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Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coatings & Protection / Tuceng yu Fanghu is the property of Coating & Protection Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, two classes of surface pre-treatment methods, namely three blast-cleaning methods with different abrasive materials (for initial preparation) and three mechanical methods (for repair applications) were applied to study their effects on surface morphology, composition, and corrosion of AA6082 substrates in artificial seawater. Coating adhesion and coating corrosion protection ability were investigated by applying a single-layer epoxy coating (250 μm dry film thickness) onto the substrates.The mechanical methods delivered cleaner surfaces with more regular surface morphologies, whereas the blast-cleaning methods revealed less clean surfaces and more irregular surface morphologies. The latter methods promoted the detrimental embedment of abrasive particles into the substrates. The corrosion performance of the pre-treated substrates was worse after blast-cleaning compared to mechanical treatments. However, all methods met the adhesion requirements for offshore applications. Regarding coating degradation, only the filiform corrosion test delivered meaningful results, whereas the duration of the cyclic corrosion test (3000 h) was too short to distinguish between the different methods because of neglectable degradation. Mechanical interlocking and isotropic surface morphologies are found to be more important for coating performance than a cleaner surface, and the remains of blasting material were neglectable too.

This contribution presents the results of research focused on changes in selected properties of organic-coated steel sheets in a corrosive environment of salt mist. The aim of this study was to characterise coated sheets and to analyse the influence of elevated temperature on changes in their selected properties. The methodology and experiments were chosen to simulate the accelerated ageing and to evaluate the surface of organic-coated steel sheets. During the research, the effect of artificial ageing due to increased temperature on changes in mechanical properties of coated sheets was monitored, which were determined by tensile testing according to STN EN 10002-1. The fracture surface of the test samples was analysed using a SEM. The following observations were made for the evaluation of coating by cross-cut tests according to EN ISO 2409. Corrosion tests were carried out by conducting salt spray corrosion tests according to EN ISO 9227. The test specimens were artificially sectioned using a laser beam. The results of the research experiments confirmed the assumption that the utilisation of the laser beam was convenient for the creation cross–cut test of the material. After the ageing test, only small significant changes in the basic mechanical properties of the tested materials were observed. It is necessary to take into account that there were changes in the appearance of the coating. The cross-cut test confirmed the results that the plastic-coated sheets could be utilised in salt corrosion environments. [ABSTRACT FROM AUTHOR]

Copyright of Coatings & Protection / Tuceng yu Fanghu is the property of Coating & Protection Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Display omitted] • Developing surface structuring of Al current collectors for battery application. • Developing crack formation on the electrodes to enhance electrolyte diffusion. • Improving electrode adhesion using structured Al current collectors. • Crack formation enabling fast charging-rates and battery cycle life. Today's society and economy demand high-performance energy storage systems with large battery capacities and super-fast charging. However, a common problematic consequence is the delamination of the mass loading (including, active materials, binder and conductive carbon) from the current collector at high C-rates and also after certain cycle tests. In this work, surface structuring of aluminum (Al) foils (as a current collector) is developed to overcome the aforementioned delamination process for sulfur (S)/carbon composite cathodes of Li-S batteries (LSBs). The structuring process allows a mechanical interlocking of the loaded mass with the structured current collector, thus increasing its electrode adhesion and its general stability. Through directed crack formation within the mass loading, this also allows an enhanced electrolyte wetting in deeper layers, which in turn improves ion transport at increased areal loadings. Moreover, the interfacial resistance of this composite is reduced leading to an improved battery performance. In addition, surface structuring improves the wettability of water-based pastes, eliminating the need for additional primer coatings and simplifying the electrode fabrication process. Compared to the cells made with untreated current collectors, the cells made with structured current collectors significantly improved rate capability and cycling stability with a capacity of over 1000 mAh g−1. At the same time, the concept of mechanical interlocking offers the potential of transfer to other battery and supercapacitor electrodes. [ABSTRACT FROM AUTHOR]

The electrical insulating, adhesive, and moisture-protective properties of thixotropic compounds of the KTT brand have been studied in the initial state under normal climatic conditions, as well as under prolonged exposure to high temperatures and environmental humidity. The research results allow one to recommend KTT brand compounds for their use in the processes of protection and sealing of microelectronics products, electronic equipment, and radio electronic equipment. [ABSTRACT FROM AUTHOR]

The effects of solution treatment on the corrosion resistance and cytocompatibility of micro-arc oxidation (MAO) coating on biodegradable Mg-2Zn-1Gd-0.5Zr alloy were studied in this work. Microstructural characterization, coating adhesion, electrochemical, immersion and cytocompatibility tests were carried out. The results demonstrated that the MAO coating was much more uniform after solution treatment with coating adhesion enhanced by about 30% compared with the as-extruded + MAO coated. Moreover, the corrosion resistance of the solution treated + MAO coated samples was respectively improved by more than 20% and twice, compared with as-extruded + MAO coated and as-extruded samples. In addition, solution treatment further improved the cell viability of the MAO coating of the alloy with the RGR exceeding 90% during the entire culture period with MG63 cells. Consequently, solution treatment is recommended as a preferred pretreatment for improving the corrosion resistance and cytocompatibity of MAO-coated Mg alloys. [ABSTRACT FROM AUTHOR]

