Preparation and corrosion behavior of the Al-modified MoSi2/Al2O3 coating on the surface of molybdenum metal core

Abstract The Al-modified MoSi2/Al2O3 coating was designed on molybdenum metal surface, and then its corrosion-resistant property was evaluated in a GTD111 superalloy. Results showed the Al-modified MoSi2 coating obtained by pack cementation was comprised of Mo(Si,Al)2, Al8Mo3, and AlMo3. Then, the oxidation behavior of the coating at 1300 ℃ was systematically investigated to generate a protective Al2O3 scale. After casting test, corrosion behaviors of Al-modified MoSi2/Al2O3 coating without and with Al8Mo3 phase were contrasted to illustrate the mechanism resisting to the molten superalloy at 1550 ℃. The Al8Mo3 phase and thermal shock give rise to the coating failure.