Solution-Based Processing of Sc₂O₃ Nanopowders Yielding Transparent Ceramics

A basic sulfate precursor [Sc(OH)SO₄·2H₂O] for well-sinterable Sc₂O₃ powders was precipitated from mixed solutions of scandium nitrate [Sc(NO₃)₃] and ammonium sulfate [(NH₄)₂SO₄] at room temperature and which was subsequently converted to Sc₂O₃ via dehydroxylization and desulfurization at temperatures ≥900 °C. With the reactive powders synthesized in this work, polycrystalline Sc₂O₃ ceramics showing high inline transmittances of approximately 70% in the visible wavelength region (corresponding to ∼90% of the theoretical value of single crystals) have been fabricated via vacuum sintering at a relatively low temperature of 1700 °C.