Vaporization and Diffusion of Manganese–Zinc Ferrite

Abstract Vaporization and diffusion of Mn–Zn ferrite were studied for both powdered and bulk sintered samples by a mass-spectrometric method and EPMA analysis. Equilibrium vapor pressures were obtained using the powdered sample and the predominant vapor species was Zn(g) with small fractions of FeO(g) and MnO(g). Over the bulk sintered sample, the vapor pressures of Zn(g), FeO(g), and MnO(g) exponentially decreased with time and approached finite values. The surface was depleted severely with Zn atoms and slightly with O atoms while it was enriched with Mn and Fe atoms. The diffusion equation is solved for the Zn profile using the time-dependent boundary condition of the surface, and the diffusion profile of Zn is analyzed. The activation energy of diffusion obtained is 410 kJ mol −1 , which is about three times larger than the literature value obtained by the tracer method.