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Crystallography of Interfaces and Grain Size Distributions in Sr ‐Doped LaMnO 3
Author(s) -
Liu Qinyuan,
Bhattacharya Sudip,
Helmick Lam,
Donegan Sean P.,
Rollett Anthony D.,
Rohrer Gregory S.,
Salvador Paul A.
Publication year - 2014
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/jace.12984
Subject(s) - materials science , sintering , isotropy , grain size , annealing (glass) , microstructure , grain boundary , porosity , upper and lower bounds , mineralogy , analytical chemistry (journal) , composite material , physics , chemistry , mathematics , optics , mathematical analysis , chromatography
Grain‐boundary plane distributions ( GBPD s), grain size distribution ( GSD s), and upper tail departure from log‐normal GSD s were quantified in dense and porous La 0.8 Sr 0.2 MnO 3 samples to understand expected microstructures in solid oxide fuel cells. Samples were sintered at 1450°C for 4 h and then annealed between 800°C and 1450°C. The GBPD s and normalized GSD s reached steady state during sintering and little variation occurred during annealing. The GBPD s were nearly isotropic, with the relative areas of {001} planes being slightly higher than random (and the relative areas of {111} planes being less than random). The porous sample had an almost identical GBPD , whereas the almost isotropic pore boundary plane distribution was essentially opposite to the GBPD . The upper tails of the experimental GSD s, and several theoretical distributions, were characterized using peaks‐over‐threshold analysis. Dense samples, and all normal grain growth models, exhibit lower frequencies of large grains in the upper tail than would a log‐normal distribution, and the experimental distributions are similar to the Mullins distribution. Porous samples, however, have an anomalous increased frequency of large grains in the upper tail, as compared to all the model distributions, even though other metrics of the microstructure indicate the dense and porous systems are similar.