Diamonds have many extreme physical properties that lead to a host of technological applications. Their main use as a tool or abrasive for the machining of hard materials involves diamonds rubbing against the material being worked and often against each other. The strength and frictional properties of diamond are thus of great practical, as well as academic interest. Studies of the reciprocating sliding of one diamond on another for extended periods have shown that the changes in friction and wear are linked with the formation of debris. Analysis of the debris shows it does not consist of diamond fragments. Investigations of the effect of low-pressure gases on diamond friction also indicate debris plays an important role, and that the friction and wear are markedly dependent on the state of adsorbants on the diamond surface. Details are also given of the friction and wear of steel, glass and sintered diamond in contact with diamond. An associated study of the solid particle erosion of diamond has shown that cracking can occur at impact velocities of 25 m s<SUP>-1</SUP>. To facilitate the friction studies two existing friction apparatus have been automated. Computer control now allows data to be collected and analysed more rapidly and thoroughly than was possible before. The equipment has also been adapted to extend the conditions under which friction studies can be made.

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This master thesis report evaluatesthe lubricating effect of graphene (G)and graphene oxide (GO). Thesematerials have been added, in particlecondition, in Ag-based slidingcontacts and lubricating greases. Thework focuses on the tribologicalevaluation of these materials,especially friction, wear and contactresistance analyses. The friction andwear behaviors of Ag-based contactscontaining of a wide concentrationrange of graphene and graphene oxideare tested against pure silver using atest load of 2 and 10 N at a constantspeed of 5 cm/s. It was revealed thatsmall amounts of G and GO are able tosignificantly reduce the frictioncoefficient and wear rate. Contactresistance measurements revealed thatresults similar to pure Ag can beachieved with G content up to 10vol%.Possible mechanisms, which maycontribute to this tribologicalbehavior are the Ag-C interactions andthe lubricating nature of graphene.Friction tests with G and GOcontaining lubricating greases showinconsistent results, and both greasesand corresponding test methods forevaluation require furtheroptimization. The overall, promising,tribological behavior of G and GOholds for the implementation invarious industrial applications. Thereis no doubt that these kinds ofmaterials can play an important rolein ABBs future work. This masterthesis report shows yet anotherapplication area for theseextraordinary materials.

Thesis (M.S.)--Ohio University, August, 1992. / Title from PDF t.p.

In Tribology, the well-known Stribeck curve is often used to relate friction behaviour to the properties of a system. Richard Stribeck, (Jacobson, 2003), (Stribeck, 1902) developed these curves while researching various bearings and found that the Stribeck curve can be generated for all tribological contacts of the Hertzian type. These curves give a relation between the coefficient of friction and the Sommerfeld number for a lubricant and given surfaces. All his test work was done on contacts that move in a single direction, unidirectional motion. This leaves the question, could Stribeck curves be applied to reciprocating contacts and how does linear velocity affect wear in these contacts? This research project is aimed to further the knowledge on how linear velocity affects reciprocating contacts with a focus on Stribeck curves and lubricity. Tests were conducted on two reciprocating instruments using ball and disk configurations. Two parameters were varied to change the linear velocity, namely oscillating frequency, and stroke length. To shift focus away from viscosity, n-Hexadecane was used as the base fluid due to its lack of lubrication properties. To improve the base fluid lubricity 3 carboxylic acids with 3 different chain lengths were used as additives. / Dissertation (MEng (Chemical Engineering)) Univercity of Pretoria, 2021. / Chemical Engineering / MEng (Chemical Engineering) / Restricted

Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 189-198).

Thesis (M.E.-Res.)--University of Wollongong, 2008. / Typescript. Includes bibliographical references: leaf 226-238.

