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

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.