Characteristic and kinetics of hydrogen absorption during the heat preservation stage and the cooling stage of TC21 alloy

TC21 alloy is hydrogenated under different initial hydrogen pressures at hydrogenation temperatures in the range of 450 degrees C-850 degrees C. Hydrogen absorption characteristic and kinetics during the heat preservation stage and cooling stage, hydrogen content and activation energy are investigated. The hydrogen absorption reaches equilibrium first at higher hydrogenation temperature and initial hydrogen pressure during the heat preservation stage. The hydrogen absorption reaches equilibrium first at lower hydrogenation temperature and initial hydrogen pressure during the cooling stage. Mechanisms of hydrogen absorption are analyzed during the heat preservation stage and the cooling stage. Phase compositions of the hydrogenated TC21 alloys are analyzed by XRD. Hydrogen content increases first and then decreases, then increases slightly, and finally decreases with the increase of hydrogenation temperature. Hydrogen content increases gradually with the increase of initial hydrogen pressure. The activation energy of hydrogen absorption in TC21 alloy is about 18.304 kJ/mol. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

The hydrogen absorption characteristics and kinetics of TC21 alloy under different initial hydrogen pressures and temperatures were studied. Equilibrium was reached during the heat preservation and cooling stages, with higher temperature and pressure leading to faster equilibration. XRD analysis revealed the phase compositions of the hydrogenated TC21 alloy. The hydrogen content varied with hydrogenation temperature and pressure, and the activation energy for hydrogen absorption in TC21 alloy was approximately 18.304 kJ/mol.