Відео

Thanks for reaching out :) The green hydrogen can be directly used in many applications to replace fossil fuels, e.g. metal industry, heating systems, full cell vehicles. Such applications would drastically reduce CO2-emissions in these areas.

@@mpisusmat thanks for your reply. I will investigate the industrial application. Fuel cell doesn't really track for me just yet, using ammonia for fuel seems far more practical. It can basically directly substitute for diesel. With hydrogen he energy density, supply chain, energy loss in cooling to a liquid, etc. But I will continue learning and doing some math.

@@Greenammonianews You can also have a look at this website: www.mpie.de/4595091/all-about-hydrogen - here we sum up our research about hydrogen, also involving ammonia. Hope that helps :)

This statement is wrong. Although water vapor is a greenhouse gas, CO2 is a significantly more potent greenhouse gas. Replacing CO2 with water vapor is therefore a very good idea.

You're talking to an earth scientist. Vapor is by far in volume & potency because it has more windows open to IR. You are just trying to "will" something to be true because you follow the cult. It's seen readily in Plancks Radiation v Greenhouse Gas chart which you can find readily on the internet. @@luag_a

Great to see your interest in pursuing a PhD. Please have a look at out open positions and research school: www.mpie.de/3880486/job-offers www.mpie.de/2747306/doctoral-program

We use various techniques like Scanning Kelvin Probe or Atom Probe Tomography. Please have a look at our website: www.mpie.de/4595091/all-about-hydrogen www.mpie.de/4200660/materials-under-harsh-environments-and-their-stability-of-surfaces-and-interfaces

Of course! Liam used the Lammps (www.lammps.org) package. For some time now he has been using pyiron (www.pyiron.org) to manage his calculations; If you have conda installed, you can get a python interface to running Lammps quickly and easily with `conda install -c conda-forge pyiron_atomistics lammps` (installation is pretty similar for Windows machines (pyiron.readthedocs.io/en/latest/source/installation.html#lammps-molecular-dynamics-with-interatomic-potentials))

@@mpisusmat Thank you for your reply.

Absolutely. We are working on many aspects of hydrogen embrittlement and its prevention through coatings, self-healing and trapping.

Research and industry are both working on understanding the mechanisms and upscaling them. To be cost-efficient, not only reduction costs, but (green) energy and hydrogen production and transportation costs have to be considered.

Thank you for your nice comment. In this study, the samples were freshly polished and the native surface oxide was removed before hydrogen charging. We also did not observe the existence of native oxide in the atom probe experiments. Al oxide is indeed very important. We are currently working on the influence of the oxide on the hydrogen-related embrittlement of this alloy. Stay tuned :)

Hi Jon this is a complex issue, but a heat treatment may not enable the "detrapping" of some of the trapped hydrogen - it depends on how deeply it is trapped, ie what is the energy binding the hydrogen to its trapping site, which depends on the trapping site itself (e.g. a grain boundary, a carbide-matrix interface, a dislocation), along with the diffusivity of hydrogen in the surrounding matrix. So in ferritic or martensitic steels, in which hydrogen diffusion goes fast, detrapping could work efficiently, but in austenitic steels not so much... it might mean that even if we provide sufficient thermal agitation to move the hydrogen out of its site, it remains more or less close to the trapping site and might even progressively move back there it is also theorised that hydrogen may be more deleterious when free to move through a microstructure as it can facilitate the movement of dislocations, ie accelerate the deformation. Yet at some interfaces, when it agglemerates, it can facilitate their decohesion and cause embrittlement... our colleague Huan discusses this here: ua-cam.com/video/oMpdMyLTMC0/v-deo.html I hope this answers your question :)

Dear Shahab, thanks for reaching out. Do you mean using pyiron or do you mean working in the department "Computational Materials Design" as a researcher?

Using pyiron?

@@victormavika9168 please have a look at the pyiron software package (open source): github.com/pyiron

Work as a researcher ?

@@suparnabiswal8118 Dear Suparna, please have a look at our career page www.mpie.de/2747317/career - you can also apply anytime by sending your application to the group leader you want to work with, even if no open position is announced.

Thanks for reaching out. Concerning your question: Not for glasses or plastics, but for all crystalline materials yes! In crystals (e.g. a chunk of regular steel), plastic deformation typically happens via the creation and motion of a type of defect called a dislocation. The idea behind the Hall-Petch relationship is that when these dislocations are travelling through the material facilitating deformation, they sometimes run into a grain boundary. These boundaries aren't easy for the dislocations to get past, so this winds up impeding the dislocation motion and making it harder to deform the material. Eventually enough of them pile up at the edge of one of these boundaries to force the deformation process to continue. So the idea is that with smaller grains, there's room for fewer dislocations to pile up and they have a harder time reaching this critical mass to actually keep deformation going. Since there's no such animal as a dislocation in amorphous materials (e.g. glasses and plastics), and the model doesn't apply there.

If you mean using coatings as corrosion protection: this is done since a long time, e.g. think about coatings for metal sheets. However, we are also working on more efficient coatings and also on questions concerning scratches in coatings, thus locally ineffective corrosion-protection.

Thanks for your interest. Please have a look here: Materials under harsh conditions: www.mpie.de/4200660/materials-under-harsh-environments-and-their-stability-of-surfaces-and-interfaces All about hydrogen: www.mpie.de/4595091/all-about-hydrogen

yes, H2 on the surface of many metals may be more stable as a split molecule and hence as atomic hydrogen

@@mpisusmat are you saying that H2 disassociates into atomic H spontaneously at an Fe surface? One would think this is p and T dependent. Can you please refer to literature?

@@oeneroorda2699 Dear Oene, thank you for your interest. Usually hydrogen adsorbs in a dissociated state on metal surfaces. Please have a look at this paper: www.sciencedirect.com/science/article/pii/016757298890009X

@@mpisusmat thank you, I will read the article with great interest. Did you mean to say that there is also a mechanism by which molecular hydrogen is absorbed at the metal surface, without prior dissociation?

Thanks for reaching out. Please have a look at these two links where we summed up our research on hydrogen and hydrogen embrittlement: www.mpie.de/4595091/all-about-hydrogen www.mpie.de/4200660/materials-under-harsh-environments-and-their-stability-of-surfaces-and-interfaces

Dear Nirmal, thanks for your interest. Yes, you can but please state the "Max-Planck-Institut für Eisenforschung GmbH" as copyright and insert the link to this video. Good luck for your presentation :)

@@mpisusmat Thank you so much 🙏🙏

Dear Sandip, we are currently preparing a video on this topic. Meanwhile, the short answer is: coating or trapping. Please have a look here: www.mpie.de/4580549/dead-ends-for-hydrogen-induced-cracks?c=2914286 www.mpie.de/4339224/hydrogen-h2bs?c=2914286

Dear Geoff, thank you for your advice. We have now added English subtitles. All the best from the MPIE😊

Please have a look at our website: www.mpie.de/2281/en