ANODIC SYNTHESIS OF OXIDE-MATRIX COMPOSITES - COMPOSITION, MORPHOLOGY, AND STRUCTURE OF PBO2-MATRIX COMPOSITES

PbO2-matrix composites containing either Al2O3 or TiO2 as dispersed ph ase have been obtained on rotating disk Ni anodes by electrolyzing Pb2 + solutions containing up to 5 wt % of suspended particles. With the a im of gathering basic information on poorly known anodic electrodeposi tion of composites, the effect of experimental variables such as conce ntration of suspended particles, current density, and mass-transport r ate on composition, morphology, and structure of the deposited materia ls has been investigated. The amount; of particles embedded in the dep osits increased with the particle concentration in the suspension and the angular speed of the rotating disk electrode; increasing current d ensities produced deposits with decreasing particle content. SEM-EDX a nalysis showed a homogeneous particle distribution in both the radial and perpendicular direction. Under all conditions, the matrix was high ly oriented alpha-PbO2. The results are compared with those typical of electrodeposition of metal-matrix composites and discussed on the bas is of some of the available models.