High temperature oxidation of a nanolayer laminated (Cr0.95Ti0.05)2AlC compound in air.

High-purity, dense nano-laminated (Cr0.95Ti0.05)2AlC compounds were synthesized via a powder metallurgical route. Their oxidation characteristics were investigated by exposing them to temperatures between 900 and 1200 degrees C in air. The alloying Ti in the Cr layer of Cr2AlC did not significantly change the crystal structure and microstructure of Cr2AlC. But, it increased the oxidation rate of the Cr,AlC. The scale morphology of the (Cr0.95Ti0.05)2AlC was basically similar to that of the pure Cr2AlC. The main difference was that the (Cr0.95Ti0.05)2AlC contained oxide nodules. These formed because the titanium oxidized to TiO2, making the Cr2AlC susceptible to nodular oxidation. However, alpha-Al2O3 was still the major oxidation product in both the (Cr0.95Ti0.05)2AlC and pure Cr2AlC.