Preparation and failure analysis of silicide coating on tantalum 10 tungsten alloy
Tantalum tungsten alloy (Ta10W) has high temperature strength, good ductility, weldability and excellent corrosion resistance, suitable for high temperature, high pressure, corrosion resistance and other working environment, widely used in chemical, aerospace, atomic energy industry and high temperature components and other fields. But the high temperature oxidation resistance of Tantalum 10 Tungsten alloy in the atmosphere is relatively poor, at 500℃ Tantalum 10 Tungsten tantalum tungsten alloy will appear "PEST" oxidation phenomenon, the higher the temperature, the more intense the oxidation, until the complete "pulverization" damage. With 1500 ℃ ~ 1600 ℃, heat preservation for 10 min ~ 30 min slurry fuse burning process, in the tantalum tungsten alloy surface preparation has good thermal stability and high temperature oxidation resistance of silicide coating, coating can protect the metal substrate from high temperature corrosion or slow down the corrosion rate, the tantalum tungsten alloy substrate composition unchanged, can reserve base material strength is not lower than the original base material strength at room temperature of 9 0%, elongation not less than 10%. Through observation and analysis, it is found that the static oxidation resistance failure of the silicide coating on the tantalum tungsten alloy surface is caused by the continuous oxidation and peeling of the coating, and the thermal shock oxidation resistance failure is caused by the fine crack formed by the difference of thermal expansion coefficient between the coating and the substrate. The closer the thermal expansion coefficient between the coating and the substrate, the better the thermal shock resistance of the coating.
