Wear Performance Of Coatings Research Articles

Multi-layer formation by oxidation and solid-state crystallization of cold sprayed amorphous coatings during dry sliding wear

Amorphous alloy coatings, known for the exceptional wear resistance, have emerged as a key solution for enhancing the wear performance of magnesium alloys under harsh environments. In this study, Fe-based amorphous alloy coatings were deposited on magnesium alloy by cold spraying technology, and the influence of microstructural evolution on the wear performance of coatings under dry sliding wear conditions was discussed. The results showed that a dense adherent oxide layer with a thickness of ∼700 nm comprising nanograins of less than 8 nm was formed at the outmost surface, which played a role of self-lubricating. Underneath, a 1 μm thick nanocrystalline-amorphous layer with nanograins of ∼20 nm dispersed in the amorphous alloy matrix was formed through in-situ crystallization induced by flash temperature. This composite structure prevented the formation of shear bands in amorphous alloys and enhanced the durability. Therefore, the transition from abrasive wear to adhesive wear was a consequence of the microstructural evolution from a dual-phase composite layer to a self-lubricating oxide layer.

Wear and neutron shielding resilience of titanium-hexagonal boron nitride coatings against extreme lunar radiation and thermal cycles

Ti6Al4V and Al6061 are aerospace alloys used in lunar structural components and rovers owing to their high specific strength. However, they deteriorate rapidly when subjected to demanding conditions of the lunar environment, such as extreme thermal cycles, solar particle radiation, and abrasive regolith. Cryo-milled powders were employed to deposit hBN-reinforced protective titanium coatings through plasma spray (atmospheric-APS and vacuum-VPS) with 2 and 10 vol% of hBN on Ti6Al4V and Al6061 substrates. These coatings were evaluated for durability under extreme lunar-like conditions, including thermal cycling, electron radiation, and synergistic (electron radiation-thermal cycle) exposure. The coatings exhibited radiation-induced hardening, resulting in a substantial increase in their microhardness ~20–40 % compared to virgin condition. Bright-field transmission electron microscopy (TEM) analysis reveals the presence of high dislocation densities, black dot defects, and dislocation clusters, providing evidence of the severe impact of synergistic environmental stresses. Ball-on-disk tribological tests were conducted in the presence of JSC-1 A lunar regolith simulant to evaluate the wear performance of coatings. Compared to conventional Ti6Al4V substrate, 50 %, 90 %, and 70 % reductions in wear volume were observed in the Ti/2 vol% hBN coatings in thermal-only, radiation-only, and synergistic environments. Neutron shielding tests indicate that the synergistic coatings offer higher neutron shielding performance by up to 28 % compared to virgin coatings, attributed to improved neutron capture by 10B isotopes. Upon a comprehensive assessment and ranking of multiple coatings under varying conditions, the VPS Ti/2 vol% hBN coating emerges as the top choice for protection against extreme radiation and thermal cycles for future lunar explorations.

The overlap rate influences the microstructure and properties of laser-cladded Fe-Ni-Ti composite coatings

The overlap rate has a significant impact on the quality and performance of laser cladding coatings. In order to prepare high wear-resistant laser cladding coatings. Single and multi-pass Fe-Ni-Ti composite coatings were prepared on the surface of 45 steel using a semiconductor laser. The microstructure and phase composition of the fusion layers were analyzed using metallographic microscopy, XRD diffraction, scanning electron microscopy, and energy dispersive spectrometry. Friction coefficients and microhardness of fusion layers with different overlap ratios were tested using a multifunctional surface performance tester and a microhardness tester. The wear performance of coatings with different overlap ratios was tested using a wear testing machine.The results indicate that when 6% Ti was simultaneously added to the Invar alloy matrix during the laser fusion of Fe-Ni-Ti alloy coatings, the phase composition of the fusion layer mainly consists of γ-[Fe, Ni] austenite, Fe3Ni2, α-Fe, and other metallic compounds. Simultaneously, in-situ formation of TiC reinforcement is dispersed in the matrix of γ-[Fe, Ni] solid solution. When the overlap ratio is 46%, the fusion layer exhibits a uniform, dense structure with fewer defects and higher coating hardness, resulting in improved wear resistance. At this point, the microhardness of the fusion layer is 450 HV, 1.5 times that of the substrate material and 2.2 times that of the base material. The friction coefficient on the coating surface is 0.412, with a percentage weight loss of 0.17%. The wear theory of the cladding layer is mainly adhesive wear, which also includes abrasive wear.

