WC-Co tungsten carbide plays an important role in tungsten carbide field. To improve mechanical property of WC-Co tungsten carbide, crystalline size of WC should be strictly controlled, which is to prepare WC-Co tungsten carbide. Grain size is usually 0.5~1.0um. For producing ultrafine cemented carbide, super fine WC powder is still an important researching topic.
Materials academics in and abroad research many producing method for super fine tungsten powder and WC powder such as low temperature reduction carbonization, direct carbonation of oxides, plasma chemistry - carbonization, halide carbonization, double salt precipitation. It can be concluded into three categories: (1) Producing super fine tungsten powder first, then produce super fine WC powder. (2) Direct carbonization of tungsten compounds. (3) WC-Co composite precipitation method.
1.Use violet tungsten oxide as raw material, process hydrogen reduction by traditional method with four tube furnace, boat charge is 600g, push the boat with speed 20min/boat, hydrogen flow is 30m3/h, reduced to obtain tungsten powder. Mix it evenly by same carbon content and in the same carbon furnace, carbonization temperature is 1 100 ～1 400°C.
2.Mix WC powder and Co powder by 10% Co content requirement of carbide. Then add grain growth inhibitor WC, Cr3C2 for 0.4~0.5%, ball to powder ratio is 5:1, grinding for 48h, grinding media is hexane. Ball mill speed is 100r / min. The sintering temperature is 1370-1,400 ℃ and the pressure was 8-10MPa in a vacuum furnace. The superfine WC-Co cemented carbide was prepared by the above process.