Abstract
Surface-related characteristics (growth of surface layer and crystal preferred orientation) and the resulting mechanical strength of apatite-containing glass-ceramics in the system MgO-CaO-SiO 2 -P 2 O 5 were investigated. The variations of surface-layer thickness and crystal preferred orientation were explained by a criterion considering both the surface and bulk nucleation of apatite phase. Glass-ceramics with a fairly high strength of 250-410 MPa could be obtained by an appropriate two-step heat treatment. The high strength in the present study is closely related to the growth of the surface layer, which might result in surface compressive-stress.