ANN SUPPORTED STUDY ON THE PERFORMANCE AND SLURRY EROSION RESISTANCE OF THERMAL SPRAYED WC20CR3C27NI COATINGS

The thermal spray coatings are commonly employed in slurry pump components and hydrodynamic turbine blades, where wear progression is an intricate phenomenon. In this research work, the performance analysis of HVOF and APS sprayed WC20Cr3C27Ni coatings for slurry erosion wear is carried out by using artificial neural networks (ANN). The influence of time, particle size, impact angle, speed, and slurry concentration on wear performance of coatings and turbine steel substrate are evaluated. Under the experimental settings, slurry erosion wear rates and mass loss for both coatings and substrate were determined. When ASTM A743 steel was coated with thermal sprayed WC20Cr3C27Ni coatings, the slurry erosion wear resistance of the steel was enhanced by 2 and 3.5 times for APS and HVOF coatings, respectively. The design of ANN made it possible to examine the interactions between the seven input variables. A robust model was formed by the two outputs that followed. This model enables the prediction of slurry erosion wear rate and mass loss of WC20Cr3C27Ni coatings and substrate.

Microstructure and Wear Resistance of Laser-Clad Ni-Cu-Mo-W-Si Coatings on a Cu-Cr-Zr Alloy.

To improve the wear resistance of high-strength and high-conductivity Cu-Cr-Zr alloys in high-speed and heavy load friction environments, coatings including Ni-Cu, Ni-Cu-10(W,Si), Ni-Cu-10(Mo,W,Si), and Ni-Cu-15(Mo,W,Si) (with an atomic ratio of Mo,W to Si of 1:2) were prepared using coaxial powder-feeding laser cladding technology. The microstructure and wear performance of coatings were chiefly investigated. The results revealed that (Mo,W)Si2 and MoNiSi phases are found in the Ni-Cu-10(Mo,W,Si) and Ni-Cu-15(Mo,W,Si) coating. WSi2 phases are found in the Ni-Cu-10(W,Si) coating. The degree of grain refinement in Ni-Cu-10(Mo,W,Si) was greater than that of the Ni-Cu-10(W,Si) coating after the effect of Mo. The excellent wear resistance and micro-hardness of the Ni-Cu-15(Mo,W,Si) coating were attributed to the increase in its dispersion phase, which were approximately 34.72 mg/km and 428 HV, 27.1% and 590% higher than the Cu-Cr-Zr substrate, respectively. The existence of silicide plays an important role in grain refinement due to the promotion of nucleation and the inhibition of grain growth. In addition, the wear mechanism transformed from adhesive wear in the Ni-Cu coating with no silicides to abrasive wear in the Ni-Cu-15(Mo,W,Si) coating with high levels of silicides.

Tailoring the scratch adhesion strength and wear performance of TiNiN nanocomposite coatings by optimising substrate bias voltage during cathodic arc evaporation

The tribological properties of TiN-based coatings can be substantially influenced by the choice of substrate bias employed during physical vapor deposition. However, the effects of applied substrate bias voltages during cathodic arc evaporation on to the scratch adhesion strength and wear resistance of TiNiN coatings have not been previously studied. In this present work, a series of TiNiN coatings were fabricated onto tool steel (M2) substrates using the cathodic arc evaporation method by applying a range of bias voltages to the substrate. The aim of this study is to investigate the scratch response and wear performance of these coatings along with an investigation of the deformation mechanisms in operation during scratch and wear tests. The best scratch adhesion strength (i.e., greater LC1, LC2 and CPRs values) was noted for the coating prepared at a bias voltage of −100 V, which was ascribed to the synergistic responses arising from superior mechanical properties, the influence of a high compressive residual stress and a fine, equiaxed nanocomposite structure, that acted to promote effective resistance against cohesive and adhesive failure. Further, the failure mechanisms under progressive loading conditions were also investigated through observation of the complex crack patterns generated, compressive residual stress values and the coatings' hierarchical design. An approximately 85 % enhancement in wear resistance for these TiNiN coatings was achieved as the bias voltage was increased from 0 V to −100 V. This −100 V coating exhibited the highest values of H/Er (>0.1) and We (>60 %), as well as the highest Ni concentration (~ 4 at.%).

