Rapid Synthesis for Tungsten Carbide Composite Powder

Tungsten carbide is a compound composed of tungsten and carbon, mainly used for the production of cemented carbide. The tungsten oxide is first reduced to tungsten powder with hydrogen, and then carbonized at a high temperature with tungsten powder to form tungsten carbide powder. However, this method is not easy to produce ultra-fine tungsten carbide powder, let alone produce ultra-fine particles. Tungsten carbide - metal cobalt composite powder. A more practical tungsten carbide composite powder synthesis method has been innovated. The process flow is as follows:

(1)Preparation—take a certain amount of tungsten trioxide and tricobalt sulphate with purity of 99%, react with graphite powder to produce tungsten carbide—Cobalt metal, use 70 to 125% of theoretical carbon amount with carbon source, and use a ball mill to mill for 2 hours after loading the mixture into graphite boat.

(2)Into the furnace reaction—-The graphite boat with the mixture is pushed into a high-temperature molybdenum wire tube furnace or a single-tube push boat high-temperature furnace at 900 to 1850°C, and reacts for 0.5 to 6 hours in a reducing atmosphere.

(3)Furnace detection - The reactants are cooled in the furnace cooling zone for 0.5 to 1 hour, and the total carbon, free carbon and oxygen content of the reactants are measured after passing through a 80 mesh sieve to remove some mechanical impurities. The total carbon content shall be 6.12 to 6.25 weight percent. %, free carbon should be between 0.1 and 0.2% by weight and oxygen content should be less than or equal to 0.25 % by weight.

(4)Adjustment— When the product is tungsten carbide powder and the test result does not meet the requirements, the product should be fine-tuned with carbon or tungsten oxide, and when the product is tungsten carbide - metal cobalt powder, the fine-tuning needs to be complemented The gold process requires the cobalt oxide in the amount of cobalt metal or the oxide of tungsten required by the gold-compounding process. The adjusted material is then ball milled and mixed for 0.5 to 2 hours. The gas is protected at 900 to 1850°C in the high-temperature molybdenum wire tube. Furnace and then react for 0.5 to 6 hours, after cooling, ball milling, screening, testing, packaging.

Tungsten oxide, cobalt and carbon can achieve the precursor state of sintered cemented carbide with a single procedure. This method has a short process flow, good product quality, simple equipment and high efficiency.

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