As the global energy market shifts from coal, petroleum fuel, and natural gas to more environmentally friendly primary energy sources, hydrogen is becoming a crucial pillar in the clean energy movement. Developing safe and cost-effective storage and transportation methods for hydrogen is essential but complicated given the interaction of hydrogen with structural materials.

Hydrogen can cause brittleness in several metals including ferritic steel—high-chromium, magnetic stainless steels that have a low carbon content that are used in structural components of buildings, automobile gears and axles, and industrial equipment. Recent advancements in experimental tools and multiscale modeling are starting to provide insight into the embrittlement process.

a) The arrowhead-shaped delaminations in stainless steel reveal cracks with significantly higher deuterium concentrations b) Secondary ion cross-sectional profile for one such delamination. Credit: O. Sobol, G. Holzlechner, G. Nolze, T. Wirth, D. Eliezer, T. Boellinghaus, and W.E.S. Unger

A review of various methods, published in Applied Physics Reviews has improved the understanding of the structure, property, and performance of ferritic steels that are subjected to mechanical loading in a hydrogen environment. While there are many studies of stainless steel, the researchers concentrated on ferritic steel, a cheaper steel that is used in the construction of pipelines and other large structures.

Understanding where the hydrogen goes under strain in a bulk material is critical to understanding embrittlement.

Determining the location of the hydrogen in the host metal is the million-dollar question. We haven’t answered this question but by combining techniques, we are getting closer to that answer.—May Martin, co-author

The researchers highlighted several combinations of techniques and methods, including atom probe tomography (APT). APT combines a field ion microscope with a mass spectrometer to enable 3D imaging and chemical composition measurements at the atomic scale, even for light elements such as hydrogen.

Other techniques that show promise are 2D mapping by secondary ion mass spectrometry to answer the question of where hydrogen lies in a material. Ion mass spectrometry is a technique used to analyze the composition of solid surfaces and thin films by sputtering the surface of the specimen with a focused primary ion beam and collecting and analyzing the ejected secondary ions.

The researchers said it is particularly in the last decade that large advances have been made in hydrogen embrittlement, thanks to the development of new experimental capabilities. As new experimental techniques are refined it is expected the field will continue to develop at a remarkable pace.

Ling Martin, Matthew Connolly, Frank W. DelRio, and Andrew Slifka (2020) “Hydrogen embrittlement in ferritic steels” Applied Physics Reviews doi: 10.1063/5.0012851

Posted on 06 October 2020 in Hydrogen, Market Background, Materials | Permalink | Comments (7)

No pipes, make it where you use it.

Posted by: SJC | 06 October 2020 at 11:04 AM

"Type 316/316L austenitic stainless steels are considered the benchmark for resistance to hydrogen embrittlement in gaseous hydrogen environments. Type 316/316L alloys are used extensively in handling systems for gaseous hydrogen, which has created engineering basis for its use. This material class, however, is relatively expensive compared to other structural metals including other austenitic stainless steels, thus the hydrogen fuel cell community seeks lower-cost alternatives. " From: https://asmedigitalcollection.asme.org/PVP/proceedings-abstract/PVP2014/46049/V06BT06A023/284260

Another way to cut cost would be to make H2 locally and store it locally to avoid using long pipelines as with natural gas or petroleum.

Posted by: Roger Pham | 06 October 2020 at 01:48 PM

I imagine it is more economical to have fewer, larger, hydrolizers than one at every gas/petrol station. Once "they" set their mind to it, they'll probably find an economical way to transport it / pipe it around. Maybe they could line normal steel pipes with a stainless steel coating.

Posted by: mahonj | 06 October 2020 at 03:53 PM

@mahonj, Local H2 piping system that are of low-pressures can be made from polyethylene or iron that can tolerate low-pressure H2, instead of steel. Thus, existing low-pressure residential piping for natural gas can take 100% H2 as-is. Thus, a local electrolyzer can serve the entire city, to ensure economy of scale.

Posted by: Roger Pham | 06 October 2020 at 04:14 PM

@Roger, OK, but it sounds like a waste to use H2 in gas boilers. Better to keep it for fuel cells. Maybe you could make large bore low pressure H2 pipes to move it around (or maybe I am talking through my hat).

Posted by: mahonj | 07 October 2020 at 01:29 AM

Anyone suggesting a pipeline or truck / train distribution of H2 should bear in mind that every ton of steel produced to warrant such infrastructure is the cause of 1.7 tons of CO2 emissions.

Posted by: yoatmon | 07 October 2020 at 08:52 AM

It may make 2 tons of CO2 to make a unibody, but it creates 6 tons every year operating.

Posted by: SJC | 08 October 2020 at 06:50 AM

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