Impact-sliding behavior of Ni-based coating prepared on tunnel boring machine disc cutter material produced using a plasma transferred arc welding process

The working condition of the disc cutter of the tunnel boring machine (TBM) is extremely harsh and is severely worn during the rock-cutting and tunneling process. Reducing the wear rate of the cutter and extending the service life of the cutter are essential to improving the economic costs and safety of the TBM. This article explores the feasibility and effectiveness of using surface coatings to improve the wear resistance of the cutter ring. NiCrBSi/WC coatings with different current intensities were prepared on the disc surface using plasma surfacing technology. The wear performance of the coating was evaluated using a bespoke impact-sliding device that fits the actual working conditions, and the wear mechanism was studied in detail. According to the “tadpole-like” wear scar characteristics of the coating after the impact-sliding wear experiment, the wear scar zone can be divided into two regions: the impact region and the sliding region, which are consistent with the actual wear characteristics of the cutter ring. In addition, the wear behavior of the coating noticeably changed under each experiment parameter, and the evolution process of the impact-sliding wear of the gage cutter at each position can be well reproduced. When the impact angle was 45°, the wear depth and wear volume of the coating were significantly smaller than those of the uncoated samples. This is mainly due to the metallurgical bond between the Ni-based alloy zone (binder phase) and the spherical WC particles (hard phase) on the surface of each specimen. When impacted by the tribo-ball, the WC particles can undergo plastic deformation and relaxation through the Ni-based alloy zone under the applied force, thereby obtaining excellent impact and sliding resistance. When the impact angle was 60°, the impact dominates, causing the impact force to increase. Furthermore, compared with the uncoated specimens, the wear depth and wear volume of the coated specimens significantly increased, indicating that the anti-impact ability was seriously degraded in such situation. In summary, the powder composition and preparation process parameters should be reasonably selected according to the impact angle, and the impact-sliding wear experiment can effectively evaluate the impact and sliding wear performance of different coatings. This approach has an important directive function in the promotion and application of cutter ring coatings.

Study and comparison of wear behaviour of Ni-Al2O3 coatings deposited by hot and cold spray

The sliding wear of hot and cold spray nickel-alumina coatings on SA 213-T 91 boiler steel has been evaluated and compared. The investigation was conducted with pin-on-disc apparatus. The wear testing was done by varying normal loads of 30, 40, and 50 N at a constant sliding velocity of 1 ms−1. Then another set of experimentation was done at different sliding velocities of 0.5, 1, and 2 ms−1 at a constant normal load of 30 N. This experimentation was designed to study the effect of varying normal loads and sliding velocities on the wear performance of coatings developed with hot and cold spray techniques. The variation of friction coefficient and wear rate with variation in normal loads and sliding velocities were plotted and analyzed. The evaluation of wear mechanisms and characteristics of Ni-Al2O3 coatings is done with the help of weight change measurements and FE-SEM analysis. The wear resistance of hot spray coatings was found better at high normal loads and sliding velocities in comparison to cold sprayed coatings.

Hardness, Adhesion, and Wear Performance of Duplex Treatment Coatings of Nitride/TiAlZrN with Different Zr Target Currents

The surface treatment, which includes first a thermal diffusion process, such as nitriding and then a physical vapor deposition coating process as the working layer, is called duplex treatment in the literature. In this study, the effects of the duplex treatment on the hardness, adhesion, and wear performance of TiAlZrN coatings on the hardened AISI H13 steel produced using the closed field unbalanced magnetron sputtering method with variable Zr target current (2 A, 3 A, and 5 A) were investigated. Within the scope of these investigations, scanning electron microscope, x-ray diffracrometer, optical microscope, optical profilometer, energy-dispersive spectrometer, micro- and nano-hardness, scratch, and wear tests were used. In micro- and nano-hardness tests, it was determined that the hardness of the substrate increased significantly (approximately 400%) owing to the duplex treatment. In addition, with the increase in the Zr target current, it was observed that the hardness of the coatings was in an increasing trend. Adhesion strength increased with the enhancement of both the hardness of the substrate and the coatings. It was beheld that the adhesion strength of the coatings increased with the duplex treatment. Besides, the coating produced using the highest Zr target current reached maximum adhesion strength of 79 N in relation to superior hardness. Wear performance of the samples was determined using a ball-on-disk tribometer. As a result of wear tests, TiAlZrN coatings with duplex treatment were observed to notably improve the wear performance of the substrate material by 95 times. The effects of Zr target current on the wear performance of the coatings were similar to those of hardness and adhesion strength.

