Sliding Wear Tests Research Articles

High-temperature oxidation and tribological behaviors of WTaVCr alloy coating prepared by double glow plasma surface alloying technology

Tungsten-based refractory high entropy alloys (RHEAs) are a potential candidate for plasma-facing materials (PFM) due to their excellent properties. However, the oxidation resistance of W-based RHEAs is poor. Moreover, there is still a lack of research on the evaluation of room temperature wear. In this work, several WTaVCr alloy coatings were fabricated by double glow plasma surface alloying (DGPSA) technology at different temperatures and different source ratios. The microstructure of WTaVCr coatings exhibited BCC solid solution phase. The coatings were compact and uniform. The scratch test indicates that the coating combines the substrate well. The surface hardness of the samples increases significantly after alloying, which is 5 times that of the substrate. Sliding wear tests were performed on the coating as well as the substrate. The fairly low specific wear rate of the coating (W31.7Ta13.3V42.9Cr12.2) proved its excellent wear-resisting property (The wear rate was 8 × 10−7 mm3/N∙m, which was two orders of magnitude lower than that of the substrate), and the dominant wear mechanism was abrasive wear and oxidative wear. The coating (W45Ta45.4V4.5Cr5.1) showed a favorable oxidation resistance, and a continuous Cr2O3 protective layer was formed on the surface. The oxidation resistance of the coating was approximately a quarter of the W-substrate.

Effects of surface roughness and counter body variables on the dry sliding wear behavior of AISI 4140 steel based on the elastoplastic flattening model

This study aimed to determine the effect of surface roughness and counter body material on the wear behavior of AISI 4140 steel based on the elastoplastic flattening model. Most studies in tribology based on the elastoplastic regime focus on modeling the contact between a sphere and a flat surface. However, these models’ main challenge is determining the real contact area. This study claims that the real contact area can be detected with high accuracy through interface software used in optical microscopy. The sample surfaces were roughened and then supposed to dry sliding wear tests using the AISI 52100 and Al2O3 abrasive counter bodies under varying loads and test durations. It was concluded from the calculations that the sample’s surface roughness value significantly affects the contact pair’s plasticity index and, thus, the sample’s wear behavior against the counter body material. Higher plasticity index values indicating the abrasive effect were obtained with the Al2O3 ball, which has a higher hardness and elasticity modulus than the AISI 52100 steel ball. The surface damage of the sample with a high roughness value was less than the other samples. The COF values obtained with the steel ball were detected as lower than that of the alumina ball. Also, it was seen that the surface roughness parameter and plasticity index values calculated were compatible with the wear characteristics of the test samples. As a result, determining the real contact area between the contacting surfaces and its usability in calculating the elastoplastic flattening model parameters were experimentally tested and verified.

Effect of thermal expansion on the high temperature wear resistance of Ni-20%Cr detonation spray coating on IN718 substrate

The temperature-dependent materials properties on the dry sliding wear resistance of the detonation sprayed Ni-20%Cr coating have been studied. In-situ high-temperature X-ray diffraction (HT-XRD) was used to investigate high-temperature properties such as stress relieving, recrystallization, and thermal expansion. The dry sliding wear test was performed by using a ball-on-disc tribometer by sliding velocities (0.1 m/s), varying loads (6 N and 10 N), and temperatures (25 °C and 850 °C) against alumina (Al2O3) ball. The phase evolution, thermal expansion, crystallite size, and lattice strain were determined by the Williamson-Hall method. Field emission scanning electron microscopy and a non-contact optical profilometer was used to characterize the wear scar and calculate the wear rate. The wear test results demonstrated that the as-deposited coatings coefficient of friction (CoF) and wear rate (ω) continuously decreased as the temperature increased. The primary wear mechanism changed from abrasive and surface fatigue to adhesive and oxidative wear. The impact of stress relieving, recrystallization, and forming a composite tribolayer (Cr2O3, NiO) at elevated temperatures reduced the friction and enhanced the wear resistance. The effect of stress relieving, recrystallization, thermal expansion, and oxidation on the wear resistance of the coating has been discussed with a suitable mechanism.

