The Effects of Ceria Addition to HVOFThermal Sprayed NiAl Intermetallic Coatings

摘要

In this paper, the effects of ceria addition to HVOF thermalsprayed NiAl intermetallic coatings were investigated throughmicro-indentation, thermal shock testing, and microstructuralanalysis techniques including SEM with EDX, and XRDanalysis. It has been found that the addition of ceria to NiAlcoatings reduces the tendency of brittle peeling during thermalspraying. This reduction in peeling is presumably due to theimproved wetting of the substrate by the molten coatingmaterial, which ultimately leads to better coating adhesion.The addition of ceriaalso resulted in higher coating hardnessand elastic modulus as determined by micro-indentation. Thecoatings containing ceria also exhibited significant increasesin thermal shock resistance when compared with that of thepure NiAl coatings. The possible mechanisms responsible forthe improvement of the above mentioned properties upon theaddition of ceria are also addressed in this paper.