Abstract：
Biomedical alloys, like many engineering alloys, have chemical or physical heterogeneities at the surface, and such heterogeneities can potentially act as sites for pit initiation. Alloys of particular interest are 316/316L (and 316LVM) stainless steel, nitinol, and CoCr alloys. This review focuses on the sites-generally inclusions-that have been associated with pitting in various studies of biomedical alloys in simulated physiological solutions. The effect of these sites is discussed in relation to factors such as type and size. For both 316/316L stainless steel and nitinol, pitting has been found to initiate at two different types of inclusions: sulfide and oxide inclusions in stainless steel, and carbide and oxide inclusions in nitinol. Sulfide inclusions tend to be the predominant sites for pitting on 316/316L stainless steel, while there is some evidence to suggest that carbide inclusions may be more effective than oxide inclusions for pitting on nitinol. CoCrMo alloys differ from the other two alloys in that, although particles can be present in the form of carbides, the carbides typically do not provide sites for pit initiation except possibly for alloys with a high-C content, certain heat treatments, and when anodically polarized to high potentials. CoNiCrMo differs further in that TiN inclusions can be present in the vicinity of pits and might be associated with them, but irrespective of the initiation site, any pits are unlikely to grow because of repassivation.
摘要：
生物医学合金，像许多工程合金一样，表面有化学或物理异质性，这种异质性可能会成为坑起始的场所。特别感兴趣的合金是316/316L（和316LVM）不锈钢，镍钛诺,和CoCr合金。这篇综述的重点是在模拟生理溶液中的生物医学合金的各种研究中与点蚀有关的位点-通常是夹杂物。讨论了这些站点的影响与类型和大小等因素有关。对于316/316L不锈钢和镍钛诺，已发现点蚀开始于两种不同类型的夹杂物：不锈钢中的硫化物和氧化物夹杂物，镍钛诺中的碳化物和氧化物夹杂物。硫化物夹杂物往往是316/316L不锈钢上点蚀的主要部位，虽然有一些证据表明，碳化物夹杂物可能比氧化物夹杂物更有效的点蚀镍钛诺。CoCrMo合金与其他两种合金的不同之处在于，虽然颗粒可以以碳化物的形式存在，碳化物通常不提供点蚀引发的位置，除了可能是高C含量的合金，某些热处理，当阳极极化为高电位时。CoNiCrMo的不同之处在于，TiN夹杂物可以存在于凹坑附近，并且可能与它们有关。但不管起始地点是什么，由于再钝化，任何坑都不太可能生长。
