A novel chemical co-precipitation was used to produce W-70% Cu nanocomposite powders with coating structure. The precursors consisting of CuC2O4 center dot xH(2)O and WO3 center dot 2H(2)O were first synthesized using copper nitrate, ammonium metatungstate(AMT) and oxalic acid as the raw materials at 80 degrees C for 1.5 h when the concentrations of the reactants were 0.8 mol/L and the hydrogen ion concentration was 1.2 mol/L. The precursors were calcined to produce the powders with different phase components and microstructure at various temperatures. The CuWO4 and CuO nano-powders were obtained at 300 degrees C, which is colder than the traditional reaction temperature (1000 degrees C) of CuO + WO3 = CuWO4. However, the cubic Cu2O and Cu2WO4 could be formed when the calcining temperature was 600 degrees C. The hydrogen reduction results show that the calcined powder is reduced to obtain W-Cu composite powder at 750 degrees C and 800 degrees C. In reduction process, volatile WO2(OH)(2) through chemical vapor transport(CVT) continuously spreads to the copper surface and is reduced to form W and the coated particle is eventually formed. This particle is Cu particle coated by W phase and the interface between W and Cu phases is semi-coherent. It is found that the average particle size of the reduced powder is 30-50 nm observed by TEM images. (C) 2018 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.