CoCrMo-based metal-on-metal hip implants experienced unexpectedly high failure rates despite the high wear and corrosion resistance of the bulk material. Although they exhibit a lower volumetric wear compared to other implant materials, CoCrMo-based implants produced a significantly larger 'number' of smaller wear particles. CoCrMo is nominally an extremely stable material with high Cr content providing passivity. However, despite the Co:Cr ratio in the original alloy being 2:1; chemical analyses of wear particles from periprosthetic tissue have found the particles to be composed predominately of Cr species, with only trace amounts of Co remaining. Here a correlative spectroscopy and microscopy approach has shown that these particles dissolve via a non-stoichiometric, and geometrically inhomogeneous, mechanism similar to de-alloying. This mechanism is previously unreported for this material and was not apparent in any of the regulatory required tests, suggesting that such tests are insufficiently discriminating.

尽管块状材料具有很高的耐磨性和耐腐蚀性，但基于CoCrMo的金属对金属髋关节植入物的失败率却出乎意料地高。尽管与其他植入物材料相比，它们具有较低的体积磨损量，但基于CoCrMo的植入物产生了“大量”的较小磨损颗粒。CoCrMo名义上是一种非常稳定的材料，具有较高的Cr含量，具有钝化作用。但是，尽管原始合金中的Co：Cr比为2：1；来自假体周围组织的磨损颗粒的化学分析发现，这些颗粒主要由Cr组成，仅残留痕量的Co。在这里，相关的光谱学和显微镜方法已经表明，这些颗粒通过类似于脱合金的非化学计量的和几何上不均匀的机理溶解。