Dominant Wear Mechanism Research Articles

Scratch-Induced Wear Behavior of Multi-Component Ultra-High-Temperature Ceramics

Multi-component ultra-high-temperature ceramics (MC-UHTCs) are promising for high-temperature applications due to exceptional thermo-mechanical properties, yet their wear characteristics remain unexplored. Herein, the wear behavior of binary (Ta, Nb)C, ternary (Ta, Nb, Hf)C, and quaternary (Ta, Nb, Hf, Ti)C UHTCs synthesized via spark plasma sintering (SPS) is investigated. Gradual addition of equimolar UHTC components improves the wear resistance of MC-UHTCs, respectively, by ~29% in ternary UHTCs and ~49% in quaternary UHTCs when compared to binary UHTCs. Similarly, the penetration depth decreased from 115.14 mm in binary UHTCs to 73.48 mm in ternary UHTCs and 44.41 mm in quaternary UHTCs. This has been attributed to the complete solid solutioning, near-full densification and higher hardness (~up to 30%) in quaternary UHTCs. Analysis of the worn-out surface suggests pull-out, radial, and edge micro-cracking and delamination as the dominant wear mechanisms in binary and ternary UHTCs. However, grain deformation and minor delamination are the dominant wear mechanisms in quaternary UHTCs. This study underscores the potential of MC-UHTCs for tribological applications where material experiences removal and inelastic deformation under high mechanical loading.

Tensile fracture behavior and friction and wear properties of TiB2 particle reinforced Al-Si matrix composites

In this study, TiB2/Al-Si composite material was fabricated by addition of Al-TiB2 master alloy, and the influence of varying micro-sized TiB2 particle content on the mechanical and tribological properties of the composite material was investigated. The results revealed that the introduction of TiB2 particles effectively refined the Al-Si matrix alloy microstructure, thereby enhancing the mechanical properties and wear resistance of the Al-Si matrix alloy. When the TiB2 particle content reached 0.8 wt%, the composite material exhibited optimal mechanical properties with a tensile strength of 318 MPa and elongation of 7.2 %, improving of 8.9 % and 69.1 %, respectively, compared to the matrix alloy. Moreover, wear rates of the composite material demonstrated significantly lower than the matrix alloy under different loading conditions in this paper. The improved mechanical properties of the composite material were attributed to grain refinement strengthening, second phase strengthening and the coefficient of thermal expansion strengthening. Under low loads, abrasive wear was the dominant wear mechanism; while under high loads, a combination of abrasive and adhesive wear occurred. The addition of TiB2 particles effectively enhanced the hardness of the matrix alloy, reduced the dynamic friction coefficient, suppressed adhesive wear, and improved the wear resistance of the composite material.

Surface modification of WE43 Mg alloy via combination of cold spray and micro-arc oxidation for wear related applications at high temperatures

This study investigates the high temperature wear behaviour of a WE43 Mg alloy after covering it with single and dual layer coatings. For this purpose, cold spray and micro-arc oxidation processes were employed individually and sequentially. Single-layer coatings fabricated by cold spray and micro-arc oxidation processes were Al/Al2O3 composite and MgO-based ceramic, respectively. Sequential application of cold spray and micro arc oxidation processes induced dual layer coating upon synthesizing an external Al2O3–based layer over the Al/Al2O3 composite layer. Results of the wear tests conducted under the load of 2 N revealed the superior resistance of the dual layer coated sample against the rubbing action of the counterface compared to single layer coatings. Thus, the presence of a relatively hard and tough external Al2O3-based layer over the Al/Al2O3 composite layer sustained protection up to the temperature of 320 °C, where the dominant wear mechanism was fatigue wear. However, the increase in the test temperature to 350 °C caused detachment of the external Al2O3-based layer. Reduction of the wear test load from 2 to 1 N resulted in the remaining of external Al2O3-based layer intact with the underlying Al/Al2O3 composite layer even at a test temperature of 350 °C. It is therefore concluded that the combination of cold spray and micro-arc oxidation processes is promising to broaden the reliable use of WE43 and other Mg alloys in wear related applications at high service temperatures.

