Morphology studies of a W/Cu alloy synthesized by hydrogen reduction

摘要: The major part of the present work, deals with reduction kinetics Cu2O powder and a Cu2O-WO3 mixture by hydrogen gas, studied ThermoGravimetric Analysis (TGA). experiments were carried out both isothermally non-isothermally on thin beds over different temperature intervals. During experiments, reductant gas flow rate was kept just above starvation for reaction to ensure that chemical rate-controlling step. activation energy reactions evaluated from isothermal as well non-isothermal experiments. In case Cu2O, impact stability copper oxide under identical experimental conditions is discussed. A closer investigation additions Ni or NiO did not have perceptible effect reduction. mixture, mechanism found be affected in range 923-973 K, which attributed reaction/transformation starting mixture. At lower temperatures, preferentially reduced early stages, followed tungsten oxide. higher strongly formation complex materials. It underwent could explain observed kinetic behavior. composition microstructures material products analyzed X-ray diffraction (XRD) microprobe analysis. vi Kinetic studies indicated that, changes significantly at 923 K product formed had unusual properties. structural performed XRD Cu dissolved W forming metastable solid solution, amorphous/nanocrystalline state. samples produced other hand, showed presence two phases, pure Cu. SEM results conformity analysis confirmed W/Cu alloy. TEM observations particle sizes about 20 nm. structure alloy work compared those similar conditions. hinders coalescence particles retains its nano-grain structure. open up an interesting process route towards production intermetallic phases composite materials optimized