Effect of internal stress on the hydriding kinetics of nanocrystalline Pd thin films

Delmelle, Renaud; Michotte, Sébastien; Sinnaeve, Marc; Proost, Joris

doi:10.1016/j.actamat.2013.01.003

Cited by 16 publications

(19 citation statements)

References 39 publications

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“…While the absolute stress values differ, the trend of the stress evolution upon film growth can be transferred to that of films with similar micro-structure. Different absolute stresses we ascribe to the different sputter gas pressures and different kinetic energies of the atoms acting in the atom peening, see chapter 5.1.1 [4,38].…”

Section: Intrinsic Stress Of Sputtered Palladium Thin Filmsmentioning

confidence: 99%

Mechanical stress and stress release channels in 10–350 nm palladium hydrogen thin films with different micro-structures

et al. 2016

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Section: Intrinsic Stress Of Sputtered Palladium Thin Filmsmentioning

confidence: 99%

Mechanical stress and stress release channels in 10–350 nm palladium hydrogen thin films with different micro-structures

et al. 2016

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“…Soon after the start of Pd deposition, the slope of the stress*thickness vs. thickness curve becomes constant. As detailed previously, the sign and magnitude of this slope were both observed to be a function of p Ar [28]. Consequently, one can tune the mean internal stress in the deposit (s o ) by varying p Ar , as illustrated in Fig.…”

Section: Introductionmentioning

confidence: 85%

“…Cantilever specimens with dimensions 3 Â 0.5 cm 2 were then cut from these wafers for the annealing and hydriding experiments. DC magnetron sputtering has been used to deposit the Ti and Pd films, with real-time monitoring of the specimen curvature as detailed in a previous publication [28]. The deposition parameters have been adjusted in order to generate columnar grains with a high concentration of crystalline defects [41].…”

Section: Experimental Methodsmentioning

confidence: 99%

“…On the other hand, systematic, quantitative experimental studies on the effect of microstructure on the hydriding kinetics of different metals and alloys are still missing. As opposed to our previous study [28], whose objective was to study quantitatively the effect of internal stress on the hydriding kinetics of pure Pd thin films at constant microstructure, this paper is dedicated to the quantitative study of the effect of microstructure on the hydriding kinetics at constant internal stress. The choice of the PdeH system was straightforward, since the latter earned its "model system" status in the course of the last century, notably because of its ability to readily absorb and release hydrogen at room temperature [29,30].…”

Section: Introductionmentioning

confidence: 96%

“…2 shows the temporal evolution of the stress*thickness product before and during deposition of the Ti adhesion layer, as well as after Pd deposition, and as a function of Pd thickness for the two batches studied here. After the baseline measurement, the stress in the Ti adhesion layer follows a characteristic bump-like profile, whose interpretation can be found elsewhere [28,45]. Soon after the start of Pd deposition, the slope of the stress*thickness vs. thickness curve becomes constant.…”

Section: Introductionmentioning

confidence: 97%

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Effect of structural defects on the hydriding kinetics of nanocrystalline Pd thin films

Delmelle

Amin-Ahmadi

Sinnaeve

et al. 2015

International Journal of Hydrogen Energy

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MicrostructureInternal stress a b s t r a c t While the microstructure of a metal is well-known to affect its equilibrium hydrogen uptake and therefore the hydriding thermodynamics, microstructural effects on the hydriding kinetics are much less documented. Moreover, for thin film systems, such microstructural effects are difficult to separate from the internal stress effect, since most defects generate internal stresses. Such a decoupling has been achieved in this paper for nanocrystalline Pd thin film model systems through the use of a high-resolution, in-situ curvature measurement set-up during Pd deposition, annealing and hydriding. This set-up allowed producing Pd thin films with similar internal stress levels but significantly different microstructures. This was evidenced from detailed defect statistics obtained by transmission electron microscopy, which showed that the densities of grain boundaries, dislocations and twin boundaries have all been lowered by annealing. The same set-up was then used to study the hydriding equilibrium and kinetic behaviour of the resulting films at room temperature. A full quantitative analysis of their hydriding cycles showed that the rate constants of both the adsorption-and absorption-limited kinetic regimes were strongly affected by microstructure. Defect engineering was thereby shown to increase the rate constants for hydrogen adsorption and absorption in Pd by a factor 40 and 30, respectively.

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Structural Phase Transitions in Niobium Hydrogen Thin Films: Mechanical Stress, Phase Equilibria and Critical Temperatures

et al. 2019

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Metal−hydrogen (M−H) systems offer grand opportunities for studies on fundamental aspects of thermodynamics and kinetics. When the system size is reduced to the nanoscale, microstructural defects as well as mechanical stress affect the systems’ properties. This is contemplated for the model system of epitaxial niobium−hydrogen (Nb−H) thin films. Hydrogen absorption in metals commonly leads to lattice expansion which is hindered when the metal adheres to a flat rigid substrate. Consequently, high mechanical stress of about −10 GPa for 1 H/Nb are predicted, in theory. However, metals cannot yield such high stresses and respond with plastic deformation, commonly limiting measured stresses to −2 to −3 GPa for 100 nm Nb−H films. It will be shown that the coherency state changes with film thickness reduction, shifting the onset of plastic deformation to larger hydrogen concentrations. Below critical film thicknesses, plastic deformation is fully absent. The system then behaves purely elastic and ultra‐high stress of about −10 (±2) GPa can be obtained. Arising stress controls the phase stability of M−H systems, and the coherency state strongly affects the nucleation and growth dynamics of the phase transition. In case of Nb−H thin films of less than 8 nm thickness the common phase transformation from the α‐phase solid solution to the hydride phase is completely suppressed at 300 K. Related effects can be utilised to optimise metal−hydrides used in applications.

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Effect of internal stress on the hydriding kinetics of nanocrystalline Pd thin films

Cited by 16 publications

References 39 publications

Mechanical stress and stress release channels in 10–350 nm palladium hydrogen thin films with different micro-structures

Mechanical stress and stress release channels in 10–350 nm palladium hydrogen thin films with different micro-structures

Effect of structural defects on the hydriding kinetics of nanocrystalline Pd thin films

Structural Phase Transitions in Niobium Hydrogen Thin Films: Mechanical Stress, Phase Equilibria and Critical Temperatures

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