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)-1.2Mg-2.2C and CuMoO4(II)-1.5Mg-1.6C reduced at 3MPa pressure in a temperature range of 1350-1450 degrees C were found to be the optimal conditions for the combustion formation of Mo-Cu nanocomposite with spherical particles of 50-100nm in diameter and narrow size distribution. Combustion-synthesized Mo-Cu powders were consolidated by means of spark plasma sintering (SPS) at 1000 degrees C and pressure of 100MPa in vacuum. The bulk material has demonstrated twofold enhanced microhardness as compared to microhardness of mechanically alloyed specimens.