Tribological properties of novel Al 7075(T6)-SiC-crumb rubber-MoS2-based hybrid composites: An experimental approach towards green revolution

In the present study, an experimental approach is conducted for analyzing the tribological attributes of the novel green hybrid metal matrix composites fabricated by an advanced vacuum-sealed bottom pouring stir casting comprised of Al 7075(T6) as a base metal doped with three distinct reinforcements as silicon carbide, crumb rubber, and molybdenum disulfide. Six casting process variables such as SiC, crumb rubber, MoS2, stirring speed, stirring time, and pouring temperature have opted for the fabrication of green hybrid composites via Taguchi L18 mixed-level orthogonal array. Tribological studies (in terms of wear loss, frictional force, and coefficient of friction) on fabricated green composites are examined via the high-temperature rotary pin-on-disc tribometer with fixed process parameters (such as wear track diameter, sliding speed, normal load, sliding distance, disc rotation speed, and test duration) under dry sliding wear test. Moreover, the wear test is also executed under variable temperature conditions of 35 °C, 100 °C, 200 °C, and 300 °C. The metallography of synthesized green composites and their worn surfaces is inspected via a metallurgical microscope and scanning electron microscopy–energy dispersive X-ray spectroscopy techniques. Besides, the analysis of variance is implemented to predict the percentage contribution of the combined process variables for wear loss analysis. In contrast to the as-cast specimen (S0), the developed hybrid pin specimen (S3) yields a tremendous improvement in its metallurgical and tribological attributes under varying temperature conditions. Owing to the merits of the proposed composite, it can be extensively used in lightweight, high-temperature, and wear-resistant applications of various automotive and aerospace engineering.

Understanding the effect of Pt doping on the microstructure, mechanical and tribological properties of CrN coating

This study investigated the effect of Pt doping on the microstructure, mechanical and tribological property of the CrN coating. Results showed that this CrN coating exhibited a loose columnar texture and a rough surface with a high Ra value of 3.07 ± 0.035 nm. A prominent coherent growth within the grain appeared in this coating, which provides strong bond strength of coating texture resulting in a high H/E ratio of 0.083. This CrN coating showed an unidirection scratch fracture, but also possessed good wear resistance with a smooth wear track. Pt doping induced a nearly single preferential growth of (200) plane, and resulted in a dense columnar texture and a smooth surface. The Ra value was 2.71 ± 0.285 nm for the CrN–Pt9.55 coating, and decreased to 1.04 ± 0.14 nm for the CrN–Pt17.73 coating. However, Pt atoms greatly blocked the coherent growth within the grain, and further degraded the bond strength of coating texture. The CrN–Pt9.55 coating showed serious multidirection scratch fracture, but also experienced severe wear accompanied with numerous cracks and adhesive debris. In contrast, the hindrance effect and mechanical degradation were further strengthened with the increase of Pt doping content. This CrN–Pt17.73 coating suffered from most severe fracture damage and debris adhesion during the scratch and sliding wear tests.

Oxidation of a refractory high entropy alloy (RHEA) at moderate temperatures for wear related applications

