Phase stability after aging and its influence on pin-on-disk wear properties of Ce-TZP/Al2O3 nanocomposite and conventional Y-TZP.

Recently zirconia/alumina composites have been examined by many researchers as the new generation of bearing materials in total joint replacements. In this study, the phase stability of a Ce-TZP/Al(2)O(3) nanocomposite and conventional Y-TZP after aging, and its influence on wear resistance, were investigated. Very slight phase transformation was observed in both types of ceramics 18 months after the implantation of Ce-TZP/Al(2)O(3) or Y-TZP samples into rabbit tibiae. However, Y-TZP showed marked phase transformation (approximately 80%) after aging in an autoclave (121 degrees C) for 190 h or in physiological saline at 62 degrees C for 18 months, whereas the new composite remained almost resistant to degradation. According to the results of self-pairing pin-on-disk wear tests using ceramic specimens with or without autoclave aging, the wear factor was almost the same between Ce-TZP/Al(2)O(3) samples with and without aging (6.74 +/- 0.36 x 10(-8) and 6.04 +/- 0.95 x 10(-8) mm(3)/Nm, respectively). In contrast, although non-aged Y-TZP had the lowest wear factor (4.88 +/- 0.51 x 10(-8) mm(3)/Nm) of all specimens tested, aged Y-TZP showed 10-fold greater wear than nonaged Y-TZP. The present study suggests that Ce-TZP/Al(2)O(3) nanocomposite has much greater phase stability than Y-TZP, and that its wear properties are not influenced by aging.

[1]  Takashi Nakamura,et al.  Apatite-forming ability of a zirconia/alumina nano-composite induced by chemical treatment. , 2002, Journal of biomedical materials research.

[2]  S. Affatato,et al.  Mixed oxides prosthetic ceramic ball heads. Part 3: effect of the ZrO2 fraction on the wear of ceramic on ceramic hip joint prostheses. A long-term in vitro wear study. , 2001, Biomaterials.

[3]  G. Willmann,et al.  Ceramic Femoral Head Retrieval Data , 2000, Clinical orthopaedics and related research.

[4]  B. Calès,et al.  Zirconia as a sliding material: histologic, laboratory, and clinical data. , 2000, Clinical orthopaedics and related research.

[5]  W. Burger,et al.  High Strength and Toughness Alumina Matrix Composites by Transformation Toughening and 'In Situ' Platelet Reinforcement (ZPTA) - The New Generation of Bioceramics , 2000 .

[6]  A Stark,et al.  Ultra-low wear rates for rigid-on-rigid bearings in total hip replacements , 2000, Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine.

[7]  P. Smith,et al.  Water-lubricated and dry sliding wear of yttria stabilised zirconia and silicon carbide couples: Part I: Wear rates , 1999 .

[8]  D. Goutallier,et al.  Poor eight-year survival of cemented zirconia-polyethylene total hip replacements. , 1999, The Journal of bone and joint surgery. British volume.

[9]  G. Willmann,et al.  Wear characteristics of sliding pairs of zirconia (Y-TZP) for hip endoprostheses. , 1996, Biomaterials.

[10]  B. Calès,et al.  Long-term in vivo and in vitro aging of a zirconia ceramic used in orthopaedy. , 1994, Journal of biomedical materials research.

[11]  D. Dowson,et al.  Comparative study of the wear of UHMWPE with zirconia ceramic and stainless steel femoral heads in artificial hip joints. , 1994, Medical engineering & physics.

[12]  T. Yamamuro,et al.  Time-dependent changes in the mechanical properties of zirconia ceramic. , 1993, Journal of biomedical materials research.

[13]  K Ikeuchi,et al.  Low wear rate of UHMWPE against zirconia ceramic (Y-PSZ) in comparison to alumina ceramic and SUS 316L alloy. , 1991, Journal of biomedical materials research.

[14]  R. Rawlings,et al.  Mechanical behaviour of zirconia and zirconia-toughened alumina in a simulated body environment. , 1990, Biomaterials.

[15]  D. Tréheux,et al.  Aluminas with dispersoids. Tribologic properties and in vivo aging. , 1990, Biomaterials.

[16]  J. Drummond.  In vitro aging of yttria-stabilized zirconia , 1989 .

[17]  M. Yoshimura,et al.  Role of H2O on the degradation process of Y-TZP , 1987 .

[18]  Masanori Oka,et al.  Ce-TZP/Al2O3 nanocomposite as a bearing material in total joint replacement. , 2002, Journal of biomedical materials research.

[19]  C. Piconi,et al.  Zirconia as a ceramic biomaterial. , 1999, Biomaterials.

[20]  H. Awaji,et al.  Fracture toughness measurements of ceramics by V notch technique , 1992 .