Fabrication of Transparent, Sintered Sc2O3 Ceramics


  • L. C. Klein—contributing editor

†Author to whom correspondence should be addressed. e-mail: li.jiguang@nims.go.jp


We report here the fabrication of transparent Sc2O3 ceramics via vacuum sintering. The starting Sc2O3 powders are pyrolyzed from a basic sulfate precursor (Sc(OH)2.6(SO4)0.2·H2O) precipitated from scandium sulfate solution with hexamethylenetetramine as the precipitant. Thermal decomposition behavior of the precursor is studied via differential thermal analysis/thermogravimetry, Fourier transform infrared spectroscopy, X-ray diffractometry, and elemental analysis. Sinterability of the Sc2O3 powders is studied via dilatometry. Microstructure evolution of the ceramic during sintering is investigated via field emission scanning electron microscopy. The best calcination temperature for the precursor is 1100°C, at which the resultant Sc2O3 powder is ultrafine (∼85 nm), well dispersed, and almost free from residual sulfur contamination. With this reactive powder, transparent Sc2O3 ceramics having an average grain size of ∼9 μm and showing a visible wavelength transmittance of ∼60–62% (∼76% of that of Sc2O3 single crystal) have been fabricated via vacuum sintering at a relatively low temperature of 1700°C for 4 h.