Reflection Polarization Spectral Characteristics of High Performance Coating Material La₂Zr₂O₇

Rare earth zirconate (RE2Zr2O7, RE is rare earth element) materials have the advantages of low thermal conductivity, stable high-temperature phase structure, corrosion resistance and relatively low price, etc. In recent years, it has been widely and deeply applied in the fields of the thermal barrier coating, environmental barrier coating and nuclear protective coating and has attracted extensive attention. However, the current research on these coating materials is mainly focused on thermal, mechanical and electrical properties, while the optical properties, especially the polarization characteristics of reflected light, are rarely reported. Therefore, taking La, Zr2O7 as the representative, the optical polarization characteristics of rare earth zirconate were systematically studied, especially the corresponding relationship between material surface properties and optical polarization characteristics was analyzed. In the experiment, the powder and density bulk of La, Zr2O7 were synthesized by the solid-state reaction method. The microstructure was analyzed and characterized by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscope (SEM). The results show that the prepared La2Zr2O7 is a cubic pyrochlore phase structure. In the analysis of optical properties, natural light and linearly polarized light were used as detection light sources, respectively, and the polarization characteristics of reflected light are studied under different detection angles. It is shown that, for the natural light incidents, the degree of linear polarization (DOLP) of both bulk and powder La2Zr2O7 materials is significantly dependent on the incident light wavelength. With the increase of wavelength, the DOLP increases first and then decreases. It is worth noting that the DOLP decreases rapidly and approaches zero in the infrared band, indicating that the material shows good polarization stealth characteristics in the infrared band. It is also found that the DOLP of dense bulk has amaximum value at similar to 720 and similar to 773 nm while natural light is incident, and the peak wavelength is not sensitive to the detection angle. Powder materials also have two peaks near similar to 714 and similar to 774 nm. Under the incidence of linearly polarized light, for the large angle detection angle, DOLP of bulk has two peaks at similar to 720 and similar to 763 nm respectively. Different from the incidence of natural light, two peak values are equal under the same detection angle. Two peaks near similar to 720 and similar to 755 nm respectively appear for powder materials, and the peak intensity decreases, indicating that the roughness of the coating material has a definite influence on the polarization characteristics of the reflected light. Further research shows that the wavelength corresponding to the two peaks does not become dependent on the detection angle. The results of this study provide theoretical and experimental support for the development, application and design of polarization spectroscopy of rare-earth zirconate coating materials.