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 CuMoO_4(I)–1.2 Mg–2.2C and CuMoO_4(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.