GCr15 Steel Ball Research Articles

Dry sliding wear behaviour of AZ31 magnesium alloy strengthened by nanoscale SiCp

In this work, the wear and friction behavior of nanoscale SiCp (1 vol.%) reinforced Mg composite were investigated. Experiments were carried out by rubbing a GCr15 steel ball on the surface of pin specimens with the different sliding velocities of 0.1, 0.3 and 0.5 m/s at distinctive normal loads of 10, 20, and 30 N, respectively (without the aid of lubricant). Detailed analysis demonstrated that SiCp efficiently block the grain growth and improve the mechanical properties of the composite due to grain refining and dislocation strengthening. As a result, the wear resistance of composite was more prominent s compared with the initial alloy under all test condition. With the increase of sliding speed or load, the wear rate of composite increases gradually. The wear rate is reduced by 12% compared to the alloy, particularly in high load condition. Under low speeds, abrasive wear and slight oxidative wear were prevalent. Subsequently, the wear mechanism transitions to the initial delamination wear as the sliding speed increases. Severe plastic deformation occurs on the surface of the friction sample under high load, and the surface damage is serious.

Achieving ultra‐low friction of a‐C:H film grown on 9Cr18Mo steel for industrial application via programmable high power pulse magnetron sputtering

Owing to the high hardness and hydrogen passivation of carbon bonds, hydrogenated diamond‐like carbon (a‐C:H) film has shown promising potential to achieve ultra‐low friction and wear on steel surfaces. Here, a‐C:H film was successfully deposited on 9Cr18Mo steel via programmable high power pulse magnetron sputtering and potential application for industrial was evaluated. The a‐C:H films against different mating materials of GCr15 steel balls, Al2O3, Si3N4, ZrO2, and a‐C:H‐coated GCr15 balls all showed ultra‐low friction under a normal load of 5 N in a dry ambient air environment. Among them, self‐mating tribo‐system a‐C:H films on steel surfaces and a‐C:H‐coated steel balls achieve best friction performance; the principal reason is that both contacting surfaces coated with a‐C:H film have the lower electron affinities compared with other tribo‐systems. However, the differences of coefficient of friction (COF) for uncoated‐GCr15, Al2O3, ZrO2, Si3N4, and a‐C:H(GCr15) balls can be attributed to different sizes of clustering in wear debris. This work provides new insights on synthesis and industry application of the a‐C:H films with ultra‐low friction properties.

Fretting wear behavior of the high-carbon high-chromium X210CrW12 steel: Influence of counterbody material

The effect of counterbody material on fretting wear behavior of the high-carbon high-chromium X210CrW12 steel before and after nitriding was investigated. The transformation of hard carbides into nitrides took place during nitriding, and these nitrides acted as new types of hard phases in the nitrided layer. Two counterbody materials (GCr15 steel ball and SiC ball) were used to conduct the fretting wear tests, which contributed to a better understanding of the role of hard phases in fretting wear. The results indicated that the unnitrided samples fretted against SiC balls with much higher hardness had a much lower wear volume and coefficient of friction (CoF), and the primary carbides acted as barriers against the plastic flow of softened matrix material. For the nitrided samples, the different hardness ratios of the two counterbody materials to the nitrides (transformed carbides) led to different wear damage modes, and the samples fretted against the steel balls had higher wear volume under the low loads of 10 N and 30 N. For the samples fretted against the two counterbody materials, the carbides (or nitrides) played different roles during fretting.

Comparison on the Tribological Properties of Roller and Guide Tribo-Pair Used in Antenna Deployable Structure

The tribological properties of roller and guide tribo-pair are important for the design of deployable structure for space-borne perimeter truss antenna. In this study, carbon fiber epoxy resin composites are used as the guide material; while polyimide and GCr15 steel are used as the roller material. Then, friction coefficient of polyimide ball and GCr15 steel ball against carbon fiber epoxy resin composites disk were compared and investigated on the high-temperature, ball-on-disk tribometer under different operating conditions, respectively. The wear morphology of disk was measured by laser scanning confocal microscope. The results show that the friction coefficient of the polyimide ball against carbon fiber epoxy resin composites tribo-pair has better tribological properties. Meanwhile, the friction coefficients of this pair are mainly depend on abrasive wear under low pressure and velocity conditions while the adhesive wear has dominated influence on the friction coefficient for high pressure and velocity conditions. Besides, the tribological properties of carbon fiber epoxy resin composites are mainly affected by ploughing of surface roughness at low temperature, while by surface debonding at high temperature.

