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Fretting wear of polyimide coatings sliding against a 52100 steel sphere as a function of humidity was measured. The coating life, defined as the duration for which the 52100 ball wore through the polyimide coating, shortened with increasing humidity. A hydrophobic fluorine was exploited to reduce the effect of moisture an the coating life. Microhardness tests showed that the hardness of the polyimides...
The fretting wear behaviour of heavily work-hardened eutectoid steel wire is an important issue in the construction and usage of locked coil steel ropes. These ropes, which are used for high duty applications in aggressive environments, such as those encountered in the mining industries, can exhibit a variable service life. Earlier papers examined the design features of this class of rope and aspects...
The fretting wear behaviour of PVD TiN coatings against corundum has been investigated in unlubricated contacts. Analysis of the debris indicated that titanium oxides of different composition are being generated. The volumetric wear on the TiN coatings is shown to be directly proportional to the dissipated friction energy measured on-line during the fretting tests. Furthermore, the effect of oxide...
Friction and wear characteristics of partially stabilized zirconia (PSZ) fretted against itself and against high carbon steel were investigated. The results for the transformation toughened PSZ ceramics are compared with the behaviour of more brittle alumina ceramic under the same test conditions. Fretting tests in air were carried out on a high frequency wear test rig at room temperature using a...
Particulate reinforced aluminium alloy matrix composites, produced by a powder metallurgy route, can show improved specific properties, including elastic modulus and tensile and fatigue strength, over monolithic alloys. However, these materials are difficult to join using metallurgical processes without impinging on their mechanical performance. Mechanical fasteners or adhesives, which are normally...
Fretting wear occurs when normally loaded surfaces are subject to oscillatory relative tangential movements with small amplitude. As a result, the fretting wear volumes are much smaller than macroscopic wear volumes and by consequence are much more difficult to measure. Usually, qualitative or semi-quantitative but discontinuous techniques are used to measure fretting wear (SEM, scar size measurements,...
The wear and friction behaviour of silicon nitride against bearing steel was investigated under lubricated and dry fretting conditions as a function of amplitude and test duration. Tests were performed on a high frequency fretting tester. Silicon nitride bearing balls were used as the upper oscillating specimens while the lower stationary flats were standard specimens of bearing steel. Amplitudes...
Although many engineering situations involving fretting damage are lubricated, comparatively little has been reported on this aspect of fretting wear. The viscosity of the lubricating oil and its boundary layer performance are expected to influence fretting behaviour, in addition to the normal fretting parameters, such as stroke and contact force.This paper examines the effect of lubrication regime,...
The effects of amplitudes and normal loads on the fretting wear of titanium alloy (TC11) were experimentally investigated on a SRV fretting wear test machine in air, at room temperature and without lubrication. The wear depths were measured by a profilometer, the worn areas were observed and measured by an optical microscopy, and the micro-topographies of worn scars were studied by scanning electron...
Titanium and its alloys suffer from galling, seizing, ploughing and adhesion during sliding contacts. A laser nitriding method to improve the tribological properties of pure titanium was investigated in this study. Before laser nitriding, a layer of nickel and chromium was plasma sprayed onto the surface of pure titanium in order to prevent the formation of cracks and pores during laser treatment...
A new prototype fretting-wear testing machine is developed, and its performance is evaluated. In this testing machine, a spherical specimen is oscillated by a lead-zirconate-titanate semiconductor (PZT) actuator, driven by means of computer control. Thus, an arbitratry input waveform, such as sinusoidal wave, triangular wave and so on, can be easily operated to a spherical specimen. This is the special...
Fretting damage (fretting wear and fretting fatigue) is one of the modern plagues for the orthopedic implants because the oscillatory micromovement often often occurs at the interface between the implant and bone. In this investigation, the fretting wear behaviors of plasma sprayed hydroxyapatite (HA) bioceramic coatings on titanium alloy substrate were investigated under unlubricated conditions as...
The probability of encountering fretting in machines and engineering structures is extremely high, and it is well known that aluminum alloys have poor fretting wear resistance. In this investigation, effect of laser surface alloying of Ni, Cr on the fretting resistance of 6061 aluminum alloys under unlubricated conditions was studied. The fretting wear performance of the laser treated alloys was characterized...
Accurate prediction of the growth rate of fretting wear damage of steam generator (SG) and heat exchanger (HX) tubes is needed for safe, reliable and economical operation of the nuclear power plant. The methodology currently used to predict the long-term fretting wear behaviour of the tube is based on combining the short-term wear data base with non-linear finite element impact simulation of the tube/support...
Improving the tribological functionality of diamondlike carbon (DLC) films-developing good wear resistance, low friction, and high load-carrying capacity-was the aim of this investigation. Nanocomposite coatings consisting of an amorphous DLC (a-DLC) top layer and a functionally graded titanium-titanium carbide-diamondlike carbon (Ti-Ti x C y -DLC) underlayer were produced on AISI...
All surface techniques can be roughly divided into two categories: anti-wear coatings characterized by high hardness and anti-frictions coatings with low friction coefficient. However, it is still unclear which kind of coatings is more effective for preventing the fretting damage so far. So it is of important meaning to conduct a comparative study on fretting-resistant behavior of these coatings....
The fretting wear behaviour of a number of hard coating combinations, on a bearing steel substrate, was studied without external lubrication. The coatings used were Ni-P, Mo, 88% WC-12% Co, 60% Al 2 O 3 -40% TiO 2 and Cr 2 O 3 . The Ni-P coating, thickness 11 μm, was deposited by electroless plating. The other coatings, thickness 60 to 80 μm, were deposited...
Fretting wear behavior of plasma sprayed hydroxyapatite (HA) coatings lubricated with bovine albumin solution has been investigated as a function of oscillatory cycle, normal load and slip amplitude. Wear mechanisms, wear volume and coefficient of friction of HA coating under lubricated fretting conditions were studied. Results indicated that the fretting wear mechanisms of plasma sprayed HA coatings...
An experimental analysis of the fretting behaviour in the presence of a thin polystyrene coating is presented. A 52100 ball-flat (low alloyed steel) contact was used for testing. The displacement amplitude, applied pressure and coating thickness were varied. A dynamic force analysis in combination with a subsequent metallographical examination have shown that an incubation period prior to coating...
A TiN coating, deposited by PVD, was rubbed against corundum balls in a laboratory fretting experiment for different number of cycles. The surface composition and chemical state of the wear tracks, debris found on the TiN coating and the transfer layer on the corundum counterbody were determined with X-ray photoelectron spectroscopy and Auger electron spectroscopy. The worn surfaces in all the wear...
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