|
The effect of zinc additions to the corrosion rates and
tensile strengths of aluminium system
Owate I. O*
and Chukwuocha E
University of
Port Harcourt, Materials Science Group, Department of
Physics
Choba-Port
Harcourt, Nigeria.
*Corresponding
author. E-mail:
owateio@yahoo.com.
Accepted 30
January, 2008 |
|
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. |
