Soft Magnetic Materials

Abstract

This article provides a summary of the basic properties and the essential phenomenology of application‐oriented soft magnetic materials. Starting from an introductory section, where the magnetization process and the involved energetic aspects are highlighted, the physical rationale for the soft magnetic behavior of the materials is discussed, and a comparative illustration of their main physical, mechanical, and magnetic parameters is provided, the materials are classified according to their composition. We start from pure iron, the historical benchmark for any magnetic material, and pass through the selected alloys and compounds displaying the right combination of properties, including abundance of raw elements and costs, making them attractive for applications. We thus illustrate preparation methods, physical and magnetic properties, and applicative attributes of the following materials: (i) pure iron and low‐carbon steels; (ii) nonoriented and grain‐oriented Fe–Si alloys; (iii) High‐Si, Fe–Al, and Fe–Al–Si alloys; (iv) soft magnetic composites; (v) amorphous alloys; (vi) nanocrystalline alloys; (vii) Ni–Fe and Co–Fe alloys; (viii) soft ferrites. For each material, we summarize (i) compositional features and intrinsic physical and magnetic properties; (ii) metallurgical aspects and preparation techniques; (iii) magnetization process and magnetic hysteresis; (iv) energy losses and their dependence on the magnetizing frequency; (v) dependence of the magnetic properties on temperature and stress; (vi) mechanical properties; (vii) applications.

Advanced Ferromagnetic Materials in Power Electronic Converters: A State of the Art

“…It is necessary to mention that the development of magnetic materials is in function of industrial needs, as well as the technology advancement to obtain materials with new compositions, micro-structures and manufacturing techniques [60], [61]. Fig.…”

“…There exist two kind of Fe-Si alloys: grain non-oriented sheets (GNO) and grain-oriented sheets (GO), both have different applications and characteristics, being Fe 96−99 -Si 1−4 and Fe 97 -Si 3 the most representatives [50], [60], [61].…”

“…This kind of cores is used in applications that require special geometry cores, because those present greater versatility in their manufacturer process compared to thin sheet cores (Fe-Si alloys). Also, powder cores are also suitable for medium frequency applications (from frequencies lower than 1 kHz up to tens of kHz) [8], [61].…”

“…Some design restrictions are listed to follow: maximum power, stability, efficiency, input and output voltage levels, operation frequency, thermal stability, system cooling, portability, energy losses and cost [1], [78]. Table 6 summaries the most relevant parameters [52], [61], [69], [77], [78], [89], [99], [107], [108]. Please note that parameters showed in Table 7 are provided for a specific alloy and its manufacturer provider.…”

Accurate Estimation of Frequency-Dependent Losses in High Voltage Test Transformers for the Assessment of Electric Discharge Powers

“…However, the availability of this type of transformer operating at high frequencies presents a real technical constraint. Since transformer losses are frequency-depend [5][6][7], excessive heating is generated and, if not dissipated properly, it could damage either the generator itself or cause a failure in the generator's control circuit.…”