THE CORROSION BEHAVIOUR OF Zn-4Al (AC43A) AND Sip/(Zn-4Al) COMPOSITES IN AN ARTIFICIAL SEA WATER

Abstract

The corrosion behavior of the cast Zn-4Al and Si/(Zn-4Al) alloys when attacked by 3.5% NaCl solution at different temperatures, 31, 40, 50, and 60 0 C was investigated. The Tafel intercept logarithmic polarization methods was utilized for determining the corrosion parameters. Some corrosion kinetic and mechanistic parameters have been studied in the absence and presence various concentration of K 2 CrO 4. The study indicated that the percentage inhibition efficiency increased with the increase of the inhibitor concentration and decreased with increase of solution temperature. The activation energy of corrosion increased by the increase of both the corrosion rate and temperature. The addition of Si particles into Zn-4Al can greatly improve the corrosion resistance and has a significant effect on the Tafel polarization measurements. The corrosion resistance increase with increasing the volume fraction of Si-Particles.