Wear Test Apparatus Research Articles

Influence of ceramic surface texture on the wear of gold alloy and heat-pressed ceramics.

The purpose of this study was to evaluate the influence of ceramic surface texture on the wear of rounded rod specimens. Plate specimens were fabricated from zirconia (ZrO2), feldspathic porcelain, and lithium disilicate glass ceramics (LDG ceramics). Plate surfaces were either ground or polished. Rounded rod specimens with a 2.0-mm-diameter were fabricated from type 4 gold alloy and heat-pressed ceramics (HP ceramics). Wear testing was performed by means of a wear testing apparatus under 5,000 reciprocal strokes of the rod specimen with 5.9 N vertical loading. The results were statistically analyzed with a non-parametric procedure. The gold alloy showed the maximal height loss (90.0 µm) when the rod specimen was abraded with ground porcelain, whereas the HP ceramics exhibited maximal height loss (49.8 µm) when the rod specimen was abraded with ground zirconia. There was a strong correlation between height loss of the rod and surface roughness of the underlying plates, for both the gold alloy and HP ceramics.

Enhanced wear resistance of high-density polyethylene composites reinforced by organosilane-graphitic nanoplatelets

It is known that graphite has excellent lubricant properties due to the 2D graphene layers bonded via van der Waals forces. Thus, graphite nanoplatelets (GNPs) should have high lubricating efficiency during contact frictional movement of sliding parts. However, GNPs have rarely been used to improve the tribological properties of polymeric materials. In this study, we aimed to improve wear resistance of GNP–reinforced high-density polyethylene (HDPE) composites via the synthesis of organosilane-modified GNPs. Wear resistance of the HDPE/GNP composites was examined on a pin-on-disc wear testing apparatus under various sliding velocities. The results revealed that compared to the composites without filler surface modification, significant enhancements in wear resistance under different sliding velocities were realized in silanized-GNP–reinforced HDPE composites. In particular, 97% wear resistance improvement under 1.3ms-1 sliding velocity was obtained. Furthermore, the organosilane-modified GNPs minimized the influence of sliding velocity on wear resistance of the composite and thereby maintained excellent wear resistance in a broad range of sliding velocities, and even at very high velocity (2.0ms−1). Both superior wear resistance and good stability of wear performance at various sliding velocities suggest silanized-GNP/HDPE composites are promising materials with great potential for a wide range of tribological applications.

A hybrid apparatus for friction and accelerated wear testing of total knee replacement bearing materials

The statistical survivorship of total knee replacement (TKR) devices declines dramatically after fifteen years of use because the articulating surfaces wear, and biologically active wear particles may induce osteolysis and subsequent loosening of the implant. This lack of durability leads to revision surgery or surgery postponement. Thus, friction and wear evaluation is of primary concern when designing the next generation of TKR bearings. Presently, knee simulators are used to aid in the development of TKR devices, mimicking six degrees of freedom of the knee joint under simulated gait. However, these simulator experiments are lengthy and, thus, do not allow for efficient testing of large numbers of bearing material pairs and designs. Conversely, inexpensive pin-on-disk (POD) tests allow for efficient testing, but the results may have limited clinical relevance. This paper presents the design of a hybrid friction and accelerated wear testing apparatus that combines elements of both a POD apparatus and a knee simulator. The apparatus simulates dynamic axial loading and flexion/extension rotation, and it enables fast and inexpensive screening of TKR bearing materials with boundary and loading conditions that are more clinically relevant than those of a POD apparatus.

Microstructure and Dry Sliding Wear Behavior of AA2218 Based Self-Lubricating Metal Matrix Composites

AA2218 based self-lubricating metal matrix composite was prepared with 5, 10 & 15 weight percent of fly ash and 4 weight percentage of MoS2. Dry sliding wear behavior of self lubricating composite was tested at room temperature by pin on disc wear testing apparatus. Wear rate, Coefficient of friction and volume loss of self lubricating composite has been tested as the result of applied load, sliding velocity and weight percent of fly ash particles. From this investigation it was observed that the wear rate increases with the increasing load, at the same time wear rate and coefficient of friction get reduced to increase in wt. % of fly ash particles. Another dominant factor is the formation of the tribochemical layer at the interface, which was formed by MoS2. Formation of tribochemical layer was clearly observed from SEM micrographs. This study reveals that wear resistance of the self-lubricating composites containing 15 wt. % fly ash and 4 wt. % MoS2 has been superior to that of the other compositions.

