Exp-I and II did not record the line, while Aq M, Extr M and Exp-III, IV and V reproduced this line. Under wet conditions, Aq M, Extr M and Exp-IV and V reproduced the continuous line of 50 µm, while Elt M and Exp-I, II and III failed to record this line. Performance of the materials depends on the type and amount of surfactant incorporated. These data provide useful knowledge for clinicians on recording and pouring impressions with greater accuracy of reproduction of fine details and compatibility with cast/die materials. Full article

(This article belongs to the Special Issue Biocompatible Polymer-Based Materials: Synthesis, Properties and Applications)

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12 pages, 2129 KiB

Open AccessArticle

Multisensor Feature Fusion Based Rolling Bearing Fault Diagnosis Method

by Jinyu Tong, Cang Liu, Haiyang Pan and Jinde Zheng

Coatings 2022, 12(6), 866; https://doi.org/10.3390/coatings12060866 - 19 Jun 2022

Cited by 2 | Viewed by 1813

Abstract

To fully utilize the fault information and improve the diagnosis accuracy of rolling bearings, a multisensor feature fusion method is proposed. The method contains two steps. First, the intrinsic mode function (IMF) of each sensor vibration signal is calculated by variational mode decomposition [...] Read more.

To fully utilize the fault information and improve the diagnosis accuracy of rolling bearings, a multisensor feature fusion method is proposed. The method contains two steps. First, the intrinsic mode function (IMF) of each sensor vibration signal is calculated by variational mode decomposition (VMD), and the redundant information such as noise is eliminated. Then, the time-domain, frequency-domain and multiscale entropy features are extracted based on the preferred IMF and fused into one multidomain feature dataset. In the second step, the deep autoencoder network (DAEN) is constructed and the multisensor fusion features of the first step are used as input of the DAEN, and the multisensor fusion features are further extracted and classified. The experimental results show that the proposed model has a higher classification accuracy compared with the existing methods. Full article

(This article belongs to the Special Issue Friction, Vibration and Dynamic Properties of Transmission System under Wear Progression)

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13 pages, 3676 KiB

Open AccessArticle

Application of Spectroscopic Analysis for Plasma Polymerization Deposition onto the Inner Surfaces of Silicone Tubes

by Himanshu Mishra, Nima Bolouki, Stephen T. Hsieh, Chuan Li, Weite Wu and Jang-Hsing Hsieh

Coatings 2022, 12(6), 865; https://doi.org/10.3390/coatings12060865 - 19 Jun 2022

Cited by 3 | Viewed by 1591

Abstract

In the current study, plasma-polymerized methyl methacrylate (PP-MMA) generation on the inner surface of a silicone tube was performed in a capacitively coupled discharge reactor. The possibility of generating plasma inside the tube was analyzed and calculated by using optical emission spectroscopy (OES). [...] Read more.

In the current study, plasma-polymerized methyl methacrylate (PP-MMA) generation on the inner surface of a silicone tube was performed in a capacitively coupled discharge reactor. The possibility of generating plasma inside the tube was analyzed and calculated by using optical emission spectroscopy (OES). A hollow cathode model was first proposed to determine whether plasma discharge would be generated inside the tube in the low-pressure regime. Since the ignition of plasma inside the tube is necessary for the initiation of polymerization processes, the sheath thickness was calculated analytically. To achieve the goal, the electron temperature and density of plasma should be determined beforehand. In this study, the electron temperature and plasma density were measured and calculated according to OES spectra using both the modified Boltzmann plot and the line-ratio method. The results reveal that the occurrence of plasma inside the tube can be achieved if the tube’s inner diameter is greater than two times the thickness of the sheath. The effect of methyl methacrylate (MMA) monomer concentration on sheath thickness, and, hence, plasma generation and deposition, was investigated in the presence of argon plasma and MMA monomer. According to the study, one could control the ignition of plasma discharges inside the tube followed by plasma polymerization deposition. The OES method was also applied to identify the presence of the excited species related to the fragmented monomer. The deposition of PP-MMA films on the inner surface of the tube was confirmed via attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Full article

(This article belongs to the Section Plasma Coatings, Surfaces & Interfaces)

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11 pages, 2698 KiB

Open AccessArticle

A Superhydrophobic Alkali Activated Materials Coating by Facile Preparation

by Yao Qin, Zhou Fang, Xinrui Chai and Xuemin Cui

Coatings 2022, 12(6), 864; https://doi.org/10.3390/coatings12060864 - 19 Jun 2022

Cited by 3 | Viewed by 2482

Abstract

Alkali activated materials (AAMs) were considered as economical and environmentally friendly that have attracted incrementally attention as green coating materials. However, alkali activated materials were inclined to be infiltrated and ruined by harmful ions in water due to their hydrophilicity. And the ordinary [...] Read more.

