Fujitsu Corporation

Masato Sagawa

Wataru Yamagishi

Zenzo Henmi

Tatsuji Sasaki

Takeaki Sakai

Ferromagnetic material for temperature sensitive elements or parts has a direction of easy magnetization which varies depending upon temperature. The material has the formula:

Material for temperature sensitive elements

A temperature sensitive element comprises fine grain powders which consist of a spin reorientation type ferromagnetic material having a transition temperature range, below which transition temperature range the easy direction of magnetization of the spin reorientation type ferromagnetic material is predetermined in one crystallographic direction thereof and above which transition temperature range the easy direction of magnetization is a predetermined other direction perpendicular to the predetermined one crystallographic direction. The temperature sensitive element is produced by compacting the fine grain powders at a temperature higher than the transition temperature range. According to the present invention, it is possible to use a polycrystalline rare earth cobalt alloy material in the field where low Curie point ferrite has been used or where bimetals have been used for a thermal valve or a temperature controlling device.

Process and apparatus for producing a temperature sensitive element

A temperature sensitive element comprises fine grain powders which consist of a spin reorientation type ferromagnetic material having a transition temperature range, below which transition temperature range the easy direction of magnetization of the spin reorientation type ferromagnetic material is predetermined in one crystallographic direction thereof and above which transition temperature range the easy direction of magnetization is a predetermined other direction perpendicular to the predetermined one crystallographic direction. The temperature sensitive element is produced by compacting the fine grain powders of a spin reorientation type ferromagnetic material at a temperature higher than the transition temperature range. A polycrystalline rare earth cobalt alloy material made in accordance with the invention can now be used in the field where low Curie point ferrite or where bimetals have been used previously for a thermal valve or a temperature controlling device.

The brittle nature and magnetic properties of the rare earth cobalt magnet are improved by the simultaneous addition of Cu and V. Cu and V are included in amounts of from 0.5 to 6% by weight and from 7 to 19% by weight, respectively. The simultaneous addition enables the rear earth cobalt magnet to be cast in the form of an article. In addition, the simultaneous addition not only improves the mechanical properties of the sintered article, in which form the conventional magnet was available, but also the magnetic properties, such that, for example, the coercive force is increased when the molar ratio of cobalt with respect to rear earth elements is great.

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Yokohama, Japan

Masato Sagawa