Microstructure and mechanical properties of twin-wire arc spraying Ni-5wt.%Al coating on 6061-T6 aluminum alloy

Thermal sprayed Ni-5wt.%Al coating was fabricated on the substrate of 6061-76 aluminum alloy by twin-wire arc spraying.Experimental results indicated that the average value of bond strength was around 46.90 MPa,the average hardness was 240 HV and the average value of surface roughness was about 0.14 mm.Friction and wear test results showed that the dry friction coefficient of Ni-5wt.%Al coating firstly decreased,and then tended to a slight increase after 200 cycles.In the early abrasion stage,adhesion wear played the key role for wear mechanics of Ni-5wt.%Al coating,but gradually abrasive wear became to replace adhesion wear.