The magnetic properties of Fe‐Si‐B‐M (M: additives) alloys prepared by annealing amorphous alloys made by the single roller method over their crystallization temperature have been investigated for development of new Fe‐based soft magnetic alloys. Excellent soft magnetic properties were obtained by adding the two elements Cu and Nb to Fe‐Si‐B alloys. It was found that these new alloys, called ‘‘FINEMET,’’ have an ultrafine grain structure composed of bcc Fe solid solution. They are suitable for many kinds of magnetic components such as saturable reactors, choke coils, and transformers, because they have superior soft magnetic properties and a high saturation flux density, and because different types of B‐H hysteresis loops are obtained by magnetic field annealing.

New Fe-based soft magnetic alloys composed of ultrafine grain structure

The magnetic refrigeration technique based on the magnetocaloric effect (MCE) has attracted increasing interest because of its high efficiency and environment friendliness. in this article, our recent progress in exploring effective MCE materials is reviewed with emphasis on the MCE in the LaFe13-xSix-based alloys discovered by us. These alloys show large entropy changes over a wide temperature range near room temperature. The effects of magnetic rare-earth doping, interstitial atoms and high pressure on the MCE have been systematically studied. Special issues, such as appropriate approaches to determining the MCE associated with the first-order magnetic transition, the depression of magnetic and thermal hysteresis, and the key factors determining the magnetic exchange in alloys of this kind, are discussed. The applicability of giant MCE materials to magnetic refrigeration near ambient temperature is evaluated. A brief review of other materials with significant MCE is also presented.

Recent Progress in Exploring Magnetocaloric Materials

The seminal study by Brown in 1976 showed that it was possible to use the magnetocaloric effect to produce a substantial cooling effect near room temperature. About 15 years later Green et al. built a device which actually cooled a load other than the magnetocaloric material itself and the heat exchange fluid. The major breakthrough, however, occurred in 1997 when the Ames Laboratory/Astronautics proof-of-principle refrigerator showed that magnetic refrigeration was competitive with conventional gas compression cooling. Since then, over 25 magnetic cooling units have been built and tested throughout the world. The current status of near room temperature magnetic cooling is reviewed, including a discussion of the major problems facing commercialization and potential solutions thereof. The future outlook for this revolutionary technology is discussed.

Thirty years of near room temperature magnetic cooling: Where we are today and future prospects

Fe-Based Soft Magnetic Alloys Composed of Ultrafine Grain Structure

https://iopscience.iop.org/article/10.1088/1361-6463/50/5/053002/pdf

Magnetocaloric materials for energy efficient cooling

The magnetic refrigerating device according to one embodiment includes a fixed container filled with a refrigerant, the fixed container including a magnetic material container that is filled with a magnetic material and that can move in the fixed container and an elastic member provided at the end of the magnetic material container. The magnetic refrigerating device also includes a magnetic-field applying/removing mechanism that is provided at the outside of the fixed container, and that can apply and remove a magnetic field to and from the magnetic material and can generate a magnetic torque to the magnetic material container in moving direction of the magnetic material container.

Magnetic refrigerating device and magnetic refrigerating system

PROBLEM TO BE SOLVED: To improve refrigerating efficiency with a simple structure. SOLUTION: This magnetic refrigerating machine comprises a housing, a plurality of heat exchangers fixed in the housing and filled with magnetic particles having magnetocaloric effect, a rotary driving portion, a rotating shaft rotated by the rotary driving portion, a magnetic field generating means mounted on the rotating shaft for applying or eliminating magnetic field to the magnetic particles in the plurality of heat exchangers in accompany with the rotation, a refrigerant pump for circulating a refrigerant in accompany with the rotation of the rotating shaft, a rotation-type refrigerant control valve for controlling the supply/discharge of the refrigerant among the plurality of heat exchangers in accompany with the rotation of the rotating shaft, and a refrigerant circuit formed by connecting the refrigerant pump, the rotation-type refrigerant control valve, the plurality of heat exchangers, a cooling portion and a heat exhausting portion. The magnetic refrigerating machine is constituted so that the application or elimination of the magnetic field to the magnetic particles by the magnetic field generating means is synchronized with the control of supply/discharge of the refrigerant among the heat exchangers by the rotation-type refrigerant control valve. COPYRIGHT: (C)2007,JPO&INPIT

Magnetic refrigerating machine

The magnetic composite material of the present invention is used as a working substance in the magnetic refrigeration system and comprising at least two phases, including, a first phase composed of an intermetallic compound represented by a general formula: La(Fe(Co, Ni)Si) 13 , having an NaZn 13 type crystal structure, and a second phase is composed of an iron alloy containing Si. The first phase is precipitated in an expansion size of 100 μm or less in average. Preferably, the magnetic composite material contains Fe as a principal component, La in an amount from 4 atomic % to 12 atomic %, Si in an amount from 2 atomic % to 21 atomic %, and Co and Ni in a total amount from 0 atomic % to 11 atomic %, and the total amount of Fe, Co and Ni being from 75 atomic % to 92 atomic %.

Magnetic composite material and method for producing the same

A magnetic refrigeration device, which can be reduced in size and improve magnetic refrigeration efficiency, and a magnetic refrigeration system can be provided. The magnetic refrigeration device has a heat exchanger vessel of a helical structure filled with magnetic particles having a magnetocaloric effect, a magnetic circuit, a driving unit configured to relatively move the heat exchanger vessel and the magnetic circuit so that a magnetic field can be applied to and removed from the magnetic particles, a low temperature side heat exchanging unit, a high temperature side heat exchanging unit, a refrigerant flow device, and a refrigerant circuit formed by connecting the heat exchanger vessel, the low temperature side heat exchanging unit, the high temperature side heat exchanging unit, and the refrigerant flow device by a pipe for circulating a refrigerant. The magnetic refrigeration system is arranged to use the magnetic refrigeration device.

Magnetic refrigeration device and magnetic refrigeration system

A magnetic refrigeration material has magnetic material particles with a magnetocaloric effect and an oxidation-resistant film formed on the surfaces of the magnetic material particles.

Tadahiko Kobayashi

Papers

Magnetic refrigerating device and magnetic refrigerating system

Magnetic refrigerating machine

Magnetic composite material and method for producing the same

Magnetic refrigeration device and magnetic refrigeration system

Magnetic refrigeration material and magnetic refrigeration device