Orientador: Sandro Donnini Mancini / Banca: Sandra Andrea Cruz / Banca: Maria Odila Hilario Cioffi / O programa de Pós Graduação em Ciencia e Tecnologia de Materiais PosMat tem carater institucional e integra as atividades de pesquisa em materiais de diversos campi da UNESP / Resumo: Termoplástico de muitas qualidades, em especial a manutenção das propriedades mecânicas sob temperaturas medianas, a poliftalamida - PPA, é uma das muitas alternativas para a substituição de materiais metálicos em aplicações que envolvam desgaste, resistência térmica, estabilidade dimensional e química, exigência de baixo peso e custo, além de flexibilidade de design. Neste trabalho foram analisadas, visando à substituição de materiais metálicos tradicionais usualmente empregados em bombas de óleo de motocicletas, diversas propriedades de compósitos tendo como matriz a poliftalamina: um deles com a fibra de vidro como reforço e outro com a fibra e com politetrafluoretileno - PTFE. O estudo foi dividido em duas grandes partes, sendo uma a caracterização do comportamento tribológico do compósito em três diferentes testes, objetivando determinar as taxas de desgaste sobre pressão e velocidades controladas, e outra, a caracterização de propriedades gerais após submteter cada compósito e envelhecimento em óleo e temperatura. Cm relação à segunda parte, análises de DSC e TG foram realizadas antes e após o envelhecimento, enquanto propriedades mecânicas como tração, impacto e dureza foram medidas para avaliar a manutenção das mesmas após envelhecimento. A técnica de análise dinâmico-mecânica foi utilizada para obter valores dos módulos elástico, de dissipação viscosa e complexo. Os resultados dos ensaios de desgaste demonstraram o bom comportamento do compósito frente aos materiais metálicos com redução na taxa desgaste, sobretudo frente ao alumínio. Os ensaios de tração, impacto, densidade, DSC e TG demonstraram a manutenção das propriedades mecânicas e térmicas, mesmo após envelhecimento em óleo. Foi comprovado a possibilidade de emprego dos grades desse material na aplicação bomba do óleo e validado design com ganho de desempenho em baixas rotações de até 7% / Abstract: Thermoplastic of many qualities, in special the maintenance of the mechanical properties under medium temperatures, the polyphthalamide - PPA, is one of the many alternatives for the substitution of metallic materials in applications that involve wear, thermal resistance, dimensional and chemical stability, requirement of low weight and cost, beyond flexibility of design. In this work diverse properties of this material had been analyzed aiming at to the substitution of usually used traditional metallic materials in oil pumps of motorcycles. The study it was divided in two great areas, being the one characterization of the tribological behavior or composite in three different tests objectifying the controlled wear rate on pressure ans speeds, and another the characterization of general properties after properties after the material to be submetted the aging in oil and temperature. Analysis of DSC and TG had been carried through before and after the aging. Mechanical properties as tension, impact and hardness had been carried through to after evaluate the maintenance of same the aging. The technique of analyzes dynamic-mechanics was used to get values of the modulus: storage, loss and complex. The results of the wear assays demonstrated the good behavior of the composite front to metallic materials with reduction in the wear rates, above all versus aluminium. The tension, impact, density, DSC and TG test demonstrated the maintenance of the machanical and thermal properties, even after aging in oil. It was proven the possibility of job of the grades of this material in the application oil pump and validated design with profits in low rotations of up to 7 percentile points / Mestre

Made available in DSpace on 2014-06-11T19:30:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-11-30Bitstream added on 2014-06-13T20:20:43Z : No. of bitstreams: 1 santosneto_ao_me_bauru.pdf: 1462561 bytes, checksum: f3d7a83e6f6647ca92cf8d16d8b3247a (MD5) / Termoplástico de muitas qualidades, em especial a manutenção das propriedades mecânicas sob temperaturas medianas, a poliftalamida - PPA, é uma das muitas alternativas para a substituição de materiais metálicos em aplicações que envolvam desgaste, resistência térmica, estabilidade dimensional e química, exigência de baixo peso e custo, além de flexibilidade de design. Neste trabalho foram analisadas, visando à substituição de materiais metálicos tradicionais usualmente empregados em bombas de óleo de motocicletas, diversas propriedades de compósitos tendo como matriz a poliftalamina: um deles com a fibra de vidro como reforço e outro com a fibra e com politetrafluoretileno - PTFE. O estudo foi dividido em duas grandes partes, sendo uma a caracterização do comportamento tribológico do compósito em três diferentes testes, objetivando determinar as taxas de desgaste sobre pressão e velocidades controladas, e outra, a caracterização de propriedades gerais após submteter cada compósito e envelhecimento em óleo e temperatura. Cm relação à segunda parte, análises de DSC e TG foram realizadas antes e após o envelhecimento, enquanto propriedades mecânicas como tração, impacto e dureza foram medidas para avaliar a manutenção das mesmas após envelhecimento. A técnica de análise dinâmico-mecânica foi utilizada para obter valores dos módulos elástico, de dissipação viscosa e complexo. Os resultados dos ensaios de desgaste demonstraram o bom comportamento do compósito frente aos materiais metálicos com redução na taxa desgaste, sobretudo frente ao alumínio. Os ensaios de tração, impacto, densidade, DSC e TG demonstraram a manutenção das propriedades mecânicas e térmicas, mesmo após envelhecimento em óleo. Foi comprovado a possibilidade de emprego dos grades desse material na aplicação bomba do óleo e validado design com ganho de desempenho em baixas rotações de até 7% / Thermoplastic of many qualities, in special the maintenance of the mechanical properties under medium temperatures, the polyphthalamide - PPA, is one of the many alternatives for the substitution of metallic materials in applications that involve wear, thermal resistance, dimensional and chemical stability, requirement of low weight and cost, beyond flexibility of design. In this work diverse properties of this material had been analyzed aiming at to the substitution of usually used traditional metallic materials in oil pumps of motorcycles. The study it was divided in two great areas, being the one characterization of the tribological behavior or composite in three different tests objectifying the controlled wear rate on pressure ans speeds, and another the characterization of general properties after properties after the material to be submetted the aging in oil and temperature. Analysis of DSC and TG had been carried through before and after the aging. Mechanical properties as tension, impact and hardness had been carried through to after evaluate the maintenance of same the aging. The technique of analyzes dynamic-mechanics was used to get values of the modulus: storage, loss and complex. The results of the wear assays demonstrated the good behavior of the composite front to metallic materials with reduction in the wear rates, above all versus aluminium. The tension, impact, density, DSC and TG test demonstrated the maintenance of the machanical and thermal properties, even after aging in oil. It was proven the possibility of job of the grades of this material in the application oil pump and validated design with profits in low rotations of up to 7 percentile points