New method of making Nd-Fe-Co-B full dense magnet

A novel method for fabricating an isotropic fully dense Nd-Fe-Co-B magnet is described. This method consists of a plasma-activating process and a hot-pressing process. The magnetic powder is heated by resistance heating. Plasma activation produces an improvement in the H/sub cj/ of the compacted magnet. The pressure range is from greater than 200 kg/cm/sup 2/ to less than 500 kg/cm/sup 2/. Optimum alloy composition is Nd/sub 13.5/Co/sub 1.5/B/sub 6/Fe/sub 64.5/, specified by magnetic properties and formability in hot pressing. The magnetic properties of this magnet are 15 MG-Oe for BH/sub max/ and 17 kOe for H/sub cj/. The temperature coefficient of B/sub r/ is -0.07 to -0.08%/ degrees C, and that of H/sub cj/ is -0.39 to -0.42%/ degrees C.<
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