Tribological Characteristics of Carbon Nanotubes‐Reinforced Plasma‐Sprayed Al2O3‐TiO2 Ceramic Coatings

Thermal‐sprayed coatings are widely used in various oil and gas industries for wear and corrosion applications. However, increasing performance and requirements make conventional coatings inadequate for future needs. Furthermore, the heat conductivity of bulk materials cannot be minimized easily. Therefore, the use of low porous coating with nanocomposite doping is an effective way to produce coatings with reduced thermal conductivity. Plasma‐sprayed Al2O3‐TiO2 coatings are found in a wide range of applications recently in many industries because of their exceptional properties including low expenses and ease of availability. In this work, the wear‐resistant and low porous coatings of Al2O3 + 3 wt%TiO2 and respective carbon nanotube (CNT) doped coatings are prepared and characterized. The coatings are deposited on the AISI 1020 steel substrate using air plasma spraying. The impact of CNTs reinforcement on the percentage of pores and wear performance of coatings is investigated. Also, wear tracks morphology is investigated to determine the wear mechanism that is responsible for the wear of coatings. From the analysis, it is observed that the formation of cracks as well as micropores is decreased by the addition of carbon nanotubes. Moreover, uniform CNT distribution and good adhesion of coatings with the substrate are the major factors that improve the wear performance of the coated surface.

High temperature tribological properties of Ni-based self-lubricating coatings deposited by atmospheric plasma spray

Friction and wear characteristics of atmospheric plasma sprayed Ni-Al–Ag–MoS2, Ni-Al-Ag-MoS2-5 wt% hBN and Ni-Al-Ag-MoS2-10 wt% hBN coatings were examined against alumina ball at a constant load of 5 N and sliding velocity of 0.3 m/s from room temperature (RT) to 800 °C using a high temperature tribometer. The hardness of coatings was found to decrease from 182 HV0.2 to 164 HV0.2 with addition of 5 wt% hBN which further decreased to 155 HV0.2 for 10 wt% hBN. Both the friction coefficient and the wear rate were found to decrease with increasing temperature from RT to 800 °C for all the coatings. However, the coating containing 5 wt% hBN showed a consistently lower coefficient friction and wear rate in comparison to other coatings. The coefficient of friction for Ni-Al-Ag-MoS2-5 wt% hBN coating decreased from 0.5 to 0.23 with an increase in temperature from RT to 800 °C. The observed behavior has been attributed to the presence of NiO, AgMoxOy in the tribo-layer and the synergistic action of hBN which helped Ag and MoS2 in enhancing the friction and wear performance of coatings.

Comparison of Microstructure and Properties of In-Situ TiN- and WC-Reinforced NiCrBSi Composite Coatings Prepared by Plasma Spraying.

In this study, NiCrBSi-30 wt.% TiN composite (NTC) coating was produced on carbon steel via plasma spraying, with NiCrBSi-30 wt.% WC composite (NWC) coating as the comparison object. The microstructure and phase constituents of the composite coatings were characterized using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) techniques, transmission electron microscopy (TEM) and x-ray diffraction (XRD). Atomic force microscopy (AFM) was used to measure electronic work functions. The microhardness and wear performance of coatings were also investigated. The average microhardness of the NTC and NWC coatings was 1000 HV and 850 HV, respectively. In addition, the NTC coating had a wear volume loss of 0.8118 mm3, less than 1.4772 mm3, the volume loss of the NWC coating. This was due to the presence of TiN in the form of nanograins in the composite coating and tighter binding to the matrix.