Alkali activated materials (AAMs) were considered as economical and environmentally friendly that have attracted incrementally attention as green coating materials. However, alkali activated materials were inclined to be infiltrated and ruined by harmful ions in water due to their hydrophilicity. And the ordinary ways of construct superhydrophobic coatings were costly, complex and need fluorine material. The superhydrophobic surfaces were fragile owing to the super-hydrophobicity of materials were controlled to surface merely. In this work, a facile, convenient and economical strategy to synthesize alkali activated slag materials (AAS) superhydrophobic coatings with excellent water repellence was developed. Herein, the hydrolysis and polymerization of triethoxy (octyl)silane (TTOS) were applied for generating micro/nanostructures to construct a three-dimensional overall superhydrophobic alkali activated slag materials coating. The water contact angle (CA) about surfaces and bottoms of superhydrophobic alkali activated slag materials coatings were 150.2°, 152° and the water rolling angle (SA) of surfaces and bottoms were 5°, 4° respectively. Besides, the superhydrophobic alkali activated slag materials coatings demonstrated excellent mechanical abrasion effect that still maintain super-hydrophobicity after sandpaper abrasion stand. Super-hydrophobicity of coatings could be regenerated by simple sandpaper rubbing when they were attacked chemically. Concisely, the superhydrophobic alkali activated slag materials coatings were show the benefit of affordable and feasibility so that they have the potential for expandable industrial promotion. Full article

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17 pages, 7329 KiB

Open AccessArticle

Analysis of Composite Coating of Deep Drawing Tool

by Jan Novotný, Iryna Hren, Štefan Michna and Stanislaw Legutko

Coatings 2022, 12(6), 863; https://doi.org/10.3390/coatings12060863 - 18 Jun 2022

Cited by 4 | Viewed by 1767

Abstract

Modern coating methods have become an important part of industrial practice. For some materials and operations, the use of abrasion-resistant and hard coatings is an absolute necessity; for others, they are the key to greater efficiency and productivity. The aim of this work [...] Read more.

Modern coating methods have become an important part of industrial practice. For some materials and operations, the use of abrasion-resistant and hard coatings is an absolute necessity; for others, they are the key to greater efficiency and productivity. The aim of this work was to apply and subsequently analyze a new type of thin coating micro-layers TiAlN and TiAlCN, applied using HIPIMS coating technology from a physical point of view. In particular, chemical composition (EDS) and microstructure analyses were carried out in the area of applied coatings. Prepared cross-sectional metallographic samples were evaluated using electron microscopy. A detailed microstructural characterization of the individual elements was carried out on the lamellae of the investigated sample using transmission electron microscopy. It was found that this new multilayer micro-coating based on TiAlN + TiAlCN at a thickness of 5.8 µm increases the repeatability of production strokes by 200%. This finding was confirmed by testing the production of cartridges in the real operation of a large manufacturing company. Full article

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17 pages, 5856 KiB

Open AccessArticle

Design of Photocatalytic Functional Coatings Based on the Immobilization of Metal Oxide Particles by the Combination of Electrospinning and Layer-by-Layer Deposition Techniques

by Xabier Sandua, Pedro J. Rivero, Joseba Esparza, José Fernández-Palacio, Ana Conde and Rafael J. Rodríguez

Coatings 2022, 12(6), 862; https://doi.org/10.3390/coatings12060862 - 18 Jun 2022

Cited by 6 | Viewed by 2065

Abstract

This work reports the design and characterization of functional photocatalytic coatings based on the combination of two different deposition techniques. In a first step, a poly(acrylic acid) + β-Cyclodextrin (denoted as PAA+ β-CD) electrospun fiber mat was deposited by using the electrospinning technique [...] Read more.

This work reports the design and characterization of functional photocatalytic coatings based on the combination of two different deposition techniques. In a first step, a poly(acrylic acid) + β-Cyclodextrin (denoted as PAA+ β-CD) electrospun fiber mat was deposited by using the electrospinning technique followed by a thermal treatment in order to provide an enhancement in the resultant adhesion and mechanical resistance. In a second step, a layer-by-layer (LbL) assembly process was performed in order to immobilize the metal oxide particles onto the previously electrospun fiber mat. In this context, titanium dioxide (TiO₂) was used as the main photocatalytic element, acting as the cationic element in the multilayer LbL structure. In addition, two different metal oxides, such as tungsten oxide (WO₃) and iron oxide (Fe₂O₃), were added into PAA anionic polyelectrolyte solution with the objective of optimizing the photocatalytic efficiency of the coating. All of the coatings were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) images, showing an increase in the original fiber diameter and a decrease in roughness of the mats because of the LbL second step. The variation in the wettability properties from a superhydrophilic surface to a less wettable surface as a function of the incorporation of the metal oxides was also observed by means of water contact angle (WCA) measurements. With the aim of analyzing the photocatalytic efficiency of the samples, degradation of methyl blue (MB) azo-dye was studied, showing an almost complete discoloration of the dye in the irradiated area. This study reports a novel combination method of two deposition techniques in order to obtain a functional, homogeneous and efficient photocatalytic coating. Full article

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15 pages, 3343 KiB

Open AccessFeature PaperArticle

Electrochemical and DFT Study of NaNO₂/NaNO₃ Corrosion Inhibitor Blends for Rebar in Simulated Concrete Pore Solution

by Jacob Ress, Ulises Martin, Karl Breimaier and David M. Bastidas

Coatings 2022, 12(6), 861; https://doi.org/10.3390/coatings12060861 - 18 Jun 2022

Cited by 5 | Viewed by 1979

Abstract

The use of nitrite- and nitrate-based inhibitors provides corrosion protection by the development of passive oxide film on the metal surface in reinforced concrete applications. However, the impact of the nitrite and nitrate ratio in the mixture has not been widely studied. In [...] Read more.

