title: Novel artificial hip joint: A layer of alumina on Ti-6Al-4V alloy formed by micro-arc oxidation.
abstract: In many hip replacement surgeries, monolithic alumina is used as a femoral head due to its high wear resistance. However, it is liable to fracture under load bearing operations in artificial joints. We propose a promising way to overcome this limitation by forming a dense alumina layer onto a relatively tough substrate such as Ti-6Al-4V alloy to obtain high wear resistance on a material that can sustain relatively high toughness. For this purpose, Al metal powders were deposited onto Ti-6Al-4V alloy by cold spraying in N2 atmosphere. Interfacial adhesion between Al and the Ti alloy was improved by the formation of a reaction layer of Al3Ti between them by heating at 640 °C for 1h in air. Subsequently, micro-arc oxidation treatment was performed to oxidize Al. The oxidized layer was composed of an outer porous layer of γ-alumina and inner-most dense layer of α-alumina. The α-alumina layer was almost fully densified and exhibited high Vickers hardness almost equal to that of alumina ceramics used as the femoral head. Thus, the newly developed dense alumina/Ti alloy can be potentially used to produce the reliable bearing surfaces of artificial hip joint.
authors.affiliation: Department of Biomedical Sciences, College of Life & Health Sciences, Chubu University, 1200 Matsumoto cho, Kasugai, Aichi 487-8501, Japan. Electronic address: rxk40@psu.edu.
authors.forename: Rohit
authors.initials: R
authors.lastname: Khanna
authors.affiliation: Department of Biomedical Sciences, College of Life & Health Sciences, Chubu University, 1200 Matsumoto cho, Kasugai, Aichi 487-8501, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kokubo
authors.affiliation: Department of Biomedical Sciences, College of Life & Health Sciences, Chubu University, 1200 Matsumoto cho, Kasugai, Aichi 487-8501, Japan.
authors.forename: Tomiharu
authors.initials: T
authors.lastname: Matsushita
authors.affiliation: Taiyo Nippon Sanso, Inc., 1-3-26, Koyama, Shinagawa 142-8558, Tokyo, Japan.
authors.forename: Yuuji
authors.initials: Y
authors.lastname: Nomura
authors.affiliation: Taiyo Nippon Sanso, Inc., 1-3-26, Koyama, Shinagawa 142-8558, Tokyo, Japan.
authors.forename: Norihiro
authors.initials: N
authors.lastname: Nose
authors.affiliation: Taiyo Nippon Sanso, Inc., 1-3-26, Koyama, Shinagawa 142-8558, Tokyo, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Oomori
authors.affiliation: Graduate School of Electrical and Electronics Engineering, Chubu University, Kasugai, Aichi 487-8501, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Yoshida
authors.affiliation: Graduate School of Electrical and Electronics Engineering, Chubu University, Kasugai, Aichi 487-8501, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Wakita
authors.affiliation: Department of Biomedical Sciences, College of Life & Health Sciences, Chubu University, 1200 Matsumoto cho, Kasugai, Aichi 487-8501, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Takadama
mesh_terms: D000497:Alloys; D006244:Hardness; D006621:Hip Joint; D006622:Hip Prosthesis; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000497:Alloys; C031462:titanium alloy (TiAl6V4); D014025:Titanium
keywords: Alumina; Artificial hip joint; Cold spraying; Micro-arc oxidation; Ti–6Al–4V alloy