Deposição e caracterização de revestimentos de Ni-Ti e Ni-Ti/Nb para aplicações biomédicas

• Ano de defesa: 2007
• Autor(a) principal: Vargas, André Luís Marin
• Orientador(a): Hübler, Roberto
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Pontifícia Universidade Católica do Rio Grande do Sul; Porto Alegre
• Palavras-chave em Português: ENGENHARIA DE MATERIAIS; RESISTÊNCIA DOS MATERIAIS; CORROSÃO; FILMES FINOS (ENGENHARIA DE MATERIAIS); ENGENHARIA BIOMÉDICA
• Link de acesso: http://hdl.handle.net/10923/3242

Among all kinds of shape memory alloys, NiTi are probably the most important and used due to its improved mechanical and tribological properties. Bulk NiTi alloys are widely applied as biomedical materials and in diverse fields of microengineering. The importance of NiTi alloys resides on the effects of superelasticity (pseudoelasticity) (PE) and shape memory (SME), which permits these materials alter its phase on specific conditions and the return to its the original state. Nevertheless, NiTi thin films were rarely applied on biomedical applications, mostly due to the difficulty to produce NiTi coatings capable to achieve the same properties verified in the bulk material. In order to accomplish that, it is necessary to alter the atomic concentration of the alloy precisely and to produce its crystalline phase. Other possibility is the use of multilayers films, which can be produced mostly by magnetron sputtering. Allied to a specific thermal treatment, which provides the transformation of an amorphous phase to a crystalline one, it might be possible to develop NiTi thin films focused to biomedical applications. The main objective of this work is to deposit monolhitical NiTi thin films, as well as Ti / NiTi and Nb / NiTi multilayers using the DC magnetron sputtering method, intending to achieve mechanical and tribological properties suitable for biomedical applications. X-ray diffraction (DRX) and X-ray fluorescence were applied to the characterized crystalline structure and composition of coatings respectively. Hardness and elastic modulus were characterized using nanoindentation technique. Corrosion assays were conducted according to the ASTM F746 standard. The results obtained showed that NiTi thin films presents characteristics that permits its application as biomedical materials.