PASSIVATION STUDY OF Ti3AlC2 AND Ti2AlC IN SELECT ACIDIC SOLUTIONS H2SO4, HCl AND HNO3

In this article, we evaluate the corrosion behavior of the MAX phases Ti3AlC2 and Ti2AlC immersed in selected acidic solutions of 0.36mol H2SO4, HCl or HNO3 in order to determine the influence of the number of Ti atoms on corrosion resistance. The MAX phases Ti3AlC2 and Ti2AlC were synthesized by hot isostatic pressing (HIP) of Ti-1.9TiC-Al and Ti-1.2TiC-Al powders mixture respectively at 1450 degrees C for 2h under argon. The results indicate that Ti2AlC has better passivation than Ti3AlC2 in acidic environments. The corrosion resistance of Ti2AlC is mainly due to the rapid formation of a passive film on the surface. Its kinetic corrosion is managed by the dissolution rate of Al and Ti atoms in the acidic solutions. The AAS characterization showed that the Al atoms dissolved from Ti2AlC in the acidic solution are less than those dissolved from Ti3AlC2. This phenomenon reflects the influence of Ti atoms number on the corrosion resistance in the acid solution used.