Improved hot corrosion resistance of TiBw/TA15 composite via pack cementation aluminide coating

An aluminide coating was prepared on the TiB _w /TA15 composite by pack cementation to improve the hot corrosion resistance. After 100 h test, the mass gain for uncoated and coated samples was 39.9 and 2.1 mg cm ⁻² , respectively, which showed that the aluminide coating effectively improved the hot corrosion resistance. For the uncoated sample, the circulation of sulfurization/chlorination–oxidation and the basic dissolution with basicity/acidity change in molten salt caused serious hot corrosion. For the coated sample, the continuous and dense Al ₂O ₃ film effectively weakened the basicity/acidity change by preventing the diffusion of S and Cl elements. The high Al content in the TiAl ₃ phase could maintain the continuous Al ₂O ₃ film, although parts of it could be dissolved by molten Na ₂SO _{4 .}