Influence of autocatalytic coating bath parameters on the formation of copper over surface treated boron carbide particles

The functional and structural applications of boron carbide (B4C) for neutron shielding and engineering sectors are limited due to brittleness and low temperature oxidation; however its use is enhanced by the synthesis of its composites. During composite synthesis, the interfacial compatibility of boron carbide with the matrices can be improved by the formation of metallic coatings. The present study aims at formation of autocatalytic copper coating over surface treated B4C particles with varying bath parameters and evaluating its influence on coating morphology and uniformity. An effective coating of copper over alkali treated boron carbide was obtained at pH12 and a bath temperature of 30°C. Above pH 12 as well as higher bath temperatures of 50 and 75°C leads to predominant co-deposition of metallic copper clusters within the reaction bath. SEM observations of coated boron carbide particles show the formation of copper clusters in the size range of 200–400nm. The morphology of Cu coating changes from cauliflower-like structure to angular shape with increase in bath temperature and pH. The Debye–Scherrer crystal size calculation shows that copper crystallite size vary from 17 to 25nm. ► Coating morphology and uniformity is greatly affected by bath temperature and pH. ► Alkali treated B4C shows better surface coating at pH12 in ambient bath condition. ► Co-deposition of metallic copper predominates at higher bath pH and temperature. ► Copper oxide formation observed at higher bath pH and temperature. ► Crystallite size of Cu coating on B4C particles is in the range of 17–25nm.