Dureza e caracterização do Ti c.p. quando submetido a tratamentos térmicos e à ação de fluoreto de sódio
Hardness and characterization of the c.p. Ti when submitted to heat treatments and to the action of sodium fluoride solution
Ribeiro, A.L.R.; Vaz, L.G.; Araújo, R.P.; Sartori, R.
Rev. odontol. UNESP, vol.34, n2, p.73-78, 2005
Resumo
O objetivo deste trabalho foi analisar a dureza e a caracterização metalográfica do Ti c.p. quando submetido a tratamentos térmicos e à corrosão por solução de fluoretos de sódio a 1%. As amostras foram submetidas a dois tipos de tratamento térmico, têmpera e recozimento. Em seguida, foram submersas em solução de fluoreto de sódio por 30 dias e depois por mais 30 dias. Entre cada etapa, foi feita a caracterização por meio de teste de dureza e microscopia óptica. No ensaio de dureza Vickers, verificou-se diferenças estatísticas entre os grupos estudados e que os tratamentos térmicos realizados elevaram a dureza do Ti c.p. por aliviar a tensão do material e torná-lo uma estrutura cristalina, fato este que deve melhorar as propriedades do material. Além disso, verificou-se que os grupos estudados, ao serem submetidos à ação de íons fluoreto após os tratamentos térmicos, tiveram seus valores de dureza aumentados devido, provavelmente, ao processo de friabilidade. Na análise metalográfica, foram observadas diferenças entre as amostras quando submetidas à ação dos íons fluoreto, e essa exposição à solução fluoretada danificou a superfície desse biomaterial.
Palavras-chave
Titânio, tratamento térmico, teste de dureza
Abstract
The purpose of this study was to measure the c.p. Ti hardness and to analyze the structure of the c.p. Ti surface using an optical microscopy, when submitted to heat treatments and to corrosion by 1% sodium fluoride solution. The samples were submitted to two types of heat treatment, tempering and annealing, after been submitted to sodium fluoride solution by 30 days and then by more 30 days, and the characterization was made through tests of hardness and optical microscopy technique. Statistical differences amongst the studied groups were verified by the Vickers hardness test, which resulted higher hardness c.p. Ti when used the heat treatments, that could be explained by relieving the mechanical stress of the material and making the crystalline structures more defined, and this fact should improve the material properties. Besides that, it was verified that the groups submitted to ions fluoride action, after the heat treatments, had their values of hardness increased, due, probably, to the heat process that increases the material friability. In the optical metalograph analysis, differences amongst the samples were observed when they were submitted to ions fluoride action, probably because the exposure of the titanium to fluoride solution resulted damages to the surface of this important biomaterial.
Keywords
Titanium, heat treatment, hardness tests
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