【摘要】 本文在分析近等原子比NiTi形状记忆合金实现去合金化热力学条件的基础上,研发出一种特殊的低温去合金化处理技术,对NiTi形状记忆合金进行表面改性;经SEM、XRD、XPS、EDX、模拟体液(SBF)仿生沉积等分析研究表明,NiTi记忆合金经低温去合金化处理后,在合金表面选择性地除去了有害元素镍,在表层约130nm深度内原位制备出完全无镍的具有纳米网架结构的二氧化钛层,这不仅消除了有毒元素Ni的危害,同时而且还结合上羟基(OH-);在SBF溶液中试验证明,经低温去合金化处理后的合金表面具有诱导Ca/P沉积的能力,从而提高了NiTi形状记忆合金的生物相容性.更多还原

【Abstract】 After the dealloying conditions of thermodynamics calculated,a dealloying treatment technique was investigated and applied to nearly equiatomic NiTi alloy so as to remove nickel selectively from NiTi alloys to form a Ni-free titanium oxide layer on the surface.Sample surfaces were analyzed by SEM,XRD,XPS and EDX,and then samples were immersed in SBF solution up to 14 days in order to observe Ca/P deposition.The results show that the dealloying treatment at low temperature leads to 130nm Ni-free surface layer that possesses a nanometer structure,and in situ formation of titania surface that possesses a degree of bioactivity because of the combination of hydroxyl(OH-) group in the process of dealloying treatment simultaneously.As a consequence,the dealloying treatment technique could be interest for biomedical application,as it can avoid sensitization and allergies and improve biocompatibility of NiTi shape memory alloys.更多还原