Nuclear Techniques ›› 2015, Vol. 38 ›› Issue (7): 70601-070601.doi: 10.11889/j.0253-3219.2015.hjs.38.070601

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles     Next Articles

Corrosion behaviors of nickel-based high temperature alloys in molten FLiNaK salt

QIU Jie1,2 ZOU Yang1 LI Zhijun1 XU Hongjie1   

  1. 1(Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Jiading Campus, Shanghai 201800, China) 2(University of Chinese Academy of Sciences, Beijing 100049, China)
  • Received:2015-04-20 Revised:2015-05-04 Online:2015-07-10 Published:2015-07-10

Abstract: Background: Corrosion of the structural materials of Molten Salt Reactor (MSR) has been recognized as a challenge that prevents the MSR from long term operation. Oak Ridge National Laboratory (ORNL) has revealed that corrosion occurs predominantly through dealloying of Cr from the candidate nickel-based high temperature alloys. Therefore, a systematic study on the corrosion characteristics of candidate structural materials is needed to ensure their applications in MSR. Purpose: The present work is to evaluate the corrosion behaviors of some nickel-based alloys with different Cr content as well as to supply more corrosion data of materials in molten fluoride salts for reliable selection of structural materials. Methods: Static corrosion tests of five kinds of nickel-based high temperature alloys (Hastelloy B-2, Haynes 242, Hastelloy S, GH 3030 and Hastelloy X) were performed in purified molten FLiNaK salt at 700 °C for 400 h. The microstructural morphology and chemical composition of the samples were examined by Scanning Electron Microscope (SEM) and Electron Probe Microanalysis (EPMA). Results: Hastelloy B-2 and Haynes 242 with low Cr content exhibited better corrosion resistance, while the high Cr-content alloys, GH 3030 and Hastelloy X, exhibited severe corrosion after the corrosion tests. Conclusion: It was found that the corrosion was correlated with the original Cr-content of the alloys, and the weight-loss/area due to corrosion increased with the Cr-content of alloys. When the Cr content of alloys is higher than 20 wt.%, these alloys would suffer severe corrosion in molten fluoride salt environments.

Key words: Nickel-based alloys, FLiNaK salt, Corrosion, Cr