Affiliation: | 1.Ural Federal University Named after the First President of Russia B.N.Yeltsin,Yekaterinburg,Russia;2.Ural Institute of State Fire Service of EMERCOM of Russia,Yekaterinburg,Russia;3.The Institute of Solid State Chemistry, Ural Branch,Russian Academy of Sciences,Yekaterinburg,Russia;4.Mikheev Institute of Metal Physics, Ural Branch,Russian Academy of Sciences,Yekaterinburg,Russia |
Abstract: | The hydrochemical precipitation method at 298 and 333 K with, respectively, thiocarbamide and sodium selenosulfate was used to obtain nanostructured powders of copper sulfide with formula composition Cu2S, which are composed of globules 200–500 nm in diameter, formed by 70–100-nm particles, and copper(I) selenide, composed of crystallites with polyhedral shape, sizes of 80 to 500 nm, and a formula composition Cu1.84Se. An X-ray diffraction analysis revealed the orthorhombic Cu2S structure (space group no. 39-Abm2) with unit cell parameters a = 1.182 nm, b = 2.705 nm, and c = 1.343 nm. Powders of Cu1.84Se copper selenide have a cubic structure (space group Fm3m) with lattice constant a = 0.5693 nm. A thermal analysis demonstrated that the chemically precipitated Cu2S and Cu1.84Se powders have a stable elemental composition up to 200–240°C. An intense oxidation of the samples begins at a temperature exceeding 250°C and is accompanied by a sharp decrease in their content of sulfur (selenium) and by an increase in the content of oxygen. |