Thermal Expansion Anisotropy of Cordierite Crystal

Cordierite material was prepared by talc, bauxite and kaolin, and the coefficient of thermal expansion (CTE) of cordierite crystals could be determined by high temperature X-ray diffractmeter: the volume and average liner CTE is 2.31×10-5°C-1 and 0.84×10-5°C-1 (200°C -800°C) respectively; With the temperature increasing, the CTE in a or b axis direction increases, and in c axis direction decreases rapidly below 400°C then slowly, cordierite crystal is of obvious thermal expansion anisotropy. The orientation of crystal in sample is random, expansion and shrinkage partly counteract, so that the CTE of cordierite materials is low.