Wear behaviour of aluminium/alumina/graphite hybrid metal matrix composites using Taguchi's techniques

PurposeRecent advances in modern technology have generated the need to develop newer materials for better antifriction and wear properties. The objective is to analyse the significance of design parameters that significantly affects the dry sliding wear.Design/methodology/approachThe tribological behaviour of aluminium alloy (Al‐Si10Mg) reinforced with alumina and graphite produced by liquid metallurgy is studied using pin‐on‐disc wear test apparatus under dry sliding condition. Experiments are conducted based on the plan of experiments generated through Taguchi technique. A L27 Orthogonal array is selected for analysis of the data. Influence of applied load, sliding speed and weight percentage of reinforcements on wear rate as well as the coefficient of friction during wearing process is studied using analysis of variance technique and regression equations for each response are developed. Finally, confirmation tests are carried out to verify the experimental results.FindingsMechanical property such as hardness has been evaluated and it was found that the hardness increases as reinforcement content increases. The wear rate and coefficient of friction increases by increasing load and decreases by increasing sliding speed and weight percentage of reinforcements. Results from analysis of variance reveals that the applied load has the highest influence on both wear rate and coefficient of friction, followed by sliding speed and weight percentage of reinforcement.Practical implicationsAluminium hybrid metal matrix composites showing ample success in improving strength and wear resistance by utilising the optimal process condition.Originality/valueThe results obtained by this method are useful in improving the dry sliding wear resistance.

Tribological performance of polymer composites used in electrical engineering applications

Sliding wear performance of 20% mica-filled polyamide 6 (PA6 + 20% mica) and 20% short glass fibre-reinforced polysulphone (PSU + 20 GFR) polymer composites used in electrical applications were investigated using a pin-on-disc wear test apparatus. Two different disc materials were used in this study. These are AISI 316 L stainless steel and 30% glass fibre-reinforced polyphenylenesulphide (PPS + 30%GFR) polymer composite. Wear test was carried out at 10, 20 and 30 N applied load values and 0·5 m/s sliding speed and at ambient temperature and humidity. Different combinations of rubbing surfaces were examined and friction coefficient and specific wear rate values were obtained and compared. For two material combinations used in this investigation, the coefficient of friction shows insignificant sensitivity to applied load values and large sensitivity to material combinations. For specific wear rate, PA6 + 20% mica composite has shown insensitivity to change in load, speed and materials combination while PSU + 20% glass fibre composite has shown high sensitivity to the change in load and material combinations. The friction coefficient of PA6 + 20% mica and PSU + 20 glass fibre rubbing against the AISI 4140 steel disc is between 0·35 and 0·40. In rubbing against PPS + 30% glass fibre their values were between 0·25 and 0·30. Specific wear rate for PA6 + 20% mica and PSU + 20% glass fibre composites are in the order of 10 − 13 to 10 − 14 m2/N. Finally, the wear mechanisms are a combination of adhesive and abrasive wear processes. In terms of application, especially in electrical systems, a substantial contribution was provided to extend switch life. Thus, besides robustness, this also ensured safety for the system and the users against undesirable situations.

Effect of Processing Parameters on Friction Stir Welded Aluminum Matrix Composites Wear Behavior

In the present work, the aluminum matrix composites reinforced with both SiC and graphite particles are joined using a friction stir welding (FSW) process. The wear characteristics of the welded joints were investigated at constant load of 50 N and a rotational speed of 1,000 rpm using a pin-on-disk wear testing apparatus. This study focuses on the influences of the FSW processing parameters (tool geometry, rotational speed, and welding speed) on the wear characteristics of the welded joint of the considered hybrid aluminum matrix composite under dry sliding conditions. The experimental results indicate that the wear resistance of the joint increases at high welding speeds (>45 mm/min) and/or low value of rotational speeds. Different tool pin profiles (square, octagonal, and hexagonal) are developed to perform the welding process, and the effects of the tool pin profile on the weldments were studied. It is found that joints welded with square pin profile have better wear resistance compared to the other pin profiles. The results demonstrate that the FSW processing parameters greatly affect on the wear resistance of the welded joints due to various microstructural modifications during welding that cause an improvement in the welded zone hardness and wear properties.

