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

Makoto Ohtsuka; Deog Yung Kim; Kimio Tagaki

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

Makoto Ohtsuka, Deog Yung Kim, Kimio Tagaki

Center for Mineral Processing and Metallurgy (CMPM)

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

1 Citation (Scopus)

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 language	English
Title of host publication	First International Conference on Processing Materials for Properties
Publisher	Publ by Minerals, Metals & Materials Soc (TMS)
Pages	203-206
Number of pages	4
ISBN (Print)	0873392566
Publication status	Published - 1993
Event	Proceedings of the 1st International Conference on Processing Materials for Properties - Honolulu, HI, USA Duration: 1993 Nov 7 → 1993 Nov 10

Publication series

Name	First International Conference on Processing Materials for Properties

Other

Other	Proceedings of the 1st International Conference on Processing Materials for Properties
City	Honolulu, HI, USA
Period	93/11/7 → 93/11/10

ASJC Scopus subject areas

Engineering(all)

Cite this

Mechanism of reaction rate enhancement in direct production of LaNi₅ by reduction-diffusion method. / Ohtsuka, Makoto; Kim, Deog Yung; Tagaki, Kimio.

First International Conference on Processing Materials for Properties. Publ by Minerals, Metals & Materials Soc (TMS), 1993. p. 203-206 (First International Conference on Processing Materials for Properties).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Ohtsuka, M, Kim, DY & Tagaki, K 1993, Mechanism of reaction rate enhancement in direct production of LaNi₅ by reduction-diffusion method. in First International Conference on Processing Materials for Properties. First International Conference on Processing Materials for Properties, Publ by Minerals, Metals & Materials Soc (TMS), pp. 203-206, Proceedings of the 1st International Conference on Processing Materials for Properties, Honolulu, HI, USA, 93/11/7.

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title = "Mechanism of reaction rate enhancement in direct production of LaNi5 by reduction-diffusion method",

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.",

author = "Makoto Ohtsuka and Kim, {Deog Yung} and Kimio Tagaki",

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note = "Proceedings of the 1st International Conference on Processing Materials for Properties ; Conference date: 07-11-1993 Through 10-11-1993",

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AU - Tagaki, Kimio

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N2 - 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.

AB - 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.

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