부산대학교 도서관

Hydrogen-induced embrittlement is a significant safety concern for steel pipelines used in the transmission of hydrogenblendednatural gas. To mitigate this issue, hydrogen barrier coatings can be applied to the surface of steel substrates toreduce hydrogen permeation. In this study, rare earth oxides were optimized via first-principles calculations to identify themost effective doping agents. Subsequently, a FexAly/Al/Al2O3 composite coating doped with La2O3and Ce2O3was successfullyapplied to the surface of X80 steel using hot-dip aluminum plating combined with anodic oxidation. The coatingwas characterized using various techniques, including SEM, EDS, XRD, XPS, and hydrogen permeation tests. The resultsdemonstrated that co-doping La2O3and Ce2O3resulted in a lower adsorption energy of Al2O3to hydrogen molecules, andimproved the surface quality of the aluminizing layer and the composite coating. Electrochemical hydrogen permeationtests showed that the FexAly/Al/Al2O3 composite coating significantly improved the hydrogen barrier property of X80 steel. The anodizing current density was found to have a significant effect on the coating's morphology, which in turn affected thehydrogen barrier property of the coating. The composite coating obtained at an anodizing current density of 2 A/dm2 wasuniform and dense, without noticeable defects, and exhibited the best hydrogen barrier property.