This study was initiated to exploit the poor oxidation resistance of a RHEA, namely HfNbTaTiZr, to enhance its surface hardness and wear performance. In this regard, samples sliced from vacuum arc melted HfNbTaTiZr ingots having a hardness of ∼400 HV were held at two different temperatures (450 and 600 °C) for 3 h in air. The structural examinations conducted by using X-ray diffraction (XRD) and Raman analysis along with an energy dispersive spectrometer (EDS) equipped scanning electron microscope (SEM) revealed that the samples were covered with a complex HfNbTaTiZrO11 type oxide layer (OL) having the hardness of ∼1550 HV. The average surface roughness (Ra) and the thickness of the OLs were measured as ∼0.13 μm and ∼ 1 μm after oxidation at 450 °C and ∼ 0.29 μm and ∼ 8 μm after oxidation at 600 °C, respectively. The protective nature of the OLs was confirmed by dry sliding wear tests employed at room temperature against alumina balls under a contact pressure of ∼0.5 GPa. This led to 240- and 45-times higher wear resistance for the samples oxidized at 450 and 600 °C, respectively. During the wear tests, the untreated sample was exposed to severe wear owing to the accumulation of heavy plastic deformation at the contact surface, while for the oxidized samples wear progressed in an elastic deformation regime on the OLs resulting in mild wear. However, the roughness of the OLs played a crucial role on the wear resistance of the oxidized samples, so that the oxidation temperature of 600 °C, which imposed a higher Ra value, resulted in a reduction in wear resistance when compared to the oxidation temperature of 450 °C, which formed a smoother OL.

Room and Elevated Temperature Sliding Friction and Wear Behavior of Al0.3CoFeCrNi and Al0.3CuFeCrNi2 High Entropy Alloys

In this study, processing–structure–property relations were systematically investigated at room and elevated temperatures for two FCC Al0.3CoFeCrNi and Al0.3CuFeCrNi2 high-entropy alloys (HEAs), also known as complex concentrated alloys (CCAs), prepared by conventional arc-melting. It was determined that both alloys exhibit FCC single-phase solid solution structure. Micro-indentation and sliding wear tests were performed to study the hardness and tribological behavior and mechanisms at room and elevated temperatures. During room-temperature sliding, both alloys exhibit similar friction behavior, with an average steady-state coefficient of friction (COF) of ~0.8. Upon increasing sliding temperatures to 300 °C, the average COF decreased to a lowest value of ~0.3 for Al0.3CuFeCrNi2. Mechanistic wear studies showed this was due to the low interfacial shear strength tribofilms formed inside the wear tracks. Raman spectroscopy and energy dispersive spectroscopy determined the tribofilms were predominantly composed of binary oxides and multi-element solid solution oxides. While the tribofilms at elevated temperatures lowered the COF values, the respective wear rates in both alloys were higher compared to room-temperature sliding, due to thermal softening during 300 °C sliding. Thus, these single FCC-phase HEAs provide no further benefit in wear resistance at elevated temperatures, and likely will have similar implications for other single FCC-phase HEAs.

WEAR RESISTANCE AND MICROSTRUCTURE OF THE CeO2-MODIFIED STELLITE6 BASE TUNGSTEN INERT GAS CLAD COMPOSITE COATINGS ON THE Ti–6Al–4V ALLOY

To improve the wear resistance of the titanium alloy, the tungsten inert gas cladding was used in this study. The Stellite6-CeO2-MnSi-B4C composite coatings were fabricated on the Ti–6Al–4V (TC4) alloy by the preset-powder cladding process. The scanning electron microscope analysis of the composite coatings showed the effect of the different compositions on the microstructure. The crack propagations could be retarded to some extent due to an action of B4C. The high-resolution transmission electron microscope revealed the formation of the amorphous phases and the nanocrystals. The formation of amorphous phases could be induced by the lattice distortions. The results of sliding wear tests on the samples showed that the wear resistance of TC4 could be improved due to the synergy effects of the fine grain/ dispersion/ solid solution strengthening.

