High-temperature oxidation and hot corrosion of Cr2AlC

High-temperature oxidation and hot corrosion behaviors of Cr2AlC were investigated at 800-1300 degrees C in air. Thermogravimetric-differential scanning calorimetric test revealed that the starting oxidation temperature for Cr2AlC is about 800 degrees C, which is 400 degrees C higher than other ternary transition metal aluminum carbides. Thermogravinietric analyses demonstrated that Cr2AlC displayed excellent hightemperature oxidation resistance with parabolic rate constants of 1.08 x 10(-12) and 2.96 x 10(-9) kg(2) m(-4) s(-1) at 800 and 1300 degrees C, respectively. Moreover, Cr2AlC exhibited exceptionally good hot corrosion resistance against molten Na2SO4 salt. The mechanism of the excellent high-temperature corrosion resistance for Cr2AlC can be attributed to the formation of a protective Al2O3-rich scale during both the high-temperature oxidation and hot corrosion processes. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.