Low temperature synthesis of anorthite based glass-ceramics via sintering and crystallization of glass-powder compacts

Anorthite based glass-ceramics were synthesized. The investigated glass compositions are located close to the anorthite-rich corner of the fluorapatite–anorthite–diopside ternary system. Glass powder compacts with mean particle size of 2 and 10 μm were prepared. Sintering behaviour, crystallization and the properties of glass-ceramics were investigated between 800 and 950 °C. In the case of specimens made from the finer particles, complete densification was achieved at a remarkably low temperature (825 °C) and the highest mechanical strength was obtained at 850 °C, but density significantly decreased at higher temperatures. The samples prepared from the larger particles exhibited higher values of density, shrinkage and bending strength within a wider temperature range (825–900 °C). Anorthite was predominantly crystallized between 850 and 950 °C, along with traces of fluorapatite. Diopside was detected only in the MgO richer compositions.