A comprehensive study on the processing of Co:ZnO nanostructured ceramics: Defect chemistry engineering and grain growth kinetics

•A structural characterization delivered the Co apparent incorporation activation energy and the grain growth parameters.•The Ar atmosphere promotes the ZnO incongruent decomposition, leading to a higher Zni density and a higher Co solubility.•To achieve high grain growth and densities the Co3O4 demonstrated to be a good additive for the w-ZnO sintering.•In Ar the metallic Co precursor, due to its higher solubility into the ZnO, leads to a high Co homogeneous distribution over the ZnO grain.•CoO present the lowest solubility and final grain size, being the best choice for top-down Co:ZnO nanopowders processing.