On the interactions of Ti2AlC, Ti3AlC2, Ti3SiC2 and Cr2AlC with palladium at 900 °C

Abstract

Herein we report on the reactivity between palladium, Pd, and the MAX phases, Ti2AlC, Ti3AlC2, Ti3SiC2 and Cr2AlC. Diffusion couples of Pd/MAX were heated to 900 °C under uniaxial stress of ∼20 MPa for 2, 4, and 10 h in a vacuum (<1 Pa) hot press. The diffusion couples were examined using X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. After heating to 900 °C for 10 h, the diffusion layer thicknesses in the Ti2AlC/Pd, Cr2AlC/Pd, Ti3AlC2/Pd and Ti3SiC2/Pd couples were found to be 35, 45, 105 and 410 μm, respectively. Thus, Ti2AlC is the most resistant to reaction, while Ti3SiC2 is least resistant, with Cr2AlC and Ti3AlC2, in between. In all cases, the reaction occurred by the diffusion of the A-group element into Pd, concomitant with Pd diffusion into the MAX phase. No diffusion of the M and X atoms was detected.