US 4,459,248 A · Process and apparatus for producing a temperature sensitive element

Abstract

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.

Claims15

Dependent claims

A process for producing a polycrystalline temperature-sensitive ferromagnetic element comprising the steps of:

compacting fine grain powders of a spin reorientation type ferromagnetic material while applying a magnetic field and heating the fine grain powders of the spin reorientation type ferromagnetic material to a temperature higher than a transition temperature range of said material, below which transition temperature range the easy direction of magnetization of said spin reorientation type ferromagnetic material is parallel to a predetermined one crystallographic direction thereof and above which transition temperature range the easy direction of magnetization is parallel to a predetermined other direction perpendicular to said predetermined one crystallographic direction;
and
producing from the compacted spin reorientation type ferromagnetic material a polycrystalline temperature sensitive element, in which the easy direction of magnetization is uniformly oriented and reoriented at the transition temperature range.

A process for producing a polycrystalline temperature-sensitive ferromagnetic element comprising the steps of:

(a) selecting a composition of a spin reorientation type ferromagnetic material having an easy direction of magnetization uniformly variable upon temperature for the required polycrystalline temperature-sensitive element;
(b) compacting fine grain powders of the selected spin reorientation type ferromagnetic material under pressure;
(c) applying a magnetic field to the fine grain powders of the material during compacting;
(d) heating the fine grain powders during compacting and applying the magnetic field to a temperature higher than the transition temperature range of the material for uniformly orienting the direction of the magnetization of the grain powder crystals, wherein the easy direction of magnetization of the ferromagnetic material below the transition temperature range is uniformly parallel to the basal planes (P) of the grain powder crystals and wherein the easy direction of magnetization above the transition temperature range is uniformly perpendicular to the basal planes at the A axes of the grain powder crystals;
and
(e) producing a polycrystalline temperature sensitive element from the compacted and heated spin reorientation type ferromagnetic material in which the easy direction of magentization is uniformly oriented and reoriented between the basal planes (P) and (A) axes of the grain powder crystals at the predetermined transition temperature range.

3 more elements

Dependencies are inferred from the claim text.

Process and apparatus for producing a temperature sensitive element

Life of this patent

Process and apparatus for producing a temperature sensitive element

Life of this patent

Abstract

Claims15