Investigation on indentation, scratch, friction characteristics with hydrogen embrittlement of plasma ion nitrided Al alloy for hydrogen valve of fuel cell electric vehicle

Abstract In this investigation, plasma ion nitriding was conducted to improve the hardness, wear resistance, and hydrogen embrittlement resistance of aluminum alloys. To research the surface characteristics and hydrogen embrittlement resistance of the nitrided layer, indentation experiments, scratch experiments, friction experiments, FE-SEM, XRD, EDS, and 3D laser microscopic analyses were conducted. An AlN layer was observed on the surface after plasma ion nitriding. As a results of the indentation experiment, hardness ( H IT ) of the nitrided layer decreased from 1370 to 749 MPa and 538 MPa, respectively with hydrogen embrittlement for 3 h and 6 h. As a result of hydrogen embrittlement, adhesion force between the base material and nitrided layer tended to decrease from 6.54 to 2.50 N. In addition, as a results of the friction experiment, the section where the nitrided layer was maintained was shortened as the hydrogen embrittlement time increased.