Russian researchers have suggested a new method to form crystalline nanostructure of the Fe-Cu-Nb-Si-B alloys. The nanostructures obtained under the action of gas discharge optical radiation possess better magnetic and mechanical characteristics as compared to their analogues produced via temperature methods.

Creation of materials resistant to strong mechanical and magnetic action is one of important nanotechnology tasks. New nanostructural materials based on  the Fe-Cu-Nb-Si-B (iron, copper, niobium, silicon, boron) alloys that possess a high value of permeability are potentially able to replace permalloy – the iron/nickel alloy, which is now used extensively for magnetic field shielding.

So far, the Fe-Cu-Nb-Si-B crystals have possessed a significant drawback: low mechanical strength. Researchers at Kazan State Unversity and Kazan Technology University  have managed to develop a method to solve the problem. To get nanocrystals in the Fe-Cu-Nb-Si-B alloys, high-temperature annealing has been used so far, under which a disordered alloy structure turns into a crystalline structure under high-temperature action. The specimens obtained in this way acquire the necessary magnetic properties but they become very fragile and their surface oxidizes. Rouslan Nazipov, Anatoly Mitin and Nikolai Ziuzin have suggested a new alloy annealing method – processing by gas discharge. The article published this week describes that they obtained the Fe-Cu-Nb-Si-B nanocrystals by effecting the material by optical radiation of a gas-discharge flash lamp (powerful electromagnetic source with the band varying from infrared through ultraviolet). The obtained material is a polycrystalline one, i.e., it consists of multiple differently-oriented crystals called crystallites or grains.

The researchers have determined the alloy structure dependence on the power supporting it, and described crystal creation conditions. Full crystallization of experimental specimen of an alloy (30×10×0.025 mm) into the 150-nm grains required 1,529 joules (approximately the same amount of energy is spent by a human being to walk 10 meters). To create similar structures via thermal annealing, the specimen should be heated up to 900 degrees Celsius under vacuum conditions (to avoid metal oxidation). Consequently, gas discharge utilization does not only improve mechanical properties of crystals but also enables to save power significantly.

Source of information: R.A. Nazipov, A.V. Mitin, N.A. Ziuzin. “Crystallization of amorphous alloy of the Fe-Cu-Nb-Si-B system under the action of powerful pulse optical radiation”. Preprint of the article is available at http://arxiv.org/PS_cache/arxiv/pdf/1010/1010.5010v1.pdf

Further information: Nazipov Rouslan Airatovich – assistant at department of solid state physics, Kazan State University, е-mail: Ruslan.Nazipov@ksu.ru