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Heat Treatment and Coating Application
ArticleName The influence of heat treatment of the Kh15Yu5 (Cr15Al5) alloy with an aluminide coating on its thermal and electrical conductivity
DOI 10.17580/chm.2024.01.08
ArticleAuthor V. G. Shmorgun, V. P. Kulevich, A. I. Bogdanov

Volgograd State Technical University, Volgograd, Russia

V. G. Shmorgun, Dr. Eng., Prof., Dept. of Materials Science and Composite Materials, e-mail:
V. P. Kulevich, Cand. Eng., Associate Prof., Dept. of Materials Science and Composite Materials, e-mail:;
A. I. Bogdanov, Cand. Eng., Associate Prof., Dept. of Materials Science and Composite Materials, e-mail:


The thermal and electrical conductivity of the hot-dip aluminized Kh15Yu5 (Cr15Al5) alloy after long-term heat treatment at a temperature close to the operating temperature (1100 °C) has been studied. It is shown that the heat treatment of the aluminized alloy for 20 h leads to the formation of a coating with a thickness of ~260 μm of variable composition, which changes from the surface to the base in the following sequence: FeAl(Cr, Si) → Fe3Al(Cr, Si)  Fe(Al, Cr, Si). An increase in the heat treatment time to 100 h is accompanied by the transformation of the coating surface phase composition to a solid solution of variable composition based on αFe. The microhardness of the coating surface decreases during heat treatment from 3.5 GPa to 2.4 GPa after 1000 h. It has been established that long-term high-temperature heating of the Cr15Al5 alloy with an aluminide coating leads to a decrease in its thermal conductivity, in comparison with a pure alloy, by 10–12 % due to the diffusion redistribution of the components that make up the coating. It is shown that the aluminide coating on the Kh15Yu5 (Cr15Al5) alloy surface increases the electrical resistivity of the sample by 0.2 Ohm·mm2/m, and high-temperature treatment contributes to an additional increase and stabilization of the resistance at a level above 1.55 Ohm·mm2/m. The high electrical resistivity of the Kh15Yu5 (Cr15Al5) alloy with an aluminide coating and the stability of properties during hightemperature heating make this material promising for use as heating elements.
The study was supported by the Russian Science Foundation grant No. 23-79-01245,

keywords Aluminizing, heat treatment, iron aluminides, coating, thermal diffusivity, specific heat capacity, thermal conductivity, electrical resistivity

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