Friction Wear Testing Research Articles

Processing and Analysis of Micro-Arc Oxidation Coating on 319S Aluminum Alloy

In this study, a high-hardness and wear-resistant ceramic coating was prepared on the surface of 319S aluminum alloy using the micro-arc oxidation (MAO) technique. The effects of pulse width, negative voltage, and KOH concentration on the MAO coating were investigated, and the microhardness and surface roughness of the coating were measured. The morphology, elemental distribution, and phase composition of the coating were analyzed using SEM, EDS, XRD, and digital microscopy. The influence of the MAO coating on the wear of the 319S aluminum alloy was evaluated using a friction-wear tester. The results showed that in the sodium silicate solution system, with an increase in pulse width, the thickness of the coating gradually increased and the surface hardness initially increased and then decreased. With an increase in negative voltage, the density of the coating first increased and then decreased, the thickness of the dense layer initially increased and then decreased, and the surface hardness initially increased and then decreased. With an increase in the KOH concentration, the coating thickness increased and the roughness initially decreased and then increased. When the pulse width was 3000 ms, the negative voltage was 130 V, and the KOH concentration was 1 g/L, the coating exhibited the best density, with the highest surface hardness of 1426.8 HV and the thickest dense layer of 55 μm. The reduction in surface cracks and improvement in density indicated an enhancement in the hardness and wear resistance of the coating. The decrease in width and depth of the wear scars demonstrated the excellent wear resistance of the coating.

Tribological Properties of TiN Coating on Cotton Picker Spindle

The spindle is the key working part of the horizontal cotton picker, and the wear resistance of its surface directly affects the service life of the spindle. Improving the surface performance of the spindle is fundamental for improving the performance of cotton pickers. To enhance the wear resistance of the spindle surface, this study used the physical vapor deposition (PVD) technique to prepare TiN coating on the spindle substrate surface of the cotton-picking machine to improve the spindle surface rather than the original electroplated chromium coating. The microscopic morphology of the spindle was analyzed by scanning electron microscope (SEM), the mechanical and frictional properties of the spindle were tested by a nanoindentation tester and a friction wear tester, and the morphology of the worn spindle was observed by a portable microscope and a 3D surface profiler. The test results indicated that after the PVD treatment, the surface hardness of the spindle was about 2.5 times that of the electroplated chromium spindle, and the H/E value was 2.2 times that of the electroplated chromium spindle. PVD-TiN spindle showed better mechanical properties. In the friction test, under the same conditions, the wear rate of the PVD-TiN spindle was less than that of the chrome plating spindle. In a field test of 100 hm2, the average wear area of the second tooth tip surface of the electroplated chromium spindle was about 2.17 times that of the PVD-TiN spindle. It was verified that the PVD-TiN spindle surface had better wear resistance than the electroplated chromium spindle. This study has certain research significance for the performance optimization of cotton pickers. Also, it is indicated that PVD-TiN coating can effectively improve the wear resistance of the spindle surface and provides a new method for enhancing the service life of the spindle.

Phosphonium-based ionic liquids as grease additives in rolling bearing tests

Two phosphonium-derived ionic liquids: trihexyltetradecylphosphonium bis(2-ethylhexyl)phosphate (IL1) and trihexyltetradecylphosphonium tricyanomethanide (IL2) were used as additives in lithium complex- (G1) and anhydrous calcium-based (G2) greases at 5 wt%. Friction torque and wear tests were performed using a modified four-ball machine for testing rolling bearings in order to determine the friction and wear reducing properties of these grease samples in a real component. The IL2 improved the friction reduction performance of both greases, especially G1. Both ILs improved the antiwear behaviour of grease G2. Grease G2 showed higher oxidation and thermal ageing levels than G1, but the addition of the ILs, IL2 in particular, improved this issue.

Effects of in situ NbC on the microstructure and high-temperature friction wear properties of 4Cr5MoSiV1 steel

