2009 Volume 50 Issue 7 Pages 1885-1889
The thermal decomposition of ammonium thiocyanate (NH4SCN) was studied by thermogravimetry, differential thermal analysis, and mass spectrometry. It occurred in the temperature range from 400 to 530 K. The decomposition products contained NH3, CS2, H2S, and HNCS gases. Rare-earth oxides were reacted with these gases at 1273 K for 8 h in order to prepare rare-earth sulfides. The single tetragonal β-La2S3 phase was formed after the sulfurization of La2O3. In contrast, the single orthorhombic α-Gd2S3 phase was formed after the sulfurization of Gd2O3. These powders were consolidated by pressure-assisted sintering to fabricate the thermoelectric elements.