Abstract: In order to study the spectral reflectance characteristics of the thermal barrier coatings deposited on the surface of turbine blades in aero-engines, the NiCrAlYSi and NiCoCrAlYHf bondcoat of thermal barrier coatings (TBCs) were deposited on the 304 stainless steel substrate by vacuum arc ion plating and the topcoat of YSZ was deposited by EB -PVD. The spectral reflectance of TBCs within a wavelength range of 0.3 to 2.5 μm at room temperature was measured by UV -VIS -NIR spectrophotometer. The results show that no matter which kind of bondcoat is, the reflectance spectra of the NiCrAlYSi/YSZ and NiCoCrAlYHf/YSZ with the same thickness of bondcoat and topcoat are very close in the whole wavelength band. The spectral reflectance of the NiCrAlYSi/YSZ coat shows different characteristics under the topcoat thickness of 20, 100 and 170μm. Within the wavelength range from 0.3 to 0.45 μm, the coating with a 20 μm topcoat shows the strongest reflct ability on purple light, while the other two grayish-white sample show similar ability. Reflectance has a positive relativity to the YSZ thickness in the 0.45 to 2.5 μm wavelength range. Compared with that of the conventional YSZ, the spectral reflectance of micro laminate deposited by modified EB-PVD process is improved by two times.

Key words: thermal barrier coating, EB-PVD, reflectance, YSZ, micro laminate