Polymer-Derived Ceramic Coatings with Excellent Thermal Cycling Stability

In the present work, transition metal-containing preceramic silicon polymers were synthesized via chemical modification of a commercially available organopolysilazane with Hf and Ta amido complexes as well as with borane dimethyl sulfide complex. The incorporation of transition metals into the polymer structure, their influence on ceramization and processability were thoroughly investigated. Moreover, the prepared preceramics were coated onto silicon wafers via spin coating and converted into crack-free, amorphous SiHfTa(B)CN-based ceramic coatings with excellent adhesion to the substrate. The composition of the ceramic coatings was investigated via X-ray photoelectron spectroscopy (XPS) and their high-temperature behavior was studied via oxidation tests performed at 1100 °C. Moreover, a thermal cycling procedure to temperatures above 1250 °C with rapid heating and cooling rates (i.e., in the range of 100–120 K s⁻¹) was applied to the ceramic coating, which showed no damage even after ten thermal cycles, indicating their outstanding performance and their potential for use as environmental barrier coatings at high temperatures.