A novel plasma nitriding process utilising HIPIMS discharge for enhanced tribological and barrier properties of medical grade alloy surfaces
A novel plasma nitriding process utilising HIPIMS discharge for enhanced tribological and barrier properties of medical grade alloy surfaces
复制标题
一种利用 HIPIMS 放电的新型等离子氮化工艺，可增强医用级合金表面的摩擦学和阻隔性能
DOI：
10.1016/j.matlet.2022.131782
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发表时间：
2022
影响因子：
3
通讯作者：
A. Ehiasarian
中科院分区：
文献类型：
--
作者：
P. Hovsepian;K. Shukla;A. Sugumaran;Y. Purandare;I. Khan;A. Ehiasarian
提高医用植入物的使用寿命和生物相容性的需求日益增长。在这一具有挑战性的应用中使用的材料必须在长期临床性能中表现出增强的摩擦学性能、生物相容性和减少的金属离子释放。表面改性技术，如氮化，可以显著改善用于植入物的医用级合金的使用性能。本文首次报道了利用高功率脉冲磁控溅射（HIPIMS）放电对CoCrMo合金进行氮化的新方法。新的氮化工艺已在英国谢菲尔德哈勒姆大学国家HIPIMS技术中心的工业规模的Hauzer 1000-4系统中成功实施，该系统采用HIPIMS技术。由于HIPIMS排放物中分子（N2+）和原子氮（N+）离子的产生显著增加，这是氮化层形成的主要原因，与最先进的氮化工艺相比，工艺生产率提高了四倍。所制备的表面层具有优异的机械和摩擦学性能，如高硬度、高断裂韧性和耐磨性。在模拟体液（汉克溶液）的腐蚀性环境中，氮化层的抗腐蚀保护性能显著增强。此外，数据表明，HIPIMS氮化样品中Co、Cr和Mo离子的释放量分别减少了2倍、4倍和10倍，表明氮化层具有可靠的阻挡性能。
The demand for improvement of lifetime and biocompatibility of medical implants is ever growing. The materials used in this challenging application must display enhanced tribological properties, biocompatibility and reduced metal ion release in long-term clinical performance. Surface modification techniques such as nitriding, can significantly improve the in-service behaviour of the medical grade alloys used for implants. This communication reports on a novel approach for nitriding of CoCrMo alloy using High Power Impulse Magnetron Sputtering, (HIPIMS) discharge for the first time. The new nitriding process has been successfully carried out in an industrial size Hauzer 1000-4 system enabled with HIPIMS technology at the National HIPIMS Technology Centre at Sheffield Hallam University, UK. Due to the significantly enhanced production of molecular (N2+) and atomic Nitrogen (N+) ion species in the HIPIMS discharge, which are primarily responsible for the nitrided layer formation, a fourfold increase in the process productivity as compared to the state of the art nitriding process was achieved. The surface layers produced exhibit excellent mechanical and tribological properties such as high hardness, high fracture toughness and wear resistance. The protection properties of the nitrided layer against corrosion in the aggressive environments of simulated body fluid (Hank’s solution) are remarkably augmented. Furthermore, the data showed that the amount of metal ions released from the HIPIMS nitrided samples was reduced by a factor of 2, 4 and 10 for Co, Cr and Mo ions respectively thus demonstrating the reliable barrier properties of the nitrided layer.