Characterizing thermal-oxidation behaviors of nuclear graphite by combining O2 supply and micro surface area of graphite

Yangping Zhou; Yujie Dong; Huaqiang Yin; Zhengcao Li; Rui Yan; Dianbin Li; Zhengwei Gu; Ximing Sun; Lei Shi; Zuoyi Zhang

doi:10.1038/s41598-018-31493-4

Characterizing thermal-oxidation behaviors of nuclear graphite by combining O₂ supply and micro surface area of graphite

Sci Rep. 2018 Sep 7;8(1):13400. doi: 10.1038/s41598-018-31493-4.

Authors

Yangping Zhou¹, Yujie Dong¹, Huaqiang Yin¹, Zhengcao Li², Rui Yan³, Dianbin Li¹, Zhengwei Gu¹, Ximing Sun¹, Lei Shi¹, Zuoyi Zhang¹

Affiliations

¹ Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing, 100084, China.
² State Key Laboratory of New Ceramics and Fine Processing, Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China. zcli@mail.tsinghua.edu.cn.
³ State Key Laboratory of New Ceramics and Fine Processing, Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.

Abstract

The effects of different parameters on oxidation rate are non-linear, interactive and diversified in which the change of adequacy of O₂ supply is an important indicator. The influence of microstructure on oxidation rate became stronger worsening the fitting linearity to calculate the activation energy based on present method with the decreased adequacy of O₂ supply due to the increase of temperature, the decrease of gas flow rate, etc. Here, we proposed a method to characterize thermal-oxidation behaviors of nuclear graphite by combining O₂ supply and micro surface area of graphite. The proposed method improved the linearity and reduced the standard error of Arrhenius plots of oxidized graphite IG-110 (10 L/min reactant gas) and ET-10 (0.2 L/min reactant gas). The value of activation energy of graphite IG-110 oxidized under ASTM D7542 condition is calculated as 220 kJ/mol by this method echoing the results of previous studies with sufficient O₂ supply. For the conditions with less O₂ supply at low gas flow rate and/or high temperature, the change of microstructure of oxidized graphite should be obtained as an important factor influencing oxidation rate of graphite.