Anti-wear Coatings Research Articles

Effects of Cu and WS2 addition on microstructural evolution and tribological properties of self-lubricating anti-wear coatings prepared by laser cladding

High manganese steel (30CrMnSi) is usually used to prepare the components which works under a high load for long time. In order to extend its service life, the high manganese steel covered with NiCr/TiC, NiCr/TiC–Cu or NiCr/TiC-Cu-WS2 coatings are prepared using laser cladding technology. The influence of Cu and WS2 to the microstructure, hardness and wear performance of the coatings is discussed. The tribological properties of the resulting coatings is evaluated under 100 N in atmosphere environment. The hardness of NiCr/TiC coating is about 3.5 times of that of the substrate owing to the existence of TiC in coating. Due to the addition of Cu, the wear loss of the NiCr/TiC–10%Cu coatings reduces. Furthermore, as the synergistic lubrication of Cu, CrS and WS2, the wear resistance of the NiCr/TiC–10%Cu–10%WS2 coatings are significantly improved. The wear scar width and friction coefficient of the NiCr/TiC–10%Cu–10%WS2 coatings are only 50% of the substrates. And the wear mechanism of this kind of coatings is mainly micro-plough wear. The laser clad self-lubricating anti-wear coating will be one of the most important candidates for its excellent tribological performance.

Optimisation of Mechanical Properties of Gradient Zr-C Coatings.

One of the key components of the designing procedure of a structure of hard anti-wear coatings deposited via Physical Vapour Deposition (PVD) is the analysis of the stress and strain distributions in the substrate/coating systems, initiated during the deposition process and by external mechanical loads. Knowledge of residual stress development is crucial due to their significant influence on the mechanical and tribological properties of such layer systems. The main goal of the work is to find the optimal functionally graded material (FGM) coating’s structure, composed of three functional layers: (1) adhesive layer, providing high adhesion of the coating to the substrate, (2) gradient load support and crack deflection layer, improving hardness and enhancing fracture toughness, (3) wear-resistant top layer, reducing wear. In the optimisation procedure of the coating’s structure, seven decision criteria basing on the state of residual stresses and strains in the substrate/coating system were proposed. Using finite element simulations and postulated criteria, the thickness and composition gradients of the transition layer in FGM coating were determined. In order to verify the proposed optimisation procedure, Zr-C coatings with different spatial distribution of carbon concentration were produced by the Reactive Magnetron Sputtering PVD (RMS PVD) method and their anti-wear properties were assessed by scratch test and ball-on-disc tribological test.

Effect of Secondary Deposition Parameters on the Magnetic Properties of Electrodeposited Cobalt Nickel Phosphorus Alloys

Electrodeposited cobalt nickel phosphorus alloys are characterized by interesting magnetic properties, which motivate their potential applicability in micro-electromagnetic devices like sensors and actuators. CoNiP is suitable for MEMS fabrication due to its relatively high coercivity and maximum magnetic energy product. Moreover, the columnar grain structure typical of electrodeposited layers introduces a high magnetic anisotropy, which is desirable for devices that require high magnetic flux and energy product along a specific direction [1]. In addition to their magnetic properties, CoNiP alloys are also characterized by high hardness, which makes them good candidates for the production of anti-wear coatings, and by good corrosion resistance. Finally, CoNiP coatings show a notable catalytic activity, which can be exploited in water splitting applications [2].One of the most remarkable advantages of using electrodeposition for CoNiP production is the possibility to easily tune magnetic properties by varying deposition parameters. Physical and chemical parameters like bath composition, temperature, pH, presence of additives have a great role on final properties determination [3]. Magnetic behavior can be soft or semi-hard according to the conditions employed. Magnetic properties, however, depend not only on the chemistry of the electrolyte and the primary plating parameters, but also on other secondary deposition aspects. These include, for example, the substrate on which the alloy is plated [4] and its roughness [5]. Furthermore, the application of an external magnetic field during the deposition can influence final properties of the deposited layer. Finally, also the presence of inert particles codeposited within the CoNiP layer can change the magnetic behavior of the coatings. In this context, CoNiP has been poorly characterized in the existing literature.The aim of the present work is to explore the influence of some secondary deposition parameters on CoNiP magnetic properties. In detail, a CoNiP electrolyte was selected and its chemical composition was kept constant during the experimentation. The same was done with the deposition parameters. CoNiP was deposited on different substrates, characterized by different materials (brass, copper, silver) and by different degrees of roughness. The alloy was also codeposited with inert (TiO2) nanoparticles and in presence of an external magnetic field. The influence of these variables on final magnetic properties was investigated with vibrating sample magnetometry (VSM). Surface morphology and phase composition were characterized by mean of SEM and XRD. CoNiP layers were also annealed, and the effect of the heat treatment on magnetic properties was studied.Finally, the observed substrate sensitivity of CoNiP magnetic properties was exploited to introduce a surface magnetic anisotropy in electrodeposited CoNiP layers. Brass substrates were patterned with electrodeposited copper and CoNiP was deposited on top. Magnetic force microscopy (MFM) was employed to characterize the result, evidencing differences in magnetic properties between the zones where CoNiP was plated on brass and the zones where CoNiP was plated on electrodeposited copper. The final result was a magnetically patterned CoNiP coating, which may potentially find application in microelectronics and sensors production.[1] C. J. Hsiao et al., AIP Advances 7, 056210 (2017)[2] A. Han et al., J. Mater. Chem. A 4, 10195 (2016)[3] P. Cojocaru et al., Trans. Inst. Met. Fin. 89(4), 194 (2011)[4] E. I. Manimaran et al., J. Mater. Sci. Mater. Electron. 26, 9821 (2015)[5] S. J. Steinmuller et al., J. Appl. Phys. 101, 09D113 (2007)

