Allotropic modifications of cobalt upon chemical deposition

The effect of the solution acidity on the crystal structure of cobalt during its chemical deposition is reported. It has been shown using the structural and magnetic examination and nuclear magnetic resonance study that the change in the working solution acidity leads to deposition of cobalt with different allotropic modifications in the nearest environment: the hcp type in the small (up to $\sim$ 8.5) pH region and the fcc type in the large (over $\sim$ 8.5) pH region. The formation of these cobalt modifications is attributed to the size effects caused by a decrease in the particle size with increasing pH.