The use of nitrite- and nitrate-based inhibitors provides corrosion protection by the development of passive oxide film on the metal surface in reinforced concrete applications. However, the impact of the nitrite and nitrate ratio in the mixture has not been widely studied. In this study, the corrosion protection provided by NaNO₂:NaNO₃ inhibitor blends with ratios of 0.5:1, 1:1, and 1:0.5 were studied to maximize corrosion inhibition efficiency. The nitrite species imparted higher corrosion protection, as shown by cyclic potentiodynamic polarization, with an i_corr of 1.16 × 10^–7 A/cm² for the 1:0.5 mixture, lower than for both the 1:1 and 0.5:1 mixtures. Electrochemical impedance spectroscopy was also performed, with the 1:0.5 mixture consistently displaying high resistance values, showing an R_ct of 1.31 × 10⁵ Ω cm². The effect of temperature was also assessed; the E_a’s of the corrosion reaction were calculated to be 12.1, 9.2, and 4.9 kJ/mol for the 0.5:1, 1:1, and 1:0.5 (NO₂⁻:NO₃⁻) mixtures, respectively. Density functional theory was applied to analyze the molecular properties and to determine the relationship between the quantum properties and corrosion inhibition. The ΔE of NO₂⁻ was found to be −5.74 eV, lower than that of NO₃⁻ (−5.45 eV), corroborating the experimental results. Lastly, commercially available inhibitor mixtures were investigated and nitrite/nitrate concentrations determined to evaluate their corrosion protection performance; amongst the two inhibitor blends tested, Sika was found to outperform Yara due to its greater NO₂⁻ concentration. Full article

(This article belongs to the Special Issue New Trends in Surface Protection Coatings, Films and Corrosion Inhibition)

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11 pages, 5459 KiB

Open AccessArticle

Consolidation of Fragile Oracle Bones Using Nano Calcium Sulfate Hemihydrate as a Protectant

by Yan Liu, Ruicong Lu, Lu He, Ximan Wang, Lu Wang, Xinyan Lv, Kun Zhang and Fuwei Yang

Coatings 2022, 12(6), 860; https://doi.org/10.3390/coatings12060860 - 18 Jun 2022

Viewed by 1730

Abstract

Herein, a nano calcium sulfate hemihydrate suspension in an alcohol solvent was prepared and explored as a novel protectant for fragile oracle bones. The consolidation method involved first introducing the suspension and then adding water into the bones. Through this method, cohesive calcium [...] Read more.

Herein, a nano calcium sulfate hemihydrate suspension in an alcohol solvent was prepared and explored as a novel protectant for fragile oracle bones. The consolidation method involved first introducing the suspension and then adding water into the bones. Through this method, cohesive calcium sulfate dihydrate formed in the bones and can act as a reinforcing material. The protective effect was studied by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), hardness, porosity, and color difference determination. The results showed that such consolidation increased the strength of the bone samples significantly, and only slightly changed the appearance and porosity of the bone samples, indicating a good prospect for applying nano calcium sulfate hemihydrate in the conservation of indoor fragile bone relics. Full article

(This article belongs to the Special Issue Advanced Coating Material for Heritage Preservation)

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27 pages, 23055 KiB

Open AccessArticle

Effect of Si Content on Deposition and High-Temperature Oxidation of Al-Si Coatings Obtained by Magnetron Sputtering PVD Method

by Peter-Philipp Bauer, Lisa Klamann, Radosław Swadźba and Nadine Laska

Coatings 2022, 12(6), 859; https://doi.org/10.3390/coatings12060859 - 18 Jun 2022

Cited by 2 | Viewed by 1762

Abstract

Intermetallic Al-Si-based coatings can greatly increase the oxidation resistance of γ-TiAl alloys. However, the effects of the Si addition are not fully understood. Therefore, it is difficult to determine the Si content that is optimal for oxidation resistance. Therefore, pure Al and several [...] Read more.

Intermetallic Al-Si-based coatings can greatly increase the oxidation resistance of γ-TiAl alloys. However, the effects of the Si addition are not fully understood. Therefore, it is difficult to determine the Si content that is optimal for oxidation resistance. Therefore, pure Al and several Al-Si coatings with varying Si contents between 1 and 81 at.% were studied. The coatings were produced using a combinatorial magnetron sputtering process. Scanning electron microscopy and energy dispersive X-ray spectroscopy were used for structure and chemical analysis. The phases were identified by X-ray diffraction. Cyclic oxidation tests at 900 °C were conducted up to 5000 cycles of 1 h each and subsequently evaluated by thermogravimetric analysis. Si addition in the range of 1 to 12 at.% did not deteriorate the oxidation resistance compared to a pure Al coating up for 1000 cycles (1 h) of oxidation at 900 °C, while higher Si contents led to a high mass gain. For oxidation times up to 5000 cycles (1 h), a sufficient thickness of the coatings is crucial for good oxidation resistance. The main effect of Si addition is to enhance the transformation speed of the deposited Al and Si to the high temperature stable Ti(Al,Si)₃ phase during the heat treatment. Si additions of up to 12 at.% led to increased initial mass gains and a decrease in the oxidation rates during subsequent exposures compared to pure Al coatings. Full article

