Fabrication of dense α-alumina layer on Ti-6Al-4V alloy hybrid for bearing surfaces of artificial hip joint.
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.
Visiting Research Scientist, Department of Biomedical Sciences, College of Life & Health Sciences, Chubu University,1200 Matsumoto cho, Kasugai, Aichi 487-8501, Japan. Electronic address: rkhannaJP@gmail.com.
Rohit
R
Khanna
Department of Biomedical Sciences, College of Life & Health Sciences, Chubu University,1200 Matsumoto cho, Kasugai, Aichi 487-8501, Japan.
Tadashi
T
Kokubo
Department of Biomedical Sciences, College of Life & Health Sciences, Chubu University,1200 Matsumoto cho, Kasugai, Aichi 487-8501, Japan.
Tomiharu
T
Matsushita
Department of Biomedical Sciences, College of Life & Health Sciences, Chubu University,1200 Matsumoto cho, Kasugai, Aichi 487-8501, Japan.
Hiroaki
H
Takadama
D000497:Alloys; D000537:Aluminum Oxide / Q000737:chemistry*; D019644:Arthroplasty, Replacement, Hip; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D013499:Surface Properties; D013718:Tensile Strength; D014025:Titanium / Q000737:chemistry*
D000497:Alloys; D020099:Coated Materials, Biocompatible; C031462:titanium alloy (TiAl6V4); D014025:Titanium; D000537:Aluminum Oxide
Alumina; Artificial hip joint; Cold spraying; Micro-arc oxidation; Ti-6Al-4V alloy