Study of the Effect of Different Nucleating AgentsudOn Lithium Alumino-Silicate Glass-Ceramic System

摘要

Lithium AluminoSilicate (LAS) Glass ceramic (GC) finds use in kitchenware, cooktop panels and telescope mirror because of its characteristic of very low and sometime zero thermal expansion coefficient (TEC) in the application temperature range. In this project work, conventional melt-quenching technique has been used for the development of the LAS base glass. After controlled crystallization, LAS GC has been developed using titania and/ zirconia as a nucleating agent and their effect has been studied in the presence of yittria. Here the yittria content has been varied from 1-3 wt% with corresponding variation in titania (2-4 wt%) or zirconia (2-4 wt%). Effects of temperature and time on crystallization have also been studied followed by the effect of crystallization on thermal expansion co-efficient of the developed glass ceramics. Developed crystalline phases were â-Spodumene and â-quartz solid solution (ss) which has been authenticated by X-ray diffractometer. TEC of the GC has been measured and studied using Dilatometer in the temperature range of 25oC to 750oC and its surface hardness has been measured at 0.5Kgf using Vickers indentation method.