Abrasive Wear Behaviour of Cobalt and Nickel Electrodeposited Surfaces with Cr₂O₃ Dispersions

Abstract

Electrochemically deposited composite coatings are of interest nowadays owing to the flexibility of the deposition process and to the increasing demand for highly wear resistant composite coatings. In electrochemically deposited coatings, a second phase such as fine tough particles is incorporated in the coating matrix to improve the surface mechanical properties. In the present work, the surface mechanical behaviour of cobalt and nickel coatings with dispersion of chromium oxide in the matrix is reported. The effect of heat treatment of these coatings on the surface mechanical properties is also studied. The surface microhardness and wear loss due to rubbing abrasion are studied before and after heat treatment in the range of 100 - 600 ° C and are reported for both systems. The composite containing 12 vol.-% chromium oxide (Cr₂O₃) in a cobalt matrix and heat treated at 500 - 600 ° C was found to exhibit high abrasive resistance. This is attributed to the formation of a glass-like layer found in the cobalt matrix. The coatings are found to be highly adherent and uniform and suitable for high temperature applications.