Nanostructured Gd2Zr2O7: a promising thermal barrier coating with high resistance to CaO-MgO-Al2O3-SiO2 corrosion

Nanostructured Gd2Zr2O7 (NGZO) thermal barrier coatings (TBCs) have great potential applications in airplane engines and hot sections of gas turbine engines operating in volcanic ash-exposed or dust-laden environments. In this paper, NGZO is deposited on IN738LC/CoNiCrAlY using the atmospheric plasma spraying (APS) technique. Also, yttria-stabilized zirconia (YSZ) was utilized to produce conventional TBC. The CaO-MgO-Al2O3-SiO2 (CMAS) corrosion resistance and phase stability of IN738LC/CoNiCrAlY/YSZ (YSZ: ZrO(2)4 mol.% Y2O3 as the conventional TBCs) and IN738LC/CoNiCrAlY/ NGZO (NGZO: ZrO2 33 mol.% Gd2O3 as the new generation of TBCs) were assessed at 1250 degrees C by 5-h cycles with and without the presence of CMAS particles. The X-ray diffraction (XRD) analysis and microstructural investigations by field emission scanning electron microscopy (FESEM) equipped with an energy-dispersive X-ray spectroscope (EDS) revealed that NGZO coatings had high resistance against penetration of CMAS particles by forming an accelerate non-permeable Gd8Ca2(SiO4)(6). Also, the qualitative and quantitative XRD analyses by the Rietveld refinement method indicated that the NGZO coating maintained its phase stability during the thermal cycles after 20 h of exposure to 1250 degrees C.

Automated summary

In this study, conventional yttria-stabilized zirconia (YSZ) thermal barrier coatings and nanostructured Gd2Zr2O7 (NGZO) coatings were prepared using atmospheric plasma spraying (APS) on IN738LC/CoNiCrAlY substrates. The NGZO coatings showed high resistance against CMAS particle penetration and maintained phase stability during thermal cycles.