Mo–Cu pseudoalloys by combustion synthesis and spark plasma sintering

The in situ preparation of Mo–Cu from copper molybdate in the combustion mode with the help of thermo-kinetic coupling approach using the combined magnesium/carbon reducer to provide controllable thermal conditions is reported. To determine the optimum processing parameters, the stepwise nature of reaction mechanism in the CuMoO4–Mg–C system was comprehensively explored with the help of a copper wedge quenching technique combined with X-ray diffraction and microstructural analysis of intermediate and final products. Precursor compositions of CuMoO4(I)–1.2 Mg–2.2C and CuMoO4(II)–1.5 Mg–1.6C reduced at 3 MPa pressure in a temperature range of 1350–1450 °C were found to be the optimal conditions for the combustion formation of Mo–Cu nanocomposite with spherical particles of 50–100 nm in diameter and narrow size distribution. Combustion-synthesized Mo–Cu powders were consolidated by means of spark plasma sintering (SPS) at 1000 °C and pressure of 100 MPa in vacuum. The bulk material has demonstrated twofold enhanced microhardness as compared to microhardness of mechanically alloyed specimens.