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

We investigated the preparation of bulk dense nanocrystalline BaTiO 3 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 BaTiO 3 with a grain size of 35 nm were obtained by two‐step sintering. Like the previous studies on Y 2 O 3 , 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 BaTiO 3 ceramics, and that saturation magnetization is the same in nanograin and coarse grain ferrite ceramics.