Oskouei Reza H, Barati Mohammad Reza, Farhoudi Hamidreza, Taylor Mark, Solomon Lucian Bogdan
The Medical Device Research Institute, Flinders University, Adelaide, Australia.
The Medical Device Research Institute, Flinders University, Adelaide, Australia.
Mater Sci Eng C Mater Biol Appl. 2017 Oct 1;79:390-398. doi: 10.1016/j.msec.2017.05.086. Epub 2017 May 15.
A detailed investigation was performed to characterize the fretting wear and corrosion damage to the neck component of a CoCrMo stem from a metal-on-polyethylene implant retrieved after 99months. The stem was a low-carbon (0.07wt%) wrought Co-28Cr-6Mo alloy with no secondary carbide phases in the matrix (γ-phase). The original design of the neck surface contained an intentionally fabricated knurled profile with a valley-to-peak range of approximately 11μm. Roughness measurements indicated that the tip of the knurled profile was significantly damaged, especially in the distal medial region of the neck, with up to a 22% reduction in the mean peak-to-valley height (R) compared to the original profile. As a new finding, the channels between the peaks of the profile created an additional crevice site in the presence of stagnant body fluid within the head-neck taper junction. These channels were observed to contain the most severe corroded areas and surface oxide layers with micro-cracks. SEM/EDS, XRD and XPS evaluations identified the formation of CrO as a corrosion product. Also, decobaltification was found to occur in these corroded areas. The findings of this work indicate the important role of the knurled profile in inducing additional crevice corrosion.
对一枚使用99个月后取出的金属对聚乙烯植入物的CoCrMo柄部颈部组件的微动磨损和腐蚀损伤进行了详细研究。该柄部是一种低碳（0.07wt%）锻造的Co-28Cr-6Mo合金，基体（γ相）中无二次碳化物相。颈部表面的原始设计包含一个有意制造的滚花轮廓，谷峰范围约为11μm。粗糙度测量表明，滚花轮廓的尖端严重受损，尤其是在颈部的远侧内侧区域，与原始轮廓相比，平均峰谷高度（R）降低了22%。作为一项新发现，在头颈锥度连接处存在停滞体液的情况下，轮廓峰之间的通道形成了一个额外的缝隙部位。观察到这些通道包含最严重的腐蚀区域和带有微裂纹的表面氧化层。扫描电子显微镜/能谱分析（SEM/EDS）、X射线衍射（XRD）和X射线光电子能谱（XPS）评估确定了CrO作为腐蚀产物的形成。此外，在这些腐蚀区域发现了脱钴现象。这项工作的研究结果表明滚花轮廓在引发额外缝隙腐蚀中起着重要作用。
