Wear Tests Research Articles

Comparative Study of Multilayer Hard Coatings Deposited on WC-Co Hardmetals

This paper examines the impact of a multilayered gradient coating, applied via plasma-activated chemical vapor deposition (PACVD), on the structural and mechanical attributes of nanostructured WC-Co cemented carbides. WC-Co samples containing 5 and 15 wt.% Co were synthesized through a hot isostatic pressing (HIP) process using nanoparticle powders and coated with two distinct multilayer coatings: titanium nitride (TiN) and titanium carbonitride (TiCN). Nanosized grain formation without microstructural defects of the substrates, prior to coating, was confirmed by magnetic saturation and coercivity testing, microstructural analysis, and field emission scanning electron microscope (FESEM). Nanoindentation, fracture toughness and hardness testing were conducted for uncoated samples. After coatings deposition, characterizations including microscopy, surface roughness determination, adhesion testing, coating thickness measurement, and microhardness examination were conducted. The impact of deposited coatings on wear resistance of produced hardmetals was analyzed via scratch test and dry sliding wear test. Samples with higher Co content exhibited improved adhesion, facilitating surface cleaning and activation before coating. TiN and TiCN coatings demonstrated similar roughness on substrates of identical composition, suggesting Co content’s minimal influence on layer growth. Results of the mechanical tests showed higher microhardness, higher elastic modulus, better adhesion, and overall superior tribological properties of the TiCN coating.

Effect of layer thickness and polishing on wear resistance of additively manufactured occlusal splints

ObjectiveTo evaluate the effect of polishing and layering thickness on the wear resistance of 3D-printed occlusal splint materials. MethodsSpecimens with 3 different layer thicknesses (50, 75, 100 µm) were produced in the form of a disc 3 mm thick using V-Print splint resin on a 3D-printer with digital light processing technology. (n = 16 for each thickness) All specimens were washed and cured according to the manufacturer's instructions. Half of the specimens of each layer thickness were polished with silicon carbide papers. All specimens were subjected to 120.000 cycles of a chewing simulator for 2-body wear tests. Before and after the wear test, the specimens were scanned with a laser scanner, and the images were overlaid using a 3D analysis program and the volume loss was calculated. The wear patterns of the specimens were examined under a scanning electron microscope. Statistical evaluation was performed using a Shapiro-Wilk test, 2-way ANOVA, 1-way ANOVA, and Tukey post hoc test (α = 0.05). ResultsWhile polishing had a significant effect (p = 0.003) on the wear volume of the occlusal splints, layer thickness (p = 0.105) and their interaction between polishing and layer thickness (p = 0.620) did not significantly affect the wear volume. Regardless of the polishing, the lowest mean wear was observed for D50 (0.064 mm3), followed by D75 (0.078 mm3), and D100 (0.096 mm3). However, a significant difference was observed only between polished D50 and unpolished D100. ConclusionThe polished 3D-printed occlusal splint resin showed higher wear resistance than the unpolished one, regardless of the layer thickness. Clinical significanceSince different layer thicknesses of 50 µm and greater had no effect on the wear resistance of the material, a layer thickness of 100 µm may be preferred for faster printing. However, polishing occlusal splints may reduce the amount of wear and improve clinical performance.

Wear debris analysis of Al-Si/MWCNT nanocomposite during dry sliding wear tests

This study demonstrates the enhancement of wear resistance achieved by incorporating multi-walled carbon nanotubes (MWCNTs) in LM6 aluminum alloy to form nanocomposites. Experiments on wear resistance study were performed at different test parameters for various compositions of MWCNT in LM6 alloy. The size and nature of debris obtained post experiments were significantly dependent on the MWCNT contents. Wear resistance was found to increase with increase in the MWCNT fraction in the nanocomposite. The worn surface and the shape as well as the size of the debris were studied under scanning electron microscopy (SEM). Energy-dispersive spectroscopy (EDS) analysis of the worn surfaces was used to detect and measure the constituents present in the debris. SEM micrographs of the nanocomposites show that the features of the wear debris are completely altered when MWCNT was added. Further the wear mechanism underwent a change from oxidative in LM6 to that of ploughing in LM6 nanocomposite. The recorded surface roughness values also confirm the above findings and show significantly reduced surface roughness (∼82%, 0.75 wt% MWCNT). These results clearly demonstrate the advantage of addition of MWCNT for enhancing resistance to wear in LM6 alloys.

