Tungsten Coating Carbon Fiber Based Heat Insulation Material

At present, carbon fiber-based thermal insulation material is widely used in vacuum heat treatment furnace, cemented carbide sintering furnace, single crystal silicon drawing furnace and polycrystalline silicon ingot furnace. It has the advantages of small thermal conductivity, low thermal capacity, low density, small linear expansion coefficient, high temperature resistance, strong thermal shock resistance and strong chemical corrosion resistance.

Recently, some scholars have mentioned the use of plasma spraying to tungsten coatings on carbon fiber-based thermal insulation materials. This method uses surface roughening, tungsten powder ball milling, plasma spraying and heat treatment to obtain carbon fiber-based thermal insulation materials with strong high temperature reflection and radiation ability. The steps required are as follows:

The first step is surface roughening. Carbon fiber based thermal insulation material is sandblasted and then cleaned with deionized water to obtain rough surface.

The second step is tungsten powder ball milling: the raw material of tungsten powder is treated by ball milling, in which the abrasive ratio is 1, the ball milling time is 3 h, the ball milling speed is 500 rpm, and the tungsten powder with particle size of 100 um is obtained.

The third step is plasma spraying. The carbon fibre-based thermal insulation material with rough surface is placed in plasma spraying system. Argon is used as protective gas. Tungsten powder after ball milling is sprayed on the surface of carbon fibre-based thermal insulation material with rough surface by plasma spraying. The parameters of plasma spraying process are as follows: The spraying arc voltage is 80V, the arc current is 300A, the main gas flow rate is 30L/min, and the spraying gun distance is 100mm.

Fourth step heat treatment: heat the carbon fiber-based heat insulation material with tungsten coating to 1000 ℃ for 3 hours and 4 hours. Argon protection is introduced into the heat treatment process. The flow rate is 500 mL/min and the pressure in the furnace is 92 Pa. The carbon fiber-based heat insulation material with tungsten coating on the surface is obtained.

The tungsten coating prepared by plasma spraying has the advantages of high speed, high efficiency and good spraying effect. The tungsten coating on the surface of the material obtained has strong ability of reflecting heat radiation at high temperature, and the tungsten texture is hard, which can effectively solve the problem of easy corrosion on the surface of carbon fiber-based insulation material.

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