High-temperature wear is a common wear loss in medium heat-resistant hot-work die steels. In this study, NbC-reinforced 4Cr5MoSiV1 composites were prepared by using an in situ method to increase their high-temperature wear resistance. SEM, EBSD, and TEM were used to analyze the morphology, distribution, and microstructure of NbC in composites with different NbC volume fractions. The NbC gradually became “allotriomorphic” and was more uniformly distributed in the composites as the volume fraction increased from 1 vol%, 3 vol% to 5 vol%. High temperature friction wear tests showed that the wear rate of composites with NbC was lower than NbC-free ones. The wear rate of the composites with 5 vol% NbC increased from 2.51 × 10−8 mm3 N−1 ± 0.12 m-1 to 7.07 × 10−8 ±0.35 mm3 N−1m−1. While that of the NbC-free ones increased from 5.05 × 10−8 ± 0.25 mm3 N−1m−1 to 1.727 × 10−7 ± 0.86 mm3 N−1m−1 when the temperature was increased from 200 °C to 400 °C. The wear rate of the NbC-free samples was 1.727 × 10−7 ± 0.86 mm3 N−1m−1 at 400 °C, while that of samples with 5 vol% NbC was 7.07 × 10−8 ± 0.35 mm3 N−1m−1. Their wear mechanisms were oxidative wear, abrasive wear, and adhesive wear. This study provided ideas for work on the development of wear-resistant composites and promising applications in wear-resistant engineering products, such as shovel teeth and shield machine tool rings in mining and tunneling.

Microstructure and wear behavior of arc-shaped 40CrNiMo steel after laser hardening

This study focuses on arc-shaped 40CrNiMo steel; the microstructure characteristics and formation mechanism of the hardened layer at different positions were investigated after laser hardening. Moreover, sliding friction experiments were conducted against GCr15 steel after the conventional heat treatment under dry friction conditions, and the wear characteristics of 40CrNiMo steel hardened after different laser process parameters was analyzed, the wear mechanism in different wear stages was studied. The results show that the martensite reliefs within different austenite grains have no effect on each other. The martensite relief within each individual austenite grain is closely related to the martensite growth in that grain. The laser hardening process parameters for obtaining the effective wear resistance performance of arc-shaped 40CrNiMo steel are as follows: the power was 2010 W, the spot size was 1 × 14 mm2 and the scanning speed was 800 mm/min. At the beginning of the friction wear tests, the wear type of arc-shaped 40CrNiMo steel is mainly abrasive wear. Abrasive wear causes spalling, and oxidation wear can easily occur at the peeling sites. As the dry friction wear tests continued, both oxidation wear and adhesive wear increased, and fatigue wear gradually occurred. The wear mechanism of the grinding plate with a similar hardness at different stages is similar to that of the circular-arc specimen.

Tribological properties of PEEK-based composite coating prepared by thermal spraying

To improve the friction wear performance of the aluminum alloy scroll disc of the scroll compressor under dry friction conditions, the C-MoS2-PTFE-PEEK coating was prepared on the surface of the 4032 aluminum alloy substrate by thermal spraying. The friction and wear performance of C-MoS2-PTFE-PEEK coating under dry friction conditions was investigated via friction wear test, hardness test, coating adhesion scratch test, x-ray diffraction analysis test, morphological characteristics, element distribution test, And XPS photoelectron spectrometer. Moreover, the frictional wear performance of the C-MoS2-PTFE-PEEK coating was compared with that of the anodic oxide film of 4032 aluminum alloy and the Ni-plated coating of 4032 aluminum alloy. The results show that the hardness of C-MoS2-PTFE-PEEK coating is 102.8 HV0.2. The C-MoS2-PTFE-PEEK coating has good lubrication properties under dry friction conditions due to the synergistic effect of MoS2 and PTFE, which can effectively resist deformation and reduce the coefficient of friction. The average friction coefficient under 5N, 10N, and 15N loads are 0.12, 0.15, and 0.23, respectively. The Graphite can effectively form a solid lubricating film, improve the adhesion resistance of the composite, and cause the shallow and small wear mark of C-MoS2-PTFE-PEEK coating; The wear rate and friction coefficient of C-MoS2-PTFE-PEEK coating under different loads are lower than that of the anodic oxidation film of 4032 aluminum alloy and the Ni-plated coating of 4032 aluminum alloy, showing excellent anti-friction and wear resistance. The wear mechanism of C-MoS2-PTFE-PEEK coating under different loads is mainly fatigue wear, adhesive wear, and abrasive wear.