Comparative investigation on the tribocorrosion resistance of Ti6Al4V and 60NiTi alloys inimulated seawater environment

The Ti6Al4V alloy is extensively utilized in critical marine equipment components due to its low density, high specific strength, and exceptional corrosion resistance in marine environments. However, its low hardness and inadequate wear resistance pose challenges in meeting the urgent demand for prolonged service life of relative motion friction pairs under complex wear and corrosion conditions. As a newly developed lightweight friction pair material, hardened 60NiTi is considered highly desirable owing to its combination of high hardness, high compressive strength, and excellent corrosion resistance. Nevertheless, the tribocorrosion properties of 60NiTi compared to those of Ti6Al4V are not yet fully comprehended. The present study conducted a series of sliding wear tests using a ball-on-plate configuration in artificial seawater environment to compare the response of 60NiTi with Ti6Al4V. In order to gain a comprehensive understanding of the factors contributing to the divergence in tribocorrosion response between both materials, further analysis was performed on the wear track subsurface and transfer film using focused ion beam-scanning electron microscopy, Raman spectroscopy, and x-ray photoelectron spectroscopy respectively. The 60NiTi demonstrates significantly enhanced wear resistance in artificial seawater compared to Ti6Al4V, attributed to its combination of high hardness and excellent corrosion resistance. However, Ti6Al4V exhibits a lower friction coefficient (∼0.30) than 60NiTi (∼0.45) due to the formation of a stable transfer film primarily composed of SiO2, Al(OH)3, and Al2O3.

Investigation of the enhancement in current-carrying friction performance with internal “copper network structure” constructed by pre-oxidized carbon fibers of the carbon skateboard

The increased speed requirements for high-speed rails necessitate the enhancement in specifications for carbon skateboard properties. The main challenges faced by carbon skateboards are their limited ability to withstand severe impacts and their high resistance levels. Hence, a new and innovative approach is utilized to create a novel carbon skateboard material. The key technique involved in this approach is the creation of a "copper network structure" within the carbon skateboard by using pre-oxidized carbon fibers. The matching performance of the carbon skateboard was examined through a current-carrying friction wear test conducted at various currents. The dynamic friction coefficient of the contact pair was less than 0.51 and the electrical contact resistance remained at most 15.89 mΩ. In addition, while the temperature rises of the contact interface increased, it remained less than 108 °C. This work represents a breakthrough in the preparation of a high-performance carbon skateboard, which has significant value for guiding the optimal design of carbon skateboards used in the pantographs of high-speed trains.

Enhancement of the Wear Resistance and Corrosion Resistance of Electroplated Ni-W-B Coatings Using PDA-Functionalized VC.

In this study, vanadium carbide (VC) was used as the raw material to synthesize PDA-functionalized VC (P-VC). VC and P-VC were added as nanoreinforced materials to the Ni-W-B coating. The effects of the two nanomaterials on the morphology, wear resistance, and corrosion resistance of the Ni-W-B coatings were investigated and compared. The experimental results show that the surface of the Ni-W-B/P-VC coating is denser and more uniform than that of the Ni-W-B and Ni-W-B/VC coatings, and there are no obvious defects on the surface. According to the hardness test, the Ni-W-B/P-VC coating reaches the highest microhardness of 887.1 HV. According to the friction and wear tests, the Ni-W-B/P-VC coating has the shallowest scratches, the lowest average friction coefficient (COF = 0.274), and the lowest wear rate (9.578 × 10-8 mm2/N). The corrosion resistance is the best, the corrosion rate is 0.0456 mm/y, and the impedance value Rt reaches 14,501 Ω·cm2.

