Influence of material combinations and lubricants on friction and wear in ceramic-on-ceramic sliding pairs for joint prostheses

In the high precision ceramic-on-cerarnic total hip prostheses with very low wear, significant fluid film appears to be formed for small radial clearance during walking. However, direct contact between ceramic bearing surfaces at the severe mixed or boundary lubrication mode in various daily activities produces wear debris. The friction in alumina-on-alumina (Al2O3) hip prostheses lubricated with serum solution appears to be high. In this paper, the influence of material combinations and lubricants on the friction and wear characteristics of ceramic materials for artificial hip joints was examined in order to reduce both the friction and wear. To evaluate these tribological properties for ceramic materials, the unidirectional-sliding tests were carried out in roller-on-flat tester using four kinds of ceramic materials, i.e., alumina, zirconia, silicon carbide and silicon nitride.