Vacuum sintering of novel transparent Tm2O3 ceramics: Effect of silica additive and thermal performance

Abstract

Polycrystalline transparent Tm2O3 ceramics are successfully fabricated by means of chemical precipitation route plus vacuum sintering technique. Hexamethylenetetramine as the precipitant is dripped into thulium sulphate system to directly result in a hydrated basic sulphate precursor with an approximate chemical composition of Tm(OH)1.7(SO4)0.65∙2.1H2O, followed by pyrolysis to yield a sphere-like Tm2O3 powder with an average particle size of ∼165 nm. During high-temperature sintering, the silica additive induces lattice distortion via the formation of interstitial solid solution and helps to achieve a uniform microstructure together with good optical quality. The best Tm2O3 ceramic sample has in-line transmittances of ∼71 % at 880 nm and ∼76 % in partial middle infrared spectral region with maximal infrared cut-off at ∼11 μm. The thermal diffusion and thermal conductivity of the bulk both decrease as the temperature increases.