Microstructure and Wear Resistance of Ni–WC–TiC Alloy Coating Fabricated by Laser

In this study, a Ni–WC–TiC alloy coating was fabricated by laser to improve the wear resistance and service life of Cr12MoV die steel. The microstructures and phases of the coating were analyzed by a scanning electron microscope (SEM), an energy dispersive spectrometer (EDS), and X-ray diffraction (XRD). The properties of the coating were tested by a hardness and friction wear tester. The results show that the coating has a good metallurgical bond with the substrate. The microstructures from top to bottom are mainly equiaxed crystal, columnar dendrite, and cellular dendrite. Combined with the physical phase analysis and elemental distribution of the coating, there are some phases, such as γ~(Fe, Ni), Cr23C6, WC, TiC, Fe3W3C, and Cr2Ti. Compared with the Cr12MoV steel substrate, the Ni–WC–TiC alloy coating has good properties of hardness and wear resistance. In the coating, the background region of the grains is γ~(Fe, Ni). From the EDS results, it can be seen that there are some rod-like particles, Cr23C6, which are uniformly distributed on the top of the coating. Some W and Ti carbides form in grains. The addition of TiC particles improves the WC particles refinement. The highest hardness of the coating is 770.7 HV0.5, which is approximately 3.3 times higher than that of the substrate. The wear volume is 0.26 mm3, or approximately 8.6% of the substrate, which is contributed to the reinforced phases and finer microstructure of the coating. The wear volumes of the Cr12MoV substrate are 1.8 and 4.5 mm3 at 20 and 60 min, respectively. While the wear volumes of the Ni–WC–TiC coating are 0.2 and 0.7 mm3 at 20 and 60 min, respectively. The increased amplitude of the coating’s wear volume is smaller than that of the substrate. The results show that this Ni–WC–TiC alloy coating is helpful for improving the properties and service life of Cr12MoV die steel.

The effects of resin rate (wt-%) on different temperature performance of newly designed friction composites for automobile brake lining applications

ABSTRACT Choosing the amount of binder resin in a brake lining composition is important in terms of avoiding structural deterioration of the brake lining composite and resisting mechanical and thermal stresses at different temperatures. This study evaluated the performances of new brake lining composites with 15% and 20% novolac resin additives by performing wear tests in different temperature environments. Friction wear tests were performed according to ASTM G99 using pin-on-disc test devices at temperatures of 23°C, 150°C and 300°C. The hardness and density of the samples increased by 2.4% and 3.7%, respectively, with the increase of the novolac resin ratio in the composition. In general, it was observed that the friction coefficient, thermal conductivity and vibration increased in parallel with the resin ratio. In addition, increasing the test temperature led to an increase in the friction coefficient.

Microstructure and properties of composite carbide (Ti,V)C enhanced Ni-based coatings by laser cladding

The strengthening mechanism of composite carbide (Ti,V)C enhanced Ni-based coatings was discussed by combined calculations and tests to obtain the influence mechanism of the microstructure and properties. The first principle was used to calculate the microstructure, formation energy, mechanical properties, anisotropy, and electronic properties of composite ceramic phase (Ti,V)C. It explored the effect of changes in Ti and V content on the properties of composite carbides. The influence mechanism of different Ti/V ratios on the performance and organization of coatings was analyzed by experiments to clarify the evolution process of the molten pool at different contents. The properties and crystal parameters of the composite phase greatly changed with increased V. The recombination of covalent bonds was an important reason for the increased hardness of the composite carbide. TiC with low Gibbs free energy precipitated preferentially at the solidification stage of the molten pool. The subsequent VC tended to form (Ti,V)C composite carbides with TiC as heterogeneous nucleation sites. When powder ratio Ti:V = 3:1, the hardness and wear resistance of the coating were better than those reinforced by single carbide TiC through hardness and friction wear tests. The difference in grain morphologies in the coating was the main reason for the change in coating performance. Research results provide a theoretical reference and basis for preparing composite carbide-reinforced coatings by laser cladding.

Evaluation of Methods for Superhard Material Processing to Ensure Wear Resistance of Finished Structures

New alloys and their processing methods to increase hardness and wear resistance are constantly being searched. After frictional wear and water suspension testing at various exposure angles, the impact of various composite processing techniques (laser, pulsed plasma, and freezing at −192 °C with varying exposure times from 16 to 24 h in increments of 2 h) on the strength and elasticity of the Ti(0.75)-Al2O3(0.05)-WC(0.2) alloy was investigated. The preservation of qualities after the wear test, particularly after friction, was found to be improved by the laser’s and the pulses’ effects. In comparison to laser processing, pulsed plasma processing increased the material’s hardness, elasticity, compressive strength, and tensile strength for practically all experimental types. The alloy’s tensile strength was at its peak (3.8%), following laser processing, and fell by a maximum of 0.383% when the suspension was used at the highest angle. The attribute that underwent the most beneficial change as a result of pulsed plasma processing was elasticity. This sort of processing produced a final value of 1,482 MPa. Wear-insensitive tests revealed a considerable degradation of the test material’s characteristics. The alloy’s hardness was raised by cryogenic processing. Under exposure to negative temperatures for 24 h, the highest value was attained.