Short time nitriding and nitrocarburizing of martensitic stainless steel

Plasma assisted thermochemical diffusion treatments have been extended to stainless steel and the usual process parameters are still in discussion regarding wear and corrosion performance as well as energy efficiency. In this work, a short time route for the thermochemical treatment for AISI 420 martensitic stainless was chosen, setting the duration to 2 h, changing other parameters such as temperature and N2 partial pressure. Temperatures of 420 and 440 °C were used, and two different atmospheres were applied, N2-H2 for nitriding, and N2-H2-CH4 for nitrocarburizing. The microhardness was measured, and microstructure was analyzed by XRD. Pin on disk tests were carried out according to G99 standard using alumina as counterpart, and abrasion wear tests were done following ASTM G65 standard. Corrosion behavior was evaluated using the salt spray fog test and electrochemical tests in NaCl solution. Modified layers between 5 and 15 μm thickness were obtained and surface hardness was always above 1000 HV. In XRD measurements martensite expanded by nitrogen/carbon and iron nitrides or carbonitrides were detected. The sample nitrocarburized at 440 °C showed better wear resistance under sliding conditions, however, the samples nitrided at 440 °C had the lowest mass loss in abrasive wear tests. Regarding the corrosion resistance, the sample nitrocarburized at 440 °C exhibited the best results in the salt spray fog test and in electrochemical tests. This behavior was related to the presence of the carbonitrides and the layer thickness.

Study on the microstructure and properties of a laser cladding Fe–Ni–Al coating based on the invar effect

The purpose of this study was to investigate the effect of Al content on Fe–Ni–Al coatings. A Fe–Ni–Al coating was prepared using a semiconductor laser, and the influence of the Al content on the microstructure and properties of the coating was examined. The microstructure of the coating was characterized using scanning electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. The coefficient of thermal expansion of the coating was measured using a static thermomechanical analyzer. The microhardness and wear performance of the coating were analyzed using a microhardness tester and a wear testing machine. The results were as follows. The addition of Al to the Fe–Ni ferroalloy powder resulted in the in situ formation of an AlNi/Fe–Ni laser cladding layer. When the Al content was low, the coating mainly consisted of γ-[Fe,Ni] austenite. As the Al content increased, the matrix phase structure of the cladding layer transformed into the α phase. Consequently, the Invar effect was gradually compromised, leading to the generation of defects in the coating. When the Al content was 4%, the coating performance improved while maintaining a low coefficient of thermal expansion. At this point, there were relatively few cracks in the cladding layer, and it exhibited the best wear resistance.

Microstructure and tribological properties of aluminum matrix composites reinforced with ZnO–hBN nanocomposite particles

Abstract In this study, pure and hBN-doped ZnO nanoparticles were synthesized by sol–gel method. ZnO–hBN nanoparticles were mixed with pure aluminum powders and samples were prepared using powder metallurgy processing parameters. It was observed that Al, ZnO, and hBN nanocomposite particles formed homogeneously. With the addition of ZnO–hBN, significant changes occurred in hardness, wear, and friction coefficient values compared to pure Al samples. The highest hardness value in the samples is mesh. It was obtained as 105 HB in 10 wt.% hBN added sample. In the wear tests, it is seen that the wear resistance is seven times higher in the 1 wt.% hBN added sample compared to the pure Al sample, while the friction coefficient decreases with the increase of the hBN additive.

Analysis of the development of friction and wear testing machine based on complex working conditions

Friction is one of the three main factors leading to the failure of metal materials. In order to improve the service life of machinery and reduce unnecessary losses in industrial production, it is necessary to study the friction and wear properties of industrial materials. Simultaneously in order to explore the impact of various environmental conditions on material properties, friction and wear testing machine war born as the times require. This paper mainly introduces the experimental principles and application scenarios of several universal friction and wear testing machines. At the same time, this paper also explores the situation of several special friction and wear testing machines that adapt to complex environments by organizing the industrial needs generated by the rapid development of technology. This paper collects and organizes literature on the current status and development of friction and wear testing machine in recent years. The paper has found that adding or improving special equipment to the special type of friction and wear testing machine on the basis of the universal model can better meet the needs of actual working conditions.

