经等离子体聚合四氟乙烯处理的镍钛形状记忆合金。物理化学和电化学表征。

NiTi shape memory alloys treated by plasma-polymerized tetrafluoroethylene. A physicochemical and electrochemical characterization.

作者信息

Yahia L H, Lombardi S, Piron D, Klemberg-Sapieha J E, Wertheimer M R

机构信息

Biomedical Engineering Institute, Ecole Polytechnique/Faculty of Medicine, University of Montreal, Canada.

出版信息

Med Prog Technol. 1996;21(4):187-93.

PMID:9110276

Abstract

NiTi alloy specimens were plasma cleaned and then coated with a thin film of plasma-polymerized tetrafluoroethylene (TFE) in a Radio-Frequency reactor. The corrosion protection provided by these films was studied by potentiodynamic tests performed in Hank's physiological solution. Surface properties which determine biocompatibility were characterized by X-ray photoelectron spectroscopy (XPS). The results showed that the surface of untreated NiTi was mostly composed by oxygen, carbon, titanium oxide (TiO2) with traces of nickel oxides (NiO and Ni2O3) and metallic Ni. The passivity of untreated NiTi was found to be unstable in the simulated human body media. After plasma treatment, the NiTi surface contained only carbon and fluor. The plasma-polymerized thin film was found to stabilize the NiTi passivity and to increase its pitting potential. This treatment provides a good protection against dissolution of nickel from NiTi alloys.

摘要

将镍钛合金试样进行等离子体清洗，然后在射频反应器中用等离子体聚合的四氟乙烯（TFE）薄膜进行涂层处理。通过在汉克生理溶液中进行的动电位测试研究了这些薄膜提供的腐蚀防护性能。采用X射线光电子能谱（XPS）对决定生物相容性的表面性质进行了表征。结果表明，未经处理的镍钛合金表面主要由氧、碳、氧化钛（TiO₂）组成，含有痕量的氧化镍（NiO和Ni₂O₃）和金属镍。发现在模拟人体介质中未经处理的镍钛合金的钝性不稳定。等离子体处理后，镍钛合金表面仅含碳和氟。发现等离子体聚合薄膜可稳定镍钛合金的钝性并提高其点蚀电位。这种处理对防止镍从镍钛合金中溶解提供了良好的保护。