Theoretical and Experimental Study of Friction Characteristics of Textured Journal Bearing

The proposed lubrication theory of textured journal bearing is a major innovation in the study of the tribological properties of surface morphology. When it comes to the study of surface topography, it is essential to consider the effect of surface roughness when analyzing the characteristics of journal bearing. In this paper, a Reynolds equation containing longitudinal roughness is established for journal bearing and solved by the finite difference principle to obtain the bearing load and friction characteristics. Subsequently, a combination of laser etching and ultrasonic vibration milling processes was used to prepare 5 µm, 20 µm, and 40 µm bearing friction subsets with square micro-texture surfaces. The analysis of the results shows that the surface roughness distributed in the non-texture region can substantially increase the oil film pressure. When the roughness profile and the surface weave work together, the presence of a surface texture with an optimum depth of 5 µm within a roughness range of less than 1.6 µm can improve the load-bearing characteristics by a maximum of 43%. In the study of the preparation of textured bearing friction substrate, it was found that laser etching can ablate the surface of the friction substrate to a depth greater than 20 µm with the ideal effect, while the surface texturing to a depth of 5 µm is more suitable using an ultrasonic vibration processing process. In the simplified journal bearing operating condition, the frictional wear test shows that if the effect of roughness is considered, the frictional force of the depth of 20 µm and 40 µm is significantly reduced and changes less with increasing load, while the frictional force of the textured frictional pair with a depth of 5 µm is improved but significantly affected by the load carrying capacity. Therefore, when the difference between the roughness profile and the depth of the texture is of a small order of magnitude, it indicates that the effect caused by the roughness factor is not negligible.

Comparison of the Effect of Mechanical and Ultrasonic Agitation on the Properties of Electrodeposited Ni-Co/ZrO2 Composite Coatings

Ni-Co/ZrO2 composite coatings were fabricated by electrochemical deposition from sulfamate solutions containing zirconia nanoparticles. The main purpose of this research was to evaluate the effect of mechanical stirring and ultrasonic agitation in plating solutions on the structure and properties of Ni-Co/ZrO2 composite coatings. The morphology, microstructure, microhardness, anti-corrosion and wear resistance of the composites were investigated via scanning electron microscopy, X-ray diffraction, Vickers microhardness testing, electrochemical workstation utilization and friction wear testing. The hardness, friction coefficient, wear loss, corrosion rate of the composite coating prepared with mechanical stirring, and ultrasonic agitation were 533 and 680 HV; 0.40 ± 0.02 and 0.35 ± 0.02; 2.15 × 10−5; 0.85 × 10−5 g·m−1; and 0.36 and 0.07 mm/year, respectively. In comparison to mechanical stirring, ultrasonic agitation could more uniformly disperse the zirconia nanoparticles to obtain Ni-Co/ZrO2 composite coatings, which has simplicity and compactness.

Numerical and Experimental Investigations of Cold-Sprayed Basalt Fiber-Reinforced Metal Matrix Composite Coating.

The aluminum-basalt fiber composite coating was prepared for the first time with basalt fiber as the spraying material by cold-spraying technology. Hybrid deposition behavior was studied by numerical simulation based on Fluent and ABAQUS. The microstructure of the composite coating was observed on the as-sprayed, cross-sectional, and fracture surfaces by SEM, focusing on the deposited morphology of the reinforcing phase basalt fibers in the coating, the distribution of basalt fibers, and the interaction between basalt fibers and metallic aluminum. The results show that there are four main morphologies of the basalt fiber-reinforced phase, i.e., transverse cracking, brittle fracture, deformation, and bending in the coating. At the same time, there are two modes of contact between aluminum and basalt fibers. Firstly, the thermally softened aluminum envelops the basalt fibers, forming a seamless connection. Secondly, the aluminum that has not undergone the softening effect creates a closed space, with the basalt fibers securely trapped within it. Moreover, the Rockwell hardness test and the friction-wear test were conducted on Al-basalt fiber composite coating, and the results showed that the composite coating has high wear resistance and high hardness.

