Oxidation and hot corrosion behaviors of MAX-phase Ti3SiC2, Ti2AlC, Cr2AlC

Oxidation and hot corrosion behaviours of Ti3SiC2, Ti2AlC and Cr2AlC at 750 °C were investigated in this work. Ti3SiC2 and Ti2AlC showed a linear increase in mass gain and a relatively poor oxidation resistance. This might be attributed to the porous TiO2 scale. A dense α-Al2O3 layer was formed during the oxidation test. Cr2AlC exhibited the best oxidation resistance. This dense oxide scale can effectively isolate the substrate from contact with oxygen leading to excellent oxidation resistance. In contrast to the oxidation test, Ti3SiC2 and Ti2AlC showed relatively better resistance to hot corrosion, while Cr2AlC showed inferior resistance to NaCl introduced hot corrosion. The hot corrosion mechanism of the MAX phases was analyzed. Due to the formation of Na2TiO3, Ti containing MAX phases showed a continuous increase in the mass gain. The corrosion products of Cr2AlC were Al2O3, Cr2O3 and Na2CrO4. However, due to the volatilization of Na2CrO4, Cr2AlC showed a mass loss during the hot corrosion test. The chemical reaction process of the MAX phase was also analyzed.