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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Propriedades tribomec?nicas de superf?cies de tit?nio carbonitretadas por plasma

Rocha, Ricardo Cesar da Silva 02 March 2012 (has links)
Made available in DSpace on 2014-12-17T14:07:03Z (GMT). No. of bitstreams: 1 RicardoCSR_DISSERT.pdf: 2528884 bytes, checksum: 9966cb710cbaa37dcf31b5576ecca1d8 (MD5) Previous issue date: 2012-03-02 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Interstitial compounds of titanium have been mainly studied due to the large range of properties acquired when C, N, O and H atoms are added. In this work, surfaces of TiCxNy were produced by thermochemical treatments assisted by plasma with different proportions of Ar + N2 + CH4 gas mixture. The Ar gas flow was fixed in 4 sccm, varying only N2 and CH4 gas flows. During the thermochemical treatment, the plasma was monitored by Optical Emission Spectroscopy (OES) for the investigation of the influence of active species. After treatments, C and N concentration profile, crystalline and amorphous phases were analyzed by Nuclear Reaction (NRA). Besides tribomechanical properties of the Ti surface were studied through the nanohardness measurements and friction coefficient determination. The worn areas were evaluated by profilometry and Scanning Electronic Microscope (SEM) in order to verify the wear mechanism present in each material. It has been seen which the properties like nanohardness and friction coefficient have strong relation with luminous intensity of species of the plasma, suggesting a using of this characteristic as a parameter of process / Compostos intersticiais de tit?nio t?m sido extensivamente estudados devido ? larga faixa de propriedades adquiridas quando ?tomos de C, N, O e H s?o adicionados. Neste trabalho, superf?cies de TiCxNy foram produzidas por tratamento termoqu?mico auxiliado por plasma de diferentes misturas de N2 + Ar + CH4. Foi fixado o fluxo de Ar em 4 sccm variando-se os fluxos de N2 e CH4. Durante o tratamento termoqu?mico, o plasma foi monitorado por EEO para investiga??o da influ?ncia das esp?cies ativas. Ap?s o tratamento, as superf?cies das amostras foram analisadas quanto ao perfil de concentra??o de C e N, fases cristalinas e fases amorfas. Tamb?m foram analisadas suas propriedades tribomec?nicas atrav?s da medida de nanodureza e da determina??o do coeficiente de atrito. As ?reas desgastadas foram avaliadas por perfilometria e microscopia eletr?nica de varredura (MEV) com o intuito de verificar os mecanismos de desgastes presentes em cada material. Verificouse que propriedades como dureza e coeficiente de atrito variavam com a intensidade das esp?cies, sugerindo o uso da mesma como par?metro de processos a plasma

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