Reaction Between Barium Carbonate and Pyrex Glass Powder as a Function of Temperature: XRD and Weight Loss Study

A mixture of barium carbonate and Pyrex-type powders was heat treated at 500°C-950°C temperature range, for 2 hours at each temperature. The course of the reaction was studied by XRD and weight loss analysis. Reaction of barium carbonate with the Pyrex-type glass was detected at 600°C by weight loss analysis. XRD shows formation of various barium silicates starting at 650°C. At high temperature ,850-950°C, only one crystalline phase, sanbornite, was detected. Silica phase related to quartz starts to separate from the Pyrex-type glass at 650-800°C. Another phase of silica, cristobalite, was detected at 750°C only. The separated silica phase is very reactive with barium carbonate, yielding various silicates well below the decomposition temperature of barium carbonate.