Influence of nanodiamond on compressive and dry-sliding wear behaviors of Al2O3–Al interpenetrating-phase composites

In this research, the effects of nanodiamond (ND) addition at different loadings on the compressive and wear properties of the interpenetrating phases hybrid aluminum/alumina (Al/Al2O3) composite were investigated. The samples were fabricated in a two-step process. First, the Al2O3-ND preforms were fabricated via the replica method. Second, the squeeze casting route was employed to infiltrate the molten pure Al. The ceramic preforms were made by immersing a polyurethane foam with 17 ppi pores in a slurry containing α-Al2O3 powder (1 μm), ND particles (0–10 vol%), and natural egg white. After sintering at 1500 °C for 4 h, the preheated preforms were infiltrated with molten Al. The microstructural evaluations of the preforms and composites revealed a proper distribution of the ND particles in the preform, as well as the formation of the ND agglomerates at higher volume percentages. Also, the hardness of the samples enhanced with an increase in the ND loading, reaching a maximum of 263.8 Vickers for the 10 vol% ND-loaded composite. The compressive strength of the samples enhanced up to 3 vol% ND addition and then decreased due to the agglomeration. The wear test results indicated that the best behavior was related to the 3 vol% ND-loaded composite. Embedding the 3 vol% ND decreased the weight rate and friction coefficient of the interpenetrating phases hybrid Al/Al2O3 composite by 16 % (from 8.2396×10−3 to 6.9269×10−3 mm3/m) and 12 % (0.8165 to 0.7238), respectively. The study of the worn surfaces of the samples after wear testing revealed that the dominant wear mechanisms were abrasive and adhesive for the higher and lower volume fractions of the ND, respectively.

Studies on Dry Sliding Wear Mechanisms of Al7075/Si3N4 Composites

Abstract In this investigation, Al7075 aluminum alloy reinforced with Si3N4 particles (3, 6, 9, and 12 wt%) was used as reinforcements to manufacture composites through a stir-casting approach. The microstructural characteristics have shown significant grain refinement owing to the presence of Si3N4 particle distribution during the solidification. SEM micrographs confirm the uniform distribution of Si3N4 particles with considerably fewer particle agglomerations throughout the matrix alloy. The reinforcement particle cluster formation is relatively increased for increasing the Si3N4 content. The SEM and EDS analyses showed good integrity at the matrix–refinement interface with no interfacial compound formation. The mechanical properties, such as hardness (up to 118 BHN), tensile strength (up to 281 MPa), and yield strength (up to 178 MPa), were enhanced by 30.69% and 20.27%, respectively. The wear-rate and coefficient of friction of the composites were evaluated with increasing percentages of Si3N4 content. The average wear-rate of the composites is 0.019, 0.0085, 0.0075, and 0.0065 mm3/m, respectively, for the increased Si3N4 ceramic particulate content from 3 to 12 wt%, while the average COF of the composites is 0.45, 0.37, 0.32 and 0.28 respectively. With the addition of Si3N4 particulate content, the wear resistance performance of the composites at 30 N has shown up to 46% enhancement and increased from 0.0052 to 0.0103 mm3/m with the increasing sliding velocity from 1.5 to 3.5 m/s for varying Si3N4 particulate content from 3 to 12 wt%, while reducing the COF up to 65%, and from 0.43 to 0.27. Different wear mechanisms are characterized by identifying the typical features of wear on the SEM micrographs of the worn surfaces. The dominant wear mechanisms of the composites are typically observed as abrasion, oxidation, delamination and melt wear. The mechanism and behavior of composites under dry sliding conditions are analyzed through the construction of wear maps. The windows of wear mechanisms and progression in terms of load and sliding velocity for the composites with various wt% of Si3N4 content were identified, analyzed, and presented.

