Tungsten Carbide-based Thermal Spraying Alloy Material

Tungsten carbide-based thermal spraying alloy material is one of the most widely used hard surface materials, and is also one of the strategic basic materials to support our modern industry and modern national defense. It is mainly WC-based composite powder or WC-based alloy powder formed by adding Co, Cr, Ni, Mo and other metals into tungsten carbide.

High temperature sintering is one of the key technologies in the production of alloy powder. It is also the bottleneck technology that seriously restricts the large-scale production of high quality alloy powder in China. The traditional preparation process of alloy powder is to heat the mixture powder in a container for several hours at high temperature and then crush it after cooling. Due to the long heating time, the traditional process can easily lead to the large growth of powder grains, which ultimately affects the wear resistance of sprayed coatings.

In order to overcome the shortcomings of the present process, some researchers have adopted innovative methods to prepare tungsten carbide-based thermal spraying alloy powders. The main contents include:

A.Raw materials: Using degreased tungsten carbide-based mixture powder as raw material, the degreasing temperature of the tungsten carbide-based mixture powder is 250-600 ℃, and the fine grade of the mixture powder includes 250-150 micron, 150-75 micron, etc..

B.Sintering: Tungsten carbide-based alloy powder is prepared by vertical continuous sintering furnace with water-cooled feeding tube above the continuous sintering furnace. Tungsten carbide-based powder material is continuously added from the water-cooled feeding tube. It passes through the heating zone of the furnace in the form of free falling body. It is heated rapidly in the heating zone and sintered or alloyed rapidly, then it falls down to the furnace body for cooling. In the cooling zone, the tungsten carbide-based alloy powder can be sintered continuously into tungsten carbide-based alloy powder from the bottom outlet to the barrel outside the furnace after rapid cooling to the process temperature.

By adjusting the parameters of temperature, diameter and height of heating zone and gas flow rate, the preparation process is suitable for tungsten carbide-based alloy powder with different particle size, composition and properties. The tungsten carbide-based thermal spraying powder has relatively stable grain size, can optimize particle morphology and properties, high yield and loose packing density.

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