Improved High‐Temperature Softening Resistance and Wear Resistance of AISI M42 High‐Speed Steel by N‐Alloying

Herein, a novel high‐nitrogen (0.18 wt%) M42 high‐speed steel is fabricated by pressurized metallurgy. The high‐temperature softening resistance of N‐free and 0.18N steels is evaluated by hardness measurement at room temperature after additional heating at 600 °C for various times, and the high‐temperature wear resistance is evaluated by ball‐on‐disk dry sliding wear test at 600 °C. The microstructure is characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), and high‐resolution transmission electron microscope (HRTEM). The results indicate that the hardness of 0.18N steel is 2–3 HRC higher than that of N‐free steel after additional heating at 600 °C for 4–120 h. The superior high‐temperature softening resistance of 0.18N steel is primarily ascribed to the smaller coarsening rate of M2C secondary carbides. Under the dry sliding condition at 600 °C, the wear rate of N‐free steel is approximately 1.5 times higher than that of 0.18N steel. The better high‐temperature wear resistance of 0.18N steel is primarily because the superior softening resistance makes it maintain higher hardness during the wear process to provide stronger support for the oxide layer and increase the protective ability of oxide layer to steel.

Effect of Laser-Textured Surface of Ti6Al4V on Frictional Wear Behavior

The need for titanium and its alloys has led to a significant increase in commercial manufacturing, although this material’s poor tribological qualities have been a drawback. The present study was to determine the effect of laser-textured surfaces to enhance Ti6Al4V surface wear performance. The sample underwent laser texturing based on pre-set parameter values at 15 W power at a laser scanning speed of 200 mm/s with a frequency of 50 kHz. The surface morphological and topological profile of laser-textured Ti6Al4V was characterized with also the surface microhardness. A comparative appraisal of wear rate (WR) and coefficient of friction (COF) for related samples of as-received Ti6Al4V and laser-textured Ti6Al4V was performed under dry and oil sliding conditions. The results revealed that the formation of oxidation due to the frictional force and plastic displacement plays a role of abrasive to the laser-textured surface and may result in increasing the COF. The wear rate of the laser-textured surface of Ti6Al4V exhibited 88.31% improvement compared to the as-received Ti6Al4V in the dry sliding wear test. It was proved that Ti6Al4V could benefit from LST to gain effectively enhanced wear performance.

Preparation of Carbon Nanotubes/Alumina Hybrid-Filled Phenolic Composite with Enhanced Wear Resistance

Hybrid fillers can be produced via various methods, such as physical mixing and chemical modification. However, there is a limited number of studies on the effect of hybridisation on the mechanical performance of hybrid filler-reinforced polymer composites, especially in the context of wear performance. This study investigated the wear resistance of carbon nanotubes (CNTs)/alumina hybrid-filled phenolic composite, where two hybrid methods were used to produce the CNTs/alumina hybrid filler. The CNTs/alumina (CVD hybrid) was synthesised using the chemical vapour deposition (CVD) method, whereas the CNTs-/alumina (physically hybrid) was prepared using the ball milling method. The CNTs/alumina hybrid filler was then used as a filler in the phenolic composites. The composites were prepared using a hot mounting press and then subjected to a dry sliding wear test using a pin-on-disc (POD) tester. The results show that the composite filled with the CVD hybrid filler (HYB composite) had better wear resistance than the composite filled with physically hybrid filler (PHY composite) and pure phenolic. At 5 wt%, the HYB composite showed a 74.68% reduction in wear, while the PHY composite showed a 56.44% reduction in wear compared to pure phenolic. The HYB composite exhibited the lowest average coefficient of friction (COF) compared to the PHY composite and pure phenolic. The average COF decreased with increasing sliding speeds and applied loads. The phenolic composites' wear and average COF are in the order HYB composite < PHY composite < pure phenolic under all sliding speeds and applied loads.

Experimental investigation on the spalling failure of a railway turnout made from Hadfield steel