Preparation and Characterization of Pulse Electrodeposited Ni/W-SiC Nanocomposite Coating on Mild Steel Substrate

In order to improve the performances of metal containers, furnace bodies and agricultural tools manufactured by mild steels, Ni/W-SiC nanocomposites are prefabricated on mild steel substrate by the pulse electrodeposition (PED) method. The morphology, texture, microstructure, microhardness, and wear performances of Ni/W-SiC nanocomposites are examined by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), dispersive X-ray spectroscopy (EDX), hardness tester, and friction wear testing. The results indicate that the SiC size in nanocomposites is ~32.4 nm when its concentration in electrolytes is 7 g/L. The S1 and S4 nanocomposites’ microstructures (the S1 composite was prefabricated at 4 g/L, and the S4 composite was deposited at 13 g/L) reveal many large cauliflower-shaped grains. However, the S2 nanocomposite (the S2 composite was obtained at 7 g/L) demonstrates the homogeneous, finest and smoothest surface morphology. The diffraction angles of S1 nanocomposite are 41.2°, 51.7°, and 71.2° depicting the sharpest diffraction peaks, corresponding to the (1 1 1), (2 0 0), and (2 2 0) crystal planes of Ni-W grains, respectively. Moreover, the S2 nanocomposite exhibits the lowest wear depth and width of 34.2 μm and 5.5 mm, respectively. Some shallow and fine scratches on the as-described nanocomposites’ surface indicate its excellent tribological performance. However, the S4 nanocomposite exhibits a wear depth of 86.3 μm and a width of 11.9 mm.

A tribological performance of vegetable-based oil combined with GNPs and hBN nanoparticles on the friction-wear tests of titanium grade 2

In this study, friction performance, surface textures, and wear mechanisms of Titanium Grade (Gr) 2 material were investigated with a pin-on-disc tester. The study was carried out under dry, basefluid (vegetable-based oil), graphene nanoplatelets (GNPs), hexagonal boron nitride (hBN) nanofluids, and GNPs+hBN hybrid nanofluid conditions. In addition, the fluid's viscosity and thermal conductivity coefficient measurements were carried out. As the performance criterion of the pin-on-disc test, coefficient of friction (COF), vibration peak values, surface roughness (Ra profile), and topography, wear and wear mechanisms were preferred. With the data obtained after pin-on-disc tests, it can be said that the GNPs+hBN hybrid nanofluid condition shows the best performance compared to other conditions. GNPs+hBN hybrid condition, compared to the dry condition, decreased the COF average, vibration average, and Ra values by 20%, 52%, and 62%, respectively.

Properties of Multilayered CrN/VN Films Prepared Using a Hybrid System of High-Power Impulse Magnetron Sputtering and Pulsed Magnetron Sputtering

Nanomultilayered chromium nitride (CrN)/ vanadium nitride (VN) films with different layer thicknesses were synthesized on Si substrates using a hybrid system of reactive high-power impulse magnetron sputtering (HiPIMS) and pulsed magnetron sputtering. The microstructure and properties of the nanomultilayered CrN/VN films were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), the nanoindentation method, and the friction wear test. The XRD results showed that the multilayered films exhibited nanocrystallite structure with a (200) preferred orientation, and the estimated crystallite size was not highly dependent on the CrN and VN layer thicknesses. Inserting the VN layers decreased the compressive stress slightly compared to that of the CrN monolayer film and increased the hardness by 4-5 GPa compared to that of the CrN and VN monolayer films. The friction coefficient of the multilayered films strongly depended on the CrN layer thickness rather than on the VN layer thickness.

Investigation of the Microstructure and Wear Properties of Laser Clad Al-Si Coatings Containing Different Y2O3 Contents

Y2O3-reinforced Al-Si alloy coatings were prepared on the surface of a Mg alloy by the laser cladding technique. The microstructure, hardness, and wear resistance of the coatings were analyzed using an X-ray diffractometer, a scanning electron microscope, an energy spectrometer, a Vickers hardness tester, and a friction wear tester. The effect of different additions of Y2O3 on the microstructure and properties of the coatings was investigated. The results indicate that the addition of Y2O3 leads to a significant refinement of the grain size and a denser microstructure of the coatings. Coatings with a high Y2O3 content provide superior hardness and wear resistance. With a Y2O3 content of 7.5 wt.%, the coating exhibits the finest grain size, highest hardness, and smallest wear volume. Excessive amounts of Y2O3, however, cause a reduction in the surface properties of the coating.