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14 pages, 3991 KiB

Open AccessArticle

Study on Adhesion Reliability and Particle Inhibition of Epoxy Resin Coating in DC GIL after Thermal Ageing Experiment

by Jian Wang, Zhe Wang, Renying Liu, Ruofan Xiao and Qingmin Li

Coatings 2022, 12(6), 858; https://doi.org/10.3390/coatings12060858 - 17 Jun 2022

Cited by 2 | Viewed by 1517

Abstract

The movement of metal particles is effectively inhibited when a DC GIL’s (gas-insulated transmission line) electrode is coated. This article aims to study the problem of coating falling off during GIL operation and the change in the particle-inhibitory effect after coating ageing. A [...] Read more.

The movement of metal particles is effectively inhibited when a DC GIL’s (gas-insulated transmission line) electrode is coated. This article aims to study the problem of coating falling off during GIL operation and the change in the particle-inhibitory effect after coating ageing. A closed constant temperature heating platform and a particle motion observation platform in an SF₆ atmosphere were built. The epoxy resin coating was aged for 1200 h in an SF₆ atmosphere at 160 °C. Pull-off and particle-lifting experiments were carried out for the samples. The experimental results show that the adhesion of the coating changes from rapid decline to slow decline, decreasing by 35.5%. The lifting voltage of particle startup gradually decreased, and the inhibition effect on particle activity decreased from 45.89% to 35.7%. The coating mass loss rate and surface morphology were tested to explain adhesion decline. Then, the dielectric constant, electrical conductivity and adhesion work between the coating and the particles, which are the key factors affecting the lifting of the particles, were measured. Compared with the adhesion work, the dielectric constant of the coating has a greater impact on the starting voltage. The dielectric constant of the coating decreases by 24.07%, and the conductivity increases, which weakens its inhibition of particles. After ageing, due to the decrease in the dielectric constant and the increase in the conductivity of the coating, the inhibition of coating on particles is weakened. This paper reveals the changes in coating adhesion reliability and particle inhibition in DC GIL, providing guidance for using and improving the performance of coatings in practical engineering. Full article

(This article belongs to the Special Issue Surface Modification and Surface Flashover Performance Enhancement)

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3 pages, 187 KiB

Open AccessEditorial

Synthesis and Characterization of Functional Magnetic Nanomaterials

by Ashish Chhaganlal Gandhi

Coatings 2022, 12(6), 857; https://doi.org/10.3390/coatings12060857 - 17 Jun 2022

Cited by 2 | Viewed by 1307

Abstract

Nanoscale materials have grabbed the attention of researchers from a fundamental and application point of view for over a century [...] Full article

(This article belongs to the Special Issue Synthesis and Characterization of Functional Nanomagnetic Materials)

2 pages, 178 KiB

Open AccessEditorial

New Frontiers in Novel Optical Materials and Devices

by Alexandre M. P. Botas

Coatings 2022, 12(6), 856; https://doi.org/10.3390/coatings12060856 - 17 Jun 2022

Cited by 5 | Viewed by 1387

Abstract

Optical materials can be defined as materials that are used to alter and control electromagnetic radiation in the ultraviolet, visible or infrared spectral regions [...] Full article

(This article belongs to the Special Issue New Advances in Novel Optical Materials and Devices)

14 pages, 3365 KiB

Open AccessArticle

Fluorinated-Triazole-Modified ZnO and Its Application in Marine Antifouling

by Yu Yang, Guoqing Wang, Longlin Lei, Yangkai Xiong, Zhiqiang Fang, Lei Huang, Jinbo Liu, Daxiong Hu and Jianhe Liao

Coatings 2022, 12(6), 855; https://doi.org/10.3390/coatings12060855 - 17 Jun 2022

Cited by 7 | Viewed by 1706

Abstract

The accumulation of marine biological growth has irreversible negative effects on shipping and coastal fisheries. In this paper, a new antibacterial nanofiller—triazole fluoroaromatic hydrocarbon−modified nano−zinc oxide (ZnO−APTES−TRF)—was prepared by a Cu(I)−catalyzed azide–alkyne click chemical reaction. The modification of nano−ZnO with triazole ring fluoroaromatic [...] Read more.

