Tungsten Carbide-based Thermal Spraying Alloy Material

The application of hard surface material in surface engineering is to coat it on metal or workpiece surface by thermal spraying and other thermal technology, so as to improve the wear resistance, impact resistance, high temperature resistance, corrosion resistance and other properties of the surface, significantly prolong the service life of the workpiece, and save a lot of metal materials and production costs.

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, 75-38 13 micron; < 13 micron.

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, and is heated rapidly and burned rapidly through the heating zone of the furnace body in the form of free falling body. After solidification or alloying process, it continues to fall into the cooling zone of the furnace body. After rapid cooling in the cooling zone to the process temperature, it falls continuously from the lower outlet to the barrel outside the furnace body to realize continuous sintering of tungsten carbide-based mixture powder into tungsten carbide-based alloy powder.

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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