Fundamental study for all-ceramic artificial hip joint

It is thought that all-ceramics artificial hip joints should have good geom etric conformity between sockets and femoral heads to avoid stress concentr ation. So using end-face apparatus, we investigated the steady state fricti on and wear between flat surfaces of three ceramics (alumina, silicon carbi de and silicon nitride) lubricated with bovine serum solution. According to the results, the coefficient of friction and the specific wear rate of sil icon nitride are much higher than those of alumina and silicon carbide. The coefficient of friction of silicon carbide is the lowest and that of alumi na is close to silicon carbide. The specific wear rate of alumina is very l ow and that of silicon carbide is also low. In atomic force microscopy, we observed smooth surfaces covered with tribofilm for all of the ceramics. Vi sually, we observed distinct grooves on silicon nitride surface, while the alumina and the silicon carbide surfaces were scarcely changed. In conclusi on, alumina and silicon carbide could be candidates for all-ceramic hip joi nt. (C) 1999 Elsevier Science S.A. All rights reserved.