A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Microstructural evolution of the interface between NiCrAlY coating and superalloy during isothermal oxidation
Graphical abstract Display Omitted
Highlights Interfacial oxide layer comprises α-Al2O3 and Cr2O3 sub-layers. Pure metal Al precipitates at the coating/substrate interface. AlN and TiN form in the substrate and AlN transforms into α-Al2O3 later.
Abstract NiCrAlY coating was plasma-sprayed on a Ni-based single crystal superalloy and then subjected to isothermal oxidation at 1100°C in air up to 50h. Using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), we investigate interfacial microstructure evolution of the coating induced by internal oxidation and nitridation. After 5h oxidation, α-Al2O3 and Cr2O3 sub-layers form at the coating/substrate interface. Interestingly, after 10h oxidation, pure Al phase is found at the coating/substrate interface owing to decomposition of substrate phase γ′-Ni3Al. Although, after 25h oxidation, hexagonal AlN and cubic TiN form in the substrate close to the coating/substrate interface, after 50h oxidation, AlN transforms into α-Al2O3 owing to internal oxidation while TiN remains in the substrate because of its high stability. The findings of this work provide solid experimental evidence of microstructural evolution at the coating/substrate interface, especially demonstrate the conjecture that pure metal phases and nitrides could precipitate at coating/substrate interface after high temperature oxidation.
Microstructural evolution of the interface between NiCrAlY coating and superalloy during isothermal oxidation
Graphical abstract Display Omitted
Highlights Interfacial oxide layer comprises α-Al2O3 and Cr2O3 sub-layers. Pure metal Al precipitates at the coating/substrate interface. AlN and TiN form in the substrate and AlN transforms into α-Al2O3 later.
Abstract NiCrAlY coating was plasma-sprayed on a Ni-based single crystal superalloy and then subjected to isothermal oxidation at 1100°C in air up to 50h. Using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), we investigate interfacial microstructure evolution of the coating induced by internal oxidation and nitridation. After 5h oxidation, α-Al2O3 and Cr2O3 sub-layers form at the coating/substrate interface. Interestingly, after 10h oxidation, pure Al phase is found at the coating/substrate interface owing to decomposition of substrate phase γ′-Ni3Al. Although, after 25h oxidation, hexagonal AlN and cubic TiN form in the substrate close to the coating/substrate interface, after 50h oxidation, AlN transforms into α-Al2O3 owing to internal oxidation while TiN remains in the substrate because of its high stability. The findings of this work provide solid experimental evidence of microstructural evolution at the coating/substrate interface, especially demonstrate the conjecture that pure metal phases and nitrides could precipitate at coating/substrate interface after high temperature oxidation.
Microstructural evolution of the interface between NiCrAlY coating and superalloy during isothermal oxidation
2015-05-05
7 pages
Article (Journal)
Electronic Resource
English
| British Library Online Contents | 2004
Isothermal Oxidation Characteristics of NiCrAlY Coating by Low Pressure Plasma Spraying
| British Library Online Contents | 2003
| British Library Online Contents | 2007
Characterization of Isothermal Oxidation of Air Plasma Sprayed NiCrAlY Coatings
| British Library Online Contents | 2006
Effect of NiCrAlY Coatings on Oxidation Resistance of Ni - Base Superalloy K17
| British Library Online Contents | 2002