MICROSTRUCTURE OF NiCoCrAlY COMPONENT IN PLASMA SPRAYED ZrO_2/NiCoCrAlY GRADED COATING
(1.School of Materials Science and Technology; Harbin Institute of Technology; Harbin 150001 ;
2.Center of Analysis and Test; Harbin Institute of Technology; Harbin 150001)
2.Center of Analysis and Test; Harbin Institute of Technology; Harbin 150001)
Abstract: NiCoCrAlY alloy component in ZrO2/NiCoCrAlY graded coating forms heterogeneous microstructure after plasma spraying, which consists of γ (Ni) matrix phase and some ε Co phase, as well as a little γ′ (Ni3Al) phase. Moreover, owing to the impaction of molten NiCoCrAlY droplets on the substrate at high speed, the alloy particles experience severe deformation at a high strain rate, producing a lot of dislocations. During rapid solidification, NiCoCrAlY alloy reacts with oxygen in air, and some NiO, Cr2O3, Al2O3 form in the alloy.
Key words: plasma spraying graded coating NiCoCrAlY microstructure