Fretting wear behavior of nano ZrO2 doped plasma electrolytic oxidation composite coatings on TC21 titanium alloy

Basic and ZrO2 doped composite plasma electrolytic oxidation coatings were prepared on the surface of TC21 titanium alloy. Subsequently, fretting wear tests of these two kinds of coated samples and the substrate alloy against GCr15 steel balls were conducted at 50 μm and 150 μm displacement amplitudes. The morphology, composition, valence states and topography of the fretting wear tracks were characterized and the wear mechanisms were studied. The results indicated that the porosity of the composite coatings was lower than that of the basic coatings, and the microhardness, adhesion strength and toughness were higher. When the fretting was in the partial slip regime (50 μm displacement amplitude), the fretting damage of the three materials was slight. Meanwhile, the cracks and delamination in the microslip zone of the TC21 alloy were not observed in the coated samples. When the fretting was in the slip regime (150 μm displacement amplitude), although the TC21 alloy and basic coatings experienced local wear, there was no significant material loss of the composite coatings, which demonstrated that the composite coatings could improve the fretting wear resistance.

Study on mechanical properties and wear behavior of in-situ synthesized CNTs/ CuCrZrY composites prepared by spark plasma sintering

The Cr particles catalyst uniformly distributed on the surface of CuCrZrY composite powders were prepared by solid solution and aging treatment, the treated CuCrZrY composite powders were used to in-situ synthesis of CNTs/CuCrZrY composite powders by water-assisted chemical vapor deposition (CVD), which improved the wettability and dispersion of CNTs and Cu matrix. The CNTs/CuCrZrY composites were prepared by spark plasma sintering (SPS), and 60% deformation was performed on the hot rolling mill. The results shown that the tensile strength of CNTs/CuCrZrY composites was improved to 423 MPa, which was 53% and 14% higher than Cu and CuCrZrY composites, respectively. The softening resistance temperature of CNTs/CuCrZrY composites reaching 670 °C, and the thermal stability of CNTs/CuCrZrY composites had been significantly improved. The sliding friction coefficient between the CNTs/CuCrZrY composites and GCr15 steel balls at 20 °C and 300 °C were 0.254 and 0.290, which were 55.9% and 56.7% lower than Cu, respectively.

Microstructure and Properties of Nanocrystalline Ni-Mo Coatings Prepared by Ultrasound-Assisted Pulse Electrodeposition

Electroplating Nickel-Molybdenum (Ni-Mo) coatings with superior corrosion and wear resistance has remained a challenge in materials sciences and engineering. Cracks caused by excessive Mo content and hydrogen evolution reaction during electroplated process are still abounded, resulting in properties degradation. Here, we develop a facile approach to produce crack-free Ni-Mo coatings with excellent properties by using ultrasound-assisted pulse electrodeposition. Effect of current density on microstructure, chemical composition, microhardness, corrosion and wear resistance of Ni-Mo coatings is systematically investigated. With the increase in current density, Mo content increases, grain size decreases and Ni-Mo coatings change from colony-like to cauliflower type morphology. The higher Mo content and smaller gain size enhance the microhardness and endow Ni-Mo coatings with superior corrosion resistance for electrochemical tests in 0.5 M H2SO4 solution. The higher microhardness improves the wear resistance of Ni-Mo coatings in tribological tests sliding against GCr15 steel ball under dry sliding condition.

Surfactant assisted and in situ formed micro liquid metal as excellent lubricant additive in polyimide coating

Liquid metal (LM) can be well distributed in polyimide (PI) coatings by ultrasonic shear into 1–2 μm diameter. The LM incorporated PI (PI-LM) coatings show remarkably enhanced tribological properties when the coating slide against GCr15 steel ball at room temperature, while the mechanical properties are slightly reduced. When the filling amount is 8%, the wear is just 10% of pure PI and the friction coefficient can be reduced by 31.6%. During friction process, the LM microspheres are squeezed to the frictional interface and form a transfer film together with PI debris, achieving lower wear and friction coefficient. These results show that PI-LM coatings have high potential as advanced self-lubricating materials.

