Sintering and crystallization of CaO-Al2O3-ZrO2-SiO2 glasses containing different amount of Al2O3

In this work several complementary techniques have been employedto carefully characterize the sintering and crystallizationbehavior of CaO–Al2O3–ZrO2–SiO2 glass powder compactsafter different heat treatments. The research started from a newbase glass 33.69 CaO–1.00 Al2O3–7.68 ZrO2–55.43SiO2(mol%) to which 5 and 10 mol% Al2O3 were added. The glasseswith higher amounts of alumina sintered at higher temperatures(9531C [lower amount] vs. 9871C [higher amount]). Acombination of the linear shrinkage and viscosity data allowedto easily find the viscosity values corresponding to the beginningand the end of the sintering process. Anorthite and wollastonitecrystals formed in the sintered samples, especially at lowertemperatures. At higher temperatures, a new crystalline phasecontaining ZrO2 (2CaO. 4SiO2 . ZrO2) appeared in all studiedspecimens.