Effective Application of Solid Lubricants in Spacecraft Mechanisms

Solid lubricants, antiwear coatings, and self-lubricating composites are used in applications on spacecraft where oils and greases cannot be used because of the need to avoid lubricant volatility/migration, and where the application requires significant temperature variation, accelerated testing, higher electrical conductivity, or operation in boundary conditions. The purpose of this review is to provide spacecraft designers with tools that can aid in the effective use of solid-based tribological materials, both to increase their usage, and to reduce anomalies. The various tribological material formulations are described, including how their materials, physical, and chemical properties affect their performance. Included are typical solid lubricants like PTFE and bonded or sputter-deposited MoS2, as well as low shear metal coatings, hard coatings, and composite materials (including bulk composites and nanocomposite coatings). Guidance is given on how to develop mechanisms that meet performance requirements, but also how to optimize robustness, so that success is achieved even under unforeseen circumstances. Examples of successful applications are given, as well as how to avoid potential pitfalls, and what the future of solid tribological materials may hold.

THE INFLUENCE OF THE MULTILAYER STRUCTURE OF HARD COATINGS ON THEIR RESISTANCE TO MICRO-IMPACT FATIGUE WEAR

Fatigue cracking of thin hard anti-wear coatings occurs, among others, in the tribological contact of sliding friction pairs, in the top layers of cutting tools coatings, as well as in the surface of elements subjected to erosion processes. Coating fatigue wear is initiated as a result of cyclic interactions with micro-roughness of counterpart or other elements or particles that repeatedly impact the surface. The selection of appropriate coatings can increase the durability of machine components that are subjected to fatigue impact loads. The paper presents the results of tests on micro-impact fatigue wear of elements covered with single TiN and DLC coatings, as well as multi-layer (Ti/TiN)×8 type. Fatigue tests were carried out using the micro-impact method by cyclic impact of the surface of the coating with a diamond ball. The experiments were performed using a special laboratory stand. The correlation between fatigue life of coatings and their micromechanical properties such as Young's modulus and hardness were also examined. The hardness and Young's modulus were determined by an instrumented indentation method. The test results proved that the (Ti/TiN)×8 multilayer coating demonstrates wear 1.4 times smaller than the sample with the TiN coating and 1.2 than the sample with the DLC coating.

Study of the durability of the working body the dryer

In this article, the plant for heat treatment of grain material, namely perfo-rated spiral operating part, developed by the authors was chosen as the object of improving the wear resistance. The research was conducted in the laboratory of the Technology of Metals and Machinery Repair Department of Kemerovo State Agricultural Institute. The aim of the research is to select the most appropriate method of hardening the functional surface of perforated spiral operating part with the use of low-cost anti-wear coatings. The basis for choosing the method of surfacing the coating was the use of a method of forming the technological repair units (TRU), which allowed electric spark treatment with unalloyed white cast iron.