Fabrication of AlTiN coatings deposited on the ultrasonic rolling textured substrates for improving coatings adhesion strength

This paper aims to provide a method in improving the adhesion strength of the AlTiN coating/steel substrate system, which is considerable for tribological applications. The surface pre-treatment was implemented by the ultrasonic surface rolling technology to fabricate linear micro-textures with different spacing. Then the AlTiN coatings were subsequently deposited on the polished and textured AISI 1045 steel surfaces. The scratch tests and reciprocating sliding wear tests were conducted to assess the adhesion strength and the wear performance of different coatings. Results revealed that the adhesion of AlTiN coatings deposited on textured substrates with the micro-groove spacing of 150 μm was improved and the anti-adhesive wear property of AlTiN coating against GCr15 steel ball was greatly improved with the aid of ultrasonic rolling texturing pre-treatment than that of the polished one. The contribution of ultrasonic rolling texturing was primarily providing a mechanical locking and a large interfacial contact area, a narrowing difference between the interactions in coating surface energy, an ideal surface residual compressive stress, and a highly active substrate, thus enhancing the adhesion strength and anti-adhesive wear performance of the hard coating/soft substrate system.

Influence of preparation method on microstructure and tribological behavior of C/C-BN composites

In this study, with 2.5D needle punched carbon felt as reinforcement, hexagonal boron nitride (h-BN) was introduced through chemical vapor infiltration (CVI) and slurry impregnation (SI) methods, and then pyrocarbon was deposited through CVI to convert the BN-containing preform into carbon fiber reinforced carbon-boron nitride binary matrix composites (C/C-BN). The microstructure and mechanical properties of C/C-BN(P) composites prepared by SI combined with CVI were compared with those of C/C-BN(CVI) composites prepared by CVI. The tribological behavior of C/C-BN(P) composites containing different contents of h-BN fillers and C/C-BN(CVI) composites with and without heat treatment was investigated by the ball-on-disk technique in dry sliding conditions using GCr15 steel balls and Si3N4 balls as sliding counterparts at two different sliding speeds (v = 0.2 and 0.8 m/s), and compared with the C/C composites used as a reference. C/C-BN(P) composites exhibit improved tribological behavior, which can be explained by the combined effect of SI and CVI on the microstructure and mechanical properties, leading to changes in the wear mechanism of the C/C-BN composites. The excellent reinforcement is attributed to the integrity structure of the C/C-BN(P), which can make the self-lubricating friction layer stably exist on the surface of the material and significantly reduce the friction coefficient and wear loss of the C/C-BN(P) composite. Furthermore, the mechanical and tribological properties of C/C-BN(P) composites can be adjusted by using different volume content of h-BN. The present work shows that C/C-BN(P) composites have wide application prospects as anti-friction and wear-resistant materials.

Evolution of wear damage in gross sliding fretting of a nitrided high-carbon high-chromium steel

Fretting wear tests were performed to examine the evolution of fretting wear damage of the nitrided high-carbon high-chromium X210CrW12 steel against GCr15 steel ball, and to identify the role of nitrides (converted carbides) in fretting wear characteristics. The nitrided layer was characterized by optical microscope (OM), scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), electron probe microanalyses (EPMA), X-ray diffraction (XRD), and microhardness analysis. The worn surfaces were evaluated by SEM, EDS and 3D optical profiler. The results indicated that the initial carbides in the nitrided layer undergone a transformation into nitrides during nitriding. The nitrided specimens showed excellent wear resistance compared to the steel balls, and their wear damage was mainly caused by the adhesive/abrasive action of oxidized particles. Coarse nitrides led to the rapid wear of steel balls, and acted as barriers against the grooving of oxidized particles. Higher loading conditions of 40 N and 80 N induced the generation of central smooth zone and W-shaped wear scar. The formation of the central smooth zone was very beneficial for reducing the wear rate and friction coefficient, thus the expected increase in wear volume with increasing applied load from 40 N to 80 N was not observed.

Microstructure and Wear Behavior of Nano-TiB2p/2024Al Matrix Composites Fabricated by Laser Direct Energy Deposition With Powder Feeding

Abstract The purpose of this study is to investigate the effect of TiB2 content on the microstructure and wear behavior of nano-TiB2p/2024Al composites fabricated by laser direct energy deposition (L-DED). The dry sliding friction and wear behavior was evaluated using a ball-on-disk tribometer by sliding samples against a 6-mm diameter GCr15 (AISI52100) steel ball under applied loads of 2.2 N at room temperature. Microstructural characterization of the as-deposited 2024Al alloy showed the presence of oriented columnar grains. Once 3 wt% TiB2 particles were introduced, the as-deposited microstructure consisted of a mixture of columnar and equiaxed grains. It was found that the addition of TiB2 particles can significantly improve the wear resistance of L-DEDed 2024Al. For instance, the wear-rate of an 8 wt% TiB2p/2024Al matrix composite with full equiaxed grains is almost 20 times lower than that of the unreinforced alloy. A grain morphology-induced wear mechanism for the L-DEDed TiB2p/2024Al composites is proposed and is dominated by mutual oxidation and abrasive wear. The research results are beneficial to understand the wear mechanism of L-DEDed nano-TiB2p/2024Al matrix composites and can also provide theoretical guidance for the selection of TiB2 content.

