Si3N4 as a biomaterial and its tribo-characterization under water lubrication
详细信息 查看全文
文摘
Hip implant wear is recognised as the main cause of hip implant failure therefore has been widely investigated both experimentally and clinically, demonstrating the coexistence of abrasive, adhesive, fatigue and corrosive wear. Many clinical in vivo and bulk material wear rate data from published literature have been presented for non-oxide ceramic implants. Several studies have shown that the coefficient of friction of self-mated silicon nitride in water decreases from an initially high value to about 0.002 after a certain run-in period. Since the worn surfaces become extremely smooth, the low friction is attributed to the initiation of hydrodynamic lubrication by a thin water film at the interface. The possibility of mixed lubrication, i.e. hydrodynamic lubrication by water and boundary lubrication due to the presence of colloidal silica on the wearing surfaces, has also been proposed.