The development by Perm Polytechnic has enabled a thorough investigation into the onset of corrosion in aircraft engines.

This article was published in the journal "Inorganic Materials: Applied Research" in 2024. The research was conducted with financial support from the Ministry of Education and Science of the Russian Federation as part of the strategic academic leadership program "Priority-2030."

The corrosion impact on alloys can be studied through tests in a high-speed flow of combustion products from aviation fuel, enhanced by special agents—substances that induce corrosion. This method allows for a reliable simulation of the actual operating conditions of a gas turbine engine, which cannot be achieved through laboratory studies.

During engine operation, the surface structure of aviation alloys experiences constant damage, leading to an increased rate and extent of corrosion. This is influenced by temperature, defect concentration in the material, and the concentration of corrosive agents in the combustion products and the air being fed into the engine.

Scientists from Perm Polytechnic University, in collaboration with JSC "ODK-Aviadvigatel," have developed a unique automated test bench for studying high-temperature gas and salt corrosion, as well as the thermal stability of alloys intended for manufacturing parts of the hot section of gas turbine engines.

"Conducting experiments on such a setup ensures a high-quality investigation of materials at elevated temperatures, their cyclic variations, and high gas flow rates. We can simulate situations similar to real engine operating conditions, such as exposure to sea water vapors, volcanic ash, desert sand, and the gas atmosphere of large industrial cities," explains Vladimir Poilov, professor at the Department of Chemical Technologies of PNIPU and Doctor of Technical Sciences.

In gas turbine installations, heat-resistant nickel alloys are widely used for components that operate at extreme temperatures (turbine blades and combustion chambers). These alloys are characterized by high strength, thermal resistance, and corrosion resistance. For the experiments, the polytechnic researchers tested samples of this alloy on the developed test bench at temperatures of 750 and 850 degrees. Aqueous solutions of sea salt and mixtures of sodium sulfate and chloride were used as corrosive agents.

The results showed that with increasing temperature and the number of cycles, the corrosion intensity of the alloy increases. However, the effect of sea salt on nickel alloy differs significantly from that of the sodium sulfate and chloride mixture due to differences in the chemical processes occurring on the surface.

"Sea salt promotes the formation of a protective layer in the form of deposits on the surface, which hinders further corrosion. In contrast, the sodium sulfate and chloride mixture acts more aggressively, leading to more intense damage to the alloy. As a result, the geometric shape of the sample changes, its working part becomes thinner, and mass is lost," explains Vladimir Poilov.

The unique test bench developed by the PNIPU scientists has allowed for a detailed investigation of the corrosion resistance of aviation alloys. The test results contribute significantly to the creation of new materials and the enhancement of existing ones for gas turbine engines with improved corrosion resistance.