Corrosion behavior of AZ31-WC nano-composites

In this study, the effects of WC nano-particles amount and surface roughness on corrosion behavior of magnesium metal matrix nanocomposites in 3.5% NaCl solution are examined with the help of electrochemical test. Varying wt% of WC nano-particles (0.5, 1, 1.5 and 2) are used to fabricate metal matrix nano-composites through ultrasonic vibration assisted stir casting method. Basic characterizations of fabricated composites are performed by using scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDAX). SEM images show that nano-particles are well distributed throughout the magnesium matrix while EDAX results confirm the presence of WC particles in nano-composites. Micro-hardness result shows increasing trend with increasing weight percentage of WC. Mg nano-composite containing 0.5 wt% WC nano-particles is found to be the most corrosion resistive one followed by base alloy, Mg-2wt%WC, Mg-1.5 wt%WC and Mg-1 wt%WC. Additionally, corrosion behavior of Mg-2WC with different surface quality is examined and it is observed that sample with lowest surface roughness shows better corrosion resistance. In the end, corrosion mechanisms are assessed with the help of SEM and EDAX study of corroded surfaces. (C) 2019 Published by Elsevier B.V. on behalf of Chongqing University.