Effect of Cryogenic Heat Treatment on Multiple Tempered D-2 Tool Steel

The present day scenario in the manufacturing sector demands high productivity and the life of cutting tools plays a major role in increasing productivity. The freezing of metals has been acknowledged, for many decades, as an effective method for increasing" wear life" and decreasing residual stress in tool steels. Wear test using pin-on-disc machine was used to investigate the effect of multiple tempering after cryogenic treatment of D-2 tool steel. Conventional quenching (1010◦C) and tempering (515◦C) treatments were given along with intermediate cryogenic treatment (−196◦C). Specimens were subjected to wear tests on pin-on-disc machine in dry sliding condition for sliding distance of 6000 m at 6 kg load and for sliding speed of 3.0 m/s. Hardness data, microstructures, wear loss and Microstructure analys is analysis of worn surface throw light on the underlying metallurgical mechanism responsible in improving wear resistance property of the D-2 tool steel

Experimental Evaluation of Ceramic Coatings for Die Protection in Low-Pressure Die-Casting Process

One of the most important factors in the LPDC process is the heat transfer during the solidification of the molten alloys, which is responsible for the resulting microstructure and, thus, the quality of the cast piece. The use of foundry coatings has been lately suggested as a proper strategy to control the heat transfer while protecting bonded moulds from aluminium adhesion by providing a barrier between the surface and the liquid metal. LPDC die coating failures usually come from the loss of adherence or excessive wear originated in the successive filling processes, which requires stopping production for the reapplication of the coating. In the present work, coatings with different insulation capabilities have been evaluated, in terms of adherence and wear tests, in order to select the most promising alternative for LPDC die coating. This study confirmed that surface preparation and cleanliness are vital for an adequate adhesion of the coatings to ensure their durability. The results evinced that the use of a primer layer provided a higher adhesion of the coatings and considerably improved their perfomance. The coating that presented the best results in terms of adhesion and wear resistance under different abrasive testing conditions was coating B3.

Wear and corrosion properties of laser treated Cr2O3 on stainless steel

In this study, a highly wear and corrosion resistance coating was fabricated on 304 stainless steel. Herein, air plasma spray coating of Cr2O3 was deposited on 304SS which was subsequently treated with laser at different travel speeds these were: 25 mm/min, 50 mm/min and 100 mm/min, respectively. The morphology of coatings was studied by using scanning electron microscopy. It revealed that ultrafine grain structure is found as travel speed is increased, the as-solidified microstructure got more and more refined. Wear test demonstrated that with increase in laser t speed, the wear rate increaased. Furthermore, wear rate of laser treated coating at travel speed of 25 mm/min exhibits very comparable result at 8 N and 16 N. The potentiodynamic polarization results described that pitting potential was increased and current density (Icorr) was decreased two orders of magnitude for laser treated coating at travel speed of 25 mm/min as compared to faster laser scan rate

Characterization of low-damage cutting of alfalfa stalks by self-sharpening cutters made of gradient materials

Abstract The use of self-sharpening cutters can increase crop survival and regrowth by reducing the extent of stem damage incurred during the mowing stage and reducing the healing time at the harvest site. In this study, a self-sharpening cutter was prepared using a two-stage rare earth catalytic carbon–nitrogen–boron co-infiltration process, and the self-sharpening and wear-resistant properties of the cutter were verified by using metallographic organization testing, hardness testing, friction and wear performance testing, and the homemade tool wear test bench, and the low-damage cutting characteristics of the cutter were examined through field tests on alfalfa. The results show that the thickness of the penetration layer on the back face of a self-sharpening cutter made of gradient material is about 800 μm, with a maximum hardness of 1,800 HV. The coefficient of friction of the gradient material self-sharpening cutter is 67% lower than that of the commercially available 65Mn cutter. Gradient material self-sharpening cutter wear resistance is 2.15 times more than that of commercially available 65Mn cutter. The gradient material self-sharpening cutter reduces cutting damage by 11.42% compared to the commercially available 65Mn cutter. The application and promotion of self-sharpening cutting blades with gradient materials reduce alfalfa cutting damage, thereby improving reproductive yield.