The article presents the outcomes of industrial testing of technologies for final finishing of elastic leathers with natural and polished surfaces. The quality of technological processes for finishing leather was assessed using a comprehensive set of qualitative and quantitative indicators. The degree of adhesion of the resultant polymer coating to the leather surface was quantified. The impact of technological finishing processes on the alteration in the hygienic properties of semi-finished leather products was investigated. The physical and mechanical properties of the resulting leathers were examined for their technological appropriateness and compliance with the stipulations of regulatory and technical documentation. It was determined that the technologies tested for finishing the front surface of semi-finished leather products enable the production of high-quality finished leather, satisfying most criteria outlined in regulatory documents. Recommendations were formulated for optimizing the technology of finishing semi-finished leather products to enhance the quality attributes of finished leather. The industrial application of the tested technology will significantly augment production efficiency, expand the product range and generate additional profit from the production and sale of new products that are in demand on the market.

Copyright of Silicone Material is the property of Silicone Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Multiprocess additive manufacturing (MPAM) unlocks new materials and design spaces where multimaterial components consisting of polymers, metals, and ceramics can be produced as one consolidated part. MPAM enables state-of-the-art 3D-printed electronics and devices with embedded functionality by combining fused deposition modeling with chemical deposition and electroplating processes. However, the metalized plastic devices produced by these processes have a short lifespan because of their poor structural integrity due to the low adhesion at the metal-polymer interface. In this study, we elaborated on the adhesion mechanism at the 3Dprinted metal-polymer interface and identified the MPAM factors that elevated significantly the integrity of metalized plastic components. The effects of the 3D-printed surface texture and surface treatment on the adhesion strength of copper plated on acrylonitrile-butadiene-styrene parts were analyzed. We found that a certain 3D-printed topography modified by quick acid etching created a hierarchically structured interface with superimposed macroscale, microscale, and nanoscale roughness that symbiotically improved the metal-polymer adhesion. These results have practical implications for automated equipment manufacturers and the electronic industry adapting MPAM for the 3D printing of multimaterial components and devices with embedded functionality. [ABSTRACT FROM AUTHOR]

Electrochemical plating is the most widely used coating process for metalizing commodity polymers, such as acrylonitrile–butadiene–styrene (ABS). Conventionally, ABS polymer is pretreated in concentrated sulfochromic acid solution before plating to develop a highly porous surface topography that ensures coating adhesion. Unfortunately, using chromic acid produces extremely hazardous chemical waste, which costs manufacturers millions of dollars in fines. This study proposes a threefold greener route by employing a newly developed in-mold patterning of polymeric parts before plating. We hot-embossed micron-sized dimples on the ABS polymer and acid-etched it for as short as 1 min to obtain a hierarchical micro–nanotextured surface. The coating adhesion on such surfaces appeared to be two times higher as compared to the conventional electroplating, while the etching time was reduced three times. Microscopic characterization of the fracture surfaces revealed that the adhesion strength at the hierarchically structured interface exceeded the strength of the ABS polymer, causing a cohesive crack in the polymer far below the interface when peeling the plated metallic film. These results imply that the use of toxic acids in the electroplating industry can be drastically reduced by the proposed hybrid preparation method without sacrificing the coating quality.

The paper deals with the actual topic of mechanical properties of 3D prints made from the polymer material rPET-G and its changes. Using this material in additive technology has great potential in the automotive industry. The research evaluates five different post-processing modifications of 3D prints from rPET-G (recycled polyethylene terephthalate-glycol) material produced by the Fused Filament Fabrication technology. The post-processing included the chemical smoothing of the samples using dichloromethane vapors and heat treatment in an annealing furnace. An epoxy resin, a synthetic coating, and a water-based coating were also applied. The standard was represented by samples without post-processing modifications, both in the form of recycled material and in the form of virgin PET-G. The texture of the samples was evaluated according to EN ISO 4287. Furthermore, the moisture absorption of the samples was evaluated using the gravimetric method according to EN ISO 62. The mechanical testing of the samples was carried out using a tensile test (EN ISO 527-2), a three-point bending test (EN ISO 178), impact strength (EN ISO 179-2), and a cupping test (EN ISO 1520). Degradation of the coatings took place using cyclic tests, which used a combination of exposure in a salt fog environment and in a climate chamber. The results of the experiments indicate that heat treatment appears to be a universal post-processing technology, as this method statistically improves not only the mechanical properties but also significantly reduces moisture absorption. [ABSTRACT FROM AUTHOR]

Although coating the biomaterials with hydroxyapatite powder (HAp) mixed electro discharge machining (EDM) is required to improve their biological responses, the modified 316L stainless steel shows a low coating adhesion and cracked surface, which is prone to poor corrosion resistance and surface integrity. In addition, inferior biological responses are noticed, since a little amount of HAp is detected in the coating. The primary objective of this study is to assess the CNT reinforced HAp-based coating on a 316L stainless steel to improve the surface features, corrosion and biocompatibility. This study also establishes a link between the process variables and the material's properties and shows the feasibility of multiple additive mixed EDM method. Following ASTM standard, several surface characterization tools were used to characterize the surface of the modified 316L stainless steel. CNT (0.4 g/l) added to the HAp mixed-EDM method results in a uniform and thin coating of 12.4 µm with shallow craters, nanopores and no cracks. A small corrosion rate of 0.00033 mm per annum is recorded. The presence of carbon incorporated Ca–P-based alloys in the coating ensures a high coating adhesion of 32.6 MPa and a high biocompatibility of more than 95% alive cells. [ABSTRACT FROM AUTHOR]

