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Effects of CrN and TiN Coating by Hydrogen Embrittlement of Aluminum Alloys for Hydrogen Valves of Hydrogen Fuel Cell Vehicles on Mechanical Properties
수소연료전지 자동차의 수소밸브용 알루미늄 합금의 수소취화에 의한 기계적 특성에 미치는 CrN과 TiN 코팅의 영향
Ho-Seong Heo, Dong-Ho Shin, Seong-Jong Kim
허호성, 신동호, 김성종
Keywords: Hydrogen embrittlement, Aluminum alloy, CrN, TiN, Arc ion plating
Received: January 13, 2023; Revised: February 01, 2023; Accepted: February 01, 2023
Abstract: The mechanical properties of the hydrogen valve responsible for supplying and blocking hydrogen gas in a hydrogen fuel cell electric vehicle (FCEV) were researched. Mechanical properties by hydrogen embrittlement were investigated by coating chromium nitride (CrN) and titanium nitride (TiN) on aluminum alloy by arc ion plating method. The coating layer was deposited to a thickness of about 2 μm, and a slow strain rate test (SSRT) was conducted after hydrogen embrittlement to determine the hydrogen embrittlement resistance of the CrN and TiN coating layers. The CrN-coated specimen presented little decrease in mechanical properties until 12 hours of hydrogen charging due to its excellent resistance to hydrogen permeation. However, both the CrN and TiN-coated specimens exhibited deterioration in mechanical properties due to the peeling of the coating layer after 24 hours of hydrogen charging. The specimens coated at 350 oC presented a significant decrease in ultimate tensile strength due to abnormal grain growth.