Influences of additives on crystal multiformity and composition in a CaO–Al2O3–MgO–SiO2–based glass–ceramics

Crystallization of a CaO–Al2O3–MgO–SiO2 (CAMS)–based glass–ceramic with different additives, Fe2O3 and CeO2, was investigated. The compositions of crystals formed in the glass–ceramic were related to the coordination polyhedron of Fe–O and Ce–O in the glass matrix. Fe existed in the glass network in a form of [Fe3+O4–SiO4] (variant of Q2), which facilitated the formation of diopside. CeO2 addition led to the formations of [CeO4] and [CeO6]. [CeO4] was assembled in the diopside crystal, forming a Ce-containing diopside solid-solution. As a glass modifier, [CeO6] consumed Na ions, achieving electric neutrality and increasing the fraction of Q4 (SiO2 O2/2)2−. This enables the precipitation of albite and anorthite. EBSD observation of CaCe4(SiO4)6O crystal