材料期刊网

The phase transformation and magnetic properties of the NdFe11.35-xVxNb0.65 (x = 0-1.35) alloys prepared by mechanical alloying (MA) have been studied. Phases of 2:17, 1:7 and 1:12 are formed in the as-annealed alloys with x = 0, 0.3-0.7 and 1.0-1.35, respectively. With increasing V content in the NdFe11.35-xVxNb0.65 (x = 0.3-0.7) alloys, the Curie temperatures of the matrix 1:7 phases monotonically increase. Upon nitrogenation, with increasing V content, the intrinsic coercivity mu(0)H(c) of the nitrided alloys monotonically increases. The increase becomes sharp at x = 1.0 due to the formation of a great amount of Nd(Fe, V)(12)N-delta. The remanence J(r) and the maximum magnetic energy product (BH)(max) of the nitrided alloys monotonically decrease with increasing V content. The 1: 12 phases are formed in all the NdFe11-xNbxV1 (x = 0, 0.3, 0.65 1.0) alloys annealed at 850degreesC for 20 min. With increasing Nb content, the crystallization of the 1: 12 phase is improved and the relative volume fraction of the 1: 12 phase tends to be higher. While mu(0)H(c) of the nitrided alloys monotonically increase, and J(r) and (BH)(max) of the nitrided alloys monotonically decrease. With increasing Nb content in the nitrided alloys, the average grain size of alpha-Fe decrease while the nitrogen content increases. (C) 2002 Elsevier Science B.V. All rights reserved.