Effect of ion beam etching on the tribological performance of laser textured Co-Cr-Mo alloy

The micro-texture is a relatively well-established method for improving the tribological performance of Co-Cr-Mo alloy. Currently, to fabricate the micro-textures on the alloy surface, laser micromachining technology is the commonly used method. However, the low fabrication quality (such as irregular protrusions inside and on the edges of the micro-textures) caused by laser ablation limits the numerous application of laser surface textures. Therefore, a novel method of combining nanosecond (ns) pulse laser texturing with ion beam etching was proposed to prepare the micro-textures on the surface of Co-Cr-Mo alloy. The tribological properties before and after ion beam etching were tested by ball-disk friction wear test for three different micro-texture morphologies (grooved micro-texture (G); hexagonal micro-texture (H); concentric micro-texture (C)), and the micro-topography, mechanical properties and wettability of the ion beam/laser textured Co-Cr-Mo alloy were also investigated. The results showed that the friction coefficient and wear amount of the specimen surface were reduced after ion beam etching, and the ion beam/laser textured sample with hexagonal micro-textures showed the best wear performance, with the average friction coefficient reduced by 11.9 % and the wear amount of polyether ether ketone balls reduced by 14.9 %. The worn surface of the ion beam etched samples was relatively smooth, and the adhesive wear was also reduced. This report established the friction reduction model of ion beam/laser textured alloy and revealed the friction reduction mechanism of ion beam etching, providing a new idea of fabricating high-quality micro-textures to enhance the wear performance of artificial hip joints.

Effect of C2H2 flow rate and a Ti/TiN/TiCN interlayer on the structure, mechanical and tribological properties of a-C:H films deposited using a hybrid PVD/PECVD process with an anode-layer ion source

Diamond-like carbon (DLC) films were deposited onto 316L stainless steel using the hybrid physical vapor deposition (PVD)/plasma-enhanced chemical vapor deposition (PECVD) process with an auxiliary anode-layer ion source at C2H2 flow rates of 40–100 sccm to enhance mechanical and tribological properties of a-C:H films. The films were characterized using transmission electron microscope (TEM), field emission scanning electron microscopy (FESEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), nanoindentation and ball-on-disk rubbing tribometry. The hardness, tribological properties and interfacial bonding were significantly improved in the presence of the Ti/TiN/TiCN interlayer deposited by high-power impulse magnetron sputtering (HiPIMS). Results showed that a-C:H films were uniform and dense, the sp3 C content increased with an increase in the C2H2 flow rate from 40 to 80 sccm, and decreased when it was further increased to 100 sccm. The a-C:H film with the interlayer prepared at 80 sccm C2H2 exhibited the highest hardness (27.2 ± 0.5 GPa), H/E (0.137), and H3/E2 (0.510). Moreover, friction-wear tests demonstrated that the incorporation of the Ti/TiN/TiCN layer increased the wear resistance of the a-C:H film, achieving the lowest coefficient of friction (CoF, 0.148), wear rate (1.08 × 10−9 mm3 N−1 mm−1) and width of the wear track (177 μm) at 80 sccm C2H2.

Investigation on the interaction between corrosion and wear of U68CuCr rail steel with different corrosion periods

The interaction between corrosion and wear of U68CuCr rail steel was investigated. The samples were alternately subjected to the neutral salt spray tests with different corrosion periods (6, 24 and 48 h) and rolling friction wear test for 4 h. The corrosion and wear rates after the corrosion test and wear test were measured, respectively. The surface morphologies of the rail samples after the corrosion test and wear test, and the subsurface morphologies of the rail samples after the last test were observed. The results show that compared to the samples without corrosion, the damage degree of the corroded samples after wear tests became severer, and the wear mass loss and wear rate increased with the number of corrosion-wear cycle. In addition, rolling contact fatigue cracks initiated and propagated at a high angle and the structure of sample surface became unstable after corrosion, leading to easy spalling during the following wear tests compared to the only wear tests without corrosion. Moreover, the plastic deformation layer was destroyed by corrosion and the area of wear pits increased after the interaction test. Therefore, wear was accelerated by corrosion, and the longer is the corrosion period, the more severe is the wear degree. Additionally, regarding to the effect of wear on corrosion, corrosion was accelerated by wear. This is attributed to the facts that (1) the wear pits and delamination on the worn samples provided favorable locations for the deposition of the salt spray solution during the corrosion, and (2) the subsurface and matrix were corroded along rolling contact fatigue cracks to increase the corrosion rate during the corrosion test after wear. This work provides a foundation to the further investigation on the interaction between corrosion and wear of steels.