Tribological properties of textured surfaces fabricated on AISI 1045 steels by ultrasonic surface rolling under dry reciprocating sliding

This paper aims to demonstrate an effective surface texturing fabrication approach in improving the tribological properties of AISI 1045 hardened steel surface. Ultrasonic surface rolling technology was employed to fabricate strengthened surface and line array textured surface on substrates. Characterizations such as morphology, surface residual stress, microhardness, elasticity modulus and surface roughness with different surfaces were examined. Ball-on disk reciprocating sliding dry friction tests were performed. Results indicate that textured surfaces with good quality and accuracy were fabricated by ultrasonic rolling treatment. Increased microhardness and residual compressive stress of surfaces treated by ultrasonic rolling were obtained. Textured surfaces played a positive role in improving tribological performance. The surface with line array textures presented the best efficiency of anti-friction and anti-wear while sliding against GCr15 steel ball, the friction coefficient and sliding ball wear rate decreased by 79% and 98%, respectively, compared with the polished ones. Additionally, the possible tribological mechanism of ultrasonic rolling texturing was discussed. Multistage structure with mm/micro/nano-textures combined with a strengthened layer caused by ultrasonic rolling technology, increased the mechanical and tribological properties of surfaces. The synergistic combination of strengthened layer and texture structure could contribute to prolonging the friction and wear life of materials.

Investigation into reciprocating dry sliding friction and wear properties of bulk CoCrFeNiMo high entropy alloys fabricated by spark plasma sintering and subsequent cold rolling processes: Role of Mo element concentration

For the first time, a systematic investigation into effect of Mo element concentration on the crystal lattice constant, microhardness, and reciprocating dry sliding friction and wear properties of face-centered cubic (FCC) single phase based CoCrFeNiMo high entropy alloys (HEAs) were specifically conducted in the present study. Both the lattice constant and microhardness were found to increase with the amount of Mo element. Moreover, increasing Mo element concentration in the CoCrFeNiMo HEA was beneficial into reductions of friction coefficient and its specific wear rate when sliding wear against the GCr15 steel balls in a dry condition at room temperature. Interestingly, all studied CoCrFeNiMo HEAs exhibited almost the same wear mechanisms, which strongly depended on the applied normal load during sliding wear tests. Mo element addition had a remarkable influence on the cross-sectional microstructures after sliding wear, and grain coarsening in the middle transition region was effectively retarded by increasing the amount of Mo element in the CoCrFeNiMo HEA.

Structure vs chemistry: Tribological behavior of TiN films in the nitrogen atmosphere

Traditional view holds that transition metal nitride films have high friction coefficient and difficult to regulate. It is very challenging to obtain low friction consumption, which limits their wide application. Here, the tribological behavior of TiN films prepared by multi-arc ion plating and GCr15 steel balls under nitrogen atmosphere have been systematically investigated. It is interesting that TiN film in an alternating atmosphere shows a good adaptability similar to that of H-DLC films in the atmosphere of nitrogen. Specifically, the friction coefficient is higher in vacuum, but lower in nitrogen atmosphere. The multi-cycle variation in the frictional environment confirms the adsorption of nitrogen molecules at the sliding interface. The X-ray photoelectron spectroscopy results from the wear tracks show the formation of oxide and the adsorption of nitrogen at the sliding interface. In addition, the synergistic mechanism of N2 molecule as electron donor and electrostatic repulsion and nitrogen atoms and tribo-transfer film was established. It provides a general strategy for the regulation of hard films in nitrogen atmosphere.

Electroplated Co-Ni/WS2 Composite Coating with Excellent Tribological and Anticorrosion Performance

High-performance coatings with self-lubrication, superior wear, and corrosion resistance are sought after in modern industry. Here we reported a cobalt–nickel/tungsten disulfide (Co-Ni/WS2) composite coating fabricated by a pulse electrodeposition approach. The codeposition of WS2 significantly affects the microstructure, hardness, and tribological and electrochemical behaviors of the Co-Ni/WS2 composite coating. Scanning electron microscopy, X-ray diffraction, and energy dispersive X-ray spectroscopy analyses show that the Co-Ni/WS2 composite coating is characterized by a hierarchical “cactus-like” structure with WS2 embedded and distributed uniformly in the Co-Ni matrix. Tribological and electrochemical tests reveal that the Co-Ni/WS2 composite coating exhibits a low coefficient of friction (COF) and wear rate sliding against a GCr15 steel ball under dry sliding conditions and remarkable corrosion resistance in 5.0 wt% NaOH solution under room temperature and is thus a promising composite coating for practical applications.