Functionalized boron nitride nanosheets and their polypropylene nanocomposites: influence on thermal, mechanical, rheological and wear behaviour

ABSTRACT The few-layer hexagonal boron nitride (hBN) nanosheets with hydroxyl (−OH) functional group at edges are synthesized using heat treatment of micron size hBN powder followed by sonication. These nanosheets are modified with a silane coupling agent, 3-Aminopropyl,triethoxysilane (APTES). The synthesized hBN nanosheets are mixed with the PP matrix using twin-screw extrusion followed by injection moulding. In case of APTES-modified hBN nanosheets incorporation in the PP matrix with PP-grafted maleic anhydride (PP-g-MA) shows the formation of an imide bond between the MA functional group of PP-g-MA and the amine group of APTES modified hBN nanosheets revealing compatibilization. The flow behaviour index values are lower for hBN nanosheets filled PP nanocomposites showing the improved processability from Rheological characterization. The few-layered – OH and APTES modified hBN nanosheet incorporation in the PP matrix improves the tensile and thermal properties. The incorporation of APTES modified hBN nanosheet in the PP matrix shows an increase in tensile modulus (18.1%) and tensile strength (8.1%) respectively. Wear studies show the incorporation of – OH and APTES modified hBN nanosheets in the PP matrix decreases the coefficient of friction and wear rate significantly. The wear rate at 4 min of wear testing for modified hBN nanosheet in the PP nanocomposites is ~ 96% less in comparison with neat PP. The wear mechanism is established from wear measurements and scanning electron microscopy (SEM) of worn-out wear surfaces of PP nanocomposites.

Microhardness, Surface Roughness, and Wear Resistance Enhancement of Reinforced Conventional Glass Ionomer Cement Using Fluorinated Graphene Oxide Nanosheets.

Conventional glass ionomer cements (GICs) have been considered the most prevalent restorative material however; the reduced mechanical qualities and decreased wear resistance have been the main challenges facing their wide clinical application. This study was designed to assess the mechanical properties of fluorinated graphene (FG) oxide-modified conventional GIC. Composites of FG/GIC samples were prepared using (Medifil from PROMEDICA, Germany, shade A3) at different concentrations (0wt%) control group and (1wt%, 2wt% and 3wt% FG) groups using cylindrical molds (3mm × 6mm). FG was prepared using hydrothermal technique and characterized using XPERT-PRO Powder Diffractometer system for X-ray diffraction analysis and JEOL JEM-2100 high resolution transmission electron microscope. Vickers' hardness and wear resistance of GI samples were measured. Mechanical abrasion was performed via three-body tooth brushing wear test using ROBOTA chewing simulator coupled with a thermocycling protocol (Model ACH-09075DC-T, AD-Tech Technology Co., Ltd., Leinfelden-Echterdingen, Germany). Comparisons between groups with respect to normally distributed numeric variables were performed using one-way analysis of variance test followed by posthoc test. While paired t-test was utilized for comparing data within the same group. The surface roughness values of GICs (1wt% FG) and (2wt% FG) composites were significantly lower than those of the control and 3wt%FG groups. Vickers' hardness numbers were significantly higher in FG/GICs composites than in the control group (p≤0.05). GIC/FG combinations have sufficient strength to resist the occlusion stresses with improved hardness as compared with conventional GIC. GIC/FG appeared to be a promising restorative material.

Tribological performance of functional coated fiber reinforced additively manufactured polymer composite

Additive manufacturing has witnessed an upward trend in utilization across diverse industries in recent years. This study examines the tribological properties of polymer composites produced using additive manufacturing. The polymer composites were produced using the fusion deposition modeling process. Subsequently, they undergo thermal spray coating and spin coating processes that deposit hafnium carbide particles onto their surface. The wear test studies were conducted at three distinct temperature levels in accordance with the ASTM standard procedure. The findings demonstrated that the application of a ceramic particle coating led to a substantial decrease in the specific wear rates. Additionally, there were observed differences in the wear rates depending on the specific methods used for applying the coating. The application of thermal coating shown high efficacy in reducing wear rates and safeguarding the underlying materials against material loss. The uncoated carbon fiber reinforced polylactic acid (PLA-CF) material showed a slightly significant amount of material degradation as the test chamber temperature increased, in comparison to the coated specimens. The average specific wear rate of the thermally coated carbon fiber reinforced polylactic acid specimen at a temperature of 70 °C is 0.000156 kg Nm−1.

