Preparation of Al/SiC Composite Coatings on Surface of Aluminum Alloy by Atmospheric Plasma Spraying

Al/SiC composite coatings were deposited on the surface of aluminum alloy by atmospheric plasma spraying. The effects of SiC volume in Al/SiC composite powders on the deposition behavior and the properties of the Al/SiC coatings were investigated. It is found that the decarburization and oxidation of pure SiC powder occur in the plasma flame. With the increase of SiC content, the deposition of the Al/SiC composite powder becomes more difficult through plasma spraying. There exist cracks between the bond coat and the aluminum alloy substrate resulting in poor adhesion between them. The hardness of the composite coating becomes higher with the increase of SiC content. The Al/SiC (50:50) deposit with a thickness of 70 μm and a hardness of 3690 MPa can strengthen the surface of aluminum alloy.