Visualizing micro leakage position by dynamic measurement in operando hydrogen microscope

Abstract

We developed an operando hydrogen microscope (OHM) to determine where in materials hydrogen is trapped and causes embrittlement, and the location of hydrogen leak from gas lines, by hydrogen visualization. In the OHM, hydrogen atoms that permeate through a sample are ionized by incident electrons on the sample surface, desorbed into an ultra-high vacuum environment, and then detected. We visualized the surface hydrogen distribution from the hydrogen desorption position. It is also possible to visualize atoms adsorbed from gas phase, as well as gases that leak rather than permeate. The probability that a gas will be adsorbed depends on the substance. The amount of adsorbate increases at a site of locally high pressure. We created guidelines for background evaluation and quantitative analysis of leakage amount under the experimental conditions. Therefore, by visualizing the distribution of adsorbed substances using OHM, we can identify the location of a leak. We visualized a controlled leak of hydrogen in a sintered stainless steel body.