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Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/485

Title: Fabrication of multilayer ring transformer
Authors: Wong, Nga-yan
Chan, Helen L. W.
Choy, Chung-loong
Subjects: Piezoelectric transducers
Piezoelectricity
Multilayer ring transformers
Electromagnetic technology
Issue Date: 2002
Publisher: IEEE
Citation: ISAF 2002 : proceedings of the 13th IEEE International Symposium on Applications of Ferroelectrics : Nara, Japan, May 28-June 1, 2002, p. 299-302.
Abstract: Residual porosity is one of the most common defects found in multilayer ceramic structures. The pores are created in the binder burnout process when solvents and binders are released from the ceramic green body. Without a well-controlled compaction technique, defects between sheets in the stacked body often exist, leading to delamination problems. Also, it is difficult to fabricate a ring-shaped multilayer structure without cracks, especially near the center hole. Due to the difference in thermal expansion coefficients of the mould and the ceramic green body, large intemal stress is often induced in the ceramic green body during hot pressing and cracks are initiated during sintering. In this work, the fabrication process of a lead zirconate titanate (PZT) ring-shaped multilayer to be used as a transformer is described. By a specially designed mould and adjustment of the hot pressing conditions, the intemal stress induced during hot pressing has been reduced effectively. In particular, the hot pressing process is divided into two steps in order to reduce the clamping of the inner shaft by the ceramic green body. Therefore, the inner shaft can be released easily and the delamination problem can be improved. Also the binder burnout process has been designed carefully by studying the TGA profile. Scanning electron microscopy is used to study the cross-sectional area of the transformer. It is found that the resulting multilayer transformer did not have cracks, pores and delamination. The performance of the transformer will be measured and reported in later work.
Rights: © 2002 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.
Type: Conference Paper
URI: http://hdl.handle.net/10397/485
ISBN: 0780374142
ISSN: 10994734
Appears in Collections:MRC Conference Papers & Presentations
AP Conference Papers & Presentations

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