Effect of Kaolin on sintering and machinability of fluor-phlogopite glass ceramic

The effect of kaolin on pressability, sintering, mechanical properties, and machinability of a fluor phlogopite glass ceramic was investigated. Crystallinity and microstructure of specimens were determined by X-ray diffraction and scanning electron microscopy methods. Machinability of sintered specimen was investigated by visual assessment of chipping of the drilled specimen rims and measurement of the particle size distribution of chips obtained during drilling. The results indicated that while adding of kaolin improves pressability and hardness of samples, reduces their machinability and bending strength. Furthermore, in the high bearing kaolin specimens, beside fluor-phlogopite, sapphirin and spinel, mullite was also precipitated.