Abstract

Zinc oxide concentrations of 0.2778, 0.3012, 0.3821, 0.4942 and 0.5915 wt% were added to a standard mixture of the composition of an aluminium system. The systems were produced into rectangular flat sheet samples of about 5 mm thickness produced by First Aluminium Alloy Ltd, Port Harcourt, Nigeria. Ten coupon specimens (5 x 20 x 50 mm size) identified as A, B, C, D and E were polished, cleaned, washed in running warm-water and dried. Standard corrosion test technique was applied to the samples under different acidic concentrations. Likewise the tensile strengths of the system were measured before and after exposure to various media. The data obtained indicated a progressive increase and latter decrease of corrosion rates as exposure period increases.  The tensile strengths decreased in the reverse order. Similarly corrosion rates increased relative to increasing exposure time except sample C (0.3821 wt%) that had a deviation from the trend. Generally results showed normal rate profile (for passivity of metals). There was an initial steep rise, then a progressive decline in all the media. This attack could be linked to increased grain boundary concentration arising from maximum solid solubility process.

Key words: Corrosion, zinc addition, aluminium, tensile strengths, acid media.