tungsten oxide-doped lithium salt, the temperature of the reduction and carbonization method principle is: by adding additives to accelerate the evaporation process WO3 reduction deposition rate, resulting in the tungsten powder particle size can be grown under a relatively low temperature, for tungsten powder grown lithium salt additives, the method is mainly used for making mine and cold micro-alloy mold alloy.
3 adds cobalt, nickel, tungsten carbide powder with high carbon while adding a small amount of cobalt, nickel or their oxides, can change the carbonization Molybdenum tube, improve the speed of carbonation, this method of production of coarse crystal grain size of the WC with cobalt by great impact, the greater the amount of cobalt proceeds with WC thicker.
4 adds a sodium salt added in the APT method, and then reduction at higher temperatures, may have a size greater than 10μm thick tungsten powder, and then can be obtained by high-temperature carbonization coarse WC powder. The law is still in the study, some of the technology is not mature.
5. APT rapid calcination rapid reduction method This method is the essence of the APT 850-1000 ℃ under rapid heating in an oxidizing atmosphere calcined, and then rapidly heated in a hydrogen furnace to a temperature of 1100-1300 ℃ reduction, using this method can be prepared 25-36μm particle size of tungsten powder.
6. Halide hydrogen reduction method boiling layer of tungsten chlorides or fluorides used in boiling layer H2 reduction. First, the H2 and the original tungsten powder into the reactor bottom, made of tungsten boiling layer, and the halide vapor from the reactor into the upper portion of the reactor, at a given optimum temperature is reduced to tungsten powder H2 and deposited In the original tungsten powder, so that the original tungsten powder becomes coarser, periodic internal reactor unloading tungsten powder. Prepared by this method using tungsten powder particle size of greater than 40μm.
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