Synthesis an Thermal Expansion Property of Cubic Cs₂MSi₅O₁₂ (M=Cd, Ni, Zn) Powders

Abstract

Monolithic Cs₂MSi₅O₁₂ (M=Cd, Ni, Zn) with cubic symmetry, space group Ia3d, was synthesized in air according to a two stage heat treatment. Mixed raw material powders were calcined at 973 to 1023K for 20 to 40h until the Cs₂MSi₅O₁₂ (M=Cd, Ni, Zn) phase were recognized by XRD and then they were heated at 1273 to 1473K for 20h. The thermal expansion of the synthesized Cs₂MSi₅O₁₂ (M=Cd, Ni, Zn) powders was investigated using high-temperature X-ray diffraction at 298 to 1273K. The Cs₂MSi₅O₁₂ (M=Cd, Ni, Zn) powders having SiO₄/MO₄^2-=5, displayed a lower thermal expansion than those of CsMSi₂O₆ (M=Al, Fe) having SiO₄/MO₄^-=2 in the low temperature range. With increasing the ionic radius of M²⁺, the thermal expansion coefficient of the synthesized Cs₂MSi₅O₁₂ (M=Cd, Ni, Zn) was increased in the low temperature range.