Microstructures of NiCoCrAlY coatings grown by plasma activated electron beam physical vapor deposition

A novel technique-the plasma activated electron beam-physical vapor deposition (PAEB-PVD)-was developed by modifying the conventional electron beam physical vapor deposition (EB-PVD) to significantly reduce the columnar and linear defects of the NiCoCrAlY coatings, grown by EB-PVD. The high quality NiCoCrAlY coatings were deposited by the newly-developed technique. The impacts of the deposition conditions on microstructures and mechanical properties of the coating were evaluated. The results show that the energy of the impinging adatom strongly affects its microstructures. The energy of the adatom can be increased by increasing the arc discharge voltage and substrate bias. As the adatom energy increased, the columnar grains of the coating changed into the more compact equiaxial ones, accompanied with grain growth. Meanwhile, strong segregation was observed, resulting in an increased of Al content, a decreased Cr content, and an increase of plasticity.