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Abnormal Grain Growth and Intergranular Amorphous Film Formation in BaTiO 3
Author(s) -
Choi SiYoung,
Kang SukJoong L.,
Chung SungYoon
Publication year - 2007
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.1551-2916.2006.01436.x
Subject(s) - materials science , equiaxed crystals , grain growth , amorphous solid , annealing (glass) , abnormal grain growth , intergranular corrosion , grain boundary , sintering , redistribution (election) , grain size , metallurgy , composite material , mineralogy , crystallography , microstructure , chemistry , politics , political science , law
The effect of abnormal grain growth on the formation of amorphous films at grains boundaries was studied in a model system BaTiO 3 . 0.4 mol% TiO 2 ‐excess BaTiO 3 powder compacts were sintered at 1380°C for various times up to 16 h. During the sintering, abnormal grains formed. With the growth of the abnormal grains, amorphous films formed and eventually thickened up to 19.2 nm at grain boundaries. The film formation is attributed to the accumulation of Ti solutes at grain boundaries with the grain growth, while the film thickening is mostly caused by the redistribution of liquid at triple junctions. Extended annealing of the 16‐h‐sintered sample at 1350°C for 15 days resulted in a thinning of the film to nearly 1.7 nm without a change in the grain size, showing an equilibrium thickness. This result demonstrates that the film thickness observed during the growth of the grain may not be the equilibrium thickness. The result further suggests that the shape of the abnormal grains, even when equiaxed, can differ from the equilibrium shape.