Effects of pre-oxidation on the corrosion behavior of pure Ti under coexistence of solid NaCl deposit and humid oxygen at 600 °C: the diffusion of chlorine

Lei Fan; Li Liu; Yuhai Lv; Hao Wang; Anqing Fu; Juntao Yuan; Ying Li; Fuhui Wang; Chengxian Yin

doi:10.1038/s41598-020-73034-y

Effects of pre-oxidation on the corrosion behavior of pure Ti under coexistence of solid NaCl deposit and humid oxygen at 600 °C: the diffusion of chlorine

Sci Rep. 2020 Oct 1;10(1):16291. doi: 10.1038/s41598-020-73034-y.

Authors

Lei Fan^{1

2}, Li Liu³, Yuhai Lv⁴, Hao Wang⁴, Anqing Fu¹, Juntao Yuan¹, Ying Li², Fuhui Wang⁵, Chengxian Yin¹

Affiliations

¹ State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, CNPC Tubular Goods Research Institute, NO. 89, Jinyeer Rode, Xi'an, 710077, Shaanxi, China.
² Institute of Metal Research, Chinese Academy of Sciences, NO. 62, Wencui Road, Shenyang, 110016, Liaoning, China.
³ Key Laboratory for Anisotropy and Texture of Materials (MoE), School of Materials Science and Engineering, Northeastern University, NO. 3-11, Wenhua Road, Shenyang, 110819, China. [email protected].
⁴ NO.1 Gas Production Plant of Changqing Oilfield Company, Jingbian, 718500, Shaanxi, China.
⁵ Key Laboratory for Anisotropy and Texture of Materials (MoE), School of Materials Science and Engineering, Northeastern University, NO. 3-11, Wenhua Road, Shenyang, 110819, China.

Abstract

The effect of pre-oxidation on the corrosion behavior of pure Ti covered with a solid NaCl deposit in the humid O₂ flow at 600 °C is studied. The oxide scale, formed by pre-oxidation, protects the substrate from the NaCl induced corrosion during the initial stage. However, the corrosion of the pre-oxidized sample is severely accelerated by solid NaCl after an incubation period. The chlorine, generated from the decomposition of solid NaCl, diffuses into the oxide/substrate interface as ions during the incubation period, which was observed by ToF-SIMS. The chlorine at the oxide/substrate interface induces the fast corrosion after the incubation period although the pre-oxidation scale is complete and compact.