Surface quality improvement of B4C particles for electroless copper coating by Cu activation and oxidation roughening methods

Surface quality improvement by Cu activation and oxidation roughening process was studied during electroless coating Cu on boron carbide (B4C) particles. The surface morphology was characterized by scanning electron microscope (SEM) and the phase identification was determined by X-ray diffraction (XRD) analysis. Two aspects concluding surface activation and surface roughening were investigated to understand the effect of each on Cu coating. Cu activation process increased surface activity of B4C by pre-deposition Cu nano-crystals, which was effective and cost-saving when compared with conventional Pd activation method. The influence of activation pH on electroless Cu coating was discussed and a moderate pH 12 is suitable for Cu deposition. Surface roughening process availably promoted wettability of B4C particles with aqueous solution. Etched pits were formed on B4C surface and resulted in fresh surface exposed after oxidization roughening process, which was beneficial for Cu bonding and coating on B4C surface.