Diamond-coated tools often fail due to coating graphitization and delamination caused by poor coating adhesion, large contact stress, and thermochemical reactions. To address these issues, this research utilized a combination of micro-nano double-layer diamond coating, WS2 coating, and micro-textures. The WS2 coating inhibits the graphitization of the diamond coating through a transfer film mechanism, while the micro-textures and nanocrystalline diamond coating store WS2, resulting in a prolonged lubrication life. Additionally, the influence of micro-texture on coating-substrate residual stress and coating-substrate mechanical interlocking was discussed, and it was proved that proper micro-textures effectively improve the coating adhesion. Under the same cutting flux conditions, taking coating peeling as the judging standard, the cutting distance of textured WS2/Micro-Nano diamond coating tool is more than three times that of ordinary, diamond-coated tools, which greatly improves the service life of the tool. [ABSTRACT FROM AUTHOR]

Atmospheric pressure plasma (AP) treatment, using an open-air jet of ionized CO2, N2, or air, was applied to AZ91D Mg alloy surfaces to investigate its effects on primer coating adhesion and corrosion resistance. The CO2 and air AP treatments formed an O- and C-rich surface layer (Mg-O-C) consisting of agglomerated nanoparticles and pits with a depth of a few microns and increasing the surface roughness by 6–8 times compared with the reference 600 grit-finished surface. Then, three commercial primers, zinc phosphate (ZnP), chromate-containing epoxy, and MIL23377, were applied on the treated surfaces to evaluate the corrosion resistance associated with the coating adhesion. Microscopic analysis demonstrated stronger interlocking between the primer layer and the nano-/microrough Mg-O-C surface compared to the untreated (600 grit-finished) surfaces, indicating improved coating adhesion and corrosion resistance. Crosscut tests of the MIL23377 primer on the CO2 and air AP-treated surfaces showed the highest level of adhesion, ASTM class 5B. Salt spray corrosion tests showed that after 8 days of exposure, the primer coatings on air AP-treated surfaces had corrosion areas that were more than four times smaller than that of the 600 grit-finished surface. The N2 AP treatment showed similar adhesion enhancement. The preliminary operation expenses for AP treatment using CO2, N2, and air were estimated at USD 30.62, USD 35.45, and USD 29.75 (from an air cylinder)/USD 0.66 (from an air compressor) per m2, respectively. [ABSTRACT FROM AUTHOR]

Biomedical implants interact with human tissues introducing significant perturbation into the body. Implant surfaces can be then functionalized enabling better biocompatibility. At the same time, the additional use of a coating provides further functions such as corrosion protection, osteointegration, and drug delivery. In this context, a composite made of chitosan and bioactive glass nanoparticles has been used for coating Ti6Al4V alloy samples processed beforehand using different processes, i.e., polishing, milling, grit blasting, and electrical discharge machining. Experiments have been carried out to correlate substrate surface conditions and coating effectiveness in terms of scratch resistance with the final aim to obtain suitable guidelines to improve substrate-coating performances. [ABSTRACT FROM AUTHOR]

Currently, methods of thermal spraying are widely used to restore and harden various worn parts of machines. In most cases, metal and composite wires are used as materials for gas-thermal coating applying methods. As a rule, metal coatings applied by thermal spraying have lower strength characteristics than cast materials. An important factor characterizing the possibility of using metal coatings in various industries is their density and adhesion strength of coatings with the base metal. In this paper, the structure and density of coatings, as well as the adhesion strength of coatings made of steel and titanium wires deposited by hypersonic metallization were studied.

The paper content is focused on the various evaluation methods of mechanical pre-treatment of hot-dip galvanized surface performed in order to increase the organic paint adhesion (both synthetic and waterborne). Emphasis was placed on low volatile organic compounds (VOC) values in coating systems. Corrosion degradation of the tested coatings was also monitored. The mechanical surface pre-treatment was performed using a standard technology, so-called sweeping, with synthetic corundum with F40 grain size (these samples served as a standard). Alternative methods that can be used in operations without blasting equipment were also investigated. These included regrinding with two different grain sandpapers (P40 and P100) and regrinding with a corrosion resistant steel brush (wire diameter 0.3 mm). The surface texture was evaluated in accordance with the ČSN EN ISO 4287 standard. Corrosion-mechanical resistance was evaluated by a pull-off adhesion test (according to the ČSN EN ISO 4624 standard) and in a salt spray environment (according to the ČSN EN ISO 9227 standard). Based on the obtained results, mechanical pre-treatment with a corrosion resistant steel brush and possibly P100 grit sandpaper can be recommended, as pre-treatment with these tools showed statistically the best corrosion-mechanical properties.