Data-driven predictions of retained austenite content and yield strength and elucidation of the sliding wear performance of carbide-free bainitic steels

Carbide-free bainitic (CFB) steels have drawn much attention due to their high strength and toughness. The present work aims to build machine learning (ML) based surrogate models to predict retained austenite (RA) content and yield strength (YS) of isothermal transformed CFB steels and study the sliding wear performance. The input data for ML prediction were related to compositions, heat treatment process, and phases. The Random Forest regression and Gaussian process regression were respectively selected to build the predictive models for RA content and YS. Result shows that the predicted RA content agrees well with the experimentally determined ones in steel with high stability of untransformed austenite. For YS prediction, the present surrogate model can predict YS of CFB steels even without additional microstructural information such as dislocation and effective substructure size. Steels with different YS and RA content were designed to study the sliding wear performance. Result shows that the dominant wear mechanism of the tested steels is abrasive wear and the weight loss is inversely proportional to hardness when the load and wear distance are constant. Increasing YS and RA content can increase the initial hardness and work hardening ability at the worn surface, thereby enhancing wear resistance.

Synergetic effect of in-situ TiB2 reinforcement and nano precipitation on wear behavior of ZE41 magnesium matrix composite

The rise in carbon dioxide pollution and energy consumption has increased the demand for lightweight materials such as magnesium in automotive and aerospace industries. However, magnesium alloys face challenges like poor wear resistance and mechanical strength. To overcome these limitations, a promising approach involves developing heterogeneous hybrid microstructures through reinforcement addition and microstructural engineering. This study focuses on the tribological performance of a newly developed in-situ sub-micron sized TiB2/ZE41 composite under various microstructural conditions, comparing it to the unreinforced ZE41 Mg alloy. Wear experiments were conducted using a pin-on-disc tribometer under normal loads of 10, 20, 40, and 60 N at a sliding velocity of 1 m/s. Scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) was used to analyze the worn surfaces in order to identify damage types and surface distortions. By correlating worn surface microstructures with test parameters, predominant wear mechanisms for each material condition under specific loads were determined. Results consistently showed that the presence of in-situ TiB2 reinforcements, β-phase, and rare-earth precipitates enhanced wear resistance regardless of the load conditions. Additionally, the study established a scientific understanding of the wear behavior of ZE41 Mg alloy, with and without in-situ TiB2 particles and precipitates, through analysis of dominant wear mechanisms, wear-induced subsurface deformation mechanisms, kernel average misorientation, grain orientation spread, and microhardness evaluation.

Effect of external magnetic field on the fretting wear mechanism of the ferromagnetic materials

With the widespread implementation of maglev technology in fields such as rail transit and military, it is imperative to investigate the effects of magnetic fields on fretting damage in metallic materials. This study conducted multi-parameter fretting wear tests on typical ferromagnetic counterparts in the presence of an external permanent magnetic field. Subsequently, the wear behavior and damage mechanism of the fretting interface were elucidated through multi-scale characterization analysis. The results indicated that the operation state of the fretting interface was shifted towards the partial slip regime under the magnetic field. Meanwhile, the external magnetic field transformed the dominant wear mechanism from abrasive wear to adhesive wear. The influence of the external magnetic field on fretting wear has been demonstrated to manifest in dual aspects: Firstly, the Hertzian contact stress at the interface is enhanced by the magnetic field induction force, resulting in a remarkable reduction of about 79.83 % in accumulated dissipation energy; Secondly, the effectiveness of debris being expelled from the worn interface decreased, and the wear progression was further impeded by the accumulated debris, so that the abrasion loss is significantly reduced by about 60.66 %. These findings provide valuable theoretical data and practical reference for the protection of fretting damage in ferromagnetic materials under the action of a magnetic field.