The accumulation of marine biological growth has irreversible negative effects on shipping and coastal fisheries. In this paper, a new antibacterial nanofiller—triazole fluoroaromatic hydrocarbon−modified nano−zinc oxide (ZnO−APTES−TRF)—was prepared by a Cu(I)−catalyzed azide–alkyne click chemical reaction. The modification of nano−ZnO with triazole ring fluoroaromatic hydrocarbons were testified by FT−IR, XPS, and EDS. The grafting rate of ZnO−APTES−TRF can reach 32.38%, which was verified by the TGA test. The ZnO−APTES−TRF was mixed with zinc acrylate resin to produce a low surface energy antifouling coating with a surface water contact angle of 106°. The bactericidal rate of ZnO−APTES−TRF against Escherichia coli, Staphylococcus aureus, and Pseudoalteromonas sp. can reach more than 98% due to the synergistic effect of triazole and fluorine. The 120−day marine experiment shows that the low surface energy antifouling coating of ZnO−APTES−TRF/ZA is expected to be widely used in the field of marine antifouling. Full article

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10 pages, 3848 KiB

Open AccessArticle

Enhanced Metal Coating Adhesion by Surface Modification of 3D Printed PEKKs

by Inwoo Baek, Chul-Min Lim, Kyoung Youl Park and Bong Ki Ryu

Coatings 2022, 12(6), 854; https://doi.org/10.3390/coatings12060854 - 17 Jun 2022

Cited by 8 | Viewed by 1886

Abstract

PEKK (polyether-ketone-ketone) polymer has been actively studied in applying electronic devices in satellites owing to its excellent light weight and thermal resistance. However, the limitation of metal coating to form on the PEKK surface is due to the high-volume resistivity and surface resistance. [...] Read more.

PEKK (polyether-ketone-ketone) polymer has been actively studied in applying electronic devices in satellites owing to its excellent light weight and thermal resistance. However, the limitation of metal coating to form on the PEKK surface is due to the high-volume resistivity and surface resistance. Here, we have investigated the correlations between the chemical treatment of the surface and adhesion strength between polymer–metal coating. Three-dimensional printed PEKK objects were manufactured and nickel was deposited on the surface by electroless plating. As the concentration of H₂SO₄ increased from 12.5 to 14.3 mol/L, the pore diameter showed a tendency to increase. However, as growing pore induced connecting each other, the pore size re-decreased from 15.1 to 18.0 mol/L. To control pore size and uniformity, we investigated the pore diameter of 3D printed PEKK as a function of treatment time and temperature. Uniform pores were observed at a temperature of 50 °C which were formed after 10 min and the average pore size was 0.28 μm. After H₂SO₄ swelling, samples were re-treated in the KMnO₄-H₃PO₄ etching system for the hydrophilic group. KMnO₄ broken C=C bonding and generated hydrophilic groups such as -COOH and -OH, the contact angle decreased from 64.7 to 51.1° compared with H₂SO₄ swelling. XPS survey spectra confirmed that not only breaking C=C bonding but also increasing hydrophilicity due to -OH, -C-, -SO3 and the catalyst absorption of Pd was improved. As a result of adhesive strength by ASTM D3359, compared with the H₂SO₄ swelling, the KMnO₄-H₃PO₄ etching system showed 5B which is the best result in standard test methods by adhesive tape test and peeling amount on the tape was less than 0.01%. Full article

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13 pages, 4727 KiB

Open AccessArticle

Simulation of Epitaxial Film–Substrate Interaction Potential

by Sergey V. Belim, Ilya V. Tikhomirov and Igor V. Bychkov

Coatings 2022, 12(6), 853; https://doi.org/10.3390/coatings12060853 - 17 Jun 2022

Viewed by 1129

Abstract

The formation of the substrate surface potential based on the Lennard-Jones two-particle potential is investigated in this paper. A simple atom’s square lattice on the substrate surface is considered. The periodic potential of the substrate atoms is decomposed into a Fourier series. The [...] Read more.

The formation of the substrate surface potential based on the Lennard-Jones two-particle potential is investigated in this paper. A simple atom’s square lattice on the substrate surface is considered. The periodic potential of the substrate atoms is decomposed into a Fourier series. The amplitude ratio for different frequencies has been examined numerically. The substrate potential is approximated with high accuracy by the Frenkel–Kontorova potential at most parameter values. There is a field of parameters in which the term plays a significant role, with a period half as long as the period of the substrate atoms. The ground state of the monoatomic film is modeled on the substrate potential. The film may be in both crystalline and amorphous phases. The transition to the amorphous phase is associated with a change in the landscape of the substrate potential. There are introduced order parameters for structural phase transition in the thin film. When changing the parameters of the substrate, the order parameter experiences a jump when changing the phase of the film. Full article

(This article belongs to the Special Issue Protective Composite Coatings: Implementation, Structure, Properties)

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1 pages, 156 KiB

Open AccessRetraction

Retraction: Zhu et al. The Effect of Vacuum Annealing Temperature on the Properties of AlCrTiSiN Coating Prepared by Arc Ion Plating. Coatings 2022, 12, 316

by Qiang Zhu, Yanmei Liu, Wanqi Cong, Dongmei Chang, Qixiang Fan, Fengting Cao and Tie-Gang Wang

Coatings 2022, 12(6), 852; https://doi.org/10.3390/coatings12060852 - 17 Jun 2022

Cited by 1 | Viewed by 1166

Abstract

The author and journal retract the article (The Effect of Vacuum Annealing Temperature on the Properties of AlCrTiSiN Coating Prepared by Arc Ion Plating) [...] Full article

12 pages, 6401 KiB

Open AccessArticle

Preparation of Core–Shell Structure W/Gd₂O₃ and Study on the Properties of Radiation Protection Materials

by Yong Xia, Tao Yang, Gangwei Pan, Sijun Xu and Lirong Yao

Coatings 2022, 12(6), 851; https://doi.org/10.3390/coatings12060851 - 17 Jun 2022

Cited by 3 | Viewed by 1533

Abstract

W/Polydopamine (PDA) was prepared by adding W powder into the dopamine (DA) solution and adjusting the pH value of the solution. PDA contains several phenolic hydroxyl and amino groups, which provide abundant active sites for the complexation of metal ions. Therefore, we prepared [...] Read more.

