Study of corrosion behavior of al-Si-Cu WC composites in 0.1 N NaOH solution

Abstract EN

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.