HVOF sprayed tungsten carbide coating

       HVOF sprayed tungsten carbide coating





In tungsten carbide, carbon atoms are inserted into the gaps of the tungsten metal lattice without destroying the original metal lattice, forming an interstitial solid solution, so it is also called an interstitial (or insertion) compound. Tungsten carbide can be made by heating a mixture of tungsten and carbon at high temperature. The presence of hydrogen or hydrocarbons can accelerate the reaction. If the oxygen-containing compound of tungsten is used for preparation, the final product must be vacuum treated at 1500°C to remove the carbon and oxygen compounds. Tungsten carbide is suitable for mechanical processing at high temperatures, and can be used to make cutting tools, structural materials for kilns, jet engines, gas turbines, nozzles, etc.

Another compound of tungsten and carbon is tungsten carbide, the chemical formula is W2C, the melting point is 2860°C, the boiling point is 6000°C, and the relative density is 17.15. Its nature, preparation method and use are the same as tungsten carbide.

A 7KW cross-flow CO2 laser was used to conduct laser cladding experiments of nano-WC powder on a 2Crl3 stainless steel substrate. Scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray energy dispersive spectrometer (EDAX), microhardness tester and other equipment were used to examine the structure and performance of the coating. The results show that the method of laser cladding nano-WC powder can obtain a dense composite coating; the coating cladding area presents typical Fe cellular dendrites and Fe-CW structures between dendrites; XRD analysis shows that the composite coating The layer is mainly composed of Fe, WC, W2C and Fe3C phases; the performance test results of the coating show that the surface hardness is 1750HV. The average hardness of the cladding layer is 1200HV, and the wear resistance is 2.5 times higher than that of the matrix.

Picture (1) is tungsten carbide alloy powder

Valves are one of the main basic components in the machinery industry that are widely used and widely used. During frequent opening and closing processes, the sealing surface of the valve is scratched, coupled with the corrosion, erosion and high temperature of the medium, and the valve is sealed Premature damage to the surface has become one of the root causes of leaks and leaks.