W/Polydopamine (PDA) was prepared by adding W powder into the dopamine (DA) solution and adjusting the pH value of the solution. PDA contains several phenolic hydroxyl and amino groups, which provide abundant active sites for the complexation of metal ions. Therefore, we prepared W/Gd₂O₃ with core–shell structure by self-assembly method and homogeneous precipitation method, respectively. At the same time, polyurethane (PU) coating fabrics with W and Gd₂O₃ mixed powder and core–shell W/Gd₂O₃ powder were prepared, and their X-ray protection performance was tested. Results show that compared with W and Gd₂O₃ mixed powder PU coating fabrics, the protection efficiency and lead equivalent of core–shell structure W/Gd₂O₃ powder PU coating fabrics against different energy rays are obviously improved. With the increase in incident energy, the protective efficiency of core–shell structure W/Gd₂O₃ powder PU coating fabric decreases more slowly than that of W/Gd₂O₃ mixed powder PU coating fabric. When the incident energy is 65–100 keV, the protective efficiency of the core–shell structure W/Gd₂O₃ powder PU coating fabric is above 60%, showing a good synergistic protective effect. When the incident energy is 83 keV, the X-ray protection efficiency of core–shell W/Gd₂O₃ powder PU coating fabric is 65.5%, and the lead equivalent is 0.4051 mmPb. Full article

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24 pages, 9344 KiB

Open AccessFeature PaperArticle

Fabrication of Efficient Gold−Nickel-Supported Titania Nanotube Electrocatalysts for Sodium Borohydride−Hydrogen Peroxide Fuel Cells

by Aldona Balčiūnaitė, Aušrinė Zabielaitė, Zita Sukackienė, Virginija Kepenienė, Dijana Šimkūnaitė, Algirdas Selskis, Loreta Tamašauskaitė-Tamašiūnaitė and Eugenijus Norkus

Coatings 2022, 12(6), 850; https://doi.org/10.3390/coatings12060850 - 17 Jun 2022

Viewed by 1754

Abstract

Here we report the optimization of the fabrication conditions for AuNi bimetallic catalysts supported on self-ordered titania nanotube arrays (AuNi-TiO₂ntb). A series of efficient AuNi-TiO₂ntb catalysts with small amounts of Au in the range of 1.74 to 15.7 μg [...] Read more.

Here we report the optimization of the fabrication conditions for AuNi bimetallic catalysts supported on self-ordered titania nanotube arrays (AuNi-TiO₂ntb). A series of efficient AuNi-TiO₂ntb catalysts with small amounts of Au in the range of 1.74 to 15.7 μg_Au·cm⁻² have been fabricated by anodization, electroless Ni plating, and galvanic displacement techniques. The electrocatalytic activity of the catalysts has been evaluated for BH₄⁻ ion oxidation in an alkaline medium using cyclic voltammetry and chronoamperometry. The performance of a NaBH₄-H₂O₂ fuel cell with Ni-TiO₂ntb and AuNi-TiO₂ntb anode catalysts has been investigated at different temperatures. It was found that the electrocatalytic activity of AuNi-TiO₂ntbs catalysts was improved remarkably when the Ni layer of 100 and 400 nm was used for the deposition of Au crystallites. The Ni-TiO₂ntb catalyst generates the maximum power density values of ca. 85–121 mW·cm⁻² at a temperature of 25–55 °C, whereas the AuNi-TiO₂ntb catalysts that have the Au loading of 3.07 and 15.7 μg_Au·cm⁻² achieve the power density values of ca. 104–147 and 119–170 mW·cm⁻², respectively, at a temperature of 25–55 °C. Full article

(This article belongs to the Special Issue New Advance in Nanoparticles, Fiber, and Coatings)

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13 pages, 3044 KiB

Open AccessArticle

Micropatterned Polypyrrole/Hydroxyapatite Composite Coatings Promoting Osteoinductive Activity by Electrical Stimulation

by Ji Xu, Yuan He, Yanan Sun, Xiuming Zhang, Yunfeng Yi, Wei Shi and Dongtao Ge

Coatings 2022, 12(6), 849; https://doi.org/10.3390/coatings12060849 - 17 Jun 2022

Cited by 3 | Viewed by 1903

Abstract

Conductive polypyrrole (PPy) has excellent biocompatibility and structural stability. It is an ideal electroactive biomaterial that can apply exogenous electrical stimulation to promote osteoblast differentiation. However, PPy is a kind of bio-inert material, which does not have osteoinductive capacity. Therefore, we have introduced [...] Read more.

