Cathode growth stability of electrodeposited metal matrix particulate composites

A simple model is proposed correlating operating conditions (electrochemical kinetic behaviour of the metal matrix deposition process, concentration of suspended particles, particle dimensions, hydrodynamic conditions) and cathode growth stability for electrodeposited metal matrix particulate composites with dispersions of non-conducling particies. Even though variations of all the considered variables have a bearing on growth stability, the most important single effect is polarisation (as, e.g., expressed by the local Tafel slope): the deposition of metal with high polarisation makes codeposition possible and renders viable the achievement of sufficiently smooth and thick materials; metals deposited at low overvoltage are mostly associated with unsuccessful composite plating The predictions of the model were confirmed with deposition experiments, cathode stability was judged according to SEM in-plane and cross-sectional micrographs as well as by roughness measurements.