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Effects of SiO2/CaCO3 Additions on the Production of Mn-Zn Soft Ferrites for Yoke Ring Applications.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Effects of SiO2/CaCO3 Additions on the Production of Mn-Zn Soft Ferrites for Yoke Ring Applications./
Author:	Taylor, Simone M. O.
Description:	1 online resource (215 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 80-05, Section: C.
Contained By:	Dissertations Abstracts International80-05C.
Subject:	Materials science. -
Online resource:	click for full text (PQDT)
ISBN:	9780438687097

Effects of SiO2/CaCO3 Additions on the Production of Mn-Zn Soft Ferrites for Yoke Ring Applications.
Taylor, Simone M. O.

Effects of SiO2/CaCO3 Additions on the Production of Mn-Zn Soft Ferrites for Yoke Ring Applications. - 1 online resource (215 pages)

Source: Dissertations Abstracts International, Volume: 80-05, Section: C.

Thesis (Ph.D.)--The University of Manchester (United Kingdom), 1994.

Includes bibliographical references

Several batches of ferrites with a basic composition: Mn0.55Zn0.35Fe2.1O4 + SiO2:CaCO3 were prepared, with varying ratios and total amounts of SiO2 and CaCO3 (CaO), at levels which were higher than is normally used in commercial production. The effects of these various combinations on the ferrite formation reaction, and the subsequent sintering operation were monitored using Scanning Dilatometry, Simultaneous Thermal Analysis (Thermogravimetric Analysis and Differential Thermal Analysis), Differential Scanning Calorimetry and X-ray Diffraction Analysis. The final microstructures were assessed using Optical and Electron (Scanning and Transmission) Microscopy. Mechanical (breaking strength) and magnetic (initial permeability, power loss) properties were determined on industrial equipment. Results indicate that while the properties of the finished ferrite ultimately depend on the total amount of additives/impurities present, differences in the relative ratios of the additives may significantly influence the final product characteristics. The maximum permissible total additive level for the production of industrially acceptable yoke rings was found to be 18 g (~0.9 wt%). Excess SiO2 was shown to enhance sintering and grain growth, but degrade the magnetic properties. In contrast, excess CaO improved the magnetic properties, albeit at the expense of the breaking strength. Fractured toroid samples of CaO-rich compositions showed extensive grain boundary fracture, suggesting that such compositions could be developed for the commercial production of yoke rings.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9780438687097Subjects--Topical Terms:

557839
Materials science.
Subjects--Index Terms:

MetallurgyIndex Terms--Genre/Form:

554714
Electronic books.

Effects of SiO2/CaCO3 Additions on the Production of Mn-Zn Soft Ferrites for Yoke Ring Applications.
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504 $a Includes bibliographical references
520 $a Several batches of ferrites with a basic composition: Mn0.55Zn0.35Fe2.1O4 + SiO2:CaCO3 were prepared, with varying ratios and total amounts of SiO2 and CaCO3 (CaO), at levels which were higher than is normally used in commercial production. The effects of these various combinations on the ferrite formation reaction, and the subsequent sintering operation were monitored using Scanning Dilatometry, Simultaneous Thermal Analysis (Thermogravimetric Analysis and Differential Thermal Analysis), Differential Scanning Calorimetry and X-ray Diffraction Analysis. The final microstructures were assessed using Optical and Electron (Scanning and Transmission) Microscopy. Mechanical (breaking strength) and magnetic (initial permeability, power loss) properties were determined on industrial equipment. Results indicate that while the properties of the finished ferrite ultimately depend on the total amount of additives/impurities present, differences in the relative ratios of the additives may significantly influence the final product characteristics. The maximum permissible total additive level for the production of industrially acceptable yoke rings was found to be 18 g (~0.9 wt%). Excess SiO2 was shown to enhance sintering and grain growth, but degrade the magnetic properties. In contrast, excess CaO improved the magnetic properties, albeit at the expense of the breaking strength. Fractured toroid samples of CaO-rich compositions showed extensive grain boundary fracture, suggesting that such compositions could be developed for the commercial production of yoke rings.
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