Investigation of the deposition mechanism for the aerosol deposition of ceramics by evaluating of the processes that occur when micrometer-sized particles impact on surfaces
Chemical and Thermal Process Engineering
Synthesis and Properties of Functional Materials
Final Report Abstract
The powder aerosol deposition method (PADM or PAD) is a relatively new process to manufacture ceramic coatings completely at room temperature directly from the raw ceramic powder. It is a dry spray coating process. An aerosol is formed from the ceramic particles using a carrier gas and is accelerated onto a substrate. The impact of the particles leads to their deposition and the formation of dense layers on the substrate. The goal of this project was a better understanding of the coating formation mechanism. This included the following key model ideas: Are whole particles deformed, embedded, and deposited, or do the particles break on impact and only outer fragments are deposited into the layer? For this purpose, the deposition of so-called core-shell particles was considered: ceramic particles are coated with another ceramic, in this case Al2O3 particles are provided with a SiO2 shell. These model powders have a certain elemental ratio between core and shell. Subsequently, the layer formed by PAD is examined for a shift in the element ratio. The SEM-EDS analyzes of the particles of the manufactured PAD films have shown that elements from the core as well as elements from the shell are deposited. However, when comparing the element ratios between core-shell particles and the PAD layer, a significant increase of elements from the shell can be detected in the PAD layer. Interpretation of these results suggests a deposition mechanism in which only fragments of the particles contribute to the layer formation. These results were reinforced by STEM-EDS measurements of a section of the PAD layer, where the accumulation of material from the shell could also be observed with very fine resolution. In order to support the universality of the results, core-shell particles (NMC core with LiNbO3 coating) prepared by another research group were also deposited using the PAD method. The above-mentioned model for the deposition mechanism could be fully confirmed.
Publications
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Discontinuous Powder Aerosol Deposition: An Approach to Prepare Films Using Smallest Powder Quantities. Coatings, 11(7), 844.
Linz, Mario; Exner, Jörg; Kita, Jaroslaw; Bühner, Florian; Seipenbusch, Martin & Moos, Ralf
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Making powder aerosol deposition accessible for small amounts: A novel and modular approach to produce dense ceramic films. International Journal of Applied Ceramic Technology, 18(6), 2178-2196.
Exner, Jörg; Linz, Mario; Kita, Jaroslaw & Moos, Ralf
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Mobile sealing and repairing of damaged ceramic coatings by powder aerosol deposition at room temperature. Open Ceramics, 10, 100253.
Linz, Mario; Exner, Jörg; Nazarenus, Tobias; Kita, Jaroslaw & Moos, Ralf
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Revealing the Deposition Mechanism of the Powder Aerosol Deposition Method Using Ceramic Oxide Core–Shell Particles. Advanced Materials, 36(7).
Linz, Mario; Bühner, Florian; Paulus, Daniel; Hennerici, Lukas; Guo, Yiran; Mereacre, Valeriu; Mansfeld, Ulrich; Seipenbusch, Martin; Kita, Jaroslaw & Moos, Ralf
