Crystallization of oxynitride glasses in the system MgCaAlSiON prepared with the aid of a polymeric precursor

Abstract

The crystallization of oxynitride glasses in the system MgCaSiAlON has been studied. Oxynitride glasses possessing nitrogen contents of up to 7.2 wt% were prepared with the aid of a polymeric precursor yielding AIN during calcining. Crystallization takes place at temperatures above 1000°C. The incorporation of nitrogen in basic oxidic glasses suppresses the crystallization of anorthite. With increasing nitrogen content new oxidic phases such as spinel and gehlenite are formed as well as nitrogen containing Mg-petalite and different sialon phases. Properties such as density, hardness and fracture toughness are increased whereas the thermal expansion is decreased by the growing content of nitrogen containing phases.