Corrosion inhibition of T-6 treated 6061 Al-SiC(p) composite in hydrochloric acid

Abstract

Addition of reinforcements like SiC to aluminium matrix has been reported to decrease the corrosion resistance of the matrix due to several reasons, one of them being the galvanic action between the reinforcement and the matrix. Aging of aluminium alloys can also have similar effects as aging results in precipitation of intermetallics. The work deals with effect of aging (T-6 treatment) on the corrosion behaviour as well as corrosion inhibition of 6061Al-SiC composite. Corrosion behaviour of 6061 Al-SiC(p) composite were determined in HCl by Tafel extrapolation technique in the temperature range of 30�C-50�G. Further, the inhibition studies were made using two inhibitors viz. (i) Allyl Thiourea and (ii) Glycyl Glycine. The results indicate that both the organic compounds act as anodic inhibitors and are moderately effective in inhibiting the corrosion of 6061Al-SiC(p) composite. The inhibition efficiency increases with increase in inhibitor concentration. Similar inhibition studies were made on the aged samples. However, in the case of T-6 treated samples, the inhibition efficiency was found to be poor compared to the non-heat treated samples.