Mechanism of reaction rate enhancement in direct production of LaNi5 by reduction-diffusion method

Makoto Ohtsuka, Deog Yung Kim, Kimio Tagaki

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The previous experimental study on the reduction-diffusion (R-D) method to directly make a RmNi5 (Rm: La-base mischmetal) compound has suggested that a CaNi5 layer, which was formed between the RmNi5 compound and the unreacted Ni core, played an important role in enhancing the reaction rate to form the RmNi5 compound. To clarify the mechanism of the enhancement, the inter-diffusion coefficients in the LaNi5 compound were determined and diffusion experiments were undertaken for the Ni-La system at temperatures around 1373K using two kinds of diffusion couple, the Ni/Ni-La melt and the Ni/CaNi5/Ni-La melt. The morphology of the specimens after diffusion was also investigated. It was considered that slow lattice diffusion could be prevailing for the LaNi5 layer formed in the couple of Ni / Ni--La melt, while rapid grain boundary diffusion prevailed for the LaNi5 layer formed in the couple of Ni / CaNi5 Ni--La melt.

Original languageEnglish
Title of host publicationFirst International Conference on Processing Materials for Properties
PublisherPubl by Minerals, Metals & Materials Soc (TMS)
Pages203-206
Number of pages4
ISBN (Print)0873392566
Publication statusPublished - 1993 Dec 1
EventProceedings of the 1st International Conference on Processing Materials for Properties - Honolulu, HI, USA
Duration: 1993 Nov 71993 Nov 10

Publication series

NameFirst International Conference on Processing Materials for Properties

Other

OtherProceedings of the 1st International Conference on Processing Materials for Properties
CityHonolulu, HI, USA
Period93/11/793/11/10

ASJC Scopus subject areas

  • Engineering(all)

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