Thermally sprayed Zn2TiO4 heating coatings with adaptive electrothermal properties

• Applicants: Professor Dr.-Ing. Christoph Leyens; Dr. Annegret Potthoff
• Subject Area: Coating and Surface Technology ; Glass, Ceramics and Derived Composites
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 428362963

• Final Report Year: 2024

Final Report Abstract

Preliminary work based on TiOx and TiO2-Cr2O3 provided an alternative to metallic, thermally sprayed heat coatings, but their maximum application temperature is limited to about 300 °C due to irreversible transformation into TiO2 and changing semiconducting properties to insulating ones. This project aimed to improve the temperature stability of these coatings by using Zn2TiO4, which is stable up to 1550 °C and has semiconducting properties. The project included the development of suspensions and precursors to produce homogeneous heat coatings with minimal porosity, the investigation of a possible in-situ alloying of Zn2TiO4 from ZnO and TiO2 during the spraying process and the establishment of a scientific basis for understanding interactions within the feedstock, the spraying process, and the use of doping in the coating. The results showed that the expected electrothermal properties of the Zn2TiO4 core material did not meet the expectations.

Publications

• „Current Trends in the Development of Suspensions and Liquid Precursors for Thermal Spraying: Case of Zn2TiO4“, Vortrag, ITSC 2022, Wien
  A. Meyer, F.-L. Toma, O. Kunze, A. Böhme, B. Matthey, A. Potthoff, A. Kaiser, T. Gestrich & C. Leyens
  
• „Development of cost-effective feedstock for suspension spraying of Zn2TiO4 coatings“, Vortrag, RIPT 2022, Jülich
  A. Meyer, F.-L. Toma, O. Kunze, A. Böhme, B. Matthey, A. Potthoff, A. Kaiser, T. Gestrich & C. Leyens
  
• „Influence of suspension formulation on microstructural and photocatalytic properties of S-HVOF ZnO- TiO2 coatings“, Vortrag, RIPT 2022, Jülich
  F.-L. Toma; A. Meyer, O. Kunze, B. Matthey, A. Potthoff & C. Leyens
  
• Development of Suspension Feedstocks for Thermally Sprayed Zn2TiO4 Coatings. Journal of Thermal Spray Technology, 32(2-3), 502-513.
  Meyer, Anja; Toma, Filofteia-Laura; Kunze, Oliver; Böhme, Andreas; Matthey, Björn; Potthoff, Annegret; Kaiser, Arno; Gestrich, Tim & Leyens, Christoph
  
• „Development of Zn2TiO4 coatings by suspension spraying of binary ZnO-TiO2 suspensions“ Fachposter, Ceramics 2023, Jena
  A. Meyer, F.-L. Toma, O. Kunze, P. Biswal & A.Potthoff
  
• „Photocatalytic activity of suspension sprayed ZnO-TiO2 coatings under ultraviolet and visible light irradiation“, Vortrag, ITSC 2023, Quebec
  A. Meyer, F.-L. Toma, O. Kunze, P. Biswal, A. Potthoff & C. Leyens
  
• „Parameters influencing the photocatalytic activity of suspension sprayed ZnO-TiO2 coatings“, Vortrag, ITSC 2024, Mailand
  A. Meyer, F.-L. Toma, O. Kunze, A. Potthoff & C. Leyens
  
• „Parameters influencing the photocatalytic activity of suspension-sprayed coatings in the binary ZnO- TiO2 system“, Vortrag, RIPT 2024, Jülich
  A. Meyer, F.-L. Toma, O. Kunze, S. Scheitz, A. Potthoff & C. Leyens