Rafferty, Aran and Gun'ko, Yurii and Raghavendra, Ramesh (2004) An investigation of co-fired varistor-ferrite materials. Journal of the European Ceramic Society, 24 (7). pp. 2005-2013. ISSN 1873-619X
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Abstract
The purpose of this work was to co-fire crack-free varistor-ferrite ceramic multilayers fabricated via a dry pressing route. Multilayers were sintered using a standard industrial grade varistor sintering regime. Sinter shrinkages of both varistor and ferrite materials were measured using dilatometry and showed that the varistor shrunk significantly more than the ferrite material. X-ray diffraction analysis indicated that no significant phase changes occurred in the materials under investigation as a result of the sintering process. Scanning electron microscopy observations of the dry-pressed co-fired varistor-ferrite revealed vertical cracking in the ferrite due to thermal expansion mismatch between the materials. By pressing a mixed composition interlayer in the ratio 50:50, between the varistor and ferrite materials, a crack-free multilayer structure could be obtained. Energy dispersive X-ray analysis of the co-fired ferrite and varistor confirmed diffusion of Fe and Ni components from the ferrite into the varistor material. The degree of diffusion was reduced by using 50:50 ratio mixed composition interlayers.
Item Type: | Article |
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Departments or Groups: | South East Applied Materials Research Centre |
Divisions: | School of Engineering |
Depositing User: | Ramesh Raghavendra |
Date Deposited: | 10 Mar 2014 11:21 |
Last Modified: | 22 Aug 2016 10:27 |
URI: | http://repository-testing.wit.ie/id/eprint/2776 |
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