Polyetheretherketone (PEEK) and its fiber-reinforced materials are thermoplastic polymer materials with broad application prospects. Depositing Ni-P alloy on them can improve their poor conductivity and electromagnetic shielding performance, and further expand their application field. The application effect of the plated parts is significantly impacted by the bonding strength between PEEK and coating. The bonding strength between non-metallic substrate and coating is largely influenced by the surface characteristics of the substrate. Therefore, it is significant to study how the surface roughness of PEEK materials and the modified fibers in materials affect the adhesion of the coating. In this study, Ni-P alloy was electroless deposited on PEEK, 30% carbon-fiber-reinforced PEEK (CF30/PEEK), and 30% glass-fiber-reinforced PEEK (GF30/PEEK) with varying surface roughness. The influence of surface roughness and modified fibers on the coating adhesion was studied. Additionally, the effect of the concentrations of nickel sulfate, sodium hypophosphite, pH, and temperature on the deposition rate of the coating was investigated for the three materials. Based on the highest deposition rate, the process parameters were then optimized. The results demonstrated that as surface roughness increased, adhesion between substrate and coating first increased and then decreased. The surface roughness Ra of 0.4 μm produced the highest coating adhesion. Additionally, fiber-reinforced PEEK adhered to coatings more effectively than PEEK did. The mechanism of the difference in bonding strength between different PEEK-modified materials and coatings was revealed. The optimal process parameters were: nickel sulfate: 25 g/L, sodium hypophosphite: 30 g/L, pH: 5.0, and temperature: 70 °C. [ABSTRACT FROM AUTHOR]

The applicability of galvanized products in various industries has increased the demand for highly corrosion-resistant coatings to counter harsh environments. Among these, Zn–Mg–Al ternary alloy coatings have excellent corrosion resistance, resulting in their commercialization and industrial demand. To increase the diversification of their products, the ideal flux composition in these coatings should be optimized. In this study, we investigated the effects of conventional flux (ZnCl2:NH4Cl) in the hot-dip galvanization of Zn–Mg–Al ternary alloy coatings. Additionally, we developed a new flux to improve the coating properties of Zn–Mg–Al ternary alloy coatings on steel sheets. During hot dipping, SnCl2 on the steel substrate decomposed faster than conventional flux, thereby eliminating the AlCl3 residues in the coating and surface defects. The thermogravimetric-differential thermal analysis studies unveiled the mechanisms for improved coatings. The thermodynamic calculations confirmed the spontaneous substitution owing to the presence of SnCl2 in the flux. Therefore, the developed and optimized flux enhanced the adhesion of the alloy coating. [ABSTRACT FROM AUTHOR]

Bamboo scrimber refers to a lignocellulosic structural material, which is usually attacked by water, ultraviolet radiation and fungus. Surface coating is an effective way to protect it, and its coating properties depend on surface wettability. In this study, the surface wettability of bamboo scrimbers with varying resin content was investigated via the comprehensive analysis of surface roughness, surface contact angle, surface free energy, surface chemical composition and coating properties. The resultant scrimbers had a similar profile with low roughness. Their surface was hydrophilic, but the hydrophilicity decreased with the increase in resin content. High resin content gave rise to low total free energy, in which the Lifshitz–van der Waals component was dominant and it decreased with the increasing resin content. Meanwhile, the ratio of the electron-accepting component to the electron-donating component becomes higher. This was due to the decreasing hydrophilic groups (e.g., -OH and -COOH groups) and the increasing oxygen-free groups (e.g., C-H and -CH2 groups) on the scrimber surface. The resin content affected the adhesion by decreasing the surface wettability, but the coating adhesion still reached the level of 2 for all bamboo scrimbers. The results will provide a theoretical reference for the surface coating of bamboo scrimbers in the structural application for good coating durability. [ABSTRACT FROM AUTHOR]

A PVD coating is often applied on the surface of metallic alloys to improve their high-temperature resistance. In the present work, a thin titanium layer (1.2 µm) was deposited by PVD on the surface of a stainless steel substrate before high-temperature exposure (800 °C in ambient air). The underlying idea is that metallic Ti converts into Ti oxide (TiO2) during high-temperature aging at 800 °C, thereby slowing down the substrate oxidation. The stability of the coating with and without substrate pre-oxidation was investigated. Morphological, structural, and chemical characterizations were performed and completed by simulation of the film growth and measurement of the mechanical state of the film and the substrate. In the case of the sample that was not pre-oxidized, the oxidation of the steel was slowed down by the TiO2 scale but spallation was observed. On the other hand, when the steel was pre-oxidized, TiO2 provided more significant protection against high-temperature oxidation, and spalling or cracking did not occur. A combination of different kinds of stress could explain the two different behaviors, namely, the mechanical state of the film and the substrate before oxidation, the growing stress, and the thermal stress occurring during cooling down. [ABSTRACT FROM AUTHOR]

. It is known that at present, methods of thermal spraying are widely used to restore and strengthen various worn-out machine parts. As a rule, metal coatings applied by thermal spraying have lower strength characteristics than solid materials. It is believed that the strength of coatings is proportional to their adhesive and cohesive strength. The value of adhesive and cohesive strength depends on various factors, including the nature of the materials and the technology of coating. An important factor characterizing the possibility of using metal coatings in various industries is the strength of adhesion of coatings to the base metal. The paper presents the determination of the adhesive and cohesive strength of coatings from different materials, applied by the method of hypersonic metallization. The results of testing the strength of metal coatings made of ER316LSi-grade wire, nichrome (Cr20Ni80) and molybdenum wire are given in the paper. Based on the results of metallographic studies, the proportion of the participation of cohesive and adhesive components in the strength of coatings has been determined, and some features of coating destruction have been described. It has been found that the participation of the cohesive and adhesive components of the coating strength differs depending on the material used. The cohesive component prevails in the strength of coatings made of high-alloy wire of the ER316LSi-grade, at which destruction mainly occurs along the coating-base boundary. For nichrome coatings and especially for coatings made of molybdenum, the cohesive component is predominant, in which the destruction of the coating occurs not along the coating-base boundary, but between the coating layers.