Grinding of C/SiC ceramic matrix composites: Influence of grinding parameters on tool wear

C/SiC Ceramic Matrix Composites (CMCs) have been identified as a key material for improving high-speed braking systems and aerospace components as they offer low density, and high specific strength at high temperatures. Grinding is often used for the machining stage due to the high hardness, heterogeneity, and brittle nature of CMSs. Previous studies have explored the effect of grinding parameters, but most of them do not indicate whether they have used the same grinding wheel for all tests. In fact, there is limited understanding of how wear impacts process performance over the grinding wheel's lifespan. In this work, the effect of grinding wheel wear on cutting forces is addressed and grinding wheel topography is analyzed with the objective of identifying a parameter that allows to quantify grinding wheel wear in a non-destructive way. Results have shown that, after a short conditioning stage, cutting forces increase approximately linearly with the machined length. For the machining conditions analyzed, normal forces increase 200 % in the first machined meter (first stage), then rise 17 % per meter thereafter (second stage). Tangential forces rise 300 % in first meter and then climb 27 % per meter subsequently. In this second stage, force ratio approaches a constant value and the generation of flat surfaces on the diamond grains is the dominating wear mechanism. Under such conditions, 3D surface roughness parameters Sa, Sq, Spk and Sku have been proven to be useful for monitoring wheel wear.

Effect of SiC Contents on Wear Resistance Performance of Electro-Codeposited Ni-SiC Composite Coatings

This paper focuses on the wear resistance performance of Ni-SiC composite coatings with various contents of SiC particles. The coatings were characterized via a scanning electron microscope (SEM), X-ray diffractometer (XRD), and transmission electron microscopy (TEM), and the wear behaviors of different coatings were tested. The results show that SiC particle incorporation results in a nanocrystalline metal matrix and nanotwins in nickel nanograins. The microhardness and wear resistance Ni-SiC composite coatings increased with the increasing SiC content. Microhardness was improved due to the grain-refinement strengthening effect and the presence of a nanotwin structure. The dominant wear mechanism was described in two stages: the first stage involves the interaction of SiC particles/the counter ball, and the second stage involves the formation of the oxide film its breaking up into wear debris. A higher SiC content increased the duration of the first stage and slowed down the rate of breaking up into debris, thereby decreasing the wear rate.

Orientation effect of chopped steel fiber on tribological performance of very low metallic brake pads: An interface study

The orientation effect of chopped tiny steel fibres (length < 3 mm; diameter < 200 µm) in brake pads parallel (NAPA) to the sliding direction is studied using two different methods. Inverting the specimen during testing yields fibre perpendicular (NAPE) to the sliding direction, which is compared to commercial random-oriented fibre pads (NARA). The orientation coefficient value of near unity is achieved only in NAPA. NAPA and NAPE have a lower density than NARA by 13.2% due to less than 54.55% of steel fibres in the formulation. More and larger plateaus stabilized friction in NARA, utilising the elongation properties of parallel steel fibres, than in NAPE, which produced only tiny plateaus. However, the wear resistance decreases when the sliding path or direction changes from parallel to perpendicular. The measurement of thickness loss is misleading during wear because of the swelling effect, and hence energy requirements are considered. The energy required to wear 1 cc of specimen in the NAPE is 23.78% greater than that in the NAPA, and hence wear resistance is better. Adhesion followed by delamination at elevated temperatures are the dominant wear mechanisms in NAPA, whereas abrasion is dominant in NAPE. Thus, semi-metallic performance can be obtained in a very low metallic pad by orienting these fibres.

