Nano Tungsten Carbide Preparation Process

The preparation technology of nano cemented carbide is very active. The preparation of nano cemented carbide must first prepare nano tungsten carbide powder with excellent properties. At present, there are methods mainly including direct carbonization, gas phase reaction, high frequency plasma, microwave induction plasma, spray conversion, chemical precipitation and high energy mechanical ball milling.

A method of nano tungsten carbide powder made from nanometer tungsten powder and nano carbon black can significantly improve the yield, quality and stability of tungsten carbide. The following steps are as follows:

The combined oxygen content of nano tungsten powder was determined by using 0.1μm nanometer tungsten powder and nano carbon black and paraffin as raw materials. The weight of nano tungsten powder and carbon powder is calculated according to W+C = WC and O₂+2C to 2CO. The nano tungsten powder and nano carbon black are put into the high efficiency mixing mixer, and the inert gas is poured into the high efficiency mixer. Under the protection of the inert gas, the nano tungsten powder is mixed with the nano carbon black. 1.8% organic active material paraffin is added to the mixing process, which is pressed into block and lump mixture under the pressure of 1000kg/cm2. W+C is calcined at low temperature, and its calcining temperature is 1000°C and calcined for 90 minutes. After calcining, nanometer tungsten powder and nano carbon black in the block are formed to form nanometer grade tungsten carbide (WC) of 0.12μm.

After the formation of tungsten carbide (WC), high pressure inert drying gas is used in a closed loop air flow grinding method, and tungsten carbide (WC) is grinded by air to obtain high performance nano tungsten carbide powder. The size of the tungsten carbide powder is less than 0.2microns and carbon Cc is more than 6.10%.

The above method uses the characteristics of high free energy and short diffusion distance on the surface of nanometer powder. At low temperature, calcining pressure block can not only guarantee the full and thorough reaction of W+C = WC, but also prevent the growth or sintering of tungsten particles and tungsten carbide particles, so that high performance nano tungsten carbide powder can be prepared. The process is short, the investment is low, the output is large, the product quality and stability can be greatly improved. It is an environmentally friendly preparation method.

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