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Although many wear criteria have been proposed, none is intrinsic to the materials and to the structures in contact, We propose new computational methods for modelling the wear phenomenon and to improve the meaning of these criteria.To interpret sliding wear experiments, numerical calculations have been performed to estimate the mechanical state in the vicinity of the wear region and to infer the...
Two novel methods have been used to assess the wear resistance of six different 20-70 μm thick polymer coatings on both galvanized steel and polymeric substrates. The coatings were commercially available 'clear-coats' which are used as the uppermost layer in automobile paint systems and are intended to provide resistance to both mechanical and corrosive damage. The first wear test involves solid particle...
Molybdenum disilicide (MoSi 2 ) particles have been added to silicon nitride (Si 3 N 4 ) to form ceramic matrix-intermetallic composites. Benefits associated with the addition of the MoSi 2 to Si 3 N 4 include higher strength, higher fracture toughness, no loss in oxidation resistance, and lower electrical resistivity. However, since the hardness of...
For the erosion of alloys under aqueous conditions, there have been some recent attempts to identify the transitions between the erosion-corrosion regimes using laboratory results. Such transitions can be superimposed on an erosion-corrosion map as a function of the main corrosion and erosion variables. Defining the magnitude of the wastage rate on such maps enables the relevant process parameters...
The tribological behavior of thermosetting polyester filled with CuO, ZnO, ZnF 2 , and Zn(C 18 H 35 O 2 ) 2 fillers was studied. Sliding was performed in ambient atmosphere at 1.0 m s -1 between a polyester pin and a hardened tool steel disk in a pin-on-disk machine. The worn and the unworn specimen pin surfaces, zinc stearate powder,...
The effects of a d.c magnetic field or an electric current on the frictional behaviour of steel XC48/graphite were investigated. Experimental results are as follows.(1) At ambient atmosphere, both a magnetic field present in a tribocontact and an electric current through the sliding contact decrease the mean value of friction coefficient and decrease its fluctuations also. Electric current enhances...
Wear of an AFM diamond tip, whose initial radius was 65 nm, sliding against single-crystalline silicon was observed both from the decreasing wear rate of the silicon with increasing number of cycles and from direct imaging of the diamond tip shape using a micro-fabricated Si 3 N 4 AFM tip with a nominal radius of about 10-20 nm.It was shown that the assumption, which is usually used...
Surface damage to modem plastic automotive fasciae (bumpers) arises as a result of numerous physical 'sliding' contact scenarios. The most common tribological events include fascia contact with fixed obstacles, and fascia to fascia (vehicle to vehicle) sliding contact. The tribologically induced stresses may introduce abrasion, shear, tensile, and delamination failure in the paint and the plastic...
The paper reports the first part of a project aimed at developing methodologies for the evaluation of wear-resistant materials in mining and mineral processing operations. A review of the literature revealed that almost no systematic studies have been made of wear phenomena in operating mining and mineral processing plants. There have been a multitude of laboratory studies of abrasive wear phenomena...
In this paper, the effects of thermal exposure on the microstructure and wear behavior of the Al-10 wt.% Ti alloy have been investigated. The as-extruded material contains Al 3 Ti particles homogeneously distributed in the α-Al matrix. Al 3 Ti particles coarsened during thermal exposure at 630°C, via a diffusional growth mechanism. Block-on-ring tests under dry sliding conditions show...
The friction and wear of 1.5 mm chopped aramid fiber reinforced polyamide 6,6 composites with and without polytetrafluoroethylene (PTFE) were characterized using a block on ring wear tester equipped with real time friction measurement capabilities. Experiments showed an optimum wear reduction at low levels of aramid fiber (5-15 wt.%). At higher aramid fiber levels an increase in wear rate was observed...
The effect of the temperature and time of the destabilization and sub-critical heat treatments on the abrasive wear behaviour of two high-chromium white iron alloys (15-3 Cr-Mo and 27 Cr) was investigated. The response of each alloy to the destabilization heat treatment and, therefore, the microstructures developed, differed significantly. Pin abrasion tests were conducted, and showed the wear resistance...
The object of this study was to generate erosion maps for various particulate reinforced Ni-Cr/WC metal matrix composites by investigating the effect of erodent velocity with low velocity conditions, at elevated temperatures. The erodent used was alumina and the environment was oxidizing. The results showed that the ranking order of erosion resistance, as a function of volume fraction, reversed as...
The friction and wear behaviours of hard carbon coatings have been studied mainly at low sliding speed. This paper presents a study at high sliding speed (30-35 m s -1 ). Various types of hard carbon coatings were deposited on stainless steel (304L) pins. These coatings are produced by plasma-assisted chemical vapour deposition processes under different deposition conditions. The surface...
The effects of low-energy, high current density, elevated-temperature nitrogen and carbon ion implantation parameters on surface-layer microstructures determined using X-ray diffraction and optical and electron microscopy are examined for several ferrous materials. Solid solutions, precipitates of new phases and amorphization of surface layers are observed as parameters and materials are changed....
Vacuum deposited thin-film sensors have been developed for monitoring wear and temperature in a variety of bearing applications. The sensor typically consists of one or more metallic or insulator films. This lamination of sputtered thin-film resistance elements and thermoelectric elements with appropriate insulators is deposited directly on the bearing surface. The thin-film package can be designed...
Stress-induced anisotropy is an important phenomenon in the plastic deformation of semi-crystalline linear high polymers. The significance of this phenomenon in the wear of ultra-high molecular weight polyethylene (UHMWPE) bearing surfaces in total joint-replacement prostheses is studied in this investigation. Both linear and crosslinked UHMWPE materials were studied by means of a sequential biaxial...
The dependence on the impact angle of erosion damage caused by solid particle impact was characterized on several kinds of material, as expressed by a trigonometric function of both impact angle and material hardness. Erosion tests were conducted on five metallic materials, a ceramic and a plastic material using silica sand particles (mean particle size 325 μm) at impact angles from 3° to 90°, up...
This paper describes the effect of grain boundary chemistry, which can be easily altered by the amount of introduced sintering additives or impurities, on the high-temperature wear behavior of silicon nitride. Two different kinds of silicon nitride were made to investigate the effect of minor additives on the high-temperature wear behavior. A small amount of either CaO or Fe 2 O 3 ...
Different abrasive wear tests have been applied to materials with hardnesses ranging from 80 HV (aluminium) to 1700 HV (tungsten carbide). The tests were: dry sand rubber wheel (DSRbrW); a similar test using a steel wheel (DSStlW); a new combined impact-abrasion test (FIA).The DSRbrW results were as expected, giving generally decreasing wear with increasing hardness. White cast irons and tool steels...
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