Mechanical alloying of Ni3Fe in the presence of Ni3Fe nanocrystalline germs

The influence of nanocrystalline germs on the production of the Ni3Fe intermetallic compound by mechanical alloying is reported. These germs consist in Ni3Fe nanocrystalline particles previously obtained by mechanical alloying which have been added to the Ni-Fe mixture: 0.8(3Ni + Fe) + 0.2Ni(3)Fe = Ni3Fe. The powder mixture was milled in a planetary mill in argon atmosphere. Several milling times have been used ranging from 2 to 8 h. A Ni-Fe mixture at nominal composition of Ni3Fe compound was milled in the same conditions, as blind samples. A heat treatment at 350 degrees C for 0.5, 1, 2 and 4 h has been performed in order to remove the internal stresses induced by milling and to improve the solid-state reaction. The formation of the Ni3Fe phase was checked by X-ray diffraction and magnetic measurements. The genus inoculation improves the synthesis of the Ni3Fe phase by combined mechanical alloying and annealing technique. This influence is more effective for short milling times (typically lower than 4 h). For samples milled more than 4 h the influence of the germs inoculation is more reduced, due to the Ni3Fe germs self-formation by milling. (C) 2006 Elsevier B.V All rights reserved.