Method of making permanent magnets of Mn-Al-C alloy
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsTadoa Ohtani, Nobuyuki Kato, Shigeru Kojima, Yoichi Sakamoto, Masaharu Tsukahara, Kiyoshi Kojima, Isago Konno, Takao Kubo
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Abstract
A method of making isotropic Mn-Al-C alloy magnets which comprises the step of subjecting an alloy comprising 71.0% to 73.0% by weight of manganese, (1/10 Mn -- 6.6)% to (1/3 Mn -- 22.2)% by weight of carbon and the remainder aluminum to plastic deformation at a temperature of 550.degree.C to 780.degree.C. By utilizing this method, it is possible to obtain isotropic Mn-Al-C alloy magnets having excellent magnetic characteristics, i.e. (BH)max = 2.0 .times. 10.sup.6 G. Oe or more.
Claims4
A method of making an isotropic permanent magnet, which comprises the steps of:
- 1. preparing an alloy comprising the composition of 71.0% to 73.0% by weight of manganese, (1/10 Mn--6.6)% to (1/3 Mn--22.2)% by weight of carbon and remainder aluminum;
- 2. quenching the alloy from a temperature above 900.degree.C at a cooling rate of higher than 10.degree.C/minute in a temperature range of 830.degree.C to 900.degree.C;
- 3. tempering the quenched alloy at a temperature of 480.degree.C to 750.degree.C;
- and
- 4. plasticially deforming the tempered alloy at a temperature of 550.degree.C to 780.degree.C.
Dependencies are inferred from the claim text.