Kazuhiro Yoshida1,, Hiroshi Mishina2, Shinya Sasaki3, Masafumi Morita4 and Kiyoshi Mabuchi5
1Department of Artificial Science and Systems, Graduate School of Science and Technology, Chiba University, Chiba 263-8522
The authors developed 3Y-PSZ/AISI 316L composites for the bearings of joint prostheses, which were then evaluated in terms of their mechanical properties, such as density, hardness, bending strength, fracture toughness and wear resistance, as well as corrosion resistance. The composites (AISI 316L contents were 0, 10, 20 and 30 vol%) were fabricated by spark plasma sintering. The composites consist of tetragonal zirconia and austenite stainless steel. The Vickers hardness and bi-axial bending strength of the composite decrease from 14.3 GPa to 8.93 GPa and 1585 MPa to 617 MPa, respectively, when the AISI 316L content is increased from 0 vol% to 30 vol%. Fracture toughness of the composite increased from 4.99 MPa⋅m1/2 to 6.03 MPa⋅m1/2. The composites showed improved wear resistance (3Y-PSZ; 3.08 × 10-10 mm2/N, 10 vol% composite; 2.11 × 10-10 mm2/N, 20 vol% composite; 0.28 × 10-10 mm2/N, 30 vol% composite; 0.00 × 10-10 mm2/N). The wear resistance of the 30 vol% composite was higher than conventional biometal and bioceramic (AISI 316L; 35.4 × 10-10 mm2/N, Co-28Cr-6Mo; 11.0 × 10-10 mm2/N, Al2O3; 0.30 × 10-10 mm2/N). The composites showed more than 3 times greater corrosion resistance than the monolithic AISI 316L in PBS(-) at 37°C. In particular, nickel ion release was lower than for AISI 316L. The corrosion resistance of 30 vol% composite during the wear test was more than 37 times higher than for AISI 316L. The 30 vol% composite was successfully toughened and showed higher resistance to wear and corrosion when used as bearing material for joint prostheses.
joint prostheses, biomaterial, PSZ/AISI 316L composite, toughness, wear resistance, biocompatibility
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