Characterization of tin selenides synthesized by high-energy milling
Tin selenides SnSeX (x=1,2) were synthesized from tin and selenium powder precursors by high-energy milling in the planetary ball mill Pulverisette 6 (Fritsch, Germany). The orthorhombic tin selenide SnSe and the hexagonal tin diselenide SnSe2 phases were formed after 4 min and 5 min of milling, respectively. Specific surface area of both selenides increased with increasing time of mechanochemical synthesis. The particle size distribution analysis demonstrated that the synthesized products contain agglomerated selenide particles consisting of numerous idiomorphic tin selenide crystals, measuring from 2 to more than 100 nm in diameter, which were also documented by TEM. UV-Vis spectrophotometry confirmed that tin selenide particles do not behave as quantum dots.
Electrodeposition of Sn, Se, SnSe and the material properties of SnSe films
Abstract A detailed account of the electrochemistry involved in the deposition of Sn, Se and SnSe films is presented. The redox reactions and the polarization curves of Sn and Se were studied to fix the pH and potential values V (NHE) to get uniform deposition. Films were cathodically deposited at 55°C. XRD studies show an orthorhombic structure. Films showed an indirect band-gap of 1.05 eV. Surface morphological studies were carried out using SEM, and the stoichiometry was estimated from XPS analysis. Effect of annealing in air at 200°C has been reported.
Thermodynamics on the Carbochlorination of Titanium-bearing Ores
The equilibrium compositions of the multi-component, multi-phase and multi-reaction system of carbochlorination of titanium-bearing ores are calculated with HSC, a computational chemistry software. The thermodynamic equilibrium calculation of the reaction system shows that a complete conversion of titanium-bearing ores is feasible at a temperature near 200oC. At temperatures ranging from 800 to 1600oC, the products of the reaction system are all in gaseous phase. Thermodynamic analysis accords with the industrial practice. The simulated results provide reasonable scientific basis for improving suitable technological conditions of the carbochlorination reduction.