Structure and Hot Corrosion Behavior of an Al-Co-Y Co-deposited Coating on TiAl Alloy

The hot corrosion behavior of Al-Co-Y co-deposited coatings on TiAl alloy was investigated in 25% NaCl + 75% K 2 SO 4 molten salt at 850 °C. Results show that O, S and other corrosive media are preferentially corroded by the α 2 phase of the TiAl matrix, generating corrosion products with poor density and adhesion, resulting in rapid corrosion. The Al-Co-Y co-deposited coating specimens form a dense Al 2 O 3 film during the hot corrosion incubation, which effectively improves the anti-hot corrosion performance of TiAl alloy. During hot corrosion, the Al 2 O 3 film is dissolved and ruptured under the action of mixed salts, losing its protective properties.