Comparison of the Braking Behavior Among Cast Steel, Carbon/Carbon (C/C) and Carbon/Carbon-Silicon Carbide (C/C-SiC) Materials Mated with Copper-Based Composites

Carbon-based materials (e.g., carbon/carbon [C/C] and carbon/carbon-silicon carbide [C/C-SiC] materials) are considered promising brake disk materials for high-speed trains to replace cast or forged steels. Investigating the braking behavior of copper-based composites paired with various counterpart materials is helpful in advancing the development of high-speed and lightweight brake systems. In this study, the braking behavior and wear mechanisms of a novel copper-based composite mated with cast steel, C/C and C/C-SiC materials were investigated. The average coefficients of friction for the copper-based composite against C/C and C/C-SiC materials are increased by approximately 16.5% and 6.7%, and the wear rates of the copper-based composite against C/C and C/C-SiC materials are reduced by about 25.9% and 33.9% in comparison to those of the copper-based composite against cast steel. Additionally, compared with that of cast steel, the wear rate of the C/C material is increased by more than 3 times, and the negative value of the wear rate of the C/C-SiC material is noted. The dominant wear mechanisms of the copper-based composite mated with cast steel, C/C and C/C-SiC materials are adhesive wear combined with oxidation, graphite loss combined with oxidation as well as exfoliation of the material near graphite, and the material transfer combined with oxidation, respectively.

Polymeric Composites: Failures in Dry Sliding on Steel

The investigation of a tribosystem failure is important in establishing its causes with the highest probability. This paper proposes a discussion on particular aspects of failure in polymeric composites sliding against steel in dry regime. At micro level, failure mechanisms of polymeric composites in dry sliding on steel could explain damages or malfunctioning at macro scale and initiate solutions. Investigating the tribolayers of both components in contact by scanning electron microscopy or optical microscopy helps identifying dominant wear mechanisms and failures produces under given operating conditions of the system. These conditions could be partially or totally reproduced at laboratory scale, with simpler testers that will facilitate this investigation at micro scale. The authors concluded that these studies of the failure mechanisms, based on images before and after test end are beneficial in understanding the tribological behavior of polymeric composite sliding against steel and in improving the operating parameters of a system, including precision, durability, maintenance and could be the initiation of formulating a new composite, a new shape or/and a new set of functioning parameters of the system.

Microstructure evolution and wear resistance enhancement of nano-NiCoC alloy coatings via cryogenic treatment

High-performance coatings are crucial for improving the overall lifetime of molds. In this study, multi-scale microstructure evolution in nano Ni–Co–C alloy coatings was induced through cryogenic treatment, and various strengthening mechanisms were employed to enhance their comprehensive properties, particularly wear resistance. Specifically, it was observed that lattice contraction occurred in the coatings due to stress during cryogenic treatment, accompanied by strain and dislocation accumulation. As the cryogenic treatment duration increased, the texture of the coatings exhibited a random distribution, and the emergence and subsequent increase of copper texture were identified as crucial for enhancing coating performance. Additionally, TEM results revealed a typical nano-polycrystalline structure in the coatings, with grain sizes becoming more refined and uniformly distributed after cryogenic treatment. Simultaneously, a significant increase in stacking faults was noted, which facilitated the formation of complex dislocation structures and hindered dislocation mobility. Moreover, cryogenic treatment was found to enhance coating hardness and improve fracture toughness, primarily due to dislocation strengthening and secondarily to grain refinement. Furthermore, the wear rate of the coatings was significantly reduced, and the dominant wear mechanism shifted from oxidation wear to abrasive wear with prolonged cryogenic treatment duration.

Effect of Direct Aging Heat Treatment on Microstructure and Mechanical Properties of Laser Powder Bed Fused Maraging Steel 300-Grade Alloy

