Determining the Nucleation Rate Curve for Lithium Disilicate Glass by Differential Thermal Analysis

Abstract

The crystallization of lithium disilicate (Li20 * 2Si02) glass nucleated at various temperatures was studied by differential thermal analysis (DTA). A plot of the DTA crystallization peak height versus nucleation temperature closely resembles the classical nucleation rate curve for lithium disilicate glass whose maximum is at 453°C. The glass becomes saturated with internal nuclei when heated at 453°C for 10 h. The DTA technique is a rapid, alternative method for determining the temperature for maximum nucleation. The activation energy for crystallization, E, and the heat of crystallization, H, are independent of the concentration of nuclei and are 249 f 10 and 67 -+ 3 kJ/mol, respectively. The Avrami exponent, n, depends strongly on the concentration of nuclei in the glass. [

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