Aerosol Deposition Method: Co-deposition of functional materials and fillers to replace a subsequent thermal treatment

该项目包括对陶瓷粉末气溶胶沉积过程的进一步基础研究，也称为气溶胶沉积方法(ADM)，这些研究基于对沉积机理的最新发现。例如，与块状材料相比，ADM直接沉积后产生的所有涂层的功能特性都会降低(特别是在离子或电子传导性方面)。通过AD工艺之后的热后处理，可以永久地恢复这些性能，从而使薄膜的性能永久地达到块体材料的性能。这一改进所需的温度大大低于颗粒生长所需的温度。AD涂层直接涂覆后的功能性能较差的原因是在涂层形成过程中与工艺有关的机械微观应力的产生。这就是本申请发挥作用的点。这里的重点是减少或完全避免AD工艺之后的热处理。这可以通过在功能材料(YSZ、STF)中添加化学和电惰性填料(CaF2、PE/PP和Al_2O_3)来实现。该填充材料具有机械缓冲材料的功能，从而实现了层内微观应力的降低。填充材料对涂层过程的确切影响目前尚不清楚。为了定性和定量地评价惰性填料和功能材料对涂层性能的影响，将几种填充材料和两种功能材料组合在一起。ADM是作为粉末混合物的共沉积进行的。此外，相应的粉末混合物的混合比例是不同的。随着填充材料加入量的增加，一方面可以假设薄膜内部的张力可以减小。然而，另一方面，会发生稀释，并且基于功能材料的涂层的功能特性降低。为了在混合物中实现尽可能高的功能材料比例，梯度层的构建是该项目最后一部分的组成部分。根据涂层厚度的不同，混合物中功能材料的比例将有所不同，以产生应力最小的厚层和高比例的功能材料。项目过程中的研究旨在扩大对层形成过程的基本了解，从而在未来通过室温下的气溶胶沉积方法结合具有良好功能特性的新的、特别是低熔点的组件。

This project includes further fundamental investigations on the process of aerosol deposition of ceramic powders, also known as aerosol deposition method (ADM), that are based on more recent findings of the deposition mechanism. For example, reduced functional properties compared to bulk material (especially with regard to ionic or electronic conductivity) can be observed for all coatings produced by ADM directly after deposition. By means of a thermal post-treatment after the AD process, these properties can be permanently restored so that the properties of the films reach permanently the properties of the bulk material. The temperatures required for this improvement are significantly below the temperature required for grain growth. The reason for the poorer functional properties of AD coatings directly after coating is the process-related generation of mechanical micro-stresses during layer formation. This is the point at which the present application comes into play. The focus here is on reducing or completely avoiding thermal treatment that follows the AD process. This is to be made possible by adding chemically and electrically inert fillers (CaF2, PE/PP and Al2O3) to the functional materials (YSZ, STF). The filler material has the function of a mechanical buffer material, whereby a reduction of the layer-immanent micro-stresses is achieved. The exact influence of the filler material on the coating process is currently unclear. In order to qualitatively and quantitatively assess the correlation between the inert filler and the functional material on the properties of the layer, several filling materials and two functional materials are combined with each other. ADM is carried out as a co-deposition of powder mixtures. In addition, the mixing ratios of the corresponding powder mixtures are varied. With increasing addition of filler material, it is assumed that on the one hand film-immanent tensions can be reduced. On the other hand, however, dilution occurs and the functional properties of the coating, which are based on the functional material, are reduced. In order to achieve the highest possible proportion of functional material in the mixture, the construction of a gradient layer is an integral part of the last part of the project. Depending on the thickness of the coating, the proportion of functional material in the mixture is to be varied in order to create thick layers with minimal stresses and a high proportion of functional material.The investigations in the course of the project are intended to broaden the fundamental understanding of the layer formation process, whereby in future new, especially low melting point components combined with good functional properties can be bonded by means of aerosol deposition at room temperature.