Sol–gel synthesis and sintering of submicronic copper molybdate (α-CuMoO4) powders

A sol–gel method was proposed to prepare copper II molybdate α-CuMoO4 powders. A gel was first obtained via the polymerizable complex method, using citric acid as complexing and polymerizing agent, dried at 120 °C and decomposed at 300 °C. A calcination in the temperature range 400–500 °C for 2 h led to the pure phase α-CuMoO4. The different powders obtained were characterized by X ray diffraction analysis and by transmission (TEM) and scanning (SEM) electron microscopies. Ceramics were prepared using conventional sintering and spark plasma sintering (SPS) techniques. A maximal relative density of 94.8% was reached after conventional sintering at 520 °C for 2 h. In the case of SPS, the densification was optimized by varying the temperature, the time and the applied pressure. Higher densities, up to 98.7%, were obtained at very low temperature, i.e., 300 °C, for 5 min only under a pressure of 225 MPa.