Synthesis of binary copper chalcogenides by mechanical alloying

Copper sulfides (tetragonal Cu1.92S-Cu1.99S, rhombohedral Cu1.71S-Cu1.89S, CuS), selenides (β Cu2 − xSe, Cu3Se2, γ CuSe, CuSe2), and tellurides (Cu2 − xTe, Cu3Te2) were prepared from mixtures of the elements by mechanical alloying (MA), using a high-energy ball mill. The compounds were obtained by 60–120 min of MA. It is notable that two metastable high-pressure phases were obtained by MA: tetragonal Cu2 − xS and pyrite-type CuSe2. The tetragonal phase gradually transformed to the stable phase of djurleite when kept at room temperature. Cu1.71S-Cu1.89S also formed a metastable rhombohedral phase.