Tomsk scientists have developed a system for mathematical modeling of permeability and interaction of hydrogen with other elements of high-entropy niobium-containing alloys.
The research is supported by the Ministry of Education and Science's "Priority 2030" program. According to the TPU press service, alloys created using the mathematical model are more efficient in operation and less expensive to manufacture.
Why hydrogen purification filters are needed
Pure hydrogen is used for hydrogen fuel cells, so they will last longer and more stably. But hydrogen obtained by promising and economically viable methods, such as natural gas conversion, coal gasification, pyrolysis of industrial waste, contains a very large number of impurities.
The development of efficient hydrogen purification filters is an urgent task for hydrogen energy and science in general. One of the most effective and hydrogen-resistant membrane materials is palladium and its alloys. However, the use of such membranes in industrial production is impractical due to their high cost.
Therefore, polytechnics are modeling and synthesizing high-entropy alloys containing niobium, nickel, cobalt, and a number of other elements.
High-entropy alloys have a set of unique properties due to the so-called cocktail effect from different elements. They form a single crystal lattice, do not experience phase transformations in a wide temperature range. By varying the composition of the alloy, we can change the microstructure and crystal lattice of the material to improve hydrogen permeability at relatively low temperatures.
When gas passes through a membrane filter, the hydrogen molecule dissociates into atoms when heated. Single hydrogen atoms penetrate into the material and diffuse in the crystal lattice.
After passing through the metal, they recombine into a molecule on the outer surface, where pure hydrogen is obtained. This process depends on how quickly hydrogen moves in the crystal and how much hydrogen the material can absorb.
As part of the project, scientists from Tomsk Polytechnic University have developed new numerical models to assess the mobility of hydrogen when passing through multicomponent and high-entropy alloys containing niobium.
They will allow scientists to select and optimize alloys with low activation energy of hydrogen sorption and desorption, as well as phase stability in a wide temperature range, for the subsequent creation of new generation metal membranes based on high-entropy alloys.