Gm Global Technolgoy Operations, Inc.

Jon C Shain

David E Gay

James W Herchenroeder

Oxidation-resistant, individually encapsulated neodymium-iron-boron permanent magnet particles are provided. The particles are individually coated with, preferably, three distinct organic layers and are useful for the subsequent formation of a molded permanent magnet article. The first coating is an antioxidant layer employed for the retardation of oxidation of the coated particle. The second intermediate layer consists of an appropriate thermosetting epoxy to provide the adhesion required during subsequent molding of the particles. The third and outermost layer consists of polystyrene and is employed to keep the particles free flowing, since the epoxy layer may be tacky after deposition, thereby hindering the free flowability of the particles. The coatings are applied sequentially using fluidized bed coating techniques. The encapsulated particles can then be molded and appropriately cured. In addition, the encapsulated particles exhibit enhanced oxidation resistance, including at elevated temperatures.

Encapsulated oxidation-resistant iron-neodymium-boron permanent magnet

A rare earth-containing powder is pressed into a compact at ambient temperatures using a solid lubricant applied only to the die wall and/or a core. The solid lubricant is applied by suspending lubricant powder in a fluorinated hydrocarbon liquid.

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Anderson, IN, United States of America

Jon C Shain