Polymers and their composites are widely used for designing structures in aerospace, automotive, electronic, sport industries due to their lightweight, cost, and processing advantages. However, the surface of polymeric materials typically exhibits intrinsic deficiencies, limiting their durability and functionalities, e.g., low wear resistance, low thermal and electrical conductivity, low adhesion, low bioactivity, low reflectiveness, and weak photochemical resistance. Polymer metallization is an emerging concept that addresses these deficiencies by forming a metallic skin on polymeric surfaces. Herein, the working principles, recent advances, challenges, functional capabilities, and applications of the state-of-the-art polymer metallization methods in the fields of additive manufacturing, coating technologies, and material science are reviewed on nano-, micro-, and macroscales. The polymer metallization methods applied to polymeric and polymer composite substrates are physical vapor deposition, electrochemical plating, a family of thermal spray methods (such as flame spaying, arc spraying, plasma spraying, and cold spraying), and a series of polymer–metal direct bonding methods (such as adhesive bonding, injection overmolding, and fusion joining techniques, including ultrasonic joining, friction spot joining, electromagnetic induction joining, and laser joining). Understanding the key aspects within these approaches would guide scientist and engineers for optimizing the design and durability of structural materials made of polymers/composites.

The paper deals with the actual topic of mechanical properties of 3D prints made from the polymer material rPET-G and its changes. Using this material in additive technology has great potential in the automotive industry. The research evaluates five different post-processing modifications of 3D prints from rPET-G (recycled polyethylene terephthalate-glycol) material produced by the Fused Filament Fabrication technology. The post-processing included the chemical smoothing of the samples using dichloromethane vapors and heat treatment in an annealing furnace. An epoxy resin, a synthetic coating, and a water-based coating were also applied. The standard was represented by samples without post-processing modifications, both in the form of recycled material and in the form of virgin PET-G. The texture of the samples was evaluated according to EN ISO 4287. Furthermore, the moisture absorption of the samples was evaluated using the gravimetric method according to EN ISO 62. The mechanical testing of the samples was carried out using a tensile test (EN ISO 527-2), a three-point bending test (EN ISO 178), impact strength (EN ISO 179-2), and a cupping test (EN ISO 1520). Degradation of the coatings took place using cyclic tests, which used a combination of exposure in a salt fog environment and in a climate chamber. The results of the experiments indicate that heat treatment appears to be a universal post-processing technology, as this method statistically improves not only the mechanical properties but also significantly reduces moisture absorption.

Diamond-coated tools often fail due to coating graphitization and delamination caused by poor coating adhesion, large contact stress, and thermochemical reactions. To address these issues, this research utilized a combination of micro-nano double-layer diamond coating, WS2 coating, and micro-textures. The WS2 coating inhibits the graphitization of the diamond coating through a transfer film mechanism, while the micro-textures and nanocrystalline diamond coating store WS2, resulting in a prolonged lubrication life. Additionally, the influence of micro-texture on coating-substrate residual stress and coating-substrate mechanical interlocking was discussed, and it was proved that proper micro-textures effectively improve the coating adhesion. Under the same cutting flux conditions, taking coating peeling as the judging standard, the cutting distance of textured WS2/Micro-Nano diamond coating tool is more than three times that of ordinary, diamond-coated tools, which greatly improves the service life of the tool.

In this paper, the tin coating layer is utilized as a solid lubricant for the cold steel tube drawing process. The effect of different thicknesses of tin coatings as a tribo-layer has been investigated. The electroplating process has been used for depositing a tin coating layer by deploying an environmentally benign citric acid–based electrolyte bath and the layer thickness is controlled by varying the time of the electroplating process. Characterization of the coating layer is carried out using SEM, EDS, and 3D digital microscopy techniques. Experimental trials of the tube drawing process have been conducted for tin-coated tubes and the effects on drawing force and surface roughness have been analyzed. The draw force gradually decreases and reaches a minimum value as the tin layer thickness increases from 4.5 to 16.5 μm, while for further increase in layer thickness, the draw force increases again, yielding an optimal tin layer thickness of around 16.5 μm. The drawn tube samples are found to have a superior surface finish with roughness (Ra) as low as 0.165 μm even for the smallest tin coating thickness of around 5 μm while it improves marginally up to 0.134 μm when the tin layer thickness is increased gradually to around 25.7 μm. A sizeable thickness of tin coating is retained on the drawn tube, which enhances the surface appearance as well as corrosion resistance. The tape adhesion test was carried out as per the ASTM D3359 standard and it confirmed the adequacy of adhesion of the coating on the drawn tubes. Also, comparison of draw force variation with the well-known Stribeck curve and the insights into the working mechanism of soft metal as a lubricant are presented. [ABSTRACT FROM AUTHOR]

