Fujitsu Corporation

Etsuo Hanada

Takehiko Sato

Masanori Okada

Makoto Kassai

Zenzo Henmi

Toshio Kobayashi

A semi-hard magnetic material characterized by a high coercive force (Hc), i.e. 20-50 Oe, can be produced by the disclosed process. In accordance with the process, an alloy consisting of 73 to 93% Co and 3 to 7% Nb, and the balance being iron is worked into a suitable form, solution treated, cold worked at a reduction of area not lower than 75% and aged. Said alloy contains niobium in a greater amount than the known alloy for the same application in order to enhance the coercive force. With the increase in the content of niobium, however, the cold workability of the alloy deteriorates. In order to overcome this disadvantage, the Inventors provide particular conditions for the solution treatment. The solution treatment consists of heating the alloy to a temperature not lower than 1000.degree.C and cooling it to room temperature. During the cooling, quenching of the alloy should be started at 800.degree.C or higher and continued to a temperature of 500.degree.C or less.

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Yokohama, Japan

Etsuo Hanada