Dry sliding wear behaviour of aluminium/alumina/graphite hybrid metal matrix composites

PurposeRecent trends in material science show a considerable interest in the manufacturing of metal matrix composites to meet the stringent demands of lightweight, high strength and corrosion resistance. Aluminium is the popular matrix metal currently in vogue that can be reinforced with ceramic materials such as particulates to meet the desired property. The purpose of this paper is to fabricate hybrid metal matrix composites to improve the dry sliding wear resistance and to study of the effect of sliding speed, load and reinforcement (alumina and graphite) on wear properties, as well as its contact friction.Design/methodology/approachThe present study addresses the dry sliding wear behaviour of Al‐Si10Mg alloy reinforced with 3, 6 and 9 wt% of alumina along with 3 wt% of graphite. Stir casting method was used to fabricate the composites. Mechanical properties such as hardness and tensile strength have been evaluated. A pin‐on‐disc wear test apparatus was used to evaluate the wear rate and coefficient of friction by varying the loads of 20, 30 and 40 N, sliding speeds of 1.5 m/s, 2.5 m/s and 3.5 m/s at a constant sliding distance of 2100 m.FindingsMechanical properties of hybrid metal matrix composites (HMMCs) have shown significant improvement. The wear rate and coefficient of friction for alloy and composites decreased with increase in sliding speed and increased with increase in applied load. Temperature rise during wearing process for monolithic alloy was larger than that of HMMCs and Al/9% Al2O3/3% Gr composite showing the minimum temperature rise.The worn surfaces of the composites were investigated using scanning electron microscope.Practical implicationsThe paper shows that aluminium composites can improve strength and wear resistance.Originality/valueHMMCs has proven to be useful in improving the dry sliding wear resistance.

Mechanical and sliding wear properties of multi-layered laminates from glass fabric/graphite/epoxy composites

Multi-layered laminates of bi-directionally woven E-glass fabric/epoxy with different loading of graphite particles were made by hand layup followed by compression molding. Tensile and flexural behaviors, impact strength, hardness and density of these laminates were determined. Wear behaviors of these composites were investigated by a pin-on-disc wear test apparatus. Specific wear rates of these composites strongly depend on their filler content and applied normal loads. The hybrid composite containing 3wt% of graphite exhibits the optimum mechanical and wear performances. A further increase in the graphite content increases the specific wear rate and deteriorates the mechanical behavior. The lowest (σe)−1 factor (the reciprocal of the product of tensile strength and elongation at break) signifies the lowest specific wear rate. The results of the morphology study of the wear test specimens support the results of the wear test.

The Effect of the Retrogression Process on the Wear Behaviour of a 7075 Aluminium Alloy

Abstract Retrogression and re-aging (RRA) process are applied in an attempt to enhance mechanical properties and corrosion resistance of 7075 aluminium alloys. In this study, retrogression and re-aging process have been applied to a 7075 aluminium alloy at 170°C for 5, 40, 80 min and wear resistance of RRA applied samples have been investigated by ball-on-disc wear test apparatus. Sliding distance has been chosen as 300 meters. Re-aging procedure has been carried out at 125°C for 10, 20 and 30 hours. Minimum wear loss has been obtained by retrogression for 40 min and aging for 30 hours.

The Effect of Ti Addition and Aging on Wear Behavior of AlMgSi Alloys Reinforced with In Situ Al3Ti Particles

The purpose of this study is to investigate the effects of Ti addition (1 and 2% Ti) and aging heat treatment on the mechanical and wear characteristics of Al-12Si-20Mg cast alloys. In preliminary studies conducted to determine the aging parameters, cast alloys were kept at 550 °C for 2 h before being quenched into water and aged at 200 °C for five different periods (3, 6, 9, 12, and 15 h). As the specimen aged for 12 h had the highest hardness value, all the specimens were aged at 200 °C for 12 h. The microstructures of the as-cast and aged specimens were analyzed using an optical microscope and a scanning electron microscope. The hardness of the investigated alloys was measured by micro-hardness test. The wear tests were carried out using the pin-on-disk model wear test apparatus, and the results were evaluated according to weight loss. According to the wear test results, the wear behavior of the investigated alloys changed depending on the aging heat treatment applied and the load. While Ti addition and the aging heat treatment applied reduce the weight loss at low loads (5 N), they increase the weight loss at higher loads (10 and 20 N).