High heat generation with the consequent increase in temperature is still a limiting factor for productivity and quality in machining processes. Cutting Fluids in Abundance -- CFA is the standard Lubri-cooling technique to avoid high temperatures problems. However, cutting fluids, particularly those of mineral base, bring substantial environmental and human health problems as they are toxic. Coatings are a very used method to protect the tool during machining mainly prolonging its useful life. Due to the great industrial applicability of coatings, there is a growing need to understand the fundamental properties of these thin films and how they act in protecting a surface. The study of coatings has a multidisciplinary aspect since it involves the knowledge of their chemical, physical and tribological properties. The aim of this work was to compare the coating adhesion through the Calowear test, on ISO K grade carbide inserts coated with TiAlN-Futura®, AlCrN-Alcrona®, and AlCrN-Helica®, textured by blasting and by laser-jetting. The results showed higher abrasive wear resistance of the AlCrN-Helica coating, in comparison to TiAlN-Futura® and AlCrN-Alcrona®, the latter having the least advantage. On average, the coatings wear coefficients of the deposited laser textured substrates were lower than those of the blasted substrates. [ABSTRACT FROM AUTHOR]

A two-component organosilicon composition of KKP-grade compound has been developed based on a binary system of polymers, a block copolymer of linear-ladder structure containing linear polydimethylsiloxane and ladder phenylsilsesquioxane links, and an epoxy-organosilicon resin that represents a product of epoxy resin modification. A solution of aluminum acetylacetonate in triethoxysilane has been used as a curing system. It is shown that the developed compound, as concerns electric-insulating and moistureproof properties; adhesion to silicon, aluminum, and copper; and the absence of corrosive impact on aluminum and copper, as well as due to having a minimum content of ionic impurities, is superior to such domestic analogues as the EP-9114 varnish and UR-231 varnish widely used as moisture-protective coatings in manufacturing electronic equipment and electronic components. [ABSTRACT FROM AUTHOR]

The wear resistance of coated cutting tools depends to a large extent on adhesion of applied PVD coatings. The adjustment of the surface roughness as well as the residual stresses of the sub-surface of the substrate thus represents a decisive step in tool manufacturing. For this reason, the conditioning of the surface and sub-surface constitution of ultrafine grain cemented carbide specimens via pressurized air wet abrasive jet machining (PAWAJM) was investigated in analogy tests. Regarding the coating adhesion of an applied TiAlN-PVD coating, relevant potentials resulted from the preparation via PAWAJM, especially with the finer abrasive F500 (Al2O3) at low blasting angles and high pressures. [ABSTRACT FROM AUTHOR]

The aim of this research was to study the effect of temperature on the adhesion and disinfection activities of an Ag+-doped BiVO4 (Ag+/BiVO4) coating. Ag+/BiVO4 was prepared by a sol–gel method, and spraying was used as the deposition method of coating. X-ray diffraction patterns showed that the monoclinic scheelite phase of the samples was unchanged by annealing at 450–650 °C. Scanning electron microscopy results showed that, at high temperatures, the particles melted and formed a dense coating, and the roughness of the coating decreased after initially increasing. The adhesion and disinfection activities were evaluated by ASTM D3359-08 and disinfection experiments. The results showed that the samples modified by silver had a good disinfection activity when annealed in the range of 450–650 °C. The adhesion increased upon increasing the annealing temperature. The sample annealed at 650 °C showed the best coating adhesion and completely killed Escherichia coli, Staphylococcus aureus, Shigella, and Salmonella after 2 h of visible-light irradiation. [ABSTRACT FROM AUTHOR]

The high-purity G5 graphite material is widely used for glass moulding and provides high hardness and brittleness because it is sintered to fine particles unlike other graphite materials. Hence, tool cutting of a G5 workpiece is performed by local fracture instead of plastic deformation of the machined surface. Although a diamond-coated tool with outstanding hardness is used to machine very hard graphite, the tool shows variability regarding the service life and machining performance depending on the grain size, even in the same machining environment. We investigated the wear and change trend of machined surface roughness considering microcrystalline diamond (MCD) and nanocrystalline diamond (NCD)-coated tools, which are generally used to machine graphite materials, and analysed their relation with coating. For rough machining, the MCD-coated tool, for which the delamination of coating occurred later, showed less wear and improved machined surface roughness. For precision machining, the NCD tool showed less tool wear rate relative to the cutting length, leading to a small difference in the machined surface roughness between the two tools. We conclude that if rough and precision machining processes are performed using the same cutting tool, the MCD-coated tool is advantageous in terms of service life, while the difference in roughness of the final machined surface between the tools is negligible. [ABSTRACT FROM AUTHOR]

