Nanostructured Lanthanum Zirconate Coating and Its Thermal Stability Properties

In this paper, nano-La2Zr2O7 thermal barrier coatings (MCrAlY+ La2Zr2O7) were prepared by atmospheric plasma sprayed (APS). The microstructures and thermal stability properties were systematically studied to compare with their conventional counterparts by Scanning Electric Microscopy (SEM) transmission electron microscope (TEM) and X-Ray diffraction(XRD). The results showed that the nanostructured lanthanum zirconate coatings were typical lamellar structure which was composed of columnar grains about 90nm in diameter. A large quantity of micro-cracks and homogeneous distributed fine pores formed in the nanostructured zirconia coating. After ablation at 1300°C for 24 h, no apparent phase transformation was observed in lanthanum zirconate coating. The growth mechanism of the grains was subsequently discussed.