Effect of LiAlSiO4 particle size on the properties of LAS/SiC porous ceramics with near zero thermal expansion

Abstract

Near zero thermal expansion porous ceramics were fabricated by using SiC and LiAlSiO4 as positive and negative thermal expansion materials, respectively, bonded by glassy material. The microstructure, mechanical properties, and thermal expansion behavior of LAS/SiC porous ceramics with different particle sizes of LiAlSiO4 were investigated. The results indicated that the coefficient of thermal expansion of the LAS/SiC porous ceramics decreased from 0.5206×10−6 to −1.1053×10−6K−1 with increasing the LiAlSiO4 particle size from ~45µm to ~125μm. It was attributed to the reduction in the reaction between LiAlSiO4 and SiO2 as the particle size of LiAlSiO4 increased. Young’s modulus increased from 36MPa to 54MPa as the sintering temperature increased from 850°C to 950°C because of the good bonding between the SiC grains and the glass materials.