Electrocodeposition of Ag/TiO2 nanocomposite coatings in cyanide free electrolytes

Abstract

Synthesis and characterisation of nanocomposite coatings consisting of Ag doped TiO2 nanocrystals at different concentrations have been carried out. Composites were obtained by electrochemical deposition using a slightly alkaline cyanide free electrolyte containing AgNO3 as Ag precursors. Morphology and crystalline structure of the Ag/TiO2 hybrid materials with up to 8·5 vol.‐%TiO2 were compared with those of pure Ag coatings. The presence of TiO2 nanoparticles in the bath led to an increase in the degree of orientation of crystallites on [111] and [311] crystallographic directions. During the electrodeposition, the presence of TiO2 particles at the electrode/electrolyte interface retards the crystal growth, and hence, the composites possess smaller grain sizes. The surface morphology observations show that TiO2 nanocrystals were attached within the metallic matrix surface, and the appearance of the surface indicates a porous structure with different geometrically shaped grains; this is also confirmed by atomic force microscopy measurements.