高性能涂层材料La_(2)Zr_(2)O_(7)的反射偏振光谱特性

Reflection Polarization Spectral Characteristics of High Performance Coating Material La_(2)Zr_(2)O_(7)

稀土锆酸盐(REZrO,RE为稀土元素)体系材料具有热导率低、高温相结构稳定、抗化学腐蚀和价格相对低廉等优势,近年来在热障涂层、环境障涂层和核防护涂层等领域得到广泛而深入的应用,获得了广泛关注。然而,目前对该涂层材料的研究主要还是集中在热学、力学及电学性能等,对光学性能特别是反射光的偏振特性研究则鲜见报道。以锆酸镧(La_(2)Zr_(2)O_(7))为代表,系统研究了稀土锆酸盐光学偏振特性,特别分析了材料表面属性与光学偏振特性的对应关系。实验中利用固相反应法分别合成制备了La_(2)Zr_(2)O_(7)粉体和致密块体材料,并利用XRD(X-ray diffraction),Raman spectra和SEM(scanning electron microscope)等分析表征其微观结构,结果显示制备的La_(2)Zr_(2)O_(7)材料为立方焦绿石相结构。在光学性能分析中,分别用自然光和线偏振光作为探测光源,在不同探测角下研究其反射光偏振特性。研究表明,对于自然光入射,La_(2)Zr_(2)O_(7)块体和粉体材料的线偏振度(DOLP)与入射光波长呈现显著的依赖关系,随着波长的增加,DOLP呈现出先增大后减小的趋势。值得注意的是在红外波段,DOLP迅速降低并接近于0,表明该材料在红外波段表现出良好的偏振隐身特性。研究还发现,在自然光入射时,致密块体材料的DOLP分别在波长~720和~773 nm出现极大值,且峰值波长对探测角度不敏感,粉体材料在~714和~774 nm附近也出现两个峰。在线偏振光入射,块体材料在大角度探测角下,DOLP在~720和~763 nm出现两个峰,与自然光入射光不同的是,同一个探测角下两个峰的峰值大小基本相同,粉体材料则在~720和~755 nm附近出现两个峰,且峰值强度减弱,说明涂层材料的粗糙度对反射光的偏振特性有一定影响,研究进一步显示,两个峰值对应的波长与探测角无显著依赖关系。本研究结果为稀土锆酸盐涂层材料的偏振光谱学的开发、应用和设计提供理论和实验支撑。

Rare earth zirconate(REZrO,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_(2)Zr_(2)O_(7)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_(2)Zr_(2)O_(7)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 La_(2)Zr_(2)O_(7)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 La_(2)Zr_(2)O_(7)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~720 and~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~714 and~774 nm.Under the incidence of linearly polarized light,for the large angle detection angle,DOLP of bulk has two peaks at~720 and~763 nm respectively.Different from the incidence of natural light,two peak values are equal under the same detection angle.Two peaks near~720 and~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.