Microwave-Mediated Electroless Coating of Copper on Hollow Fly Ash Microspheres

Abstract

Hollow fly ash microspheres (FAMs) were successfully coated with copper (Cu) deposits via microwave (MW) irradiation. Ascorbic acid was used to reduce Cu2+ ions from copper sulphate pentahydrate solution. Subsequently, metallic Cu wasdeposited on FAMs within 2 to 6 min of MW irradiation. Microstructural examinations revealed that the sizes of the Cu coating on FAMs increased as MW time increased. The average approximate sizes increased from 1.56 μm to 4.04 μm as the MW processing time increased from 2 min to 6 min. Therefore, coating size could be controlled by adjusting MW irradiation time. Furthermore, EDX and XRD results confirmed the presence of Cu coating on FAMs, which agreed with the findings from the microstructural characterization. The results presented here showed that MW irradiation could be used to provide rapid and uniform heating of reactants to deposit Cu on FAMs within a short time. These Cu-coated FAMs have potential use as electrical conducting fillers in composite materials.