Further Assessment of the Kissinger Formula in Simulation of Thermal Desorption Spectrum of Hydrogen

Abstract

The Kissinger-type formula, dX/dt=A(1-X)exp(-Ed/RT), which was thought to be applicable only in detrapping-controlled desorption has proved to be applicable also in the case of diffusion-controlled desorption under certain conditions including existence of effective diffusion coefficient or assumption of Oriani's local equilibrium and pre-exposure of hydrogen before temperature ramp. Analysis indicated that the constant A depends on the specimen geometry and the pre-exponential factor of effective diffusion coefficient. Numerical verification has been carried out by comparing the simulation result of Kissingertype formula with that using the rigid McNabb-Foster model for typical specimen geometry including plate, cylinder and sphere. The merit of using this formula lies in its simplicity in numerical simulation of the thermal desorption spectrum with an accuracy as high as that based on the M-F model. Two different derivative forms of the Kissinger-type formula, i.e. the Choo-Lee plot d[ln (φ/Tp2 )]/d(1/Tp)= -Ed/R and the Lee-Lee plot d[ln(φ/Tp)]/d(1/Tp)=-Ed/R, for determination of desorption activation energy have also been discussed and the analytical result showed that the Choo-Lee plot is a proper method to determine desorption activation energy while the Lee-Lee plot is not correct. The limit of application of the formula and the Choo-Lee plot in thermal desorption analysis is discussed in a semi-quantitative manner.

Hydrogen Embrittlement and Microstructure Characterization of 1500 MPa Martensitic Steel

“…According to existing studies, peak 1, the first deconvolution peak, has a lower peak temperature as shown in Figure 9a,b. Wei et al [13,[28][29][30] considered that the desorption temperature was proportional to the activation energy through mathematical fitting, and the lower the temperature was, the lower the activation energy was. The hydrogen concentrations are, respectively, 0.528 and 0.566 ppm that are very close.…”

Influence of Specimen Thickness on Thermal Desorption Spectrum of Hydrogen in High Strength SCM435 Steel

“…5,6) Except these two extreme cases much less attention has been paid to desoption in which lattice diffusion has a substantial influence and equilibrium of hydrogen is achieved only partially between the lattice and the trap site. This is called mixed-control desorption henceforth.…”

“…11) The C-L plot is also applicable to diffusion-controlled desorption if pre-exposure is carried out for a sufficiently long time, 5,6) whereas, the ln (ϕ/T p ) vs 1/T p plot, another formula of Kissinger-type desorption proposed by Lee and Lee, 12) does not yield a correct value of detrap energy.…”

“…6) Under this circumstance it is interesting to see if the Kissinger-type desorption can be achieved in the mixed-control condition.…”

On the Possibility of Determination of the Hydrogen Binding Energies With Defects From Thermal Desorption Measurements With Different Heating Rates

“…Для определения энергии выхода водорода из дефектов этот подход был впервые использован применительно к железу [10], а в недавней работе [11] он был использован и для вольфрама. Ранее в работах [12,13] исследовались границы применимости формулы (6) для определения энергии выхода водорода из железа, однако использовалось допущение о бесконечно большой скорости рекомбинации. Данная работа посвящена изучению границ применимости формулы (6) для определения энергии выхода водорода из дефектов на примере вольфрама с учётом конечной скорости рекомбинации на поверхности металла.…”