材料期刊网

The effect of enamel coating on the isothermal and cyclic oxidation at 900 degrees C in air and on the hot corrosion resistance of Ti-24Al-14Nb-3V in both 85%Na2SO4 + 15%K2SO4 and 15%NaCl + 85%Na2SO4 molten mixed salts at 850 degrees C was investigated. The results indicated that Ti-24Al-14Nb-3V alloy exhibited poor oxidation resistance due to the formation of nonprotective Al2O3 + TiO2 + AlNbO4 scales and poor hot corrosion resistance due to the spallation of scales formed in molten Na2SO4 + K2SO4 and NaCl + Na2SO4. Enamel coating suppressed the migration of oxygen and corrosive ions into the substrate to improve the oxidation and hot corrosion resistance of Ti-24Al-14Nb-3V alloy. However, the dissolution of oxides components of the coating into the molten salts degraded enamel coating and the degradation of the coating involved a process by which Cl- anion penetrated into the substrate through voids in the coating to accelerate corrosion of Ti-24Al-14Nb-3V alloy.