Sintering and Crystallization Behavior of Machinable Fluorphlogopite-Gehlenite Glass-Ceramic

摘要

Easy machining is a characteristic of fluorphlogopite glass-ceramics, that sets them apart from other glass-ceramic systems. However, these materials have low hardness and mechanical strength, which limit their performance as a structural ceramic. In this paper, we attempted to overcome this problem by incremental addition of calcium oxide to a base glass composition. In this way, various parameters of the resulting glasses like their sintering and crystallization behavior were investigated, using X-ray diffractometry, differential thermal analysis, and scanning electron microscopy. According to our results, while small amounts of CaO improved the crystallization of fluorphlogopite and induced a decrease in the sinterability of glasses, higher amounts of CaO had the opposite effect, that is, it led to a reduction in the dimensions of mica crystalline particles and caused gehlenite to precipitate.