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Two‐Step Sintering of Ceramics with Constant Grain‐Size, II: BaTiO 3 and Ni–Cu–Zn Ferrite
Author(s) -
Wang X.H.,
Deng X.Y.,
Bai HaiLin,
Zhou H.,
Qu WeiGuo,
Li L.T.,
Chen I.W.
Publication year - 2006
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2005.00728.x
Subject(s) - materials science , sintering , nanocrystalline material , grain size , ceramic , ferrite (magnet) , grain growth , metallurgy , grain boundary , mineralogy , composite material , microstructure , nanotechnology , chemistry
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.