Estudo de oxidação em ligas do sistema Fe-ND

AUTOR(ES)
DATA DE PUBLICAÇÃO

1992

RESUMO

The oxidation study of Fe-Nd system was developed from Fe-Nd binary alloys, and Fe-Nd-O ternary alloys. Optical Metallography, AC Termomagnetic Analysis, Eletronic Microprobe and Coercivity Measurements were used for alloys characterization. The binary alloys were first stabilized and then submitted to a heat treatment under oxygen atmosphere. Those alloys present a typical behaviour of diffusion pattern, as observed in diffusion couples. One observes a layer of oxidized material from the surface to the interior of the material. For short treatment times, oxygen promotes metastable magnetically ordered phases. For longer treatment times one observes the decomposition of Fe17Nd5 phase in Fe17Nd2 and Nd2O3, and the phase Fe17Nd2 in Fe and Nd2O3. The Fe rich Fe-Nd-O alloys display a liquid miscibility gap with a clear separation between oxide rich portion and metallic phases. Nd rich alloys, submitted to short and long heat treatments showed notable microstructure alterations, followed by changes in coercivity. This behaviour is quite similar to those found in binary alloys. The ternary alloys showrd metastable phases whith Curie temperatures near 100°C and 160°C, that originate another phase with Tc » 220°C, after long heat treatments

ASSUNTO(S)

ligas de ferro agentes de oxidação oxidação

ACESSO AO ARTIGO

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