From Process to Performance: Tailoring Coatings for Harsh Service Conditions

Improving efficiency and reliability in energy systems requires coatings capable of withstanding extreme environments. In this work, two classes of high-performance coatings, MAX phases and refractory compositionally complex alloys (RCCAs), were developed and optimized. Using nanostructured multilayer precursors deposited by magnetron sputtering, phase-pure Al2O3-forming MAX coatings with basal-plane orientation and controlled microstructures were synthesized at reduced temperatures. In parallel, Ta–Mo–Cr–Ti–Al RCCA coatings were produced with compositions tailored for balanced oxidation resistance and mechanical stability. By tuning deposition parameters, dense coatings closely matching bulk alloys were achieved. Both coating systems show excellent high-temperature corrosion resistance in various environments, including air, steam, and liquid metals. MAX coatings form protective alumina scales, while RCCA coatings develop complex (Cr,Ta)-rich rutile layers. These results demonstrate how microstructural design and compositional control enable next-generation coatings for extreme-service applications.