TITLE:
Corrosion Behaviour of Aluminium Engine Block in 3.5% NaCl Solution
AUTHORS:
M. S. Kaiser, Swagata Dutta
KEYWORDS:
Localized Corrosion, Gravimetric Analysis, Aluminium-Silicon Alloys, SEM, EDX
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.2 No.10,
October
28,
2014
ABSTRACT:
In the present work, the corrosion behavior
of aluminium alloy engine block in 3.5% NaCl solution was studied. The work was
carried out using conventional gravimetric measurements and complemented by
scanning electron microscopy (SEM) and X-ray analyzer (EDX) investigations. The
results obtained indicate that the main process the alloy undergoes, under the
medium of exposure studied, is related to localized corrosion that takes place
as a consequence of the process of alkalinization around the cathodic
precipitates existing in the alloy. The alloy suffers a process of corrosion
localized to the area surrounding the precipitates of the Al (Si, Mg) and
Al-Mg, which resulted in hemispherical pits. This identification was confirmed
by SEM and EDX analysis. No evidence was found of the formation of crystallographic
pitting for exposure times up to 54 days. Gravimetric analysis confirmed that
with varying exposure periods the weight loss of the alloy increases and the
corrosion rate decreases with time.