In a rail track structure, a turnout is used as a transition between straight and branching rails and therefore withstands complex dynamic rolling and impact loading. This paper reports a comprehensive failure investigation of a railway off-track turnout made from Hadfield austenitic cast steel. The worn turnout was examined using optical microscopy, scanning electron microscopy, micro-hardness, and quantitative X-ray diffraction analyses. A ball-on-disc sliding wear test was also applied to evaluate the impact of work-hardening on the wear property. The turnout exhibited surface embrittlement, severe cracking, delamination, and spalling characteristics. Severe plastic deformation of the worn turnout was observed with the formation of densely packed mechanical twins, which facilitated crack propagation. The rail top developed a gradient hardness (HV0.1) profile from the rail top of 8.9 GPa, the cracked subsurface of 5.9 GPa to the bulk steel of 2 GPa. The rail top was also found to have accumulated an extremely high residual compressive stress of 500–650 MPa. Strain induced martensite transformation was repeatedly evidenced by X-ray diffraction peak of the ferritic (110) plane although the highly strained and nanocrystallised ferrite was only detected on the severely deformed rail top. Comparative sliding wear tests showed highly deteriorated wear resistance of the strain-hardened rail top as compared to the bulk steel.

Sliding wear and rolling contact fatigue behavior of M50 steel coated with atomic layer deposited lubricious oxide nanolaminates

Atomic layer deposition (ALD) was employed to deposit highly conformal and uniform nanolaminate coatings of ZnO/Al2O3/ZrO2/Al2O3 on M50 bearing steel substrates for sliding wear testing, as well as on CrN coated M50 bearing steel cylindrical rods and cups for three-ball on rod rolling contact fatigue (RCF) testing. The nanocrystalline ZnO top layer was structurally-engineered to achieve low surface energy, textured (0002)-oriented grains. To achieve this preferred orientation, amorphous Al2O3 was deposited as a seed layer, while crystalline ZrO2 acted as a high toughness/load bearing layer. The ALD nanolaminates reduced both the sliding wear rate (2 × 10-7 mm3/N·m) and enhanced the RCF resistance of M50 steel out to 6 million rolling contact fatigue cycles with no signs of spall. Based on cross-sectional transmission electron microscopy studies inside the wear surfaces, it was determined that sliding and rolling-induced plastic deformation was observed in ZnO layer where basal plane stacking faults were sheared parallel to the sliding and rolling directions. This intrafilm shear velocity accommodation mode mitigates the friction, reduces wear, and inhibits brittle fracture. Therefore, ALD ZnO/Al2O3/ZrO2/Al2O3 nanolaminates are candidate coatings that provide both sliding and RCF resistance in moving mechanical assemblies that require thin (∼10-300 nm), uniform and conformal solid lubricants.

Optimization and wear behaviors of 316L stainless steel laser cladding on rail material

Laser cladding is a potential technology for repairing the rail with side wear. The laser processing parameters should be optimized and the wear behaviors of clads should be analyzed before its application. Therefore, single-pass and multi-pass laser cladding experiments of 316L stainless steel powder with different laser powers, scan speeds, scan modes (directions), and numbers of layers are conducted on the U71Mn rail to optimize the processing parameters. After that, sliding wear tests are conducted on different depths in clad to explore the wear behaviors. The results show that with the increase in laser power, the clad width is increased, the height is increased first and then decreased. With the increase in scan speed, both the clad height and width are decreased. Scan mode 1# produces the thinnest clads, the mode 3 produces the thickest ones. The microstructure of clad is composed of dendritic grains. With the increase in depth in clad, the grain size decreases and the hardness increases. The grain size is increased with laser power and decreased with scan speed, and the hardness is increased with the power and speed. Smallest grains and highest hardness are produced using mode 1#, and largest grains and lowest hardness using mode 3#. The Cr and Ni elements from clad permeate into the heat affected zone of U71Mn rail material. Wear depth of clad has a positive relationship with the grain size and a negative relationship with the post hardness. A wear resistance coefficient, Xphv2.55/Xgs1.56,where Xphv refers to the post hardness and Xgs refers to the grain size, is proposed to characterize the inherent anti-wear property of 316L stainless steel clad on U71Mn rail.

