Efficiency of using Nitride and Oxy-Nitride Coatings for Protection Against High-Temperature Oxidation and Embrittlement of the Surface Layer of Steel Structures

G.Zh.Moldabayeva1,Email

А.L.Kozlovskiy1,2

E.I. Kuldeyev1

А.Kh. Syzdykov1

N.S. Buktukov3

1Department Petroleum Engineering, Satbayev University, Almaty, 050013, Kazakhstan.
2Laboratory of Solid State Physics, The Institute of Nuclear Physics, Ibragimov St., 050032 Almaty, Kazakhstan.
3Mining Institute Named after D.A. Kunaev, Almaty 050013, Kazakhstan.

Abstract

The problem of gas swelling and high-temperature degradation of steels and alloys is one of the limiting factors during long-term operation of materials operating at high temperatures (about 400 - 700°C), as well as when interacting with various gaseous media. To solve this problem, the paper proposes the use of thin-film Al - O - N and AlN coatings obtained by magnetron sputtering (which is one of the most common and well scalable methods in modern materials science) to protect against high-temperature degradation, as well as associated gas swelling (in case of hydrogenation) and to maintain stability to wear. The main purpose of using AlN and Al – O – N coatings as protective materials is to increase the resistance of steel structures to the processes of hydrogenation and high-temperature oxidation, operating under conditions of aggressive exposure to high temperatures and hydrogen. Moreover, the use of these coatings is aimed at reducing the rate of degradation and oxidation by reducing diffusion processes associated with the migration of implanted hydrogen into the surface layer. During the studies aimed at determining the effectiveness of increasing the wear resistance and strength of steel structures due to applied coatings, it was found that the use of Al – O – N and AlN coatings makes it possible to increase resistance to high-temperature degradation by more than 5 times compared to the results of changes in the strength characteristics of 316 L steel. Moreover, in the case of determining the coefficient of dry friction, it was found that the processes of hydrogenation and high-temperature heating without their combination (i.e., first hydrogenation of the samples and then thermal heating) lead to almost equivalent changes in the strength parameters for the coatings under study. At the same time, a comparison of the obtained results of changes in strength parameters and wear resistance of coatings showed that Al – O – N coatings are more resistant to high-temperature degradation, for which the decrease in strength parameters is less pronounced than for AlN coatings.