New manufacturing technologies, such as Sheet-Bulk Metal Forming, are facing the challenges of highly stressed tool surfaces which are limiting their service life. For this reason, the load-adapted design of surfaces and the subsurface region as well as the application of wear-resistant coatings for forming dies and molds made of high-speed steel has been subject to many research activities. Existing approaches in the form of grinding and conventional milling processes do not achieve the surface quality desired for the forming operations and therefore often require manual polishing strategies afterward. This might lead to an unfavorable constitution for subsequent PVD coating processes causing delamination effects or poor adhesion of the wear-resistant coatings. To overcome these restrictions, meso- and micromilling are presented as promising approaches to polishing strategies with varying grain sizes. The processed topographies are correlated with the tribological properties determined in an adapted ring compression test using the deep drawing steel DC04. Additionally, the influence of the roughness profile as well as the induced residual stresses in the subsurface region are examined with respect to their influence on the adhesion of a wear-resistant CrAlN PVD coating. The results prove the benefits of micromilling in terms of a reduced friction factor in the load spectrum of Sheet-Bulk Metal Forming as well as an improved coating adhesion in comparison to metallographic finishing strategies, which can be correlated to the processed roughness profile and induced compressive residual stresses in the subsurface region. [ABSTRACT FROM AUTHOR]

Selective laser melting (SLM) is an important method in additive manufacturing. SLM has obvious advantages for the fabrication of metal parts with complex structure that cannot be processed directly and are manufactured in relatively low amounts. However, the surfaces of the SLM-formed parts contain more adhesive particles and pores than those manufactured by traditional methods, leading to the poor corrosion resistance of the parts and preventing the widespread use of SLM. To solve these problems, jet electrochemical machining and jet electrodeposition combined processing techniques were investigated for the treatment of the substrate surface in this work. Jet electrochemical machining was used to remove the surface defects of the SLM-formed parts, and the results were compared with the traditional sandblasting and sandpaper grinding surface treatment methods. Then, the nickel coating was deposited on the surface of the SLM-formed parts using jet electrodeposition to protect the surface and extend the service life of the parts. The mechanisms of the different processing techniques were analyzed, and properties such as the substrate morphology, coating morphology, corrosion resistance of the coating, and adhesion of the coating were compared. The results show that holes, adhesive particles and other defects are still present on the substrate surface after sandpaper grinding and sandblasting and affect the quality of the nickel coating. After electrochemical machining, the SLM surface defects were almost completely removed, forming a uniform microporous structure that interlocked with the nickel coating. The coating was smooth and dense and showed the best corrosion resistance and binding force. In 3.5 wt% NaCl solution, the corrosion potential reached −0.196 V, and the maximum binding force reached 35 N. [ABSTRACT FROM AUTHOR]

The development and advancement of polymeric implant materials is a frequent focus in current research. The combination of polymeric materials with diverging properties provides a wide range of new materials with innovative characteristics. One technology for combining materials is to apply a coated layer onto a base material. In this work, a hyperelastic, synthetic base material was combined with a rigid biopolymer coating layer. A multilayered material with combined characteristics of both was built. In the field of processed polymers, the analysis of coating adhesion is not feasible using established methods. Therefore, a dynamic-mechanical method was investigated, which supplements the uniaxial tensile test and provides knowledge regarding mechanical resistance of the multilayered polymer structure. Furthermore, the method gets validated by SEM-imaging and evaluation of coating composition before and after testing under dynamic conditions.

An Ag/TiO 2 coating was deposited onto glazed ceramic tiles by a sol-gel and spraying method at high temperatures. The coating was characterized by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The results showed that silver was present in rutile-TiO 2 , and the temperature did not change the phase composition of the samples. The Ag/TiO 2 coating had a higher roughness than the TiO 2 coating. The tape test (D 3359–08) showed that the coatings prepared at 950 °C and 1000 °C had good adhesion to the ceramic tile substrate. The antibacterial activity of the coating was tested by photocatalytic sterilization experiments. The results showed that the Ag/TiO 2 coating had a higher antibacterial activity than the TiO 2 coating, and the sterilization efficiency of Escherichia coli, Staphylococcus aureus, Shigella , and Salmonella exceeded 99.655% under 2 h of visible light irradiation. This research provides a method to create Ag/TiO 2 coatings with good thermal resistance, adhesion, and antibacterial activity. This improves the low photocatalytic activity caused by the anatase-to-rutile transformation of TiO 2 at high temperatures and the poor adhesion at low temperatures. [ABSTRACT FROM AUTHOR]

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The applicability of galvanized products in various industries has increased the demand for highly corrosion-resistant coatings to counter harsh environments. Among these, Zn–Mg–Al ternary alloy coatings have excellent corrosion resistance, resulting in their commercialization and industrial demand. To increase the diversification of their products, the ideal flux composition in these coatings should be optimized. In this study, we investigated the effects of conventional flux (ZnCl2:NH4Cl) in the hot-dip galvanization of Zn–Mg–Al ternary alloy coatings. Additionally, we developed a new flux to improve the coating properties of Zn–Mg–Al ternary alloy coatings on steel sheets. During hot dipping, SnCl2 on the steel substrate decomposed faster than conventional flux, thereby eliminating the AlCl3 residues in the coating and surface defects. The thermogravimetric-differential thermal analysis studies unveiled the mechanisms for improved coatings. The thermodynamic calculations confirmed the spontaneous substitution owing to the presence of SnCl2 in the flux. Therefore, the developed and optimized flux enhanced the adhesion of the alloy coating.

