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采用电化学测试技术对 Ti Ni基形状记忆合金在生理盐水中的腐蚀机理进行了研究 .结果表明 ,Ti Ni合金与 Ti Ni Cu合金相比 ,阳极钝化区拓宽、孔蚀电位正移、腐蚀率减小 .通过EDX分析和 SEM观察发现 ,Ti Ni基形状记忆合金蚀孔内存在富 Ti贫 Ni的 Ti2 Ni析出相 ,是萌生孔蚀的敏感位置 .在生理盐水中 Ti Ni Cu合金的耐蚀性比 Ti Ni合金劣 ,是由于 Ti Ni Cu合金存在不同晶体结构区域 ,造成电化学性质不均匀 ,加之晶界疏松状态的 Cu的表面富集 ,促进阳极溶解过程所致
The corrosion mechanism of Ti Ni-based shape memory alloy in physiological saline was investigated by electrochemical test.The results show that the anodic passivation area broadens and the pitting potential moves forward compared with that of Ti-Ni-Cu alloy, and corrosion EDX analysis and SEM observation showed that there is Ti-rich Ni-depleted Ti2Ni precipitates in the TiNi-based shape memory alloy cavities, which are the sensitive sites for initiation of pitting corrosion.In Ti-Cu alloys, The corrosion resistance is inferior to that of Ti Ni alloy due to the existence of different crystal structure regions in the Ti Ni Cu alloy, resulting in uneven electrochemical properties. In addition, the surface of Cu in the loose grain boundary is enriched to promote the anodic dissolution process