Abstract This paper investigates the effects of a 6-hour direct aging heat treatment at 490 °C on the mechanical, tribological, and microstructure characteristics of laser powder bed fused maraging 300 steels, which is produced at various laser energy densities. After direct aging heat treatment, the grain boundaries become irregular and vague due to the residual stress releasing, squeezing of precipitates into the grain boundaries, and phase transformations. The XRD analysis reveals the reverted austenite (γ′) phase forms during aging treatment due to the inevitable reversion of metastable martensite to the stable reverted γ′ phase. The heat-treated samples' microhardness rises with rising the laser energy density (LED) from 61.41 to 92.10 J/mm3 due to a decrease in the reversed austenite phase and a further rise in LED decreases the microhardness of heat-treated samples due to a rise in the reversed austenite phase after heat treatment. The heat-treated sample produced at LED of 92.10 J/mm3 shows maximum yield, ultimate tensile strengths, and minimum elongation percentage due to its high microhardness, and the fractography results show the failure mode as a mixed brittle and ductile fracture. The wear-rate of the heat-treated additively manufactured maraging 300 steel decreases as the LED increases from 61.41 to 92.1 J/mm3 and a further rise in LED from 92.10 J/mm3 to 166.66 J/mm3, the wear-rate increases. The wear-rate rises with a rise in sliding velocity from 1.5–3.5 m/s. The dominant wear mechanism was observed as abrasion with small grooves and saplings.

Influence of Heat Treatment on Fretting Wear Behavior of Laser Powder Bed Fusion Inconel 718 Alloy

Abstract This research paper focuses on the fretting wear characteristics of self-mated laser powder bed fusion (L-PBF)-produced Inconel 718 alloy, with the primary aim of characterizing its distinct wear-rate in relation to fretting cycles. This study investigates both the as-built and heat-treated Inconel 718 Superalloy. Experiments were conducted under aggressive contact conditions, involving a flat-on-flat contact pressure of 100 MPa (1645 N) and a temperature of 650 °C sustained over a million cycles. From the preliminary observation, the microstructure reveals that the heat-treated L-PBF alloy has denser and harder precipitates than its as-built counterpart. This indicates that heat-treated alloy is much harder (470 HV0.3) than the as-built Inconel 718 (275 HV0.3). The heat treatment process resulted in the precipitation of beneficial strengthening phases like γ′ and γ″, along with maintaining stable carbides (NbC). Notably, the heat-treated material displays an approximately two-fold lower wear-rate (0.103 μm/cycle at the end of 1000 k cycles) compared to the as-built material (0.238 μm/cycle), attributed primarily to its high strength characteristics. Additionally, the heat-treated material demonstrates a reduced steady-state friction coefficient (0.34) in contrast to the as-built material (0.37), owing to its inherent capability to form a uniform and stable lubricious glaze oxide layer. Both as-built and heat-treated systems show dominant adhesive wear mechanisms along with localized abrasion resulting from the combination of oxidation and cyclic wear processes.

Dry sliding wear behavior of the high-strength nanostructured bainitic steel containing 3.5 wt% aluminum

The acceptable wear behavior of nanostructured bainitic steels has enhanced their potential to be industrialized, and their applications in the automotive industry. This study focused on the wear behavior of the high-strength nanostructured bainitic steel containing 3.5 wt% aluminum (low-cost and low-density) to assess the dominant sliding wear mechanism and the correlation between the microstructure and applied load on the sliding wear resistance. A pin-on-disk tribometer was used to evaluate dry sliding wear behavior, and the SWR was computed by weighing the specimens. To identify the wear mechanism, the worn surfaces and cross-sections were analyzed using XRD, FESEM, and EDS. The results showed that the retained austenite volume fraction and carbon content of austenite (the stabilizer of the retained austenite) of high-strength nanostructured bainitic steels are not the only determinants of wear behavior. Indeed, the thickness of bainitic ferrite plates (strength source) is the major parameter affecting wear resistance. An increase in the Vαb/tαb ratio due to a decreased austempering temperature reduced the SWR and enhanced wear resistance. Moreover, the change from a normal load of 50 N to a load of 150 N changed the dominant wear mechanism from oxidative to adhesive. Also, increasing the isothermal transformation temperature and applied load by increasing the thickness of the tribological-transition-zone (TTZ) causes a decrease in sliding wear resistance. In summary, the formation of a thin TTZ due to the increase in the Vαb/tαb ratio is the main reason for the improvement of the wear resistance of the austempered sample at the lowest temperature (250 °C).

