Synthesis of Nd2Fe14B powders by spray-drying and reduction-diffusion processes

The magnetic Nd-Fe-B powders were prepared by a mechanochemical method, inc luding the processes of spray drying, debinding, milling, H-2 reduction, Ca reduction, and washing. The liquid solution dissolved with various metal s alts was first spray-dried to prepare the precursor powders having uniforml y dispersed Nd, Fe, and B components. The precursor powders in turn were su bjected to the subsequent processes. The particle size of the resultant Nd- Fe-B powders was about 1 mum. Effects of the process parameters on phases, morphologies. microstructures, compositions, and thermal properties of the powders were investigated.