Effect of CeO2 concentration on the microstructure and wear behavior of Co–WC composites

Abstract

A novel tungsten carbide (WC)- and ceria (CeO2)-reinforced cobalt (Co) matrix composite coating was synthesized through a one-step co-electrodeposition method. The growth mechanism of the coating and the formation mechanism of the protrusion and gully structure on the coating surface were explored. Furthermore, the mechanism of the influence of ceria concentration on the deposition rate and content of tungsten carbide is discussed. The results revealed that the coating fabricated at 6 g/l ceria achieved a dense structure, a fine grain size, a high content of tungsten carbide (19.9 wt.%) and a high deposition rate (78.2 μm/h). The average thickness of the coating was 118.48 μm, and the composite coating had a preferred orientation of cobalt (101) texture. In addition, the maximum microindentation hardness of the coating deposited at 6 g/l ceria was obtained as 627 HV. The electrodeposits possessed a superior anti-wear behavior, which was mainly ascribed to the synergistic effect of tungsten carbide and ceria in improving the mechanical properties of the cobalt matrix composite coating.