Optimisation of mechanical properties of ZrC multilayer coatings

One of the key issues related to designing a structure of anti-wear coatings is the analysis of the state of stress in the substrate/coating systems, arising from external mechanical loads. In the present work, the object of research was a coating, deposited on a hard substrate consisting of four layers performing different functions: (1) increasing coating/substrate adhesion, (2) improving load support, (3) reducing surface stress and (4) improving crack propagation resistance. The aim of numerical and experimental research was to optimize the structure of the multi-layer coating due to anti-wear properties. For this purpose, an optimisation procedure using finite element modelling was created, in which six original decision criteria were adopted, which are functions of the state of stress and strain in the substrate/coating system. Proof of the concept of optimisation procedure (virtual coating prototypes) was carried out on the example of multi-layer ZrC coatings with different carbon concentrations deposited by reactive magnetron sputtering physical vapour deposition. Experimental verification of selected prototypes with the use of scratch and Rockwell C adhesion tests and wear assessment via ball-on-disc method confirms the relationship between the values of adopted decision criteria and their anti-wear properties. In particular, for prototypes characterized by low values of selected criteria, higher critical loads and lower wear ratios were obtained.

High performance epoxy/polyester-based nanocomposite coatings for multipurpose applications: A review

Epoxies are important thermosetting polymers with exceptional features, which have been successfully employed for coatings. Polyester blends with epoxy enhances their chemical inertness, anti-rusting, toughness, strength, glass transition temperature, and heat stability, Epoxy/polyester blends have been further reinforced with nanocarbon, nanoclay, and inorganic nanoparticles to form nanocomposite coatings. Incorporating nanoparticles in epoxy/polyester has further improved their engineering properties. This review article principally offers state-of-the-art review of epoxy/polyester blends and epoxy-/polyester-based nanocomposite coatings. The epoxy/polyester and epoxy/polyester-based nanocomposites have been employed in non-flammable, anti-corrosion, anti-microbial, and anti-wear coatings in automotive, aerospace, energy, electronics, biomedical, and civil engineering applications. In order to fully utilize their potential, rigorous future attempts are needed for progress in the related technical fields.

Tribological Wear-Preventive Coatings

This article discusses wear-preventive tribological coatings that increase the operational life of artillery, tank, and rifle barrels. Studies have been conducted using some of them. The presence of a sufficiently large scientific and technical reserve in the field of material science of heat-resistant alloys and antifriction antiwear coatings is noted.

Tribological Aspects of Cutting Tool Wear during the Turning of Stainless Steels.

The research paper presents the tribological aspects of cutting tool wear during the turning of stainless steels. An experiment was conducted in order to assess the wear of carbide cutting inserts with CVD-applied anti-wear coatings (CNMG 12 04 08 ZSZ and CNMA 12 04 12-KR 3205) and an uncoated ceramic cutting insert (CNGA 12 04 08 T0102 WG 650). The test subject included the following stainless steel grades X20Cr13 (1.4021) and X8CrNiS18-9 (1.4305). The analysis involved the direct wear indicator, VBBmax, and the indirect wear indicator, which was the roughness of machined surfaces and the Ra parameter. Based on the obtained results for both X20Cr13 and X8CrNiS18-9 steels, it was noticed that the best durability was exhibited by the CNMG 12 04 08 ZSZ insert, whereas the worst durability was identified for the CNGA 12 04 08 T0102 WG 650 insert. When analysing the results obtained with the VBBmax direct indicator, it was observed that in the case of each of the insert, most often the course of their wear was of nature similar to linear. Comparing the VBBmax direct indicator with the indirect indicator, namely, the measured Ra parameter, it was concluded that they were convergent. Upon the deterioration of the surface quality, greater values of the selected geometric measure of wear on the flank face were also identified.

THE ABILITY OF NANOCOMPOSITE CARBON COATINGS TO WITHSTAND FRICTION UNDER SEVERE CONDITIONS

The paper presents an analysis of the micromechanical properties of selected thin, hard anti-wear coatings of the type nc-TiN/a-C and nc-TiC/a-C, which were deposited by magnetron sputtering on a steel substrate. The load carrying capacity of the nanocomposite coatings was analysed in point contact with the use of indentation method, a scratch test, and friction test in contact with a ceramic ball. The hardness and modulus of elasticity of the coatings were determined by an instrumented indentation method using a Vickers indenter. The coating adhesion to the substrate was examined in a scratch test. Tribological tests in sliding contact with an Al2O3 ball were made at various loads to determine the limit load in which normal friction occurs. The results of tribological tests were compared with the resistance to plastic deformation index (H3/E2). It was found that the basic micromechanical parameters of coatings provide important information concerning durability and load carrying capacity. However, while predicting wear, it is also important to investigate the nature of the wear process during friction. The wear nature of the nc-TiN/a-C and nc-TiC/a-C coatings depends on the load value and the number of forced loads.

