Comparative Study of NiCoCrAlYTa Coatings After Burner-Rig Test
The NiCoCrAlYTa coatings were prepared on aero-engine turbine blades samples by low pressure plasma spraying.Different powders were used for the preparation.The burner-rig test was carried out at 1 000 ℃ for 75 hours.The size of coated blades,the surface morphology,phase composition,microstructure,thickness and uniformity of coatings were investigated.The results showed that there was no significant variation in the overall dimensions of different coated blades after burner-rig test.Al2O3 oxide film and NiAl2O4 spinel formed on the surface of coatings,which retained good structural integrity.The phase composition of coatings is γ-Ni,γ'-Ni3Al and a small amount of β-NiAl.Typical microstructure including Al-depleted zone,interdiffusion zone,and secondary reaction zone were observed in the cross-section.The precipitated TCP phase was R phase.The NiCoCrAlYTa coatings prepared by different powders all showed good thermal shock resistance.
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