Effect of enamel coating on long-term oxidation and hot corrosion behavior of Ti-24Al-17Nb-0. 5Mo alloys

摘要

The effect of enamel coating on long-term isothermal oxidation at 700℃ and cyclic oxidation at 800℃ in air and hot corrosion resistance of Ti-24Al-17Nb-0. 5Mo in 75%(Na_2SO_4 + K_2SO_4) + 25%NaCl (mass fraction) molten mixed salts at 700℃ was investigated. The results indicate that Ti-24Al-17Nb-0. 5Mo alloy exhibits relatively poor long-term oxidation resistance due to the formation of Al_2O_3 +TiO_2 +Nb_2O_5 mixed scales and poor hot corrosion resistance due to the spallation of scales formed in molten (Na, K)_2SO_4 +NaCl. Enamel coating can effectively protect Ti-24Al-17Nb-0. 5Mo alloy from long-term oxidation at high temperature in air and remarkably improve the hot corrosion resistance of Ti-24Al-17Nb-0. 5Mo alloy, and can act as the barrier to suppress the migration of oxygen and corrosive ions into the substrate.