Thermal barrier coating is a layer of ceramic coating, which is deposited on the surface of high-temperature resistant metal or super alloy. Thermal barrier coating plays a heat insulation effect on the substrate material and reduces the temperature of the substrate, so the device made can operate at high temperature.
Zirconium alloy under high temperature and high pressure water in the nuclear reactor environment is easy to react with water vapour Zr + 2 h2o + 2 = ZrO2 h2 write, produce hydrogen gas in high temperature environment is easy to cause hydrogen explosion, nuclear safety accident caused by ceramic coating of high strength, high hardness, wear resistance, high temperature resistance, oxidation resistance, corrosion resistance and chemical character such as stable performance can resolve the situation. For example, silicon carbide ceramic coating has high temperature resistance, corrosion resistance and excellent performance in nuclear reactor. Deposition of SiC coating on zirconium alloy surface can effectively insulate water and zircon encased tube from hydrogen absorption and corrosion in reactor environment. Wang meiling et al. prepared silicon carbide coating on the surface of zirconium alloy. The coating was closely combined with the substrate, and there were no holes or cracks in the interface. The coating particles were small and uniform. The improvement of comprehensive properties of zircon encased tubes depends on the coating's resistance to high temperature oxidation and corrosion, its stable structure at high temperature, its surface compactness, low porosity, good bonding performance of coating substrate, and the matching of thermal expansion coefficient. Ti 3 SiC2 and Ti 2AlC coatings were prepared on the surface of zirconium alloys, and the antioxidant experiments were carried out in the range of 1100~1300 ℃. In the process of high temperature oxidation, Si and Al elements in the coating and the substrate conduct mutual diffusion to form zr-si, zr-al and other intermetallic compounds. The bonding strength between the coating and the substrate is significantly improved, and the coating has excellent high temperature oxidation resistance. In the literature [7], silicon and chromium coatings were prepared on zirconium alloy surface to improve the high-temperature oxidation resistance and corrosion resistance of zircon encased tubes in nuclear reactor environment. The glass SiO2 formed by the silicon element in the coating at high temperature fills the pores in the coating, increases the bonding strength between the zirconium alloy substrate and the coating, reduces the rate of oxygen and corrosion fluid entering the coating, and greatly improves the corrosion resistance of the zirconium alloy.
