LAUSR

Abstract β-eucryptite (β-LiAlSiO4) ceramic has been fabricated via a novel solid state reaction method by taking hydroxides LiOH∙H2O, Al(OH)3 and SiO2 as reactants. The changes of mass, heat and evolution of crystal phases during the reaction process, as well as the reaction sequences, sintering characteristic, micro-morphology and thermal expansion property of the β-LiAlSiO4 ceramic have been fully studied. The results show that a highly reactive intermediate phase γ-Al2O3 forms after heating Al(OH)3 over 550℃. γ-Al2O3 preferentially reacts with dehydrated LiOH to form LiAlO2, which further reacts with SiO2 to produce β-LiAlSiO4 at 700℃. Single-phase β-LiAlSiO4 powders can be obtained at a low temperature of 950℃. The β-LiAlSiO4 ceramic sintered at 1200℃ for 1 h shows dense and less cracked microstructure with zero coefficient of thermal expansion α=-0.5 × 10-6/K, which is expected to be a promising material in laser gyroscope and telescope fields.