Nitrogenation effect of Nd(Fe,Mo)12 alloys prepared by strip casting technique

Nd(1.1)Fe(10.)5Mo(15) alloys are prepared by strip casting technique and their nitrides are synthesized using the cast strips. It is found that the NdFe(10.)5Mo(1.5) strips can be directly nitrided to obtain interstitial NdFe10.5Mo1.5Nx compounds without pre-crushing. A phenomenon of spontaneous pulverization in the strips induced by nitrogenation is found for the first time. This kind of pulverization may result from the inter-granular failure along the grain boundary of Nd-rich phase as well as trans-granular failure of primary phase NdFe10.5Mo1.5, which is different from mechanical crushing of the strips where trans-granular failure is dominant. The nitrided strips are used to prepare anisotropic NdFe10.5Mo1.5Nx powders, and the anisotropic powders with a remanence (B-r) of 1.08 T, a coercive force (H-i(c)) of 400 kA/m, and an energy product ((BH)(max)) of 144 kJ/m(3) are obtained. The results show that high performance NdFe10.5Mo1.5Nx nitrides can be prepared by a new and simpler technical route without pre-crushing. (C) 2010 Elsevier B.V. All rights reserved.