Enhanced surface crystallization of glass by adding traditional oxide nucleating agents

In the preparation of glass-ceramics, bulk crystallization of glasses can be improved by adding nucleating agents. However, surface crystallization of glasses conventionally can only be enhanced by using small particles, whose surfaces provide nucleating sites. Herein, oxide nucleating agents such as TiO2 and Cr2O3 which are normally used to improve bulk crystallization were introduced into a lithium-iron-phosphate (LIP) glass. Differential thermal analysis results suggest that tendency to bulk crystallization of the LIP glass increases to some extent after addition of the nucleating agents. However, no bulk crystallization really occurred in the thermally treated samples. Instead, surface crystallization of the glass is facilitated by the nucleating agents. The samples containing nucleating agents show thicker crystallized surface layers compared with the pure LIP glass. It is proved nucleation stage to be important to increase the surface crystallization, further confirming the enhancement effect of the nucleating agents on surface crystallization. The results enrich the understanding of surface crystallization of glass and provide useful information for the preparation of glass ceramics via glass powder sintering process which is based on surface crystallization. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.