Desulfurization Model Using Solid CaO in Molten Ni-Base Superalloys Containing Al

Yuki Kishimoto*, Satoshi Utada, Taketo Iguchi, Yuhi Mori, Makoto Osawa, Tadaharu Yokokawa, Toshiharu Kobayashi, Kyoko Kawagishi, Shinsuke Suzuki, Hiroshi Harada

*この研究の対応する著者

研究成果: Article査読

8 被引用数 (Scopus)

抄録

Details of the desulfurization for molten Ni-base superalloys containing Al using solid CaO have been investigated, and the formula that explains the reaction rate has been developed. A cylindrical CaO rod was inserted into 500 g molten Ni-base superalloy TMS-1700 (MGA1700) containing 200 ppm S and held for a certain period at 1600 °C in each experiment. Sulfur content in the melt decreased with the increasing holding time of the CaO rod. Results of electron probe microanalysis show that Ca, O, S, and Al distribute in the same part of the melt/CaO interface as well as the particle boundaries of the CaO rods. The distribution of these elements suggests that CaO reacted with S in the melt to generate CaS, and Al reacted with O and CaO to form calcium aluminate slag. The desulfurization rate formula was obtained by the assumption that the rate-controlling process of the desulfurization is S diffusion through the generated layer composed of CaS and calcium aluminate slag. This formula expresses the amount of S in the melt by the diffusion term with the effective diffusion coefficient, which was obtained from the experimental results. Moreover, the time required for the desulfurization of 2 kg molten Ni-base superalloy PWA1484 using a CaO crucible, was calculated by this desulfurization rate formula which resulted in fair agreement with the actual result.

本文言語English
ページ(範囲)293-305
ページ数13
ジャーナルMetallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
51
1
DOI
出版ステータスPublished - 2020 2 1

ASJC Scopus subject areas

  • 凝縮系物理学
  • 材料力学
  • 金属および合金
  • 材料化学

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