A Review of Wear Mechanisms of Ceramic-Reinforced Metal-Matrix Composite: Case Study of Nano Silica Reinforced Iron

Available information on the composition and methods of production for particulate reinforced metal matrix composites (PRMMCs) for wear resistant applications is reviewed. In general, PRMMCs exhibit better wear resistance compared to its unreinforced counterparts. Nevertheless, under specified conditions, the wear performance of PRMMCs is similar to or lower than its respective alloy. Conflicting results were found among investigators with regards to different tribological parameters used in their investigations. A general framework was developed by identifying three parameters that affect the effectiveness of wear mechanisms model; fabrication method, types and characteristics of reinforcement and wear testing apparatus.

Tribological behaviour a-C and a-C:H films doped with Ti in biological solutions

The coatings were deposited in a multi magnetron Teer sputtering device with two C targets and a Ti target in Ar atmosphere, on steel and Si substrates. To deposit hydrogenated coatings methane was introduced in the discharge atmosphere. The films were deposited in a range of 7–14 at.% Ti content. X-ray diffraction patterns revealed the presence of a nanocrystalline TiC phase. The hardness varied from 8 to 9 GPa. The tribological tests were performed under dry sliding and lubricated (0.9% NaCl water solution, physiological solution, PS, and 10% fetal bovine serum dissolved in Ringer’s saline solution, FBS) conditions, using a 100Cr6 steel balls with a diameter of 6 mm, in a pin-on-disc wear test apparatus.

Wear mechanism of abrasion resistant wear parts in raw material vertical roller mills

► Investigation of vertical roller mills mechanisms. ► Assumptions and considerations verified using lab equipment. ► Main emphasis is grinding bed movements between the rollers and table. ► Results are supported by microscopic analysis. The raw materials industry is faced with severe challenges due to ever changing heterogeneous mixtures and thus each industrial comminution system needs to be analyzed one by one. This study is aimed at identifying the most common degradation mechanisms occurring in closed circuit high stress comminution equipment such as vertical roller mills. Both a macroscopic and a microscopic analysis of the wear parts has been conducted. A laboratory scale vertical roller mill with a transparent roller/table has been developed to further understand the material movements during grinding. The development of a simple wear test apparatus has verified the type of wear mechanism dominating the process. Optical microscopy revealed that strain incompatibility resulted in fracture and decohesion of the carbides below the worn surface. The emphasis of this work are wear related issues and thus detailed rock mechanical considerations have been omitted and are not within the scope of this study.

Hydro-Abrasive Erosion Resistance of C45 Steel in Different Heat-Treated States on a Designed Wear Test Apparatus

Abstract In this study, the hydro-abrasive erosion behaviour of a C 45 steel in different heat-treated states, which are normalizing, oil-quenching, tempering after oil-quenching and boronizing thermochemical surface treatment, was investigated on a designed and manufactured hydro-abrasive wear test apparatus. Boronizing was performed in a solid medium consisting of B4C, SiC, and KBF4 at a temperature of 900 °C for two hours. The microstructure and the wear regions of the specimens were characterized using an optical and a scanning electron microscope. In the tribogical system, the specimens were rotated in a system instead subjecting them to a fluid and moving abrasive particles. The wear tests were performed under a fixed rotational speed of 53 rpm for each specimen in the respective heat-treated state. The weight loss at the end of each wear period of 10 hours was measured using a precision electronic balance with an accuracy of 1 mg. It was concluded from the investigation that oil-quenching and tempering treatments led to significant improvement of the hydro-abrasive erosion resistance, while as-boronized and as-normalized specimens exhibited the lowest erosion resistance. In spite of its high surface hardness in the boronized state, the C45 steel did not affect positively its hydro-abrasive erosion resistance. In the as-normalized specimen, the low hydro-abrasive erosion resistance corresponded with a decrease of hardness. An increasing amount of ferrite and pearlite in the C45 steel led to the reduction of the hydro-abrasive erosion resistance.

