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Effect of Internal Stress on the Strength of BaTiO 3
Author(s) -
POHANKA R. C.,
RICE R. W.,
WALKER B. E.
Publication year - 1976
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.1151-2916.1976.tb09394.x
Subject(s) - materials science , porosity , internal stress , composite material , stress (linguistics) , grain size , tetragonal crystal system , curie temperature , phase (matter) , dielectric , atmospheric temperature range , mineralogy , condensed matter physics , thermodynamics , chemistry , philosophy , linguistics , physics , optoelectronics , organic chemistry , ferromagnetism
The strength of BaTiO 3 which had been hot‐pressed to ∼99% of theoretical density and tested above the Curie temperature was—9000 psi greater than at room temperature. This measured difference in strength is attributed to internal stress from the cubic→tetragonal phase transformation. Correction of measured strength to zero porosity predicts internal stresses of ∼11,000 psi, in good agreement with the dielectric theory for fine‐grain BaTiO 3 . The internal stress is nearly independent of grain size in the range ∼1.5 to 150 μm, showing that 90° domains do not reduce internal stresses causing failure. Lower internal stress in commercial BaTiO 3 is attributed to greater porosity, large flaw sizes, and possibly the effects of additives.