Surface Modification of 5082 Al-Alloy with Plasma Sintered SiC-Al₂O₃ Coatings

The surfaces of 5082 Al-alloy,a window & door material,were modified with SiC-Al₂O₃ coatings deposited by plasma sintering.The influence of the pulsed DC current on the microstructures and tribological properties was investigated with scanning electron microscopy and mechanical probes.The results show that the current had a major impact.To be specific,as the current density increased,the compactness,spherical grain-size,wear-resistance and interfacial adhesion of the~100 μm thick SiC-Al₂O₃ coatings increased; the voltage on SiC-Al₂O₍3)coatings increased,resulting in an increase of glow-discharge onset voltage and fast initial deposition-rate.The SiC-Al₂O₍3)coatings comprised a decreasing SiC and an increasing Al₂O₃ depth profiles.The SiC-Al₂O₃ coating thickness increased with an increase of deposition time.The plasma sintering technique outperforms the micro arc oxidation(MAO) method because of the stronger hardness,larger thickness and greater surface modification efficiency.