Abstract
A relatively large amount of Al2O3 and P2O5 containing sodium borosilicate glasses phase-separated into two phases, SiO2-AlPO4 rich and B2O3-Na2O rich phases. Porous glass ceramics in the system SiO2-AlPO4 was found to be obtained by the leaching with hot H2O and weak organic acids. About 40wt% of P2O5 was remained and AlPO4 crystal precipitated in these porous glass ceramics. These porous glass ceramics had pore volumes from 0.3 to 0.4cc/g and surface areas from 50 to 150m2/g.
