Hydrogen trapping of carbides during high temperature gaseous hydrogenation

This study evaluates the hydrogen absorption and trapping in carbide containing steels from a very low hydrogen partial pressure atmosphere at elevated temperatures. Two generic titanium-containing Fe-C steels, differing in carbon and titanium content, are studied. The steels are subjected to a quench and temper treatment, where tempering is performed in a dilute hydrogen gas atmosphere. Detailed microstructural analysis via SEM and TEM together with characterization via thermal desorption spectroscopy and hot extraction are performed to analyze the hydrogen trapping ability of the different types of carbides.A significant amount of hydrogen is introduced in the Fe-C-Ti alloys during tempering. Moreover, the hydrogen appears to be strongly trapped. This could be related to trapping at the carbon-vacancies inside the TiC, and more specifically the large undissolved carbides. The binding energy is estimated to range between 80 kJ/mol and 90 kJ/mol and appears to be independent of the undissolved carbide size.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study evaluates the absorption and trapping of hydrogen in carbide-containing steels at elevated temperatures from a low hydrogen partial pressure atmosphere. The titanium-containing Fe-C steels absorb a significant amount of hydrogen during tempering and exhibit strong trapping ability. This may be attributed to trapping at the carbon-vacancies inside TiC and large undissolved carbides.