Surface Property Modification of Copper by Nanocomposite Coating

Abstract

Copper has high electrical and thermal conductivities and good corrosion resistance at ambient temperatures but has poor mechanical properties such as hardness and wear resistance. Due to its excellent properties it has been used as electrical wires, cables, electrical busbars, circuits inter connectors, heat exchangers, heat sinks, etc., but some applications like electrical contacts in switches necessitate the improvements in the mechanical properties without much loss of electrical and thermal conductivities because of frequent rubbing action due to switching. Bulk modification/alloying deteriorates the conductivity largely and thus surface modification is another route to improve the surface mechanical properties (hardness, wear) by developing a hard/tough coating on the surface of the component without affecting the bulk properties much. Nanocomposite coating obtained by electrophoretic depositon is such one which can serve the purpose. In the present study Cu-ultrafineTiO2/Al2O3 nanocomposite coatings were developed by electrophoretic deposition with different process variables like current density and TiO2/Al2O3 concentrations. Deposition bath pH values were selected after measuring the iso electric points by Zetasizer. The iso electric points obtained were around 4.2 pH for TiO2 and around 5.3 pH for Al2O3. Different characterization techniques like XRD, EDS, SEM, FESEM, microhardness testing and (ball on plate) wear testing were utilized to study the properties of the coatings developed.