Wear and oxidation behavior of Ti-7Al-1Mo/TiN composites fabricated via spark plasma sintering

The research on the alloys of titanium (Ti) has been extensive due to the need for materials with remarkable resistance to oxidation and wear in demanding applications including the automotive, aerospace, and marine sectors. Even though they have excellent qualities, they frequently require improvements due to the harsh tribological environments they encounter. This study focuses on the ternary alloy of titanium-aluminum-molybdenum (Ti-7Al-1Mo) and its composite (Ti-7Al-1Mo/titanium nitride (TiN)). Utilizing spark plasma sintering (SPS) method, we fabricated these materials with varying TiN weight percentages (1, 3, 5, and 7 wt.%). The microstructural analysis revealed a transition from lath-like morphology to a bimodal structure as TiN content increased. The presence of intermediate Ti2N phases and hard TiN within the α-Ti matrix was confirmed. Wear tests indicated improved wear resistance in composites, especially at higher TiN fractions, while oxidation resistance increased with TiN content. This research demonstrates the potential of Ti–Al-Mo/TiN composites in high-performance applications, highlighting the nuanced relationship between TiN reinforcement, microstructural evolution, mechanical, and oxidation properties.

Investigation on tribological properties of high-velocity air fuel spraying WC–Cr3C2–Ni coating on the surface of continuous casting crystallization rollers

To overcome the wear problem of the substrate of thin-strip continuous casting crystallization rollers and improve economic efficiency, high-velocity air fuel (HVAF) technology was used to deposit WC–Cr3C2–Ni wear-resistant coatings on the surface of the crystallization rollers. The existing performance and wear condition of curved WC–Cr3C2–Ni coatings during continuous casting were investigated by the ring-block wear system. The experimental results showed that the WC–Cr3C2–Ni coating with a thickness of 300 μm effectively reduced the coefficient of friction (by 16.4 %) and the wear rate (by 82.5 %) on the surface of the crystallization roller and significantly reduced the roughness of the wear interface (by 71.2 %), which provided reliable protection for the substrate. The results of high-temperature (200 °C) wear tests showed that the WC–Cr3C2–Ni coating deposited via HVAF protected the substrate in actual long-cycle production and exhibited an excellent resistance to the emergence and expansion of failure cracks. This study provided a theoretical basis for the selection and preparation of surface coatings for thin strip continuous casting crystallization rollers.

A practical approach to fabrication of nano-Al2O3 reinforced MMC coatings by cold spray: Characterization of nanomechanical and tribological performance

Cold spray is a crucial solid-state deposition technique involving high-speed spraying of different-sized particles onto a base material. In this study, Ni-based powder reinforced with different proportions of nano-Al2O3 particles was sprayed onto Al6061 alloy by cold spray to improve the coating performance. Nanoparticles are very difficult to deposition as they are affected by the aerodynamic forces generated during cold spraying. With a practical approach, nanoparticles were agglomerated with micron-sized feedstock powders, and nanoparticles in the sprayed powder acted as larger particles and successfully defeated the aerodynamic force. The effects of adding nano-particles on the microstructural, nanomechanical, and tribological properties were investigated. Microstructural analyses revealed that MMC coating layers comprised ceramic particles and metal matrix (Ni and Zn). Due to the high spraying speed, the nano-particles were spread in the relatively ductile matrix formed by Ni and Zn. The micro- and nanohardness values were increased with nanoparticle volume by two mechanisms. In the first mechanism, the hard particle volume increased with the addition of nano powders, and in the second mechanism, the plastic deformation of the matrix increased due to the nano-particles. The sample without nanoparticle reinforcement exhibited plastic deformation during the initial stage of the nanoscratch test. The dry sliding wear test results showed that the nano-Al2O3-reinforced spraying powders increased the wear resistance approximately 1.9 times. According to FESEM and EDS examinations of worn surfaces and WC counter-bodies, nano-particles reduced the transferred layers caused by adhesion to the abrasive counter-body. In addition, the nano-particles were provided a more homogeneous hard particle distribution and improved wear performance.