Understanding tool cutting-edge microstructure and deformation mechanism induced by adhesive wear in the turning of nickel-based superalloys

Nickel-based superalloy has great potential in the aerospace industry as key components. However, difficult-to-machine characteristics have further limited its application. Thermal-barrier coatings of the titanium-based family on carbide tools offer exceptional performance in cutting superalloys, combining high-temperature stability and remarkable toughness. This work primarily concentrates on understanding cutting-edge microstructure and deformation induced by tool adhesive wear in the turning of nickel-based superalloys with experiment and modelling. The dominant tool wear mechanisms are revealed to be adhesive wear and abrasive wear by SEM/EDS. The microstructure of the cutting-edge interface is qualitatively and quantitatively investigated by SEM/EDS and EBSD. The adhesive layer thickness at cutting edge is about 10–30 μm. The GND density of WC grains at cutting edge is 15-20 × 1014/m. The nanomechanics properties of the tool wear interface were quantitatively evaluated by nanoindentation. The average hardness of WC and Ni-superalloy at cutting-edge interface is evaluated to be 15–19 GPa and 6.2–6.5 GPa, respectively. Further, the underlying deformation mechanisms induced by tool wear behaviours are revealed through the transient heat conduction model and cutting-edge stress distribution model. This research offers a framework and mechanism for the cutting tool wear surface/interface characteristics targeted to the difficult-to-cut superalloy materials.

Tribology and airborne particle emissions from grey cast iron and WC reinforced laser cladded brake discs

Laser cladding (LC) is a promising technique to overlay a protective coating on grey cast iron (GCI) brake discs to enhance the wear and corrosion resistance. This study utilized a pin-on-disc tribometer in an aerosol chamber to investigate the tribology and airborne particle emissions from tungsten carbides (WC) reinforced coating overlayed onto GCI substrate through laser cladding. Uncoated GCI brake discs served as reference material, while low-metallic (LM) and non-asbestos organic (NAO) brake pads were used as counterparts. The results indicate that LC coating exhibited slightly higher coefficient of friction and significantly lower wear than uncoated GCI discs. Abrasive wear is the dominant wear mechanism for both uncoated GCI brake discs and LC coatings. LC coatings substantially decreased the particle mass concentrations. All three friction pairs displayed a mass weighted size distribution with a major peak around 2–3 μm. The number size distribution was dominated by a mode below 1 μm. Emissions by number were generally low. Meanwhile, all three friction pairs emitted sheared off and agglomerated particles, with iron being the dominant element. Tungsten was identified in the particles emitted from LC coatings, indicating that the hard coating has a potential to wear off and become airborne particles.

Effect of applied load on wear of microwave sintered alumina-graphene ceramic composite material

The present work is mainly focussed on the preparation of alumina ceramic composite material reinforced with different weight proportions (wt%) of graphene ranging from 0.15 wt% to 0.45 wt% (with an interval of 0.1) and fabrication using microwave sintering method. Wear studies are performed on graphene reinforced alumina ceramic material samples using pin-on-disk apparatus at different loads of 5 N, 10 N, 15 N keeping speed of 0.8 m s−1 and sliding distance of 40 m constant. The obtained wear results are compared with wear performance of pure alumina samples which are prepared in the same condition. Wear tests even at higher load of 15 N revealed that the decrease in the wear rate of the ceramic composite samples reinforced with 0.35 wt% of grapheme is 35.14% and in the ceramic composite samples reinforced with 0.45 wt% of graphene is 34.85% when compared with the wear rate of samples prepared with pure alumina. The effect of different wt%s of graphene on wear properties of prepared ceramic composites is studied through SEM analysis, and observed that the abrasive wear phenomenon is found to be the dominant wear mechanism.