Effect of Al 2 O 3 Nanoparticles and Heat Treatment on the Wear Resistance of Electrodeposited Ni-W/Al 2 O 3 Composite Coatings

In this work, Ni-W/Al 2 O 3 composite coatings with Al 2 O 3 content from 0 to 8 wt.% were electrodeposited and heat treated to study the influence of Al 2 O 3 nanoparticles and heat treatment on the wear resistance of Ni-W/Al 2 O 3 coatings. The wear resistance of as-deposited Ni-W/Al 2 O 3 coatings is obviously improved by incorporation of Al 2 O 3 nanoparticles, which can strongly alleviate the serious plowing during the sliding abrasion. By heat treatment at 300 °C, microhardness and wear resistance of Ni-W/Al 2 O 3 are simultaneously improved. For the Ni-W/Al 2 O 3 coatings heat treated at 700 °C, the grain size increases while the microhardness is barely changed in comparison with the as-deposited coatings, and the wear resistance is improved with low Al 2 O 3 content but degraded at high Al 2 O 3 content. The evolution of wear resistance of Ni-W/Al 2 O 3 coatings can be related to microhardness, incorporation of Al 2 O 3 , precipitation strengthening and interphase interfaces.