抄録
Dense metallic-nickel shells are formed on each particle of NiO-MgO solid solution during the reduction with hydrogen. This is confirmed by microscopy. By doping of the oxide solid solution with FeO, however, porous metallic-nickel shells are formed. The change in the metallic-nickel morphology by doping with FeO can be interpreted in terms of the magnitude of vacancy fraction in the oxide solid solution by use of Ilschner’s one-dimensional model for metal formation during the reduction of metal-oxides. According to the model, the spacing between nuclei of the metal increases, as the vacancy fraction in the oxide increases. Doping of the NiO-MgO solid solution with FeO which is known to possess a very large fraction of vacancy introduced the increment in vacancy fraction. The metallic-nickel particles are more difficult to be sintered, as the size of metal grains and the spacing between them increase.
