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Surface potential and friction coefficient were measured simultaneously during scratching of insulating materials made of ceramics and polymers with a diamond stylus in ambient air. The insulating solids used were Al 2 O 3 , Si 3 N 4 , glass and polytetrafluoroethylene (PTFE). It was found that the surface potential and friction coefficient have a positive correlation.
Dynamic mechanical measurements of the viscoelastic behavior of magnetic tapes and substrates are presented. Five types of tapes were analyzed including three polyethylene terephthalate (PET) tapes with metal particulate, barium ferrite particulate, and metal-evaporated coatings. A polyethylene naphthalate (PEN) tape with a barium ferrite particulate coating was also analyzed along with an aromatic...
Transfer films play an important role in the tribology of polymers and other sliding contacts where wear debris constitutes a significant portion of the interfacial tribosystem. In addition, counterface topographical features strongly influence the physical and mechanical entrapment of wear debris and influence the growth and propagation of transfer films. In this study, to investigate the effects...
Friction and wear tests of pure polymers, polytetrafluoroethylene (PTFE), nylon 6, and polymethyl methacrylate (PMMA), vs. stainless steel were carried out on an MM200 tester. The XPS spectra and the atomic relative concentrations of elements on friction surfaces of stainless steel were analysed. The ESR spectra of radicals in polymer wear debris were determined. The results indicate that complex...
Results of the study into the forms of surface failure of cross-linked polystyrene, polycarbonate and polymethylmethacrylate resulting from rolling contact are presented. Also the influence of two different lubricating liquids on the time to failure is quantitatively assessed and discussed. Under the contact stress ranged from 1.5 to 2.6 GPa it was found that in case of certain polymers the surface...
Friction and wear tests of various polymers/stainless steel, PTFE/various metals and JS material (a multilayer composite)/stainless steel were carried out. The XPS spectra and atomic relative concentrations of elements on mating surfaces, the EPM spectra of element line distributions on frictional surfaces and the ESR spectra of radicals in polymer wear debris were determined. The test results indicated...
Wear experiments have been carried out with a range of filled and unfilled engineering polymers sliding against a hardened steel mating surface under different conditions of sliding speed, mating surface roughness and roughness orientation. The tests were carried out under dry reciprocating sliding conditions that can be compared to the conditions frequently found in the moving parts of various electronic...
Static and kinetic contact of a steel ball against a polycarbonate half-plane was experimentally examined to study its friction and wear behavior. Changes in friction were correlated with the apparent wear volume. The finite element method, using a physically based visco-plastic constitutive model, simulated the initial stage of sliding contact through indentation, sliding and unloading stages. Detailed...
This paper presents a simple and reliable technique for nanometer-scale layer modification of a polycarbonate (PC) surface using an atomic force microscope (AFM). The AFM tip, coated with amorphous carbon was made to oscillate vertically at its resonance frequency. With tip oscillating in tapping mode, it scan-scratched the PC surface to make the desired modification. This action carved the PC surface...
In the present paper, an artificial neural network (ANN) approach was applied to the erosive wear data of three polymers, i.e. polyethylene (PE), polyurethane (PUR), and an epoxy modified by hygrothermally decomposed polyurethane (EP-PUR). Three independent datasets of erosive wear measurements and characteristic properties of these polymers were used to train and test the neural networks. For the...
In order to gain greater insight into the relation between the wear rate, counterface surface topography and the characteristics of the transfer layer formed, a series of wear experiments have been performed with a commercial POM-20% PTFE composite sliding against hardened tool steel counterfaces in a pin-on-plate reciprocating configuration. The surface topography of the steel counterface with respect...
An understanding of abrasion resistance and the associated surfaces deformation mechanisms is of primary importance in materials engineering and design [Wear (1998)].Instrumented scratch testing has proven to be a useful tool for the characterisation of the abrasion resistance of material. Although most studies on scratch resistance have been conducted for metals, assuming a purely plastic behaviour,...
A methodology to monitor wear behaviour of polymer horseshoes was developed and applied in a field investigation. Results show that wear is proportional to the distance run on hard grounds while other typical horse activities performed on softer grounds do not contribute significantly to degradation. Slight modifications of the shoe structure affect the distribution of wear on the shoe sole and may...
Cryogenic blasting is a pneumatic jet based process in which solid carbon dioxide (CO 2 ) particles impinge upon a surface. It may be employed to remove paint layers from a variety of substrate materials. During this process, the substrate material may be damaged due to the carbon dioxide particles striking the substrate surface. For applications where the component is to be recoated, such...
The authors present an experimental approach of abrasion resistance of material currently used in ski: ultra high molecular weight polyethylene (UHMWPE) is used as the main element of ski sole: cross country skiing, speed skiing, alpine skiing, ….The aim of this work is to characterise abrasive wear and tribological performance of ski sole when one slides on ice in different conditions of loads, ice...
The wear resistance of bulk polytetrafluoroethylene (PTFE) and fluorinated ethylene propylene (FEP) fluoropolymer pin samples when sliding against polished steel countersurfaces is shown to be improved by over two orders of magnitude through the use of gamma irradiation. Wear rates were found to drop monotonically with increasing irradiation dose for both PTFE and FEP, with PTFE having a stronger...
Bearings made of polymer-based composites are often used when corrosive environments prevent the application of other kinds of materials [N.N., Gleitlager mit Wasserschmierung, Materialwissenschaft und Werkstofftechnik 30 (1999) S243; N.G. Fontana, Corrosion Engineering, second ed., McGraw-Hill, New York, 1978; M. Pourbaix, Lectures on Electrochemical Corrosion, Plenum Press, New York, London, 1973,...
This paper presents a PEEK filled PTFE composite that exhibits low friction and ultra-low wear. It is hypothesized that a synergistic effect shuts down the dominant wear mechanism of each constituent. The friction coefficient and wear rate of this composite material on lapped stainless steel were evaluated for samples with PEEK wt.% of 0, 5, 10, 20, 30, 40, 50, 70 and 100 using a linear reciprocating...
Tribological systems are complex systems that require a multi-disciplinary (mechanical, material, physico-chemical) approach where numerous influence factors can be involved. To characterize a contact couple, the intrinsic parameters of the materials as well as the parameters related to the contact loading and the surrounding environment need to be taken into account. Fretting analysis, by means of...
Delamination wear is found in the literature of metals, ceramics and composite materials involving layers of different polymers. In the tribological investigations on polymers, the phenomenon of delamination in polyurethane has not generally been cited. This work focuses the damage mechanism of delamination noticed in flat surfaces of thermoplastic polyurethane elastomer (TPU), when sliding against...
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