University of Oulu

Väätäjä M, Kähäri H, Juuti J, Jantunen H. Li2MoO4-based composite ceramics fabricated from temperature- and atmosphere-sensitive MnZn ferrite at room temperature. J Am Ceram Soc. 2017;00:1–10.

Li₂MoO₄-based composite ceramics fabricated from temperature- and atmosphere-sensitive MnZn ferrite at room temperature

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Author: Väätäjä, Maria1; Kähäri, Hanna1; Juuti, Jari1;
Organizations: 1Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, Oulu, Finland
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 1.2 MB)
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Language: English
Published: John Wiley & Sons, 2017
Publish Date: 2018-04-27


The first magnetic ceramic composites manufactured, using the room-temperature densification method are reported. The samples were prepared at room temperature using Li₂MoO₄ as a matrix and MnZn ferrite with loading levels of 10–30 vol-% followed by postprocessing at 120°C. The method utilizes the water solubility of the dielectric Li₂MoO₄ and compression pressure instead of high temperatures typical of conventional solid-state sintering. Hence, composite manufacturing using temperature- and atmosphere-sensitive materials is possible without special conditions. This was demonstrated with MnZn ferrite, which is prone to oxidation when heat treated in air. Samples manufactured with room-temperature densification showed no signs of reactivity during processing, whereas reference samples sintered at 685°C suffered from oxidation and formation of an additional reaction phase. The densities achieved with different loading levels of MnZn ferrite with both methods were very similar. Measurements up to 1 GHz showed relatively high values of relative permittivity (21.7 at 1 GHz) and permeability (2.6 at 1 GHz) with 30 vol-% loading of MnZn ferrite in the samples manufactured by room-temperature densification. In addition, pre-granulation is proposed to improve the processability of the composite powders in room-temperature densification.

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Series: Journal of the American Ceramic Society
ISSN: 0002-7820
ISSN-E: 1551-2916
ISSN-L: 0002-7820
Volume: 100
Issue: 8
Pages: 3626 - 3635
DOI: 10.1111/jace.14914
Type of Publication: A1 Journal article – refereed
Field of Science: 213 Electronic, automation and communications engineering, electronics
Funding: The work leading to these results has received funding from the European Research Council (ERC) under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement No. 291132. Authors M. V. and H. K. gratefully acknowledge the Finnish Foundation for Technology Promotion for financial support. In addition, author M. V. acknowledges the Infotech Oulu Doctoral Program and the Riitta and Jorma J. Takanen Foundation for funding. Author H. K. also acknowledges financial support from the Foundation for Women in Academic Research, the Tauno Tönning Foundation, the Ulla Tuominen Foundation, and the KAUTE Foundation. Author J. J. acknowledges funding by the Academy of Finland (grant agreement No. 267573).
EU Grant Number: (291132) ULTIMATE CERAMICS - Printed Electroceramics with Ultimate Compositions
Academy of Finland Grant Number: 267573
Detailed Information: 267573 (Academy of Finland Funding decision)
Copyright information: © 2017 The American Ceramic Society.