Corrosion Behavior of a Discontinuously Reinforced Composite in Salt Water Environment

Abstract

In this study, the corrosion behavior of Al 6092/17.5 SiC(p) alloy is investigated. The alloy offers a good resistance to corrosion in 3.5 wt% NaCl as shown by weight loss and electrochemical studies conducted in a smoothly stirred condition up to 70 C. The alloy also offered a strong resistance to corrosion in a salt spray chamber. The corrosion behavior of the alloy, however, declined with an increase in velocity, temperature, and addition of polystyrene particles in the electrolyte. The declining corrosion resistance is attributed to the cracking and breakdown of the protective boehmite layer at elevated temperatures, higher velocities, and impact of polystyrene particles. Microanalytical studies reveal the intermetallic precipitates to be the preferred sites for initiation of pits. The alloy offers good service prospects in a marine environment at controlled flow velocities and temperatures.