Properties of Nd-Fe-B Magnetic Powder Prepared by Reduction-Diffusion Process Using a Spray-Dried Precursor
Effect of washing step in R-D process on the structure and magnetic properties of Nd-Fe-B powder fabricated by the process using a spray-dried precursor was investigated. Although the powder washed in water contained much more residual CaO than that washed in dilute acetic acid, magnetic properties of the former were much better than those of the latter due to less removal of Nd-rich phase. In the powder washed in water Nd2Fe14B particles were enclosed with thin layer of Nd-rich phase, and each particle consisted of one or more subgrains of the size 50 ~ 100 nm or more. Milling the powder before water washing was effective to remove more CaO, thereby increased the remanence of the powder.
S.-G. Kang and T. Kobayashi
T. S. Jang et al., "Properties of Nd-Fe-B Magnetic Powder Prepared by Reduction-Diffusion Process Using a Spray-Dried Precursor", Materials Science Forum, Vols. 449-452, pp. 1057-1060, 2004