Structured ceramic surfaces by preceramic polymer demixing processes

Polymeric and ceramic coatings with a cellular structure have been manufactured based on demixing processes by the use of two different preceramic polymers and silicon carbide fillers in a dip coating process. The rheological properties of the coating system were adjusted by adding a monomeric silane and methanol, and the crosslinking process was triggered by the addition of catalysts. The surface tension of the coating system was measured and a temperature range for coating and structure formation was identified. The as coated substrates were investigated with respect to an influence of the substrate microstructure and the coating speed on the cellular structure of the coatings. While the substrate microstructure has no influence on the cell structure the coating speed led to a minor change in the cell width. The as received thermoset coatings were pyrolyzed and the structure was intact even after firing at 1100 °C in different atmospheres.