A comparison study of applying metallic coating on SiC particles for manufacturing of cast aluminum matrix composites

Ceramic particles typically do not have a sufficiently high wettability for incorporation into molten metal during aluminum matrix composite manufacturing. Metallic coatings on ceramic particles could improve their wettability by the molten aluminum and hence provide a better bonding between the reinforcement and matrix. In this study, micrometer-sized SiC particles were coated by copper, nickel, and cobalt metallic layers using electroless deposition method. These metallic layers were produced separately prior to ceramic incorporation into molten pure aluminum, in order to compare their effects on the microstructure and mechanical properties of the produced composites. The experimental results showed that copper was the most effective and nickel the least effective of these coating metals for incorporation of the SiC particles into the molten aluminum. It was additionally found that the composite, which contained the copper coated SiC particles, produced the highest microhardness and tensile strength, while that fabricated with the cobalt-coated SiC particles produced the lowest microhardness and tensile strength.