Effect of sintering additives on fabrication of silica porous glass structure

Silica (SiO 2 ) porous glass materials is expected as a support in environmental fields due to transparency, high surface reactivity and so on.In this study, silica porous glass with high strength was fabricated by addition of potassium carbonate (K 2 CO 3 ) as sintering aid and mullite as reinforcing materials.At first, a sintering condition was investigated using silica disk-type samples.A brittle amorphous silica disk with low density was obtained by firing at 1200 °C.At 1400 °C, crystallization was occurred and cristobalite formed.A small amount (~1 wt%) of K 2 CO 3 was effective to densification of amorphous silica., whereas more than 1 wt% K 2 CO 3 addition accelerated the crystallization of silica.This was due to the formation of liquid phase.In addition, a highly dispersed mullite to SiO 2 matrix was effective to enhance the mechanical property.The porous structure was successfully fabricated by template method using polyurethane.