新型燃气轮机用热障涂层研究

Next Generation Thermal Barrier Coatings for the Gas Turbine Industry

本文旨在开发新型的具有低的导热系数及高的使用寿命的大气等离子喷涂热障涂层。使用了工业上广泛应用的等离子喷枪制备出系列涂层体系。通过改变涂层材料的化学特性,如使用高纯度材料以提高抗烧结能力,使用镝稳定的氧化锆粉末和预含孔隙结构的粉末。同时,团聚烧结(A&S)与空心球形粉末(HOSP)被运用以期获得有益的微观结构。最终,使用不同形态的粉末制备出具有双层结构的涂层。通过激光闪烁法对涂层在室温到1200℃条件下的导热性能进行评价。测试是在1150℃条件下热处理100h的涂层上进行,这用于评价涂层体系在烧结过程中第一阶段的抗烧结能力。涂层的导热性能与涂层的显微结构有关,本文采用图像分析法对孔隙与裂纹含量进行分析,结果表明,孔隙的存在会降低涂层的导热性能。

The aim of the study presented in this paper was to develop the next generation of production ready air plasma sprayed thermal barrier coating with a low conductivity and long lifetime.In order to achieve these goals;a number of coating architectures were produced using commercially available plasma spray guns.Modifications were made to powder chemistry including;high purity powders for sintering resistance,Dysprosia stabilised Zirconia powders and powders containing porosity formers.Agglomerated Sintered（AS） and Hollow Oven Spherical Powder（HOSP） morphologies were used to attain beneficial microstructures.Finally,dual layer coatings were produced using the different powder morphologies.Evaluation of the thermal conductivity of the coating systems from room temperature to 1200oC was conducted using laser flash technique.Tests were done on as-sprayed samples and samples heat treated for 100 hours at1150oC in order to evaluate the first stage sintering resistance of the coating systems.Thermal conductivity results were correlated to coating microstructure using image analysis of porosity and crack content.The results show the influence of beneficial porosity on reducing the thermal conductivity of the produced coatings.