Optimization of energy consumption in coating removal for recycling scrap coated cemented carbide tools using hybrid laser-waterjet

In order to purified recovery of scrap cemented carbide, stripping of coatings was mandatory as engineering tools for improving service life were almost modified with anti-wear coatings. However, the low efficiency of current coating removal technologies leaded to the overmuch energy consumption, it was of great importance to achieve energy conservation to relieve the environment impact because of sustainable development. Reducing the energy consumption during processing could significantly improve the environmental performance of manufacturing systems. According to the energy consumption characteristics of hybrid laser-waterjet machine, a multi-objective optimization model for energy prediction with key parameters under actual constraints is constructed to trade off two responses: the cutting specific energy consumption (CSEC) and the processing time, which is transformed into a single-objective model and then solved by genetic algorithm. Simultaneously, the orthogonal experiment is proposed to identify the parametric influence on the multi-objective optimization and to validate the feasibility of the proposed model with the comparisons between single-objective and multi-objective optimization. Finally, the comparisons about energy consumption, carbon emission and the mechanical properties between high temperature oxidation method and hybrid laser-waterjet technology are carried out. The results indicate that larger feed speed and larger laser offset distance can benefit the energy conservation due to the shortened processing time. The multi-objective optimization model realizes about 80% of energy conservation compared to minimum CSEC, and 40% of which compared to minimum processing time. Contrasted to the energy conservation and substrate quality after processing, the hybrid laser-waterjet technology is much better than the high-temperature oxidation method.

НЕКОТОРЫЕ АСПЕКТЫ ЭФФЕКТИВНОСТИ НАНЕСЕНИЯ АНТИФРИКЦИОННЫХ ПОКРЫТИЙ ТЕХНОЛОГИЯМИ ФИНИШНОЙ АНТИФРИКЦИОННОЙ БЕЗАБРАЗИВНОЙ ОБРАБОТКИ

The article analyzes the effectiveness of anti-friction coatings obtained by finishing anti-friction non-abrasive treatment (FANT), including processing in metal-clad technological media, in order to improve the performance of machine parts. The analysis of the application of coating technologies FANT on materials operating at elevated temperature and at high pressure, as well as with high values of energy fluxes in the environment, was carried out. The results of the application of various compositions of cladding elements and FANT technologies for various engineering products are presented. The results of studies of the use of FANT technologies developed with the participation of the authors confirm their high efficiency for improving the wear resistance of artillery gun barrel materials. Decrease in wear ranging from two to three times compare to regular technology. Field testing of anti-friction anti-wear coatings, carried out by specialists of the FSE SRI «Geodesia», confirmed the prospects of this direction for increasing the survivability of artillery barrels.

The initial evaluation of performance of hard anti-wear coatings deposited on metallic substrates: thickness, mechanical properties and adhesion measurements – a brief review

Abstract The demand for metallic materials of exceptional tribological performance is rapidly growing due to constant development of automotive, tool or implant industry. As great attention nowadays is being paid to the surfacemodified materials, there is a need of establishing reliable methods for evaluation of coated metallic alloys. In this paper, methods for thickness, adhesion and mechanical properties measurement of anti-wear coatings are considered. The importance of altering the mechanical properties of the coating with regards to its expected wear performance is also discussed. According to the numerous findings, it is reasonable to pay attention to the hardness and Young’s modulus of the developed coating, as well as on the mismatch between its Young’s modulus and the elastic modulus of the substrate material. Information provided in this paper has been thoroughly illustrated and enriched with our own experience in the field.

Investigations of Anti-Wear Coatings in Terms of Their Applicability to Tools in the FSW Process

Investigations of Anti-Wear Coatings in Terms of Their Applicability to Tools in the FSW Process

Физическая модель структурирования системы «подложка ‒ покрытие» в процессах комплексного модифицирования поверхностного слоя рабочих частей штампов и пресс-форм

Basic methods to increase durability of die working parts including processes of cold plastic deformation at anti-wear coatings application by a method of ion-plasma sputtering are considered. A physical model of cold plastic deformation of samples made of heat-resistant steel H12M is presented.

