Influence of Aggregates in α-Al2O3 Slurry on Orientation Degree of Powder Compact Fabricated by Magnetic Forming Method

The crystallographic orientation of α‐Al2O3 powder compact under a magnetic field is affected by the presence of aggregates. In this work, the influence of aggregates on the orientation degree was studied from the experimental and theoretical viewpoints. The optical parameter of birefringence was us...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 2013-08, Vol.96 (8), p.2411-2418
Main Authors: Furushima, Ryoichi, Kato, Zenji, Uematsu, Keizo, Tanaka, Satoshi
Format: Article
Language:English
Subjects:
Aggregates
Birefringence
Crystal structure
Crystallography
Magnetic fields
Mathematical analysis
Orientation
Powder compacts
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Summary:The crystallographic orientation of α‐Al2O3 powder compact under a magnetic field is affected by the presence of aggregates. In this work, the influence of aggregates on the orientation degree was studied from the experimental and theoretical viewpoints. The optical parameter of birefringence was used as an evaluation index for the crystallographic orientation of α‐Al2O3 compact samples. The effect of aggregates on the orientation degree was estimated from the simulation of the distribution of the relative angles between the crystal axes of primary particles for any constituting number of aggregates. The orientation of an aggregate depends on the apparent crystal axes calculated from the vector summation of the crystal axes for all constituting particles. The measured degree of orientation of the powder compact was consistent with the theoretical values for all powder compact samples containing various concentrations and constituting numbers of aggregates. The elimination of aggregates is the key for good particle alignment under a magnetic field.
ISSN:0002-7820
1551-2916
DOI:10.1111/jace.12408