Two‐Step Sintering of Ceramics with Constant Grain‐Size, II: BaTiO3 and Ni–Cu–Zn Ferrite

Abstract

We investigated the preparation of bulk dense nanocrystalline BaTiO3 and Ni–Cu–Zn ferrite ceramics using an unconventional two‐step sintering strategy, which offers the advantage of not having grain growth while increasing density from about 75% to above 96%. Using nanosized powders, dense ferrite ceramics with a grain size of 200 nm and BaTiO3 with a grain size of 35 nm were obtained by two‐step sintering. Like the previous studies on Y2O3, the different kinetics between densification diffusion and grain boundary network mobility leaves a kinetic window that can be utilized in the second‐step sintering. Evidence indicates that low symmetry, ferroelectric structures still exist in nanograin BaTiO3 ceramics, and that saturation magnetization is the same in nanograin and coarse grain ferrite ceramics.