Bell Telephone Laboratories

Bud Caesar Wonsiewicz

John T Plewes

Gilbert Y Chin

Sungho Jin

A method is disclosed for making a metallic body having desirable magnetic properties. The metallic body is made from an alloy which contains Fe, Cr, and Co and which may also contain one or several additional ferrite forming elements such as, e.g., Zr, Mo, V, Nb, Ta, Ti, Al, Si, or W. According to the disclosed method the alloy is cooled at a rate of at least 60 degrees C. per hour from an initial temperature at which the alloy is in an essentially single phase alpha state to a second temperature which is in a vicinity of 600 degrees C. Subsequently, the alloy is cooled at a second, slower rate to a third temperature which is in the vicinity of 525 degrees C. The disclosed method allows for a relatively broad range of initial temperatures, is relatively insensitive to compositional variations of the alloy, and permits simple reclamation of suboptimally treated parts. As a consequence, the method is particularly suited for large scale industrial production of permanent magnets as may be used, e.g., in relays, ringers, and electro-acoustic transducers.

Fe-Cr-Co magnetic alloy processing

Alloy compositions based on ternary alloys of the chromium-cobalt-iron system modified by addition of zirconium molybdenum, niobium, vanadium, titanium, and/or aluminum, are found to manifest improved formability. Exemplary compositions are magnetic and evidence coercivities of 350-550 Oe., remanent magnetizations of from 10,000 - 7,500 Gauss, and maximum energy products in excess of one million. Improvement in formability may take the form of room temperature stamping, sometimes in air, to final configurations including curvatures of radius equal to thickness. Novel compositions particularly desirable from such standpoint necessarily contain zirconium together with aluminum, niobium, and/or titanium.

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Summit, NJ, United States of America

Bud Caesar Wonsiewicz