Microstructure, friction and corrosion resistance properties of a Ni-Co-Al₂O₃ composite coating

Ni-Co-Al₂O₃ composite coatings were prepared by pulsed electrodeposition and electrophoresis-electrodeposition on aluminum alloy. The content of Al₂O₃ particles of the Ni-Co-Al₂O₃ composite coating prepared by electrophoresis-electrodeposition was significantly higher than the composite coating prepared by pulsed electrodeposition. The composite coating prepared by electrophoresis-electrodeposition exhibited a better anti-wear performance than that prepared by pulsed electrodeposition. The morphology, composition and microstructure of the composite coatings were determined by means of X-ray diffractometer (XRD) and scanning electron microscopy (SEM). The hardness and friction properties of the samples were tested on the microhardness tester and the friction and wear loss tester respectively.