Improvement of Wear Performance of Nano-Multilayer PVD Coatings under Dry Hard End Milling Conditions Based on Their Architectural Development

The TiAlCrSiYN-based family of PVD (physical vapor deposition) hard coatings was specially designed for extreme conditions involving the dry ultra-performance machining of hardened tool steels. However, there is a strong potential for further advances in the wear performance of the coatings through improvements in their architecture. A few different coating architectures (monolayer, multilayer, bi-multilayer, bi-multilayer with increased number of alternating nano-layers) were studied in relation to cutting-tool life. Comprehensive characterization of the structure and properties of the coatings has been performed using XRD, SEM, TEM, micro-mechanical studies and tool-life evaluation. The wear performance was then related to the ability of the coating layer to exhibit minimal surface damage under operation, which is directly associated with the various micro-mechanical characteristics (such as hardness, elastic modulus and related characteristics; nano-impact; scratch test-based characteristics). The results presented exhibited that a substantial increase in tool life as well as improvement of the mechanical properties could be achieved through the architectural development of the coatings.

The effect of plastic deformation rate on the wear performance of hardfaced coatings

The objective of this study aimed to investigate the effect of plastic deformation rate and heat treatment routes on the wear performance of surfaced coatings obtained using submerged arc welding (SAW) and flux supplemented by additions of alloying powder. Powder of cemented tungsten carbide and high-speed tool steel has been selected as additives to the composition of shielding flux AMS1. Graphite powder was used as addition in two test batches in order to compensate carbon content, which burns out during welding. Results of spectrum analysis have revealed high concentration of alloying elements (Co 0.91–1.573%, W 2.5–9.5%, Mn 1.67–2.39%), which ensured low wear of tested coatings. Tempering at different temperatures showed formation of retained austenite; this fact was confirmed after X-ray diffraction analysis. Different extent of plastic deformation was accomplished to all test batches on the purpose of evaluation of influence on the wear performance of coatings. Wear results showed proportional dependence of rate of deformation and weight loss values. Addition of graphite helped to reach the lowest wear of coatings obtained using the flux alloyed with cemented tungsten carbide and high-speed tool steel (weight loss 0.12 and 0.148 g, respectively).

Characterization of air plasma-sprayed yttria-stabilized zirconia coatings deposited with nitrogen

Air plasma-sprayed (APS) yttria-stabilized zirconia (YSZ) conventional and nanostructured coatings were deposited with nitrogen as the primary plasma gas. Nanostructured coatings were deposited as a function of critical plasma spray parameter (CPSP). Microstructural characteristics, e.g., phase distribution, porosity, microhardness, percentage of partially melted (PM) regions, surface roughness, and wear performance, were evaluated for deposited coatings. Effect of CPSP on wear performance of coatings was most prominent at highest normal load considered. Conventional and nanostructured coatings deposited with nitrogen showed different trends for specific wear rate as a function of normal load. While specific wear rate for conventional coatings was nearly constant, it increased with increasing load for nanostructured coatings. Thus, even though nanostructured coatings provided better wear resistance at lower normal loads, conventional YSZ coatings become more wear resistant at higher loads. For example, at highest normal load considered, specific wear rate of conventional coatings was around 12 % smaller than that for corresponding nanostructured coatings.

Sliding wear performance of nickel-based cermet coatings composed of WC and Al2O3 nanosized particles

Abstract This paper investigates the sliding wear performance of two types of co-electrodeposited cermet coatings composed of nano-sized tungsten carbide (WC) and combined tungsten carbide and alumina (Al2O3) particles incorporated in a nickel matrix. For this purpose, the effects of alternating the ceramic particle concentration in the electrolyte solutions on microhardness of the coatings and also the effect of applied loads on wear performance of the coatings have been studied using ball-on-flat sliding wear tests. The wear track volumes and the progression of wear depths as a function of time and at three applied loads were recorded and wear track morphologies were investigated using FE-SEM and microhardness testing. The results showed that microstructure, microhardness and wear performance of the coatings composed of WC improved when Al2O3 particles were introduced into the matrix. It was also found that the rule of mixtures for composite materials provides a good explanation for microhardness behaviour while Archard equation can explain the changes in wear performance due to the hardness and microstructural changes.

