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Grain Growth of ZnO in ZnO‐Bl 2 O 3 Ceramics with Ai 2 O 3 Additions
Author(s) -
Nunes Silvia Irene,
Bradt Richard C.
Publication year - 1995
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.1151-2916.1995.tb08687.x
Subject(s) - grain growth , spinel , sintering , activation energy , materials science , grain size , ceramic , grain boundary , diffusion , mineralogy , analytical chemistry (journal) , chemical engineering , metallurgy , microstructure , chemistry , thermodynamics , physics , chromatography , engineering
Grain growth of ZnO during liquid‐phase sintering of a ZnO‐6 wt% Bi 2 O 3 ceramic was investigated for A1 2 O 3 additions from 0.10 to 0.80 wt%. Sintering in air for 0.5 to 4 h at 900° to 1400°C was studied. The AI 2 O 3 reacted with the ZnO to form ZnAl 2 O 4 spinel, which reduced the rate of ZnO grain growth. The ZnO grain‐growth exponent was determined to be 4 and the activation energy for ZnO grain growth was estimated to be 400 kJ/mol. These values were compared with the activation parameters for ZnO grain growth in other ceramic systems. It was confirmed that the reduced ZnO grain growth was a result of ZnAl 2 O 4 spinel particles pinning the ZnO grain boundaries and reducing their mobility, which explained the grain‐growth exponent of 4. It was concluded that the 400 kJ/mol activation energy was related to the transport of the ZnAl 2 O 4 spinel particles, most probably controlled by the diffusion of O 2‐ in the ZnAl 2 O 4 spinel structure.