INFLUENCE OF P_2O_5 UPON THE CRYSTALLIZATION OF LITHIUM DISILICATE AND FLUOROAPATITE IN BIO-GLASS CERAMICS

摘要

Referred work is a preliminary investigation of the lithium disilicate (LS_2) and the fluoroapatite (FA) crystallization in bio-glass ceramics. Composite glass-ceramics with various content of P_2O_5 in oxide system SiO_2-Li_2O-CaO-CaF_2P_2O_5 were prepared by heat treatment of glass at different temperatures. Two crystalline phases lithium disilicate (LS_2) andfluorapatite (FA) were developed in the samples depending on P_2O_5 content and temperature. The increase of temperature as well as the content of P_2O_5 promote the crystallization of FA. XRD measurements supplemented by DTA results showed that LS_2 crystallization at lower temperature is inhibited because of the present of amorphous FA. On the contrary, crystalline phase of FA promoted the crystallization of LS_2. Phase separation of the samples is well observed in scanning electronic micrograph. The Vickers hardness values of prepared bio-glass ceramics are higher than the average hardness of biological tooth and these materials could be applied as mechanically loaded biomedical implants.