Formation of Spherical Colloidal Nickel Ferrite Particles as Model Corrosion Products

Abstract Ni-ferrite particles of various sizes and chemical compositions were prepared by aging at 90 C for different periods of time coprecipitated ferrous and nickel hydroxide gels in the presence of nitrate ion. The size and the stoichiometry of the final solids were found to be strongly dependent on the initial composition of the systems. Under certain conditions, the so prepared particles are spherical and of narrow size distribution. The formation of Ni-ferrite by incorporation of Ni2+ ions into magnetite, crystallizing from a ferrous hydroxide gel at 90 C in a mild oxidative medium, was also studied. The developed procedures suggest possible pathways by which the corrosion crud is formed in nuclear power plants.