Fabrication and High Temperature Friction Behavior and Oxidation Resistance of Ni-Co-ZrO2 Composite Coating

Abstract

Ni-Co alloy and ZrO2 micron particles were codeposited on 45 carbon steel by electrodeposition. The composition and microstructure of the composite coating were characterized. The high temperature tribological properties were carried out by a pin-on-disk tribo-tester. Additionally, the oxidation resistance was evaluated via high temperature circulating oxidation test. The results indicated that the deposited composite coating showed dispersed ZrO2 particles and continuous Ni-Co matrix, and there were no obvious pores, cracks and other defects at the interface between the composite coating and the substrate. The embedded ZrO2 particles changed the friction mechanism from adhesive wear to abrasive wear, the wear loss rate and friction coefficient of Ni-Co-ZrO2 composite coating were lower in comparison with that of Ni-Co alloy coating and carbon steel substrate. In addition, the embedded ZrO2 particles exerted a reactive-phase effect on the growth of nickel oxide and cobalt oxide, and effectively reduced the oxidation rate of the substrate at high temperature. Therefore, the Ni-Co-ZrO2 composite coating presents better oxidation resistance, when compared with Ni-Co coating.

Keywords

• Electrodeposition
• Ni-Co-ZrO2 composite coatings
• High temperature tribological behavior
• Oxidation resistance