Corrosion studies on powder metallurgy and stir cast processed AL7075/SiC nanocomposites

Abstract

In present study corrosion studies were conducted on Al7075/SiC nanocomposites processed by powder metallurgy and stir casting techniques. The weight percentage of SiC nanoparticles was varied from 1% to 4% for preparing the nanocomposites. The corrosion studies were conducted by means of salt spray technique by following ASTM B117 standard in which samples were immersed in highly corrosive environment of 3.5% NaCl. The weight losses of Al7075 alloy and its nanocomposites showed that with the increase in test duration from 12 to 96 hours, the weight losses of all nanocomposites increased significantly. Powder metallurgy processed nanocomposites showed higher weight loss when compared to those processed using cast route. Corroded surface analysis revealed pitting corrosion as main corrosion mechanism for all materials processed using both the processing techniques. Overall for as cast materials the localized corrosion in form of micro-pits were observed while in case of powder metallurgy processed materials the corrosion was spread over entire surface.