Tribological Performance of Steel With Multi-Layer Graphene Grown by Low-Pressure Chemical Vapor Deposition

Abstract To explore the potential of directly grown multi-layer graphene as an agent in reducing friction and wear of steel on steel tribo-pair, multi-layer graphene films were synthesized on GCr15 steel in a low-pressure chemical vapor deposition (LPCVD) setup using a gaseous mixture of acetylene and hydrogen onto a bearing steel substrate. An interlayer of electroplated nickel was deposited on steel to assist and accelerate the graphene deposition. The tribological performance was evaluated using a ball-on-disc tribometer with an average Hertzian pressure of 0.2, 0.28, 0.34, and 0.42 GPa over a stroke length of 5 mm against GCr15 steel ball and compared with bare steel and nickel-plated steel. The results indicate that the friction coefficient is dependent on the applied load and decrease with increasing load, and the minimum friction coefficient of ∼0.13 was obtained for an applied normal load of 1 N; however, the coating failed after 250 cycles. The decrease in friction coefficient has been attributed to the homogenization of the deposited multi-layer graphene along the sliding direction and transfer of graphene to counter-face ball leading to inhibition of metal-metal contact. The investigation suggests that this kind of coating has the potential of improving the tribological performance of metal-metal tribo-pairs.

Tribological properties of phenyl-silicone rubber composites with nano-CeO2 and graphene under thermal-oxidative aging

Phenyl-silicone rubber composite components have been used in the sealing field under various working conditions. However, research on friction behavior during service is somewhat lacking. Thermal-oxidative aging’s effects on the tribological properties of phenyl-silicone rubber composites are investigated in this work. With the addition of nano-CeO2 and graphene, the coefficient of friction (COF) gradually decreases between the GCr15 steel ball and phenyl-silicone rubber composites, which can be attributed to nano-CeO2’s and graphene’s protection of surface matrices during aging and friction-heat generating processes. The results of this study indicate that the COF gradually decreases as the load increases because frictional heat generation increases with loads, resulting in softening the matrix and decreasing friction resistance. When the graphene content increases (0.8–1.5 phr), the wear rate (Ws) of phenyl-silicone rubber composites increases due to the destruction of graphene transfer films and severe fatigue wear. This study provides new ideas for improving the friction and wear properties of phenyl-silicone rubber composites before and after thermal-oxidative aging.

Extraordinary macroscale lubricity of sonication-assisted fabrication of MoS2 nano-ball and investigation of in situ formation mechanism of graphene induced by tribochemical reactions

We first fabricate MoS2 nano-ball in isopropanol using sonication-assisted method. We systematically probe the lubrication mechanism of MoS2 nano-ball in isopropanol. Hydroxylated MoS2 nano-ball could effectively reduce the contact area for GCr15 steel balls and possess superior load-capacity and make the tribosystem achieve ultra-low friction and wear under 98 or 196 N and 600 rpm. For comparison, the lubricity of tribosystem sliding in isopropanol is conducted. Interestingly, graphene layers are formed sliding under 196 N and 600 rpm, the graphene-based transfer film on GCr15 steel ball makes the lubrication condition fast transfer from mixed lubrication condition to full film lubrication condition, which results in high friction and wear. The formation mechanism of graphene is discussed and proposed in details.

Tribological properties of microarc oxidation coatings on Zirlo alloy

ABSTRACTThe ceramic coatings were prepared on Zirlo alloy using Microarc Oxidation (MAO) technology. Their tribological properties were evaluated by a ball-on-disc friction and wear tester in dry sliding against GCr15 steel ball, and their wear mechanism was also discussed. Compared to bare Zirlo alloy, the MAO coatings had good wear resistance. Their lowest wear rate was about 4.59 × 10−6 mm3 N−1 m−1, which was only about 1/60 of bare Zirlo alloy. In addition, the polishing treatment of MAO coatings could reduce the wear rate and improve their wear resistance. Composition and micrograph of worn surface indicated that the wear mechanism of MAO coatings was mainly the adhesive wear while the bare Zirlo alloy showed mainly the abrasive wear.