Tribological properties and microstructure of sprayed high silicon aluminum alloy coatings

In order to improve the wear resistance of an aluminum alloy, plasma sprayi ng has been carried out to 2017 aluminum alloy substrate by using high Si-A l alloy powders. In these high Si-Al coatings, Si particles with very fine sub microns grains were observed and the hardness of the coatings reached h igher than HV200. The tribological properties of high Si-Al coatings were studied using ball on disk test. The coatings were slid against the bearing steel (JIS SUJ2) b alls to investigate fundamental friction and wear properties under unlubric ated conditions. The results showed that the wear resistance of high Si-Ai coatings was much higher than that of A390 castings. The friction coefficient of the coating s ranged from 0.2 to 0.3, which was lower than that of A390 castings. The t ribological properties of Al-40Si-Cu-Mg coatings were superior in these hig h Si-Al coatings, which promoted the formation of boundary film on the rubb ed surface of the counter material by tribo-chemical reactions.