The Moscow Institute of Steel and Alloys (MISIS) has proposed a method of coating that protects heat-resistant alloys from oxidation at extreme temperatures up to 850°C. The technology makes it possible to avoid defects in materials and, when implemented in production, will increase the durability of turbine blades and aircraft engines under high temperature conditions.
Heat-resistant alloys based on intermetallide containing titanium and aluminium are widely used in aircraft engine building due to their oxidation resistance and low density, but the complexity of machining parts from such alloys causes difficulties in production. Currently, orthorhombic intermetallide of titanium, aluminium and niobium (Ti-Al-Nb) is a promising alternative. The mechanical stability of niobium-containing heat-resistant alloys is important for their use in jet and rocket engines, but low oxidation resistance limits the use of such alloys at high temperatures.
MISIS scientists used a pulse-arc method of vacuum non-contact melting of granular layers to create a protective coating on the surface of parts made of Ti-Al-Nb alloy. This method allowed controlling the composition of the formed layer, providing high aluminium content to increase oxidation resistance. The developed technique ensures good adhesion to the base material while maintaining optimum mechanical properties.
“After oxidation at 850°C, a thin layer of protective oxide only 1.5 µm thick is formed on the coating. After 100 hours of heating, this layer remained practically unchanged, which allows us to conclude that the developed coating is capable of protecting the material under long-term use and high temperatures,” Alexander Sheveyko, a researcher at MISIS, commented to the Russian Aviation website.
The method of vacuum non-contact melting made it possible to create a durable coating with high resistance to oxidation at extreme temperatures. The results of the research are described in detail in the scientific journal Coatings (Q2).
