Surface-mechanical and electrical property evaluation of nano-cone structured Cu–ZrO2 composite coating

Abstract

Copper has good electrical and thermal conductivity which makes it useful for specific engineering applications. But its poor mechanical property necessitates strengthening of the same without adversely affecting its electrical conductivity for its use in electrical applications. Surface engineering approach does not adversely affect the bulk properties and among various such techniques, electro-codeposition technique is considered cost effective due to its simple operation, high production rate and capability to handle complex geometry.

In the present study, Cu-ZrO2 composite coating was prepared by pulsed electro-codeposition process from ZrO2 dispersed CTAB added acidic copper sulfate bath on a copper substrate to study the effect of CTAB concentration on structural, mechanical and electrical properties of the deposits. Coatings exhibited uniformly dispersed ZrO2 in Cu matrix which becomes finer at intermediate CTAB content. It showed duplex structure having very high hardness (3.23GPa) due to presence of ZrO2, nano-cone structured matrix with favorable crystallographic texture. Surface profile result confirmed high surface roughness due to duplex matrix formation. Tribological behavior was found similar to hardness results. It was also observed that CTAB addition marginally decreases electrical conductivity of the coatings.