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Updated: Aug 25, 2025

Metal Corrosion and the Efficiency of Corrosion Inhibitors in Less Conductive Media
Published on: November 3, 2018
Effect of Hydrogen on Corrosion Behavior of 321 Stainless Steel in NH4Cl Solution
Xiuqing Xu1, Wei Wang2, Tao Suo3
1State Key Laboratory of Performance and Structural Safety for Petroleum Tubular Goods and Equipment Materials, R&D Center of TGRI, Xi'an 710077, China.
Abstract:
For a hydrogenation heat exchanger operating under severe working conditions such as high temperature, high pressure and a hydrogen environment, perforation accidents caused by NH4Cl corrosion occur frequently. However, few reports on the effect of hydrogen on the corrosion behavior of metal materials in NH4Cl aqueous solution have been published. In this paper, X-ray photoelectron spectroscopy (XPS), electrochemical dynamic potential polarization, electrochemical impedance spectroscopy (EIS), Mott-Schottky (M-S) curves and scanning electron microscopy (SEM) were used to study the effect of electrochemical hydrogen charging (EHC) on the corrosion behavior of 321 stainless steel in an NH4Cl solution environment. The results show that: (1) hydrogen can change the structure and chemical composition of 321 stainless steel passive film and promote the conversion of metal oxide to hydroxide. At the same time, it can reduce the stability of the passive film. (2) Hydrogen can increase the thermodynamic and kinetic tendency of corrosion reaction and cooperate with Cl- to promote the occurrence of pitting corrosion.
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