Hard thick-film and wear resistance of Al–50Si–10M ternary alloys on A6063 aluminum alloy coated by low pressure plasma spraying

Aluminum-based hard thick-films were coated on A6063 aluminum alloy with a binary alloy powder of Al–50Si and three ternary alloy powders of Al–50Si–10Mg, Al–50Si–10Cu and Al–50Si–10Co by low pressure plasma spraying in Ar–H2 atmosphere. Experimental results show that thick-films were compact without large porosity and cracking in them or at interface between coated films and base metal, and intermetallic compounds of Mg2Si, CuAl2 and Co2Al9 were dispersedly precipitated in their matrix by X-ray diffraction analysis. Compared with hardness of A6063 base metal (45 HV), hardness of coated films was 250 HV for Al–50Si, 350–400 HV for Al–50Si–10Mg and Al–50Si–10Cu, and 650 HV for Al–50Si–10Co. The hardness was obviously modified by dispersion strengthening mainly from precipitated intermetallic phases and partly from primary Si particles. Wear property was determined by ball-on-disc sliding wear test under Al2O3 ball revealed that friction coefficient of coated films was decreased from 0.61 to 0.34 and wear depth was remarkably reduced as one third as that of A6063 since dispersion hardening of those intermetallic phases is beneficial to improvement of wear resistance.