Investigation of the coating formation mechanisms and system properties of thermal barrier coatings on internal surfaces

• Applicants: Privatdozent Dr.-Ing. Georg Mauer; Professor Dr.-Ing. Wolfgang Tillmann
• Subject Area: Coating and Surface Technology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 456827225

Thermal spray processes are rarely applied to coat internal surfaces. In order to solve such coating tasks, special spray guns are required ("internal diameter (ID) spray gun"). Their design is smaller and combustion/plasma power is significantly lower. Currently, there is a significant development in the field of ID spray guns relying on the increasing demand for internal diameter coatings. So far, research and development is limited to coating material systems for the use in combustion engines (e.g., iron-based alloys) as well as general wear protection applications (e.g., cermet or cemented carbide systems). Due to its complexity, the field of the thermal barrier coating systems has not yet been addressed in research. As part of the applied project, the application and coating build-up process of the metallic bond coat (BC) by means of high-velocity oxygen fuel spraying (HVOF) or warm spraying (WS) and the application of the ceramic top coat (TC) by means of atmospheric plasma spraying (APS) with specialized ID spray guns are investigated. The overall aim is to describe the process-microstructure-relationship. In this context, the coating build-up mechanisms are examined experimentally and statistically modeled for each system (BC + TC). These results are used to derive a profound description of the splat-microstructure-relationship. The extension of the splat-microstructure-relationship constitutes the basis for the development of the process-microstructure-relationship.

• DFG Programme: Research Grants
• Co-Investigator: Dr.-Ing. Ingor Theodor Baumann