Khanna Rohit, Kokubo Tadashi, Matsushita Tomiharu, Takadama Hiroaki
Visiting Research Scientist, Department of Biomedical Sciences, College of Life & Health Sciences, Chubu University,1200 Matsumoto cho, Kasugai, Aichi 487-8501, Japan.
Department of Biomedical Sciences, College of Life & Health Sciences, Chubu University,1200 Matsumoto cho, Kasugai, Aichi 487-8501, Japan.
Mater Sci Eng C Mater Biol Appl. 2016 Dec 1;69:1229-39. doi: 10.1016/j.msec.2016.08.025. Epub 2016 Aug 12.
Recent advances in hip replacements are focused towards producing reliable bearing surfaces to enhance their longevity. In this perspective, progressive attempts have been made to improve the wear resistance of polyethylene to eliminate osteolysis and mechanical reliability of brittle alumina ceramics, but in vain. It is proposed that both high wear resistance and mechanical reliability can be retained if a thin layer of dense alumina is formed onto high toughness Ti-6Al-4V alloy. For this purpose, we devised a unique methodology in which a layer of Al metal was deposited onto the Ti alloy substrate by cold spraying (CS), followed by a heat treatment to form Al3Ti reaction layer at their interface to improve adhesion and subsequent micro-arc oxidation (MAO) treatment to transform Al to alumina layer. An optimal MAO treatment of cold sprayed Al formed an adherent and dense α-alumina layer with high Vickers hardness matching with that of sintered alumina used as a femoral head. Structure-phase-property relationships in dense α-alumina layer have been revealed and discussed in the light of our research findings. The designed alumina/Ti alloy hybrid might be a potential candidate for reliable bearing surfaces of artificial hip joint.
髋关节置换术的最新进展集中在制造可靠的承重表面以提高其使用寿命。从这个角度来看，人们不断尝试提高聚乙烯的耐磨性以消除骨溶解，并提高脆性氧化铝陶瓷的机械可靠性，但均未成功。有人提出，如果在高韧性的Ti-6Al-4V合金上形成一层致密的氧化铝薄层，那么既可以保持高耐磨性又能保持机械可靠性。为此，我们设计了一种独特的方法，即通过冷喷涂（CS）在钛合金基体上沉积一层铝金属，然后进行热处理以在它们的界面处形成Al3Ti反应层，从而改善附着力，随后进行微弧氧化（MAO）处理，将铝转化为氧化铝层。对冷喷涂铝进行最佳的微弧氧化处理，形成了一层附着力强且致密的α-氧化铝层，其维氏硬度与用作股骨头的烧结氧化铝相匹配。根据我们的研究结果，揭示并讨论了致密α-氧化铝层中的结构-相-性能关系。设计的氧化铝/钛合金复合材料可能是人工髋关节可靠承重表面的潜在候选材料。
