The Preparation Of (TiW)C-Ni Nano Cemented Carbide Powder

Scientists had discovered that as the require of cemented carbide tool performance improving, it's needed to increase the content of Co to improve the hardness, abradability, erosion resistance and handling characteristics. But it makes contradicton between high rigidity and intensity. Therefor, they started to use thinner powder mixtures. And they used Ni to replace costly Co, in order to reduce the facture cost of cemented carbide.Scientists had discovered that as the require of cemented carbide tool performance improving, it's needed to increase the content of Co to improve the hardness, abradability, erosion resistance and handling characteristics. But it makes contradicton between high rigidity and intensity. Therefor, they started to use thinner powder mixtures. And they used Ni to replace costly Co, in order to reduce the facture cost of cemented carbide.results of experiment show that adoptting mechanical and thermal co-activation method can synthesize ordinary micron raw materials TiO₂, W and C to (TiW)C powder with sub-micron particle size(100～200nm)nano-meter crystallite size(30～80nm). Due to the powder of nanometer grain size(about 9～18 nm) forming during the mechanical activation(high-energy milling) process, the reactant can be mixed at nano-dimension and carbothermic reaction at high tempetature was accelerated remarkably. Moreover, the synthesis reaction tempetature was lowered and the reaction time was shorted significantly. The powder synthesized invacuum brazing stove at 1200℃is optimal, and the content of uncombined carbon less than same spec powder synthesized high temperature tubular furnace. After pressing the powder synthesized at 1200℃to column, sinter to (TiW)C-Ni cemented carbide. Considering the melting point of Niand and the effect of milling , through the experiment we could get the best rigidity performance by sintering at 1400℃and the microhardness reaches up to 1443HV. Moreover, educe that sintering at 1400℃makes crystallite finer and lacuna less by observiation and analyzsis.