Hydrogen evolution on a steel surface and subsequent hydrogen diffusion into the steel matrix are evaluated using an electrochemical permeation test with no applied cathodic current on the hydrogen charging side. In particular, cyclic operation in the permeation test is also conducted to clarify the corrosion-induced hydrogen evolution behavior. In contrast to the conventional perception that the cathodic reduction reaction on the steel in neutral aqueous environments is an oxygen reduction reaction, this study demonstrates that atomic hydrogen may be generated on the steel surface by the corrosion reaction, even in a neutral environment. Although a much lower permeation current density and significant slower diffusion kinetics of hydrogen are observed compared to the results measured in acidic environments, they contribute to the increase in the embrittlement index. This study suggests that the research on hydrogen embrittlement in ultra-strong steels should be approached from the viewpoint of corrosion reactions on the steel surface and subsequent hydrogen evolution/diffusion behavior.

Abstract
 1. 서 론
 2. 실험 방법
  2.1 시험 준비
  2.2 미세조직 분석
  2.3 수소 투과 실험
  2.4 침지실험 및 XRD 분석
  2.5 Slow strain rate tensile(SSRT) 실험 및 파단면 관찰
 3. 결과 및 고찰
  3.1 미세조직 분석
  3.2 수소 투과 거동 분석
  3.3 부식거동 분석
  3.4 SSRT 및 파단면 관찰
 4. 결 론
 References

• 황은혜(순천대학교 신소재공학과) | Eun Hye Hwang (Department of Advanced Materials Engineering, Sunchon National University)
• 류승민(순천대학교 신소재공학과) | Seung Min Ryu (Department of Advanced Materials Engineering, Sunchon National University)
• 김성진(순천대학교 신소재공학과) | Sung Jin Kim (Department of Advanced Materials Engineering, Sunchon National University) Corresponding author