Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 48 for “"Wear rates"”.
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The tribological and wear properties of carbon-graphite composites
… with differing properties has been evaluated for wear resistance. These include carbons with a high degree of graphitic order (natural and synthetic graphite), those with little or no such order (pitch bonded cokes, glassy carbons) and impregnated grades. Testing has been carried out using …
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Micromechanisms of polymer sliding wear
… during water-lubricated reciprocating sliding wear. The experimental work has been extended to study also the effect of molecular weight, fillers, lubrication, counterface roughness and sliding configuration on the polymer's transfer characteristics. The wear behaviour of …
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In Vivo Wear Performance of Highly-crosslinked Polyethylene in Total Hip Arthroplasty
… hip arthroplasty (THA), significantly reducing wear rates and the need for revisions compared to conventional ultra-high molecular weight polyethylene. However, volumetric wear and the associated periprosthetic tissue response remain one of the key issues in long-term THA outcomes; in fact, …
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Design and fabrication of a twin disc tribometer and a study of wear and friction of hardened 1060 steel under combined rolling and sliding
In this research work, wear of steel was studied under different loading and sliding conditions. A twin-disc tribometer was designed and built for studying wear of steels under combined rolling and sliding contact. The samples were made from 1060 steel in the form of circular discs and heat …
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A Model for Abrasive Polymer Wear
The abrasive mechanism of polymer wear is dominant in the startup, or "breakin", stage of polymer/steel sliding systems. This mechanism controls the polymer wear rate until the voids in the hard metal surface are filled, much like the filling observed with a file when used on soft metals. This …
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Tribological and Structural Characterisation of Ceramic on Metal Hip Replacements
… hip replacements was carried out using in vitro wear testing methods. Two ceramic materials, pure alumina and an alumina matrix compound (zirconia toughened alumina (ZTA)), were articulated against as-cast CoCrMo alloy cups. The diameter was changed from 38 mm to 60 mm to explore the effect of …
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Wear of aluminium MMCs against automobile friction materials
… for use against aluminium MMC brake rotors. Wear processes at the interfaces of the specific rotor - pad combinations have been characterised through the analysis of friction traces and the use of optical and electron microscopy. Models on the interdependence of friction and wear, and models …
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Si-DLC coatings optimized for low wear and low friction applications.
… tribological coating such as high hardness, high wear resistance and a low friction coefficient. Nanolayer systems of hydrogenated diamond-like carbon (a-C:H) and silicon doped hydrogenated diamond-like carbon (Si-DLC or a-C:H:Si) have been studied. The objectives of this work are to develop layer …
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Tribological behavior of unfilled and carbon fiber reinforced polyether ether ketone/polyether imide composites
The friction and wear of injection molded Poly(ether ether ketone) (PEEK) and Poly(ether imide) (PEI), PEEK/PEI blends with the weight compositions of 50/50 %, 70/30 %, and 85/15 %, with and without short carbon fibers were measured in a pin(52100 steel ball)-on-disk(polymer blend) configuration …
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Generation of graphite particles by abrasion and their characterization
… at the contact point of the samples, calculated wear rates, measured the surface roughness of both pre-test and post-test samples, measured particle surface areas, measured pore volumes, and pore volume distributions of particles produced during abrasion of graphite surfaces under different …
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The role of oxidation in the protection of sliding metal surfaces
… is concerned with the mechanisms of growth and wear of protective oxide films formed under various tribological conditions. In the study three different tribological systems are examined in each of which oxidational wear is the dominant equilibrium mode. These are an unlubricated steel on steel …
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The tribological behaviour of aluminium matrix composites
… conditions. In abrasive environments, the wear behaviour of each composite is dominated by their ability to resist indentation by hard particles. Abrasion against fine grit particles leads to a reduced load per abrasive particle and a correspondingly significant reduction in wear loss. …
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Interactive influences of crosslinking, counterface roughness and kinematics on the wear of crosslinked UHMWPE
Ultra high molecular weight polyethylene (UHMWPE) wear debris has been shown to be a major cause of long term failure of total joint replacements. In vitro studies have shown that not only is the size and shape of the particles important for cellular response but also the volumetric concentration …
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Abrasion-corrosion of downhole drill tool components
… objective of this project was to replicate the wear-corrosion mechanisms of tungsten carbide (WC)-based hardmetals and coatings occurring in downhole environments (pH 9-11) under controlled laboratory conditions, to identify and establish a better understanding these mechanisms and the factors …
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The wear of materials in hydraulic transport pipelines
… particulate solids through pipelines results in wear of the pipeline walls. The lifetime of the pipeline is determined by this rate of material loss and is therefore critical to the designer. Due to the small amounts of material lost in in-situ tests, requiring in many cases in excess of 1000 …
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High temperature erosive wear of a boiler tube steel
… type, size, velocity and flux on the erosive wear rates of the 1Cr½Mo boiler tube steel at temperatures of up to 600°C. The response of the target to impacting erodent particles has been analysed using scanning electron and optical microscopy, transmission electron microscopy (TEM) as well as …
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Influence of surface roughness and sliding speed on the friction and wear of low density polyethylene
… of surface roughness and sliding speed on the wear mode of low density polyethylene was studied with multipass experiments at the high sliding speeds by the use of a pin-on-disk wear machine. Surface roughness was found to be the major parameter in determining the wear mode of the polymer at …
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Design and optimization of a play-free rotary magneto-rheological fluid brake for enhanced performance and durability
… titanium and ceramic materials showed higher wear rates. Ferromagnetic steel did not significantly affect torque performance, suggesting potential for further exploration. The study was limited by time constraints, which restricted the number of test runs per sample and led to occasional jig …
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An investigation of thin amorphous carbon-based sputtered coatings for MEMS and micro-engineering applications
… C films, with and without Cr doping, as a low wear / friction coating applicable to MEMS and other micro- and nano-engineering applications. Firstly, an assessment was made of the available testing techniques. Secondly, the optimised test methods were applied to a series of sputtered films of …
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Wear of Polycrystalline Cubic Boron Nitride Cutting Tools when Machining Nickel-based Superalloys
… ferrous materials precludes its use. High tool wear rates are observed when using PcBN to machine Ni-based superalloys - in particular Inconel 718. While there have been other studies on the machining of this alloy using PcBN tools, and the types of wear that occur have been described, the …
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