Anodic synthesis of oxide-matrix composites. Composition, morphology, and structure of PbO2-matrix composites

PbO2-matrix composites containing either Al2O3 or TiO2 as dispersed phase have been obtained on rotating disk Ni anodes by electrolyzing Pb2+ solutions containing up to 5 wt % of suspended particles. With the aim of gathering basic information on poorly known anodic electrodeposition of composites, the effect of experimental variables such as concentration of suspended particles, current density, and mass-transport rate on composition, morphology, and structure of the deposited materials has been investigated. The amount; of particles embedded in the deposits increased with the particle concentration in the suspension and the angular speed of the rotating disk electrode; increasing current densities produced deposits with decreasing particle content. SEM-EDX analysis showed a homogeneous particle distribution in both the radial and perpendicular direction. Under all conditions, the matrix was highly oriented alpha-PbO2. The results are compared with those typical of electrodeposition of metal-matrix composites and discussed on the basis of some of the available models.