Effects of grain boundary on wear of graphene at the nanoscale: A molecular dynamics study

Graphene has shown excellent tribological behaviors, enabling its potential applications as lubricating and anti-wear coatings, however, the grain boundaries (GBs) formed during the preparation process may deteriorate the performance of graphene. Using large-scale molecular dynamics simulations, we study the wear mechanism of graphene GBs with various misorientation angles between two grains. Compared with pure nanoindentation at the GBs, the critical load of wear failure upon nanoscratching across the GBs is much lower due to the synergetic actions of interlocking and pushing between the tip and graphene atoms. The misorientation angle between the adjacent grains significantly effects the onset and fashion of atomic-scale wear. Results show that wear resistance of the graphene with large-angle GBs is slightly lower than that of pristine graphene. Nevertheless, a number of the long bonds emerge in the vicinity of the low-angle GBs during scratching, leading to wear failure at much smaller load than the large-angle GBs. Furthermore, wear resistance of the low-angle GBs can be enhanced by increasing the interfacial strength between graphene and substrate due to the reduced number of the long bonds at the GB. This study sheds light on improving wear resistance of graphene coating by properly controlling its microstructures.

Analiza wpływu powłok przeciwzużyciowych na ostrzach skrawających na stan warstwy wierzchniej po toczeniu wykończeniowym stali C45

The results of research on the influence of multi-layer CVD and PVD coatings on carbide cutting tools on selected parameters of the surface layer after finishing turning of C45 steel (1.0503) are described. The research showed a significant effect of antiwear coatings on the condition of surface layer. In the case of all tested blades, an increase in the strengthening level of the surface layer was noted along with the increase of the feed rate.

IMPROVEMENT OF THE ION-PLASMA DUSTING METHOD OF THE INTERNAL COMBUSTION ENGINES’ VALVES BASING ON THE TOPOCOMPOSITE COVERINGS’ MULTIFRACTAL ANALYSIS

Introduction. Digital image and calculation of multifractal dimension spectra are carried out in the research basing on the investigation of the coatings’ topology, which are created by ion-plasma spraying on steel surfaces and used for internal combustion engine (ICE) valves. Results . Quantitative assessment of the structural changes received on the different power modes of ion-plasma dusting is executed in the article. Discussion and conclusion . It is concluded that complex indicators of multifractal dimensions could be used for forecasting and optimization of the ion-plasma processing modes for the purpose of anti-wear coatings on automobile parts at the repair process forming.

Laboratory and Performance Studies of Anti-wear Coatings Deposited on Nitrided Surfaces of Tools used in an Industrial Hot Die Forging Process

The paper presents the results of laboratory studies performed on produced anti-wear coatings as well as the results of performance tests conducted on tools with these coatings in industrial conditions, in the process of hot die forging. Three different coatings were selected: AlCrTiSiN, Cr/CrN and AlCrTiN, deposited by means of the vacuum-arc method on test samples as well as forging tools used in the hot forging process of a lid. The first part of the paper discusses the results of the studies performed in laboratory conditions, which included: surface morphology by means of SEM, hardness and Young modulus measurements, determination of the chemical composition by means of the EDS method, adhesion tests by means of the scratch method and tribological tests by means of the ball-on-disk method. The obtained results were correlated and applied in the analysis of the performance tests on forging punches with these coatings at an early stage of their performance (up to 4000 produced forgings), which were tested on 19 tools, of which 3 representatives were selected for each coating. A thorough analysis was performed of the wear phenomena and mechanisms and the manner of wear of hybrid layers as well as their resistance to the particular destructive mechanisms. Based on the performed laboratory and performance studies as well as their analysis, it was possible to select the optimal hybrid layer, which enables an increase in the durability of forging tools used in industrial hot die forging processes. The preliminary results showed that the best results for the whole working surface of the tool were obtained for the Cr/CrN layer, which characterizes in high adhesion as well as a lower Young modulus and hardness. In the case of high pressures and the correlated friction, better results were obtained for the AlCrTiN coating, which, besides its good adhesion properties, also exhibited the highest frictional resistance.