Ultrafine Tungsten Cobalt Carbide Powder Mixing Process

Cobalt tungsten carbide powder has high hardness and excellent wear resistance, and is widely used as cutting tools, wear-resistant tools, impact-resistant tools and metal casting materials. Moreover, when WC powder particles are finer, it has higher hardness and wear resistance.

With the rapid progress of smelting technology in China, it seems that it is not so difficult to produce ultrafine tungsten carbide powder. For example, some enterprises have adopted an advanced process to prepare ultrafine tungsten cobalt carbide powder. The process includes:

First, WC-12% Co-0.3% Cr₃C₂ 0.3% VC 0.2% Ta is used as the target powder. Ammonium paratungstate, cobalt oxalate, vanadium pentoxide, chromium trioxide, tantalum pentoxide and niobium pentoxide were loaded in a weightless mixer at a volume ratio of 65% and mixed evenly in a needle mill for 60 minutes.

Secondly, under atmospheric conditions, tungsten and cobalt oxides are formed by calcination at 650 ℃ for 30 minutes in a furnace. In hydrogen environment, the calcined powders were reduced for 4 hours at the final reaction temperature of 800 C in a tunnel continuous oven to form composite powders of tungsten and cobalt mixed with each other.

Third, by adding carbon black as carbon source for grinding treatment, according to the stoichiometric amount of carbon black is 1.15 times the amount of composite metal powder, in this carburizing process, all the added components are homogeneous mixed powder. In the hydrogen environment, the mixed powders were reduced for 4 hours at the final reaction temperature of 800 in a continuous tunnel oven to produce ultrafine tungsten cobalt carbide powders.

The shape and size of tungsten carbide powder were observed by field emission scanning electron microscopy. It was found that the prepared tungsten carbide particles were 0.1-0.2 um. The WC and Co phases in the WC-Co composite powders are displayed, and the particles are superfine WC-Co powders of 0.1-0.2 um size. The results show that the tungsten carbide particles in the sintered products have excellent coercive magnetism and hardness, and the transverse fracture strength values are similar, and the performance requirements are better than those of foreign countries.

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