Improving the wear resistance of aluminum by a nickel-filled anodized porous alumina layer

Anodizing is a widely used method for increasing the wear and corrosion resistance of aluminum alloys. However, it is known that the porous brittle alumina layer can easily crack during tribological stresses, which results in the detachment of large particles from the worn surface. Electroplating, on the other hand, can produce a compact ductile metallic coating with enough wear resistance, though a specific pretreatment like the zincate process is needed for an aluminum substrate. In this paper, a combination of the two methods, anodizing and electroplating, is applied on the surface of pure aluminum intending to improve the wear resistance. Anodizing was performed in oxalic acid by applying a constant current density of 2 A/dm2. The anodized samples were then immersed in phosphoric acid for up to 10 h to increase the diameter of the pores. Nickel electroplating was carried out on the anodized samples at a current density of 0.5 A/dm2 in a Watts solution. Cross-sectional studies show that there is an optimum pore widening time that establishes a good adhesion between nickel and anodic oxide layers, while the structure of the oxide film is largely preserved. Sliding wear tests were performed on the samples using a ball-on-disk reciprocating tribometer. The results show much higher wear life for all Ni/Al2O3 composite coatings as compared with the alumina layer. The maximum wear life was obtained for the sample etched for an optimum pore widening time of 4 h.

On the tribological behavior of cobalt-based nanocomposite coatings containing ZnO@Graphene oxide core-shell nanoparticles

A hybrid nanocrystalline cobalt-based coating was prepared by cathode plasma electrolytic deposition (CPED). Zinc oxide and graphene oxide (GO) nanoparticles were mixed to form a core-shell structure through electrostatic self-assembly by using (3-aminopropyl)triethoxysilane (APTES) modifier. ZnO@GO nanoparticles were used as additives to improve wear and friction properties of deposited coatings. The concentration effect of core-shell ZnO@GO addition (0.1, 0.2 and 0.3 %wt) on the friction, wear, coating thickness and mechanical properties was investigated. The composition and microstructure of deposited coatings were studied by scanning electron microscope (SEM), X-ray diffraction (XRD), Raman spectroscopy and energy dispersive spectroscopy (EDS). Reciprocating sliding wear tests using a ball-on-plate configuration were carried out on a PLINT TE67 tribometer. AISI 52100 steel was used as ball and the coating deposited onto a AISI 304 stainless steel substrate was used as plate. Coatings were dense, nanocrystalline and uniform with a FCC metastable cobalt structure. Core-shell concentration above to 0.2 %wt resulted in a decrease of grain size and an increase of hardness and wear resistances. Nanoparticles act as nucleation sites for grain formation, decreasing grain sizes. Samples using 0.3% ZnO@GO displayed the lowest wear and friction coefficients. ZnO@GO nanoparticles enables the formation of a protective layer consisting of oxide and exfoliated GO on the top of worn surfaces.

The effect of small additions of Nb and Ti on the sliding wear behavior of a Co–30Cr–5Mo alloy

This work studies the addition of 0.5%Nb and 0.5%Ti in a Co–30Cr–5Mo alloy as well as the increase of carbon from 0.1 to 0.3%. The main goal is to increase the wear resistance of the alloy with such additions due to the formation of primary carbides (TiC and NbC). The additions of carbon, niobium and titanium were as ferroalloys, which implies the addition of iron into the chemistry of the alloy. Microstructural prediction studies by JMatPro indicate that the addition of all of these elements promotes an increase in the amount of the sigma phase, an undesirable phase because it is a hard brittle intermetallic compound. However, this undesirable phase could be eliminated from the structure by means of a solubilization heat treatment undertaken at 1200 °C for 2 h; this heat treatment lowered the values of hardness of the alloys. An additional aging heat treatment promoted the precipitation of chromium carbides of the type M23C6 as dispersed elongated bars within the cobalt matrix, which notably increased the hardness of the alloys. Each alloy was wear tested under two loads 52 and 78 N and under dry sliding and also under lubricated sliding using Hank solution as lubricant; the tests were undertaken at a sliding speed of 0.5 m/s. Results indicate that the addition of Ti and Nb produced small amounts of TiC and NbC in addition to a light increase in the amount of the sigma phase which increased hardness in the as-cast conditions. These alloys, with Ti and Nb additions, shown the higher hardness values in the as-aged conditions. The wear resistance of the alloys are in agreement with the hardness results particularly for the dry sliding tests. Wear resistance was higher for the harder alloys (those with Nb and Ti additions in the as-aged conditions) and it is lower for the higher applied load. For the case of the lubricated wear tests, such a trend is also observed but not so clearly as for the unlubricated tests. However, friction and wear for the lubricated experiments shown values extremely low compared to these observed for the unlubricated sliding wear tests.

