Elastic versus Alloying Effects in Mg-Based Hydride Films

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Magnesium (Mg) thin films capped with palladium (Pd) exhibit higher hydrogen absorption pressures compared to bulk Mg.
• The observed phenomenon was previously attributed to elastic clamping by the Pd layer or simple Mg-Pd alloying.

Purpose of the Study:

• To resolve the controversy regarding the mechanism behind increased hydrogen absorption pressures in Mg-Pd thin films.
• To investigate the interplay between elastic clamping, alloying, and plastic deformation in hydrogen absorption.

Main Methods:

• Fabrication of Mg-Pd thin film alloys with varying compositions.
• Measurement of hydrogenation and dehydrogenation isotherms across a range of Mg-Pd compositions.
• Analysis to differentiate the contributions of elastic clamping, alloying, and plastic deformation.

Main Results:

• Hydrogenation and dehydrogenation isotherms were successfully measured for Mg-Pd thin film alloys.
• The study successfully disentangled the distinct effects of elastic clamping and alloying on hydrogen absorption.
• The significant role of plastic deformations in influencing hydrogen absorption pressures was identified.

Conclusions:

• The high hydrogen absorption pressures in Mg-Pd thin films are not solely due to elastic clamping or simple alloying.
• Plastic deformation emerges as a critical factor affecting hydrogen absorption behavior in these systems.
• This research provides a clearer understanding of hydrogen storage mechanisms in Mg-based thin film alloys.