Incorporation of Ceramic Particles into Nickel and Cobalt Electroless Deposits

The aim of this work was to elucidate factors affecting electroless codeposition of metals with ceramic particles. Codeposition of SiC, SiO2 and Al2O3 particles with Ni-P and Co-P matrixes in citrate-malonate alkaline solutions was compared. The positive surface charge of SiC particles corresponded to increased adsorption of hypophosphite anions, while negatively charged SiO2 and Al2O3 particles showed high adsorption of metal ions. It resulted in high incorporation of the carbide into the metal layers and low percentages of oxides in the coatings. Adsorption of nickel ions on SiC particles was promoted by the presence of maleic acid in the bath, however it did not improve incorporation of the particles into the Ni-P matrix. Equilibrium distribution of the species in the plating baths was also calculated.