LiCl 및 LiCl-Li2O 용융염에서 Fe-base 합금의 부식 거동

조수행; 장준선; 주준식; 오승철; 신영준; Soo Haeng Cho; Jun Shan Zhang; June Sik Ju; Seung Chul oh; Young Joon Shin

Journal of the Korean Industrial and Engineering Chemistry, Vol.12, No.4, 422-427, June, 2001

Export Citation

LiCl 및 LiCl-Li2O 용융염에서 Fe-base 합금의 부식 거동

Corrosion Behavior of Fe-base Alloys in Molten Salts of LiCl and LiCl-Li2O

조수행^†, 장준선¹, 주준식, 오승철, 신영준

한국원자력연구소, 대전 305-353
¹대련이공대 재료공정계, 대련, 중국

Soo Haeng Cho^†, Jun Shan Zhang¹, June Sik Ju, Seung Chul oh, and Young Joon Shin

Korea Atomic Energy Research Institute, Taejon 305-353, Korea
¹Department of Materials Eng, Dalian University of Technology, Dalian, China

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초록

Fe-base 합금의 용융염 부식 거동을 650 ~ 850℃ 온도범위에서 조사하였다. 용융염 LiCl에서 KSA(Kaeri Superalloy)-4, 5, 6 합금은 LiCrO2의 치밀한 보호막이 형성되었다. 혼합용융염 LiCl-25%Li2O에서 Cr 농도가 낮은 KSA-4는 Cr의 내부산화가 발생하였고, Cr 농도가 높은 KSA-5와 KSA-6은 LiCrO2와 Ni의 다공성 비보호막이 형성되었다. 혼합용융염 LiCl-25%Li2O에서는 Cr 농도의 증가에 따라 부식속도가 증가하였으며, 부식속도의 시간의존성은 Cr 농도가 낮은 합금에서는 포물선법칙, Cr 농도가 높은 합금에서는 직선법칙을 나타내었다. 이러한 현상은 Li2O에 의한 보호성 산화물 Cr2O3의 염기성 용해기구로 설명할 수 있다.

Corrosion behavior of Fe-base alloys molten salts of LiCl and LiCl-25%Li2O was investigated in the temperature range of 650 ~ 850 ℃. In the molten salt of LiCl, a dense protective oxide coat of LiCrO2 was formed on the KSA(Kaeri Superally)-4, KSA-5 and KSA-6 alloys. In the mixed molten salt of LiCl-25%Li2O, internal oxidation of Cr took place in the KSA-4 alloy. A porous non-protective oxide coat, consisting of LiCrO2 and Ni, was formed on the KSA-5 and KSA-6. The corrosion rate of the alloys increased with the increased Cr contect. For the alloy containing low Cr content, The corrosion rate followed a parabolic function, where as it was a linear for the alloy containing high Cr content. Such corrosion behavior of the slloy in the mixed molten salt of LiCl-25%Li2O, can be explained by the basic flusing mechanism of protective oxide coating of Cr2O3.

Keywords:hot corrosion;lithium molten salt;molten salt corrosion

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