Current topics in the field of materials technology of soft ferrites
- TDK Corporation, Chiba-ken (Japan)
The present paper focuses on the recent progress of materials technology for high performance soft ferrites. The electromagnetic properties of ferrites depend on the producing process and micro- and nano-structures. MnZn ferrite is a principal ferrite for high permeability and power uses. Recently, spray roasting method of Mn-Zn-Fe ternary system has been developed. High initial permeability over 20000 at 10kHz was achieved by using highly pure spray roasted powder of Mn-Fe binary system. Low power loss is of prime importance for power application. Control of grain boundary chemistry and grain size by the adequate selection of additives and firing conditions is required for achieving low power loss at high frequencies. NiCuZn ferrites for multilayer-ferrite chip-components fired under controlled oxygen partial pressure showed high Q-value. This could be explained by nanostructure of grain boundary. MnMgZn ferrites for deflection yoke cores satisfy high cost-performance. Problems of MnMgZn ferrites are loss characteristics and instability of initial permeability. Relaxation of permeability could be depressed by the control of chemical composition and microstructure. Fine magnetite powders by thermal decomposition of iron chloride are under development. This method may be a promising way to low cost and high performance toner for copy machines. High performance such as low loss or high permeability can be achieved by controlling ferrite microstructure and grain boundary chemistry. These can be attained by a highly pure raw powder, a small amount of additives, and an adequate firing program.
- OSTI ID:
- 96624
- Report Number(s):
- CONF-940416-; TRN: 95:005317-0013
- Resource Relation:
- Conference: 96. annual meeting of the American Ceramic Society (ACS), Indianapolis, IN (United States), 25-28 Apr 1994; Other Information: PBD: 1995; Related Information: Is Part Of Ceramic transactions: Magnetic ceramics. Volume 47; Ghate, B.B.; Simmins, J.J. [eds.]; PB: 342 p.
- Country of Publication:
- United States
- Language:
- English
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