Development of Machinable Glass-Ceramics Produced from Vermiculite

In this study, machinable glass-ceramics were produced from vermiculite and K2CO3, SiO2, Al2O3 and MgF2 as additives by melting process. The starting materials were mixed together and milled in a mill with alumina ball for 2 h. The mixed powders were melted by aluminum crucible at 1500 degrees C. The melted glass was cast into graphite mold, and then it was exposed to crystallization heat treatment for glass-ceramic transformation. The glass-ceramic samples were characterized with X-ray diffraction analysis, scanning electron microscopy, mechanical tests such as hardness, fracture toughness and machinability test. The results indicate that machinability properties can be obtained from vermiculite based glass-ceramic with some additives