Structural and magnetic characterization of exchange-spring

L. G. PAMPILLO; S. PRECKEL; F. D. SACCONE; M. R. PAGNOLA

Universidad de La Plata - Argentina

Conferencia; XI Latin American Conference on the Applications of the Mössbauer Effect 2008 - LACAME 2008; 2008

Universidad de la Plata - Universidad de Buenos Aires - Depto Fisica

Exchange-spring magnetic powders are widely used for production in the new generation of Nd-Fe-B magnets. The powders consist in a mixture of soft and hard magnetic phases. By this way, an enhanced remanence and moderated energy products are obtained, with higher freedom in the nal shape of the magnet and corrosion resistance (due to the lower Nd content). However, the preservation of the nanostructure is crucial to get this and is necessary a good characterization of their crystallisation kinetic in order to prevent an excessive grain growth. In this work, we present a characterization of samples of comercial  anostructured powders SPRAX(R) and their crystallisation kinetic. By using Mossbauer spectroscopy and X-ray diraction we identi ed two type of starting materials: nanograins in an amorphous matrix (C-series) and the coexistance of two phases in a nanostructure (Xseries). These series correspond to two di erent Nd concentration in the starting alloy which promoted the precipitation of the phases named above.(R) and their crystallisation kinetic. By using Mossbauer spectroscopy and X-ray diraction we identi ed two type of starting materials: nanograins in an amorphous matrix (C-series) and the coexistance of two phases in a nanostructure (Xseries). These series correspond to two di erent Nd concentration in the starting alloy which promoted the precipitation of the phases named above. Keywords: Nd-Fe-B magnets, Exchange-spring