Project 5: High-temperature oxidation behaviour of ceramic coatings based on polymer-derived ceramic nanocomposites
Doctoral researchers
Dr. Nils-Christian Petry (1st cohort)
M. Sc. Büsra Prill (2nd cohort)
M. Sc. Sahithi Katepalli (3rd cohort)
Supervisors
Prof. Mathias Galetz,
Prof. Bronislava Gorr
Project
In project 5.2 coatings and especially filler materials for PDC-NCs are designed to improve the high temperature oxidation behavior (T ≥ 1300 °C) and phase stability of PDC-NCs. As a main goal, the thermal conductivity of Si-based PDC-NC is to be reduced by the filler materials. As filler materials, different high entropy oxides with the general formula A6B2O17 (A = Zr, Hf; B = Nb, Ta) will be synthesized. In a first step, phase and chemical composition as well as morphology of the synthesized filler materials are examined after high temperature heat treatment to identify the best candidates. Upon selection of the filler material, thermal barrier coatings with additional filler material will be fabricated together with the TUD and characterized for application temperatures above 1200 °C.
In parallel, the oxidation behavior of SiAlOC bond coats on Mo-Si-Ti and Mo-Si-Cr will be investigated for increased oxidation stability and adhesion of the PDC-NC based TBCs. The influence of the addition of reactive elements to such coatings to achieve excellent oxidation protection of the substrate will be investigated.
The initial phase of project 5.3 (the current 3rd cohort) will involve preparing bulk specimens of previously developed oxide-based high-entropy A6B2O17 filler materials from project 5.2 using spark plasma sintering, conventional sintering and coating techniques. The study will focus on the corrosion resistance of the material against calcium-magnesium-alumino-silicate (CMAS) deposits at temperatures above 1200 °C. Additionally, it will examine the effects of CMAS corrosion in steam environments on these materials.
In the later stages of the project, these corrosion studies will be carried out on the entire fabricated TBC coating system, as previously mentioned in project 5.2.