Abstract
Elastic modulus, Vickers hardness, fracture toughness, bending strength and thermal expansion coefficient of hot pressed silicate crystals (wollastonite, anorthite, gehlenite, diopside and cordierite) have been measured. The following relationships were obtained between bulk modulus K and Young's modulus E, and mean atomic volume V, K=k1Vf, E=k2Vg, where f=-2.7, g=-2.8. Diopside had the highest Young's modulus of 158.1GPa, and anorthite had the lowest of 89.9GPa. Vickers hardness, fracture toughness and bending strength were in the range of 564-924kg/mm2, 1.64-2.02MPa·m1/2 and 124-300MPa, respectively. These properties of diopside showed the largest values in five silicate crystals. A linear relationship was obtained between bending strength and Young's modulus for silicate crystals except anorthite. Anorthite had a high strength in spite of lower Young's modulus. Thermal expansion coefficient was the smallest for cordierite. The thermal expansion coefficient of anorthite and diopside were 4.7×10-6 and 10.7×10-6l/K, respectively.