A PVD coating is often applied on the surface of metallic alloys to improve their high-temperature resistance. In the present work, a thin titanium layer (1.2 µm) was deposited by PVD on the surface of a stainless steel substrate before high-temperature exposure (800 °C in ambient air). The underlying idea is that metallic Ti converts into Ti oxide (TiO2) during high-temperature aging at 800 °C, thereby slowing down the substrate oxidation. The stability of the coating with and without substrate pre-oxidation was investigated. Morphological, structural, and chemical characterizations were performed and completed by simulation of the film growth and measurement of the mechanical state of the film and the substrate. In the case of the sample that was not pre-oxidized, the oxidation of the steel was slowed down by the TiO2 scale but spallation was observed. On the other hand, when the steel was pre-oxidized, TiO2 provided more significant protection against high-temperature oxidation, and spalling or cracking did not occur. A combination of different kinds of stress could explain the two different behaviors, namely, the mechanical state of the film and the substrate before oxidation, the growing stress, and the thermal stress occurring during cooling down.

A new method for the electrodeposition of copper on oxidized aluminum alloys to form electrolytic coatings exhibiting high performance properties has been discussed. The effect of an azo compound—methyl red (MR)—additive on the structure and physicomechanical properties of the copper coatings formed on oxidized aluminum has been studied. Samples of aluminum alloys AD1M and AMg6BM have been subjected to an anodic treatment under identical conditions in two oxidation electrolytes of different compositions. Copper has been electrodeposited on oxidized aluminum alloy samples using a standard copper plating electrolyte. Comparison with a copper plating electrolyte of an identical composition with an MR azo dye additive has been conducted. The microstructure and adhesive properties of the copper coating formed on oxidized aluminum alloys have been studied. The relationship between the physicomechanical properties of the copper coating (microhardness, open porosity, adhesion) and the action of an azo dye additive in the copper plating electrolyte has been studied. The use of this technology will make it possible not only to increase the reliability and durability of machine parts and mechanisms but also to restore old parts and mechanisms. [ABSTRACT FROM AUTHOR]

The bond strength between the thin film diamond coating and the substrate has an extremely important influence on the thin film coating tool. Improving the microstructure of the surface of carbide substrates not only promotes the diamond nucleation but also increases the bond strength between the film and the substrate. In this paper, we investigate the effect of laser's instantaneous high heat on the surface of the substrate to prepare the microstructure topography, which causes the surface structure to melt, cool, and reconstruct, causing the surface topography and superficial microstructure changes of the substrate. The conclusion shows that after laser and the ultrasonic pretreatment, the surface roughness of the tool increases significantly and appears regular wavy texture, the number, and size of defects in the reconstruction area of the substrate shallow structure increases significantly, forming a unique stereoscopic defect structure and wavy step height structure, enhancing the density and number of nuclei at the defects, the hole connectivity structure strengthens the growth conditions of crystal nuclei and improves the mechanical interlocking of the coating and substrate and releases the residual stresses in the substrate surface layer. [ABSTRACT FROM AUTHOR]

This paper reports on environmentally-friendly Sr P chemical conversion treatment of AZ91D Mg alloy prior to deposition of electroless Ni P coating. Treatment duration in Sr P bath was varied through 2, 5, 10 and 15 min. The top Ni P layer was deposited for 30 and 60 min, only on 2 min Sr P treated layer. Small Sr P flakes/flowers were found to be dispersed on AZ91D Mg alloy substrate after 2 min which progressively coarsened with increase in treatment duration upto 15 min. SrHPO 4 and Sr 3 (PO 4) 2 were detected as the major phases through GIXRD after 5, 10 and 15 min of treatment. During scratch test, such flowers got embedded into the softer substrate which significantly improved scratch hardness to 1.815 GPa as compared to 0.498 GPa for bare alloy. However, pulverization of the flowers were observed during ball-on-disc tribological test. Such pulverized micro-particles participated in rolling action at the interface of coating and couterbody resulting in low coefficient of friction (~0.4) and wear loss. Coarser flowers also effectively shielded the underlying substrate against the corrosive medium (3.5 wt% NaCl solution) resulting in reduced corrosion rate of 0.00438 mm/year as comapred to 0.38531 mm/year for uncoated alloy. After 30 min of Ni P deposition on 2 min of Sr P treated layer, sporadic cauliflower-like outgrowths were observed on the sample with several exposed areas of underlying substrate/Sr-P layer. It however, improved to a dense, uniform morphology with increase in Ni P deposition duration to 60 min. Vicker's microhardness and scratch hardness also scaled with Ni P deposition duration. Dense and uniform morphology, high hardness and superior adhesion contributed towards improved wear life of Ni P coating deposited for longer duration of 60 min. The dense, uniform Ni P layer was also instrumental in further reducing the corrosion rate (0.00122 mm/year) by providing an effective barrier against penetration of corrosive medium. • Coefficient of friction reduced with increase in surface coverage by Sr P flakes. • Pulverization of Sr P flakes during sliding reduced coefficient of friction. • Hardness and critical load of adhesion increased with deposition duration of Ni P. • Hardness, adhesion and coating uniformity are crucial for wear resistance of Ni P. • Dense and uniform Ni P top layer prevented ingress of corrosive medium. [ABSTRACT FROM AUTHOR]