Dry sliding wear studies of die cast aluminium–silicon carbide composites

Aluminium alloy metal matrix composites (MMCs) have evoked keen interest in recent times for potential applications in aerospace and automotive industries owing to their superior strength to weight ratio and high temperature strength. In the present work, aluminium alloy–silicon carbide composite is developed using a new combination of vortex method and pressure die casting technique. The dry sliding wear properties on aluminium alloy–silicon carbide MMC are carried out using a pin-on-disc wear testing apparatus at room temperature. The effects of normal load and sliding speed on tribological properties of the MMC pin on sliding with En 36 steel disc are evaluated. The wear rate increases with normal load and sliding speed. The specific wear rate marginally decreases with normal load. The coefficient of friction decreases with normal load and sliding speed. The wear and friction coefficient of the aluminium alloy–silicon carbide MMC is lower than that of the plain aluminium alloy.

Microstructure and wear property of laser cladding Al+SiC powders on AZ91D magnesium alloy

Al+SiC powders were pulse-laser (Nd–YAG) cladded on AZ91D magnesium alloy. The microstructure, chemical composition and phase analyses of the cladding layer were studied by scanning electron microscopy, EDX analysis, and X-ray diffraction measurement. The composite coating is composed of SiC and β-Mg 17Al 12 phases. The laser cladding showed very good bonding with the magnesium alloy substrate. The surface hardness of cladding coating is higher than that of substrate and increases with the increase of SiC content in the cladding. Sliding wear tests conducted in a pin-on-disc wear testing apparatus showed that the composite coating with SiC particles and in situ synthesized Mg 17Al 12 phase remarkably improved the wear resistance of the AZ91D magnesium alloy.

Friction and wear properties on AZ91D magnesium alloy treated by anodizing from phosphate electrolytic solution

The effects of various surface treatments on the friction and wear properties of AZ91D magnesium alloy substrate against the SUJ2 steel ball were evaluated by using a horizontal reciprocating friction and wear test apparatus. The friction and wear properties greatly changed due to the type of surface treatment in spite of being under equal friction and wear testing conditions. Wear loss of AZ91D magnesium alloy anodized from the phosphate solution was greatly reduced in comparison with the other surface treatments such as Dow17, conversion coatings and also no surface treatment. The above results suggest that anodizing from the phosphate solution should improve the friction and wear properties of magnesium alloy used for sliding parts.

Performance and anti‐wear mechanism of Cu nanoparticles as lubricating oil additives

PurposeThe purpose of this paper is to study the tribological performance and anti‐wear mechanism of Cu nanoparticles as lubricating oil additives.Design/methodology/approachAn end‐face wear testing apparatus is used to measure the tribological properties of Cu nanoparticles as lubricating oil additives and using a commercial SJ 15W/40 gasoline engine oil for comparison. Electrical contact resistance (ECR) is measured on a universal nano and micro tester‐2 tribometer to detect the formation of tribo‐film generated by Cu nanoparticulate additive. The worn steel surfaces are investigated by scanning electron microscope (SEM), energy dispersive spectra (EDS) and X‐ray photoelectron spectroscopy (XPS).FindingsThe results show that Cu nanoparticles used as an oil additive can improve the anti‐wear and friction‐reduction performance of SJ 15W/40 gasoline engine oil remarkably. The results of SEM, EDS and XPS show that a deposit film containing metallic copper can form on the worn surface, which has a film thickness of about 120 nm.Originality/valueThis investigation establishes a baseline of Cu nanoparticles used as lubricating oil additives under face‐to‐face contact work conditions. Thus, the results are reliable and can be very useful for further applications of Cu nanoparticle additives in industry.

An Investigation on Erosion Wear Characteristics of SiC Particle Reinforced Steel Matrix Surface Composite

The erosion wear characteristics of SiC particles reinforced steel matrix surface composite were studied by self-made slurry erosion wear test apparatus with quartz slurries, and contrasted with that of plain carbon steel, high chromium cast iron and low chromium cast iron. The results indicated that the erosion wear rate of the four tested materials has the different changes not only with the quartz particles sizes in slurry, but also with the erosion angle of slurry. The erosion wear rate of SiC particle reinforced steel matrix surface composite is the lowest in four kinds of tested materials under the test conditions. And that of high chromium cast iron is less than that of low chromium cast iron under the same test conditions. The SiC particles embedded the steel matrix could prevent the steel surface from wear brought by quartz particles in slurry erosion wear, and protect the steel matrix, so that the erosion wear resistance of steel matrix could be increased.