Variation of microstructure and composition of the Cr2AlC coating prepared by sputtering at 370 and 500 °C

Cr2AlC coating was deposited at 370 and 500 °C by D.C. magnetron sputtering from an as-synthesized bulk Cr2AlC target. The phase composition and preferential orientation of the coating were investigated using XRD, and the microstructure of the coating was characterized by TEM. Results indicated that Cr2AlC coating with a strong (110) preferential orientation could be obtained. The coating microstructure was clearly affected by the deposition temperature. At 370 °C, the deposited coating possessed a triple-layered structure with an α-(Cr, Al)2O3 inner layer, an amorphous intermediate layer and a crystalline Cr2AlC outer layer. However, the coating deposited at 500 °C had a single-layered structure consisting of crystalline Cr2AlC layer. The growth mechanism of the Cr2AlC coating at different deposition temperatures is discussed.