Crystallization of Fluoride Glasses Based on AlF_3 and ZrF_4

The phase separation and crystallization of fluoride glass 8.7MgF2-17.4CaF2-8.7SrF2-13.3BaF2-13.0YF3-31.6AlF3-7.3ZrF4 in mole percent were studied. The investigation indicates that the phase separation occurs obviously when A1F3 and ZrF4 coexist in glass, the glass is more sensitive to water at high temperature and the surface crystallization often occurs. The crystallization in glass mainly occurs in Al-rich phase, and the crystallization on the surface of glass mostly comes from Zr-rich phase because of the water in atmosphere. According to the performance of glass phase separation and crystallization, the surface crystallization mechanism of fluoride glass containing A1F3 and ZrF4 was discussed.