Fabrication and Mechanical Properties of Dense Celsian Ceramics.

Abstract

Synthesis and densification of celsian was investigated. The mixture which was measured to be the stoichiometric ratio of celsian was melted by using arc melting technique to synthesize the material in glass state. Milled powder of the glass was mold pressed and CIPed to obtain green compacts. Dense celsian ceramics composed of monoclinic crystalline phase could be obtained by heat-treating the compact at 1500°C for 4h in air. Enhanced densification of the present material was ascribed to the viscous deformation of the glass phase. Existence of zirconia, which was dissolved into the glass from refractory bricks during arc melting, was considered to promote the crystallization of monoclinic phase of celsian which was required to exhibit low thermal expansion behavior. Fracture strength and the Young's modulus of the resultant celsian were 148MPa and 138GPa at room temperature, respectively. Thermal expansion coefficient of the sample was 4.0×10-6/°C between room temperature and 1000°C.