New Methods to Deposit Nickel-Aluminide Alloys as High Temperature Protective Coatings on Stainless Steels

Farhadi, Farzaneh

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New Methods to Deposit Nickel-Aluminide Alloys as High Temperature Protective Coatings on Stainless Steels

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Nickel-Aluminide intermetallic alloys have drawn attention because of their interesting properties. They have long been used as coating materials for industrial and structural applications, where their functions have been to increase the lifetime of parts at high-temperature applications by enhancing not only mechanical properties such as high temperature tensile and compressive yield strength, high-temperature wear resistance, and fatigue resistance, but also by enhancing oxidation, and carburization resistance of parts at high temperature. Nickel aluminide coatings have been used extensively in gas turbines, turbocharger components, valves, and piston head of internal combustion engines, jet engines, furnaces and furnace assembly, and forging dies. The present research focuses on developing novel methods to deposit nickel-aluminide intermetallic coatings on RA330 stainless steel. The basic aim has been to study the formation of different Ni-Al intermetallic coatings via several methods. These methods were identified to provide processes to coat complex geometries and develop the nickel aluminides. The thickness of the diffusion layers and intermetallics were controlled by post-diffusion treatment. All the coatings were characterized for their phase fractions, morphology, composition, microstructure, and adhesion to the substrate using XRD, SEM, EDS, EBSD, and optical microscopy and all methods were proven to be successful to develop one or more Ni3Al and NiAl phases.

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