Preparation of High Thermal Expansion Coefficient Glass-Ceramics in Li2O-ZnO-SiO2 System

摘要

Lithium carbonate,zinc oxide and silica as the main raw materials,potassium oxide and sodium as flux,phosphorus pentoxide as nucleating agent,the glass in Li2O-ZnO-SiO2 was synthesized by conventional melt cooling method and then converted to glass-ceramics.The crystallization behavior,microstructure and thermal expansion coefficient of the resulting glass-ceramics were investigated by XRD,SEM and thermal performance test.The results show that the Tg of the matrix glass is about 508°C,initial crystallization temperature is about 620°C.When the crystallization temperature ranges from 650°C to 750°C,the main crystal phase is Li2ZnSiO4.Increasing crystallization temperature to 850°C,much cristobalite crystals is formed.Owing to the high TEC of the cristobalite,the glass-ceramics with TEC of 12.27×10-6°C-1 were obtained,which is matched with the TEC of stainless steel SAE 1010.