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Tailoring approach to predict the microstructure of thermal barrier coatings by adjusting the distribution of splat morphologies

通过调整片形貌分布来预测热障涂层微观结构的定制方法

基本信息

批准号：
398319556
负责人：
Professor Dr.-Ing. Wolfgang Tillmann
金额：
--
依托单位：
Lehrstuhl für Werkstofftechnologie (LWT)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2018
资助国家：
德国
起止时间：
2017-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/398319556?language=en
关键词：
Tailoring approach predict microstructure thermal

项目摘要

Atmospheric plasma sprayed Alumina and YSZ (Yttria stabilized zirconia) splats have been collected by different methods using APS process and investigated by different researchers. There is an agreement on the influence of in-flight particle and substrate conditions on the obtained splat morphologies. However, the impact of the interactions between the affecting conditions remains ill-defined. Furthermore, no clear relationships were established between the investigated distributions of splat morphologies and the resulted characteristics of pores and cracks within the produced coatings. Due to the fact that the efficiency of a TBC top coating depends mainly on the density, morphology and distribution of voids as well as on the density of segmentation cracks, there are optimal specifications that combine the required characteristics of pores and cracks for each field of application. In turn, the exerted thermal and mechanical loads determine the optimal required combinations.Therefore, the main aspect of this study is to collect YSZ splats and to produce the corresponding coatings under different conditions using DoE (Design of experiments) approach. The collection of splats will be achieved by means of the innovative and self-made beam shutter setup, which is available exclusively at the institute. The proposed work plan starts by identifying series of distributions of splat morphologies through a detailed splat analysis and establishing well-defined relationships between these distributions and the associated conditions. Afterwards, generally valid relationships have to be established between the identified distributions of splat morphologies and the resultant characteristics of pores and cracks. Furthermore, identifying the distributions of splat morphologies and segmentation cracks are optimized by investigating the interactions between the conditions that lead to the simultaneous coexistence of the desired microstructure. Even though, the optimization process will enhance the distributions of splat morphologies that control the coating porosity, the achievable level of porosity remains technically limited. Therefore, it is intended to add pore formers to YSZ spraying powders in order to increase the porosity to higher levels. The feedstock powders consist of up to 50 vol.% of pore former. A mixture variation will be utilized in conducting the experiments. SEM images of cross-sectional coatings will be used to investigate the effect of adding pore former on the obtained porosity within the obtained coatings. Finally, a direct relationship should be established between all these conditions, and the obtained microstructural features. The obtained results should allow us to produce APS coatings with predefined microstructure characteristics and enhance the reproducibility

采用不同的方法收集了常压等离子喷涂氧化铝和钇稳定氧化锆薄片，并由不同的研究人员进行了研究。关于飞行中的颗粒和衬底条件对所获得的飞溅形貌的影响是一致的。然而，影响条件之间相互作用的影响仍然不明确。此外，所研究的飞溅形貌分布与所产生的涂层中气孔和裂纹的特征之间没有明确的关系。由于TBC顶部涂层的效率主要取决于孔隙的密度、形态和分布以及分段裂纹的密度，因此存在将每个应用领域所需的孔隙和裂纹特征结合起来的最佳规格。反过来，施加的热负荷和机械负荷决定了所需的最佳组合。因此，本研究的主要方面是利用DoE （Design of experiments）方法收集YSZ薄片，并在不同条件下制备相应的涂层。板片的收集将通过创新和自制的光束百叶窗装置来实现，该装置在研究所独家提供。拟议的工作计划首先通过详细的碎片分析确定一系列碎片形态的分布，并在这些分布与相关条件之间建立明确的关系。然后，必须在已识别的飞溅形态分布与由此产生的孔隙和裂纹特征之间建立普遍有效的关系。此外，通过研究导致所需微观结构同时共存的条件之间的相互作用，优化了识别片状形貌和分段裂纹的分布。尽管优化过程将增强控制涂层孔隙度的片状形貌分布，但可实现的孔隙度水平在技术上仍然有限。因此，打算在YSZ喷涂粉末中添加成孔剂，以提高孔隙率。原料粉末由高达50%体积%的孔隙成形剂组成。在进行实验时将使用混合变量。截面涂层的SEM图像将用于研究添加成孔剂对涂层孔隙率的影响。最后，应在所有这些条件与获得的显微组织特征之间建立直接关系。所得结果应使我们能够生产具有预定微观结构特征的APS涂层，并提高再现性