The Fluorine Effect on the Grain-Growth of -SiAlON Ceramics

Authors : Nurcan Çalış Açıkbaş, Hasan Mandal

Pages : 895-904

Doi:10.18038/aubtda.279857

View : 12 | Download : 10

Publication Date : 2016-12-20

Article Type : Research Paper

Abstract :SiAlON ceramics are of major interest for industrial applications due to their excellent mechanical properties. The starting Si 3 N 4 powder insert ignore into journalissuearticles values(α or β);, the type of sintering additive and sintering conditions govern the microstructural evolution of SiAlON ceramics. In this study, α ı :β ı SiAlON ceramics with an equal mole intergranular phase content, different type cation systems insert ignore into journalissuearticles values(Y:Sm:Ca and Ca:Ce); with different molar ratio insert ignore into journalissuearticles values(30:64:6 and 33:67); were produced by using coarse insert ignore into journalissuearticles values(d 50 =1 µm); β-Si 3 N 4 powder. CaF 2 and CaCO 3 were utilized as Ca sources. An increase in α ı -SiAlON amount in the case of employing CaF 2 as opposed to CaCO 3 in Y:Sm:Ca cation system was observed. Despite the fact that α ı -SiAlON phase cannot be stabilized in Ca:Ce insert ignore into journalissuearticles values(CaCO 3 as a Ca source); system, α ı -SiAlON phase stability and unpredictable α ı -SiAlON grain-growth in both a and c directions was easily achieved when use of CaF 2 . Furthermore, using CaF 2 instead of CaCO 3 gives rise to an increase in densities. Therefore, the impressive effect of CaF 2 on abnormal grain growth and α ı -SiAlON phase stabilization was discussed.
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