Hydrogen Decrepitation Behaviors of Novel RE–Fe–B Strip-Casting Alloys Based on Misch Metal.

To reduce the Nd–Fe–B material cost and balance the utilization of rare earth sources, the misch metal (MM) substitution for Nd in the sintered magnet attracts interest. Under the processing of fabricating Nd–Fe–B magnet, hydrogen decrepitation (HD) is widely used to obtain magnetic powder; however, the HD behaviors of RE–Fe–B strips based on MM may be complex. The HD behaviors of the [(Pr, Nd)1–xMMx]30.8FebalCo1.4 B0.97 ($x $ = 0–1) strips were studied under 0.2 MPa pressure. We find that it is similar to the Nd–Fe–B, 2:14:1 tetragonal structure of RE–Fe–B strips based on MM which is not broken during hydrogen decrepitating. But the REFe2 phase in MM30.8FebalCo1.4B0.97 disappears dramatically as a result of hydrogenation. For the samples with MM, the HD process is quicker and the particle size gets smaller than that for free MM, especially for samples with 35 wt.% MM, which may be attributed to La and Ce elements. [ABSTRACT FROM AUTHOR]