Evaluation of the Wear Resistance and Corrosion Behavior of Laser Cladding Al/SiC Metal Matrix Composite Coatings on ZE41 Magnesium Alloy

Aluminum matrix composites reinforced with SiC particles (SiCp) were deposited on ZE41 magnesium substrates by laser cladding in order to improve their tribological performance. Silicon and titanium were added to the matrix in order to avoid Al-SiC reactivity. The addition of these elements to avoid Al4C3 formation during the laser cladding fabrication was successfully explored in previous research, but the effect of these elements on the wear behavior and the corrosion resistance of these coatings has not been studied. During the fabrication process, there is dilution with the substrate that forms an Al-Mg matrix, which has an influence on the wear and corrosion behavior. Electrochemical polarization and impedance measurements in a 3.5% NaCl solution and the dry sliding conditions on a pin-on-disc tribometer were used to evaluate the different compositions of Al/SiCp coatings on the ZE41 magnesium alloy and uncoated ZE41. All of the composite coatings had lower wear rates than the substrate. However, the coatings showed worse corrosion behavior than the ZE41 substrate, although the addition of Si or Ti improves the corrosion behavior and the wear resistance.