Dr. Giovanni Capurso from Helmholtz‐Zentrum Geesthacht – Zentrum für Material‐ und Küstenforschung GmbH (HZG, Germany) visited Hystorsys AS (HSS) in Kjeller, Norway from 6 May 2019 until 6 June 2019 accomplishing a 1-month secondment.
Figure 1. From left to right: Vasyl Berezovets, Dr. Roman Denys (HSS), Dr. Giovanni Capurso (HZG), Dr. Jon Eriksen (HSS) and project manager Prof. Volodymyr Yartys (IFE)
Dr. Capurso from HZG has been seconded to HSS mainly in the activities of work package 1 (WP1) for summarizing the details of specification to metal hydride materials to be used in hydrogen storage and compression systems, as well as discussing and agreeing upon the most promising target compositions and preparation routes using arc‐melting. In addition, the analytical methods necessary for the materials characterization were defined.
In detail, the experimental work was focused on two phases:
- Synthesis of multicomponent intermetallic alloys using an arc-melter apparatus.
- Characterization of thermodynamic properties, by means of the Pressure-Composition-Temperature curves in a multicomponent Laves-type Ti, Zr, La, Ni, Mn, V, Fe alloy.
The first phase was important both for the preparation of samples to be characterized and because it represents a new skill to learn during the secondment: at HZG this technique has not been implemented and therefore Dr. Capurso could improve his knowledge by getting detailed instructions and then using the apparatus himself.
Figure 2. The arc-melter apparatus used
As first synthesis, a Ti20Cr40V40 BCC alloy was prepared, owing to its easy composition and interesting properties.
The second sample was prepared with the perspective of improving the knowledge of multicomponent alloys developed in the frame of the HYDRIDE4MOBILITY project. Its composition was:
In both case the selected element were weighted and prepared accordingly before the melting under Argon atmosphere. For the multicomponent sample, an annealing at 950 °C under Ar for 21 hours was recommended, to achieve a better homogeneity. After this annealing, the sample was handled in air, the metal alloy was crushed and inserted in a sample holder of the manual low pressure Sievert apparatus.
The sample mass is 1.8895 g and it was activated at 90 °C in dynamic rotary vacuum for 15 minutes.
This step was followed by an hydrogenation at approximately 25 bar and by the steps used to determine the experimental points of the isotherm.
Figure 3. Low pressure PCT setup
Below the two isotherm measured are reported. Two cycles have been performed to assess the reproducibility of the data, which is deemed good, with no difference in the slope of the plateaus or the size of the hysteresis.
Figure 4. PCT curves of the Ti0,3Zr0,7Mn0,7V0,12Fe0,12Ni1,2La0,03 sample at 20 °C
The equilibrium pressure at 20 °C is 5-4 bar at the midpoint of the plateau.
At least others two curves are necessary to determine the enthalpy and entropy values, these will be performed in the next future. In the meantime, Dr. Capurso will perform further analyses at HZG, using characterization techniques such as X-ray diffraction, electron microscopy and differential scanning calorimetry.
It is planned for Dr. Capurso to be seconded once more to HSS, to continue the work started and , in the frame of WP2, to define layout features of MH containers for hydrogen storage and compression and finally to participate in WP3, dealing with specification details and addressing integration issues for hydrogen storage and compression systems.