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Study of
Corrosion Behavior of Al-Si-Cu/WC Composites in 0.1 N NaOH
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Corrosion resistance of aluminum based alloy and its
composites reinforced by tungsten carbide have been
investigated. Al- Si-Cu alloy and
Al-Si-Cu/WC composites reinforced with 1, 2 or
3wt.% WC were subjected to
corrosive medium (0.1N NaOH) using
electrochemical method to evaluate their corrosion resistance.
The results show that introducing 1% WC has a negative
effect on the corrosion resistance of
aluminum. While 2 and 3 % WC gave
better corrosion resistance due to decreasing in
electrical conductivity of Al-alloy
and then reducing charge transfer. WC phase covered the
passive film of Al2O3 which maintain passive state for
long period.
The studies were performed at three temperatures 40, 50 and
60oC, and the results show shifting
corrosion potentials toward noble
direction with increasing temperature and obtained a variation
in corrosion
current densities. Polarization resistance calculated
according to Stern-Geary equation confirms that the
composites with 2 and 3wt% WC have
more resistance compared to base alloy and
composite with 1wt% WC.
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