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Grain Growth of ZnO during Bi 2 O 3 Liquid‐Phase Sintering
Author(s) -
Dey Debashis,
Bradt Richard C.
Publication year - 1992
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.1151-2916.1992.tb05607.x
Subject(s) - sintering , grain growth , activation energy , materials science , grain boundary diffusion coefficient , liquid phase , phase (matter) , grain size , diffusion , analytical chemistry (journal) , ceramic , grain boundary , metallurgy , chemical engineering , mineralogy , microstructure , chemistry , thermodynamics , chromatography , physics , organic chemistry , engineering
Grain growth of ZnO during the liquid‐phase sintering of binary ZnO–Bi 2 O 3 ceramics has been studied for Bi 2 O 3 contents from 3 to 12 wt% and sintering from 900° to 1400°C. The results are considered in combination with previously published studies of ZnO grain growth in the ZnO–Bi 2 O 3 system. For the Bi 2 O 3 contents of the present study, the rate of ZnO grain growth is found to decrease with increasing Bi 2 O 3 . Activation analysis, when combined with the results of similar analyses of the previous studies, reveals a change in the rate‐controlling mechanism for ZnO grain growth. Following a low‐Bi 2 O 3 ‐content region of nearly constant activation energy values of about 150 kJ/mol, further Bi 2 O 3 additions cause an increase of the activation energy to about 270 kJ/mol. consistent with accepted models of liquid‐phase sintering, it is concluded that the rate‐controlling mechanism of ZnO grain growth during liquid‐phase sintering in the presence of Bi 2 O 3 changes from one of a phase‐boundary reaction at low Bi 2 O 3 levels to one of diffusion through the liquid phase at about the 5 to 6 wt% Bi 2 O 3 level and above.