Preparation and properties of ceramic Al2O3 coating as TBCs on MCrAly layer applied on Inconel alloy by cathodic plasma electrolytic deposition

Abstract

Inconel alloys (IN738) have found a wide range of applications in industries such as high-temperature resistance materials. Furthermore, different surface treatments and coatings have been developed for improving the properties of Inconel alloys. In this study, Al2O3 as a ceramic coating was deposited on the surface of the MCrAly as a ground coat layer on Ni-based super alloy, by cathodic plasma electrolytic deposition (CPED). The CPED process was carried out in Ethanol solution of Al (NO3)3.9H2O (18g/l). Several samples were obtained in different deposition conditions and analyzed using XRD, SEM and EDS. The XRD analysis shows the presence of Al2O3 and Ni3Al phases. Based on thermal expansion, this is in agreement with the composition of the MCrAlY used as bond coat. SEM micrograph showed changes in microstructure of specimen by varying the pH of the solution in different PH of solutions.