In vitro characterisation and microstructure of B 2 O 3 /P 2 O 5 doped bioactive spodumene glass–ceramics

Glasses with compositions of (100−X−Y)Li₂O.Al₂O₃.4SiO₂+XB₂O₃+YP₂O₅ where X=0–2.5 and Y=0–10 (wt-%) were melted in a platinum crucible at 1500°C with air as the furnace atmosphere. The green compact pellets were prepared and fired at 500°C. The samples were sintered in air atmosphere at selected temperatures in the range of 750–900°C for up to 20 h. It has been found that the addition of B₂O₃ and P₂O₅ has a remarkable effect on the amount of β spodumene (β-S), relative to high quartz solid solution (h-QSS). The glass ceramics that contain appropriate amounts of B₂O₃ and P₂O₅ promise good sinterability at temperature as low as 850°C. There were two major types of phase transformation in the present investigation: crystallisation of the present glass to a metastable h-QSS and subsequent transformation from h-QSS to a stable β-S. In vitro test revealed that the spodumene glass ceramic is much more durable in human body fluid. It is further observed that the addition of B₂O₃ and P₂O₅ enhanced the chemical durability of glass ceramics.