Effect of alloying with Al on oxidation behavior of MoSi2 coatings at 1100 °C

MoSi2 - 0, 15.3, 22, and 29.3 at.% Al coatings were prepared on the nickel-based super-alloy substrates by electro-thermal explosion ultrahigh speed spraying technology. The analysis showed that the coatings had fine microstructure with grain sizes ranging from 0.5 to 2 μm. The bonding between coating and substrate was typically metallurgical cohesion. The oxidation resistance of the coating was further studied at 1100 °C in air. Al alloyed in MoSi2 coatings increased the oxidation resistance of the coatings, and the oxidation resistance of MoSi2-15.3 at.% Al coating was higher than the other two MoSi2–Al coatings. This suggested the oxidation resistance might have close relations to the obtained grain size.