The effects of the hydrogenation-disproportionation-desorption-recombination (HDDR) processing conditions on the microstructure and magnetic properties of NdFeB powders prepared from recycling sintered N42 grade magnets were evaluated. Temperatures below 840 oC and above 900 oC are deleterious to HDDR powders’ properties. The hydrogen pressure, ranging from 60 to 135 kPa, has a major influence on the remanence compared to that on the intrinsic coercivity. The best magnetic properties (Jr = 0.58 T and μ0Hc = 1.15 T) were obtained with Trecomb = 860 °C, PH2 = 135 kPa, and trecomb = 330 s. Such coercivity value corresponds to 93% of the starting material, not achieved yet by optimizing the HDDR process and without using Dy.

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