Ultrafine Tungsten Powder Preparation by Microwave Mechanical Ball Milling

With the rapid development of microelectronics industry, energy, aviation, machinery industry and other fields, the demand for ultra-fine tungsten powder is expanding. The quality of ultra-fine tungsten powder directly affects the final performance of material products in various industries, so how to lower the cost, It is of great significance to efficiently produce high-quality ultra-fine tungsten powder for production and application research.

At present, the main processes are hydrogen reduction, sol-gel, high-energy ball milling, freeze drying, molten salt electrolysis, self propagating high-temperature reduction and spray drying fluidized bed method. Unlike the past, some scholars have innovated a microwave-assisted ball milling process for preparing ultrafine tungsten-based alloy powder. The main contents of the process are as follows:

(1)Put metal powder, blue tungsten or yellow tungsten powder with particle size of 10-20 micron, ceramic ball with particle size of 0.5-1.5 millimeter, and deionized water into ceramic ball grinding pot at the weight ratio of 3:10:100:100, and put ceramic ball grinding pot into microwave oven;

(2)Start the motor and microwave oven of ceramic ball mill pot, milling in 1500W microwave oven for 40 minutes, close the microwave oven and motor, fill the deionized water evaporated, open the motor and continue milling for 40 minutes, repeat the above actions 8 times, and sift to get tungsten-based alloy oxide slurry;

(3)Tungsten based alloy oxide slurry was prepared by vacuum spray drying to obtain tungsten based alloy oxide mixed powder.

(4)Superfine tungsten-based alloy powder with average particle size of 10-50 nanometer was obtained by reducing the mixed powder of tungsten-based alloy oxides in hydrogen atmosphere, the flow rate of hydrogen is 0.5m³/h, the reduction temperature is 900 ℃, and the holding time is 4 hours.

The new process will break through the traditional thinking. Firstly, the tungsten-based alloy oxide is prepared by microwave mechanical ball milling, and then the tungsten-based alloy oxide is reduced to obtain nano-scale ultra-fine tungsten powder. The process greatly reduces the preparation of nano-oxide powder. The problem of high temperature has successfully solved the problem of serious pollution in dry ball milling and easy aggregation and growth of powder.

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