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Sintering with zero radial shrinkage of low-temperature cofired ceramics (LTCC) was investigated by means of loading dilatometry. The results indicate that constant compressive loads tend to produce either decreased or increased radial shrinkages, and this can vary as a function of density, depending on the magnitude of the applied stresses. Coupling the real-time applied uniaxial load to the radial strain of cylindrical samples afforded a sintering scheme where the radial strain was precisely kept near zero (±0.02%). This approach possibly perfects an existing hot-pressing technique for zeroshrinkage sintering technology of LTCC materials. [ABSTRACT FROM AUTHOR]

Nanograined BaTiO3 ceramics prepared from 40-nm-size BaTiO3 nanopowders exhibited the cubic as well as the tetragonal phase, while nanograined BaTiO3 ceramics prepared from BaTiO3 nanopowders coated with Mn had only the tetragonal phase. The dielectric constant of the latter was 10 times larger than that of the former; the latter exhibited PTCR behavior with a resistivity jump ratio of about 5.0 × 104. These physical properties of the BaTiO3 ceramics appeared to be significantly affected by the strain near grain boundaries; such strain resulted in a phase transition from the cubic to the tetragonal phase in the nanograined BaTiO5 ceramics, even though the grain size was about 40 nm. [ABSTRACT FROM AUTHOR]