Case study of advanced processed OFHC copper by dry sliding wear test

The wear behaviour of copper material processed by ECAP (Equal Channel Angular Pressing) and orbital forging (OF) is presented in this study. Dry sliding wear tests were carried out for the wear behaviour of the investigated system. Oxygen-free high thermal conductivity (OFHC) copper was used for testing. The new combination of metal forming processes was used because of ease of fabrication. Additionally, wear rate, friction coefficient and wears mechanisms were observed. The friction resistance is caused by the destruction of the adhesion between surface asperities in metal friction. Moreover, increased asperity interactions connected with wear particle entrapment gradually increase the friction coefficient. These results show the metal forming process's positive influence in reducing interfacial adhesion and asperity deformation. Finally, the combinations of newly used advanced processing demonstrated excellent wear characteristics of copper.

Fabrication and characterization of ZrO2 reinforced Fe-20Cr alloy composites

The reinforcement effects of the ZrO2 and the wear and mechanical behaviour of (Fe,Cr)-based alloy composites were investigated. The (100−x) (Fe80Cr20) -(x) ZrO2 composites were fabricated via powder metallurgy. The iron-chromium and ZrO2 powders were efficiently milled and mixed in ball mill. In the Fe80Cr20 alloy, the effect was investigated by changing the ZrO2 composition by 5%, 10%, and 15%. The blended powder mixture was cold compacted and sintered at 1030 °C. Scanning electron microscopy (SEM), elemental mapping, and x-ray diffraction techniques were utilized to assess the microstructural properties of the sintered composites. In addition, the mechanical properties such as hardness, flexural strength, and porosity were examined with variations in ZrO2 composites. The dry sliding wear tests with various normal loads and a constant sliding distance were used to find the composite’s wear behaviour. The composite containing 10% ZrO2 has shown the maximum flexural strength with 1470 MPa, and hardness 359.8 HV10 respectively, compared to 5% ZrO2 and 15% ZrO2. With a concentration of 10 wt.% ZrO2, the wear resistance is found to be significantly enhanced, while after 10 wt.% ZrO2, its properties deteriorate. In addition to having improved interfacial bonding, lower porosity, and microstructure uniformity, Fe80Cr20 (Fe-20 Cr) −10 wt% ZrO2 composites exhibit superior mechanical properties compared to other materials.

Deformation behavior of plasma sprayed Fe-based amorphous/ nanocrystalline coating under multi-scale tribological contact

Deformation behavior of Fe-based amorphous/ nanocrystalline coating synthesized by plasma spraying has been studied under multi-scale tribological contact. Nano- and micro-scale scratch investigation under constant and ramped loading revealed that deformation occurred mainly through plowing of coating surface by the probe. During low load (nano-scale) scratch tests, shear band generation was detected in the form of serrations in lateral force/ coefficient of friction curves under both constant (2 and 5 mN) and ramped (0–5 mN) loading conditions. Prominent shear bands around the scratch track with lesser fracture/ chipping were observed at high load (micro-scale) under ramped loading. Further, high load nanoscratch test under constant loading revealed aggravated fracture and chipping on the coating surface. Macro-scale deformation behavior studied using ball-on-disc dry sliding wear test at constant applied load (10 N) revealed that dominating wear mechanism in the coating was fatigue accompanied by abrasive and oxidative wear.