Why hydrogen causes steel to become brittle and crack is a big problem for engineers and researchers.
As a result of a new study from the University of Sydney, adding the chemical element molybdenum to steel reinforced with metal carbides can significantly improve its ability to capture hydrogen. The findings were published in Nature Communications.
They used an advanced microscopy technique called cryogenic atom probe tomography to directly observe the hydrogen distribution in the material.
Hydrogen embrittlement is a process in which hydrogen causes high-strength materials, such as steel, to become brittle and crack. Researchers say this is one of the biggest barriers to the transition to a hydrogen economy, as it hinders the efficient storage and transportation of hydrogen at high pressures. This makes understanding and solving the brittle problem a multi-billion dollar problem in the renewable energy market.
The future of the large-scale hydrogen economy depends largely on this issue. Hydrogen is known to be very harmful, as the smallest atom and molecule, it penetrates into the material and then cracks the material. This is not ideal for the efficient production, transportation, storage and use of hydrogen on a large scale. The researcher said.
How the process works
Molybdenum is added to steel and combined with other elements to form an extremely hard ceramic called "carbide". Carbides are often added to steel to improve its durability and strength.
Using their advanced microscopy techniques, the researchers found that the hydrogen atoms were located at the core of the carbide site, suggesting that the addition of molybdenum helped capture hydrogen. This is compared to benchmark titanium carbide steels, which do not exhibit the same hydrogen capture mechanism.
"The addition of molybdenum helps increase the presence of carbon vacancies – a defect in carbides that efficiently capture hydrogen," the researchers said. ”
The added molybdenum is only 0 percent of the total steel2%, the researchers say, is a cost-effective strategy to reduce embrittlement. Researchers believe that niobium and vanadium may also have a similar effect on steel.
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