Conductive polypyrrole (PPy) has excellent biocompatibility and structural stability. It is an ideal electroactive biomaterial that can apply exogenous electrical stimulation to promote osteoblast differentiation. However, PPy is a kind of bio-inert material, which does not have osteoinductive capacity. Therefore, we have introduced a kind of bioactive material, hydroxyapatite (HA), to construct PPy/HA composite to enhance bioactivity and osteoinduction. In addition, micron-topological morphology of scattered grid pattern has been designed and introduced to the PPy/HA coatings, which can further enhance the regulation ability of the coatings to the adhesion, proliferation and differentiation of MC3T3-E1 cells. In vitro simulated body fluids (SBFs) immersion test results have demonstrated that the fabricated micropatterned PPy/HA composite coatings perform bioactivity well and can promote the mineral deposition of HA on the surface. Moreover, it can also benefit the proliferation and osteognetic differentiation of MC3T3-E1 cells, when accompanied by external electrical stimulation (ES). In this study, we have successfully constructed electroactive and bioactive coatings, the method of which can potentially be applied to the surface functional modification of traditional bone repair metals. Full article

(This article belongs to the Topic Materials in Implant Applications and Regenerative Medicine)

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14 pages, 3586 KiB

Open AccessArticle

Pyrrol-Anthracene: Synthesis, Characterization and Its Application as Active Material in Humidity, Temperature and Light Sensors

by Muhammad Zeb, Muhammad Tahir, Fida Muhammad, Zahid Gul, Fazal Wahab, Mahidur R. Sarker, Mohamad Hanif Md Saad, Alamgeer, Shabina Ali, Syed Zafar Ilyas and Salman Ali

Coatings 2022, 12(6), 848; https://doi.org/10.3390/coatings12060848 - 17 Jun 2022

Cited by 5 | Viewed by 2360

Abstract

This work reports on the synthesis of small molecular semiconductor 2-(1H-pyrrol-1-yl)-anthracene-9,10-dione (PAD) via wet chemical precipitation route method for its possible potential applications in sensors. Thin film characterization of the synthesized PAD is carried out by studying its surface morphology, bond [...] Read more.

This work reports on the synthesis of small molecular semiconductor 2-(1H-pyrrol-1-yl)-anthracene-9,10-dione (PAD) via wet chemical precipitation route method for its possible potential applications in sensors. Thin film characterization of the synthesized PAD is carried out by studying its surface morphology, bond dynamics, and optical properties. For studying sensing characteristics of the PAD, its 100 nm thick film is thermally deposited on pre-patterned silver (Ag) electrodes over glass substrate having ~45 µm inter-electrode gaps to prepare Ag/PAD/Ag sensor. The effects of humidity (%RH), temperature (T), and illumination of light (E_v) on the fabricated Ag/PAD/Ag sensor are studied by changing one of the three (%RH, T, and E_v) parameters at a time and measuring the corresponding variations in capacitance (C) and capacitive reactance (X) of the device. As C and X also depend on frequency, sensing properties of the Ag/PAD/Ag sensor are measured at two different frequencies (120 Hz and 1 kHz) to find the optimum sensitivity conditions. To investigate reproducibility and repeatability of Ag/PAD/Ag sensor, each measurement is taken several times and also hysteresis loops of %RH vs. C are plotted at 120 Hz and 1 kHz to find the percent errors in each cycle of measurements. The sensor is active to sense humidity, temperature, and illumination within a broad range, i.e., from 15–93%RH, 293–382 K, and 1500–20,000 lx, respectively. Other key parameters of the sensor i.e., the humidity response time (T_Res) and recovery time (T_Rec), are measured, which are 5 and 7 s, respectively, whereas for light sensing the values of T_Res and T_Rec are measured to be 3.8 and 2.6 s, respectively. The measured values of T_Res and T_Rec for the fabricated Ag/PAD/Ag sensor are shorter and better as compared to those of previously reported for similar kind of small molecular based sensors. The sensing properties of Ag/PAD/Ag device exhibit the potential of PAD for humidity, temperature, and light sensing applications. Full article

(This article belongs to the Special Issue Functionalities of Polymer-Based Nanocomposite Films and Coatings)

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4 pages, 192 KiB

Open AccessEditorial

Special Issue: Advances in Corrosion Resistant Coatings Volume II

by Yong X. Gan

Coatings 2022, 12(6), 847; https://doi.org/10.3390/coatings12060847 - 17 Jun 2022

Viewed by 1280

Abstract

Among the various corrosion prevention methods as described in [...] Full article

(This article belongs to the Special Issue Advances in Corrosion-Resistant Coatings, 2nd Edition)

16 pages, 67340 KiB

Open AccessArticle

Contamination of Substrate-Coating Interface Caused by Ion Etching

by Peter Panjan, Aljaž Drnovšek, Miha Čekada and Matjaž Panjan

Coatings 2022, 12(6), 846; https://doi.org/10.3390/coatings12060846 - 16 Jun 2022

Cited by 3 | Viewed by 2257

Abstract

In–situ cleaning of the substrate surface by ion etching is an integral part of all physical vapor deposition (PVD) processes. However, in industrial deposition systems, some side effects occur during the ion etching process that can cause re-contamination. For example, in a magnetron [...] Read more.

