The inner surface of the nozzle made of carbon carbon composite material is relatively uniform and smooth. no pit, which is beneficial to improve the efficiency of the nozzle, is generally considered to be the best material for the throat lining at present.
In spite of the carbon carbon composite material has good thermal insulation, anti erosion and good machinability, but its production process is complex, high cost, ablation resistance as tungsten copper infiltrated materials. In order to increase of the ablated material ablation resistant ability, in the carbon carbon composite material nozzle ablation surface is coated with a layer of erosion resistant coating.
In the carbon carbon composite material is coated on the surface of the dense tungsten coating, to exert the common characteristics of carbon carobn composites and tungsten hardfacing materials and improve the ablative performance of the nozzle throat is worth research directions. The Plasma Sprayed Tungsten Coating on the surface of C/C composites can obtain good interfacial bonding and excellent coating performance.
The porous structure of carbon carbon composite material and laminated pyrolytic carbon of tungsten element has strong ability to capture, w elements tend to accumulate in the pores of the surface of carbon carbon composite material or around carbon fiber is a circle does not continuously arranged. With the increase of heat treatment temperature, the formation of tungsten carbide columnar grains is more mature.
Carbon carbon composites are widely used in fusion devices due to their high melting point and high thermal conductivity. But the material
High chemical sputtering and high adsorption of O2 and H2 lead to the enhancement of impurity and the recycling of hydrogen, which makes it difficult to control the plasma. Tungsten due to the characteristics of the high melting point, excellent thermal conductivity and low sputtering yield, high self sputtering threshold, low vapor pressure, low tritium retention capability and anti plasma erosion etc., is considered to be the future fusion reactor the most hope for the first wall material. However, tungsten and its alloys are very heavy and difficult to be processed, so the coating on the light element materials, such as the tungsten coating on the carbon materials, has attracted wide attention in the world.
