Effects of Fe 2 O 3 on crystallisation and properties of R 2 O–CaO–MgO–Al 2 O 3 –SiO 2 –Fe 2 O 3 glass ceramics

Abstract

The R₂O–CaO–MgO–Al₂O₃–SiO₂–Fe₂O₃ glass ceramics was prepared using granite wastes and Fe₂O₃. The effect of Fe₂O₃ on crystallisation and properties of glass ceramics was studied. Results show that the crystalline phases were Fe₂TiO₅ and K(NaCa)Mg₅Si₈O₂₂F₂ when the content of Fe₂O₃ was low. The main crystalline phase was Fe_1.5Ti_0.5O₃ when the content of Fe₂O₃ was high. With the increase of Fe₂O₃, the crystal size of K(NaCa)Mg₅Si₈O₂₂F₂ reduced and the atomic ratio of Si to Mg increased. The colour of sample varied from greyish green to black with different additions of Fe₂O₃. The flexural strength with a maxim (101.02 MPa) when the content of Fe₂O₃ was 4.7 mol-%. Given the low cost of granite wastes and Fe₂O₃, this new type of black glass ceramics is expected to meet the increasing demand from the market of building decoration due to its excellent properties.