In–situ cleaning of the substrate surface by ion etching is an integral part of all physical vapor deposition (PVD) processes. However, in industrial deposition systems, some side effects occur during the ion etching process that can cause re-contamination. For example, in a magnetron sputtering system with several sputter sources and with a substrate holder located centered between them, the ion etching causes the contamination of the unshielded target surfaces with the batching material. In the initial stage of deposition, this material is redeposited back on the substrate surface. The identification of the contamination layer at the substrate–coating interface is difficult because it contains both substrate and coating elements. To avoid this problem, we prepared a TiAlN double coating in two separate production batches on the same substrate. In such a double-layer TiAlN hard coating, the contamination layer, formed during the ion etching before the second deposition, is readily identifiable, and analysis of its chemical composition is easy. Contamination of the batching material was observed also on seed particles that caused the formation of nodular defects. We explain the origin of these particles and the mechanism of their transfer from the target surface to the substrate surface. By comparison of the same coating surface area after deposition of the first and second TiAlN layers, the changes in coating topography were analyzed. We also found that after the deposition of the second TiAlN coating, the surface roughness slightly decreased, which we explain by the planarization effect. Full article

(This article belongs to the Special Issue Surface Topography Effects on Functional Properties of PVD Coatings)

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18 pages, 10378 KiB

Open AccessFeature PaperArticle

Effect of Negative Bias of HiPIMS and AIP Hybrid Deposition on Microstructure, Mechanical and Anti-Corrosive Properties of Cr₂N/TiN Multilayer Coatings

by Rong Tu, Yang Yuan, Mai Yang, Rui Min, Jiao Jiao, Qizhong Li, Meijun Yang, Baifeng Ji and Song Zhang

Coatings 2022, 12(6), 845; https://doi.org/10.3390/coatings12060845 - 16 Jun 2022

Cited by 2 | Viewed by 1952

Abstract

Multi-layered nitride coatings have been widely applied to improve the mechanical and anti-corrosive of metals and/or alloys. Cr₂N/TiN multilayer coatings were prepared by the combination of high-power pulsed magnetron sputtering (HiPIMS) and arc ion plating (AIP). The Cr₂N layer [...] Read more.

Multi-layered nitride coatings have been widely applied to improve the mechanical and anti-corrosive of metals and/or alloys. Cr₂N/TiN multilayer coatings were prepared by the combination of high-power pulsed magnetron sputtering (HiPIMS) and arc ion plating (AIP). The Cr₂N layer was co-deposited by HiPIMS and AIP, while the TiN layer was deposited by a single HiPIMS. With increasing the negative bias voltage (V_s) on substrate up to −100 V, the number and size of the droplets decreased; the average grain size of the coatings decreased from 9.4 to 7.5 nm and the hardness increased from 21.5 to 25.1 GPa, and the level of the adhesion of the coatings has reached HF1. The coatings obtained at V_s = −100 V present the best corrosion resistance in NaCl aqueous solution based on the anodic polarization curves and EIS spectroscopy. Full article

(This article belongs to the Topic Inorganic Thin Film Materials)

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9 pages, 2165 KiB

Open AccessArticle

Metal-Organic Framework Fabricated V₂O₅ Cathode Material for High-Performance Lithium-Ion Batteries

by Jay Singh, Kichang Hong, Younggwon Cho, M. Shaheer Akhtar, Jungwon Kang and Alok Kumar Rai

Coatings 2022, 12(6), 844; https://doi.org/10.3390/coatings12060844 - 16 Jun 2022

Cited by 1 | Viewed by 1903

Abstract

In this article, oval-shaped V₂O₅ nanoparticles were hydrothermally synthesized using a metal-organic framework (MOF), which was then followed by calcination under an air atmosphere. The obtained sample was characterized through various characterization techniques to determine the sample purity and the [...] Read more.

In this article, oval-shaped V₂O₅ nanoparticles were hydrothermally synthesized using a metal-organic framework (MOF), which was then followed by calcination under an air atmosphere. The obtained sample was characterized through various characterization techniques to determine the sample purity and the structural and morphological details. Since V₂O₅ possesses a layered crystal structure, it exhibits promising electrochemical performances as a cathode material for lithium-ion battery applications. However, poor cycling and inferior rate capabilities are the major issues that limit its application. Thus, a strategy to fabricate unique oval-shaped V₂O₅ nanoparticles was employed here to improve electrochemical performances using an MOF, which acts as a template and provides a skeleton for the growth of a novel nanostructure. It is believed that the oval-shaped morphology is beneficial to achieving better electrochemical results due to the large surface area and the existence of numerous channels for lithiation and de-lithiation. The obtained electrochemical result reveals that the V₂O₅ electrode can be considered a prominent cathode material for next-generation lithium-ion battery applications. Full article

(This article belongs to the Collection Feature Papers of Coatings for Energy Applications)

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