Synthesis And Sinterability Of Superfine W-Cu Powders By Sol-gel Self-propagating Combustion Method

Traditional W-Cu composite materials are always prepared by infiltrating way,of which density and uniformity are not ideal.On the other hand,mechanical alloying method can also be used to obtain the W-Cu composite material,but it will bring in impurities,which would deteriorate the properties of the composite.Recently,the preparation of nano materials by wet chemical method has been studied extensively.And the sintering properties of ultrafine W-Cu composite powders are very important for the sintering density of composites.In this article,W-Cu composite powders were respectively synthesized by sol-gel self-propagating combustion method with citric acid and glycine system,which were used by the preparation for W-Cu composite materials.A new method for the preparation of W-Cu composite was explored.With ammonium tungstate,copper nitrate hydrate and citric acid?glycine?as raw materials,respectively,W-Cu composite powders were prepared by sol-gel self-propagating combustion method and hydrogen reduction.And then W-Cu composite materials were prepared by cold compression molding and sintering in hydrogen.The composition and properties of precursors and reduced powders were characterized by X-ray diffraction analysis?XRD?,Scanning electron microscopy?SEM?and laser particle size analyzer?LPS?.The morphology structure and related properties of the sintered bodies were also studied.The results showed that both the phase compositions of precursors from two systems were the mixtures of CuWO₄,WO₃ and CuO,and the grain sizes were both less than 100nm.The pure W-Cu composite powders were obtained after reduction,and the powders were all W coated with Cu,and the grain sizes of the composite powders were between 50 and 100nm.The density of W-50Cu body sintered at 1300?C with citric acid system could reach99.52%,and the conductivity and thermal conductivity coefficient could reach up to68.96%and 259.85 W/?m·K?;the hardness of the W-20Cu component could reach up to229.44HV;the sintered bodies of the W-40Cu and the W-50Cu components had plasticity,and the bending strength of the W-30Cu component could reach up to1275.19MPa.The sintered body density of the W-50Cu component under1300?C with glycine system could reach 99.51%,and the conductivity and thermal conductivity coefficient could reach up to 69.80%and 259.56W/?m·K?;the hardness of the W-20Cu component could reach up to 225.98HV;the sintered bodies of the W-40Cu and the W-50Cu components had plasticity,and the bending strength of the W-30Cu component could reach up to 1267.54MPa.