In-situ visualization of hydrogen atom distribution at micro-indentation in a carbon steel by scanning Kelvin probe force microscopy

Abstract In this work, a scanning Kelvin probe force microscope was used to in-situ visualize distribution of hydrogen atoms at micro-indentation and metallurgical phases contained in a carbon steel. Topographic profiles and Volta potentials of the steel upon various times of hydrogen-charging were measured. The hydrogen atom distribution at the micro-indentation was analyzed. Results demonstrate that the micro-indentation can serve as a preferential site to accumulate hydrogen atoms. Particularly, the vertex of the indention shows the greatest hydrogen atom enrichment, while the indentation bottom possesses a slightly lower hydrogen atom concentration. More hydrogen atoms accumulate in ferrite than in pearlite in the steel.