Corrosion behavior of stir-cast Al–TiB2 metal matrix composites
The present study evaluates the corrosion behavior of Al–TiB2 metal matrix composites in 3.5% NaCl solution. Composites are fabricated using stir-casting with varying wt.% of TiB2. Composite surfaces are characterized using scanning electron microscopy (SEM) images. Micro-hardness values of composites are obtained using a Vicker's micro-hardness tester. The hardness of the base matrix is enhanced due to the incorporation of hard TiB2 phase. Corrosion characteristics of composites are investigated using potentiodynamic polarization and electrochemical impedance spectroscopy measurements. Corrosion resistance of composites is estimated from the parameters such as corrosion potential, corrosion current, linear polarization resistance etc. Corrosion resistance of the base alloy improves due to incorporation of TiB2 but only up to a certain amount of TiB2 phase in the matrix. The composite with 1 wt.% TiB2 shows the highest corrosion resistance. Corroded surfaces are studied using SEM images that reveal localized pitting corrosion on composite surfaces.