Development of Nanostructured Lanthanum Zirconate Coating and Its Thermal Stability Properties

In this paper, nanostructure Lanthanum zirconate thermal barrier coatings (MCrAlY+ La₂Zr₂O₇) were prepared by atmospheric plasma sprayed (APS). The microstructures and thermal stability properties were systematically studied 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.