Constant Velocity High Force Microactuator for Stick-Slip Testing of Micromachined Interfaces

A chevron thermal actuator has been implemented as a constant velocity puller in a multiasperity frictional test platform. This platform enables a wide variation of puller velocity (1– $3100~\mu \text{m}$ /s, 3.5 decades), normal load (2– $4500~\mu \text{N}$ , 3.4 decades), and spring constant (0.06– $100~\mu \text{N}/\mu \text{m}$ , 3.2 decades). These characteristics are achieved by leveraging the actuator thermal time constant, which is long compared with the mechanical time constant, in combination with iterative learning control. Good thermal isolation between the actuator and the friction block is achieved by shunting heat to the substrate. Uncoated and FOTAS [tridecafluorotris(dimethylamino)silane, CF3(CF2)5(CH2)2Si(N(CH3)2)3]-coated devices were tested, and normal load induced a transition from steady sliding to stick-slip. This platform could have several important uses for mapping microscale kinetic friction phase diagrams, including determining the stick-slip to steady sliding bifurcation line, performing start-stop tests and instantaneous velocity change tests, and inferring information on wear performance of coatings as a function of load and velocity. [2015-0123]

A Effects of Nano-Particles Additives on Wear Performance of Micro-Arc Oxidation Coating Prepared on 2A12 Aluminum Alloy

Nano-particle reinforced composite coatings were prepared on 2A12 aluminum alloy by micro-arc oxidation and the effect of nano particles on wear performance of coating was studied. By means of SEM, CETR micro-nano-indenter friction and wear tester and white-light interferometer, the surface morphology and the friction and wear property were tested. Results showed that compared with the coating without nano-particle addition, the size and amount of pores on coatings were decreased substantially after additon with 20nm nano-SiO2 particles, 80nm nano-SiO2 particles and 80nm nano-TiO2 particles, and the wear resistance of the micro-arc oxidation coating was improved.

Assessment of Abrasive Wear of Nanostructured WC-Co and Fe-Based Coatings Applied by HP-HVOF, Flame, and Wire Arc Spray

Thermal spray processes have been widely used to minimize losses caused by wear mechanisms. Sprayed deposits using conventional wire and powder materials have been long solving tribological problems in engineering equipment. More recently, the option for new different technologies and consumables like nanostructured powder materials and nanocomposite cored wires have expanded the possibilities for technical solutions. Cored wire technology allows the use of compositions that cannot be drawn into wire form like carbides in metallic matrix and high-temperature materials, thus, intensifying the use of spraying processes with low operating cost to demanding wear and corrosion applications. The objective of this work was to study the mechanical characteristics and wear performance of coatings obtained by Flame, Wire Arc, and HVOF spraying using selected nanostructured WC10Co4Cr, WC12Co, and Fe-based 140 MXC powder and wire materials. Abrasive wear performance of the coatings was determinate following the ASTM G-65 standard. Based on the results, a higher abrasive wear resistance was found for the HVOF-sprayed WC10Co4Cr nanostructured coating.

Three-body wear performance of co-electrodeposited cermet coatings

In this paper, the three-body abrasive wear performance of co-electrodeposited nanostructured cermet coatings composed of two types of dispersed nanosized ceramic particles (Al2O3 and TiO2) in nickel matrix is investigated using procedures and guidelines provided by ASTM G65-04 (Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus). The main objective of this research was to evaluate three-body abrasive wear performance of co-electrodeposited cermet coatings that are designed to protect the surfaces of carbon steel pipes against moving sand grains in the transported bitumen production from some new unconventional oil production techniques such as steam assisted gravity drainage and also in-situ combustion. For this purpose, the effects of particle contents in the nickel matrix, applied current density and time of electrodeposition on the hardness and wear performance of coatings were studied. The microhardness values for coatings were measured using a microhardness Vickers tester equipped with a diamond pyramid indenter. For the three-body abrasive wear tests, the mass loss, surface roughness and depth profile of wear tracks were recorded and the surfaces of wear tracks were investigated using FE-SEM. The increase in microhardness of cermet coatings compared to the pure form of nickel was explained by the rule of mixture for composites and was correlated to grain refining and dispersion strengthening mechanisms which can take place during the co-electrodeposition of coatings. The results showed that the coatings with a greater quantity of Al2O3 in the nickel matrix provide greater microhardness and therefore, an improved wear performance can be expected. Additionally, the wear surface analysis showed that rougher surfaces can be expected for coatings with lower microhardness compared to coatings with greater microhardness and this effect was explained using Archard׳s equation.