Corrosion mechanism of Ti2AlC MAX phase coatings under the synergistic effects of water vapor and solid NaCl at 600 °C

Abstract

The corrosion behavior of Ti2AlC MAX phase coatings coated on 1Cr11Ni2W2MoV substrates in NaCl deposit in water vapor at 600 °C has been fully investigated. The results demonstrated that the substrates underwent serious corrosion, but the coatings performed better. The mass gain per unit area of coatings was less than 1/6 of substrates, because of the formed compact and uniform corrosion scale. Such dense corrosion scale was composed of NaxTiyOz fine grains with the size of 11 ± 0.4 nm and amorphous Al2O3 phases which self-healed the generated defects during corrosion, benefiting from the novel layered structure of MAX phase.