Static Fatigue Property of Apatite Ceramics
Noriyuki HISAMORI, Yutaka TAKANO and Kenichi TAKAI
Abstract:A calcium phosphate compound (Hydroxyapatite) has similar composition and crystal structure to an organism bone. Except an absorbent calcium phosphate compound, the composition that resembled apatite and a deposit having configuration generate it on the surface of apatite ceramic in vivo. In other words apatite ceramics does an organism bone and direct bonding through an apatite deposit without causing negativism. Generally this function is named bioactivity. These functions can inhibit ionic elution, roosting, wear and fretting occurring in metal biomaterial, and be extremely important from a point of view to use in vivo. However, ceramics material is extremely inferior in mechanical properties in comparison with metal material. Therefore, an application to locus accompanied by high load is difficult. It is used as bone filling material such as shank or body of vertebra under the present conditions. In other words low load is applied to locus to be accompanied by. Therefore, static load than cyclic load is important when long-term use was considered. However, bioactivity ability of apatite ceramic material and relation of mechanical properties were not clarified. A fatigue characteristic in consideration of organism environment is particularly unclear. Furthermore, it is necessary to evaluate a fatigue characteristic and crack propagation behavior when microstructure changes by apatite and chemical reaction with body fluid. This study, a static fatigue characteristic of apatite ceramics in simulated body fluid environment was examined. Key Words:Apatite ceramics, Static fatigue, Microstructure, Simulated body fluid, Bioactivity