Gaydayenko O. Formation of aluminized coatings on structural materials for coke-chemical production under conditions of self-propagating high-temperature synthesis

The dissertation is devoted to solving an urgent scientific problem in the field of materials science: the formation of new aluminized coatings on structural materials for coke production using self-propagating high temperature synthesis (SHS) to increase their operational properties. The results of thermodynamic modeling in multicomponent saturating media during alimentation under SHS conditions are presented. It was proved that for the temperature range of 700–1500 K, the decay products of the activator (AlF3, NH4I, NH4F) react with alloying elements included in SHS batch with the formation of gaseous compounds. With increasing temperature, the amount of products in the gaseous phase increases and condensed products are released. Five stages of the process of obtaining doped aluminized coatings, the temperature of self-ignition, and the maximum temperature of the amount of chromium component in the SHS mixture were established. The structure, phase composition, and distribution pattern of alloying elements are investigated. Voltammograms were obtained and the dependences of the corrosion resistance of the coatings on the type of alloying were established. Dependences of residual stresses, microhardness in thickness, and wear resistance are described by fifth-order polynomial, which made it possible to establish rational modes of their formation. It has been established that compressive stresses arise on the surface of steel 45, which they attain upon alloying: with chromium 200–220 MPa, titanium 160–180 MPa, and silicon 100–110 MPa. An efficient low-waste technological process of obtaining alloyed alitated coatings on structural materials operating under conditions of coke-chemical production has been developed. The results of the work were tested in the conditions of JSC "Zaporizhcox". Key words: aluminizing, coating, steel, alloying, coke, corrosion, heat resistance, wear resistance, synthesis.