Effect of heat treatment on cobalt and nickel electroplated surfaces with Cr2O3 dispersions

Abstract

The growing interest in the electrochemically deposited composite coatings is owing to the flexibility of the deposition process and due to the increasing demand for the highly wear resistant composite coatings. In the electrodeposited coatings a second phase is incorporated in the coating matrix like fine tough particles to improve the surface properties. In this work, the surface mechanical behavior 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, 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 the systems. The composite containing 12vol.% of chromium oxide (Cr2O3) in a Co matrix and heat treated at 500–600°C were found to exhibit high abrasive resistance. This is attributed to the formation of glass like layer found in the cobalt matrix. The coatings are found to be highly adherent and uniform and are found to be suitable for high temperature applications.