2173588 – Hydrogen in Materials: from Energy Storage to Hydrogen Embrittlement

This lecture adresses physical and chemical basics of hydrogen adsorption and absorption of different materials. It trains the understanding of the specific lattice positions that hydrogen occupies within solids, and its impact on material properties. A thermodynamical approach yields Sieverts’ law, allowing the students to describe the different solubilities of hydrogen (and other gases) in solid materials. Further thermodynamic data can be obtained using van’t Hoff plots of phase transformation pressures. The impact of ternary alloy components, as described by semi-empirical models, will be recognized. The specific mobility of hydrogen in materials will be understood, which divides into classical diffusion and quantum mechanical tunneling processes. The students can describe the interaction of hydrogen with defects in crystal lattices, which is of special interest for properties of nano-scale materials or for the hydrogen embrittlement of steels. Basic embrittlement models can be explained by the students. Actual hydrogen storage systems can be summarized. Learning objectives: o Hydrogen as energy storage – the hydrogen cycle and safety issues o Methods for hydrogen charging of materials and hydrogen detection o Hydrogen adsorption at and absorption in different solids, Sieverts’ law o Interstitial lattice sites and lattice expansion o Hydrides, van’t Hoff plots, phase transitions, M-H binary phase diagrams o Ternary alloy effects o Hydrogen mobility in materials: interstitial diffusion and quantum mechanical tunneling o Interaction of hydrogen with defects o Hydrogen embrittlement of steels, different embrittlement models o Hydrogen in nano-scale systems and new storage materials