Regularities of formation of PNKh20K20Yu13 powder material intermetallic coating

An important area in the field of gas-thermal technologies is the development of heatprotective ceramic coatings for thermally loaded parts of power and aircraft engineering (combustion chambers, working and guide blades, protective plates, heat shields of gas turbines). However, the coefficient of thermal expansion and the hardness value of metal-ceramic coatings differ significantly from the metal base of the processed parts. Therefore, in order to create a smooth transition from the substrate to the working ceramic layer, a transition layer (sublayer) is first formed from multicomponent powder materials of the Ni - Cr - Co - Al - Y system. The most popular powder materials on the domestic ferrous metallurgy market are PNKh20K20Yu13 grade from different manufacturers. The properties of this domestically produced intermetallic powder material with a particle size of 40 to 80 μm were studied and tested as a initial material for plasma spraying of a heat-resistant coating. X-ray phase and microstructural analysis methods showed that the powder has an intermetallic phase composition based on the β-Ni(Me)Al phase. Under high-temperature exposure to a plasma flow, a phase transformation β → γ’ occurs in the sprayed material. Derivatographic studies showed that the phase transition occurs in the temperature range of 660–839 °C. As a result, a coating of the Ni – Cr – Co – Al – Y system is formed with a two-phase intermetallic composition (β-Ni(Me)Al + γ’-(Ni,Me)3Al), a layered microstructure of grains and a dendritic structure of spheroidal grains. The coating is characterized by low total porosity (~5 %), Vickers hardness HV = 5.5 GPa, roughness Ra = 6.5 μm. The studied coating is recommended for use both as a sublayer in two-layer heat-protective coatings and as an independent heat-resistant coating for protecting critical parts of power and aircraft engineering.The work was carried out within the framework of the state assignment of the IAP RAS for fundamental scientific research in 2024–2026. FFUF-2024-0031. No. NIOKTR 1023032800130-3-2.3.2.