Microstructure and surface composition effects on the transpassivation of NiTi wires for implant purposes

Journal of the Brazilian Chemical Society

Giacomelli, Cristiano¹  Oliveira, Anderson Garbuglio de¹  Spinelli, Almir¹  Giacomelli, Fernando Carlos¹  Universidade Federal de Santa Catarina, Florianópolis, Brazil¹ 

关键词: NiTi alloy;    electrochemical behavior;    artificial saliva;    microstructure and surface composition of NiTi alloy;   

DOI  :  10.1590/S0103-50532005000200002

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

The microstructure and surface composition effects on the transpassivation behavior of untreated and heat treated at 500 ºC NiTi wires used for implant purposes were investigated by electrochemical techniques (open circuit potential and potentiodynamic polarization curves), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The potential at which the passive film breaks down (Eb) (transpassivation) was found to be strictly dependent on both the chemical composition of oxide covering layer and the microstructure of the biomaterial. It could be concluded that the disordered microstructure of untreated NiTi is highly resistant to transpassivation (Eb ~ 1.00 V/SCE), but the presence of a native oxygen rich oxide film onto it makes the dissolution easier (Eb ~ 0.00 V/SCE). Upon thermally treating, the microstructure becomes ordered and less resistant to dissolution (Eb ~ 0.12 V/SCE), but in this case the presence of an oxygen rich native film influenced Eb in a lower extent (Eb ~ 0.03 V/SCE).

【 授权许可】

Unknown