Comparative study on polysilazane and silicone resins as high-temperature-resistant coatings

Abstract

The development of high-temperature-resistant coatings is crucial, which demands a new adhesive resin owing to harsh service conditions. In this work, the structural evolution and basic performance of three different polysilazanes with a Si–N backbone are studied, which is further compared to a typical silicone resin with a Si–O backbone. Experimental results show that polysilazanes with different structures undergo a two-step oxidation process with a residual weight higher than 77% in comparison to the one-step degradation of silicone with a weight loss higher than 47% at 800°C under flowing air atmosphere. Additionally, the decrease in thickness of polysilazane-resin coating is below 50%, while that of the silicone-resin coating is higher than 77%, which affords a crack- and defect-free morphology in polysilazanes and blistering and particle aggregation in the silicone after a temperature treatment at 800°C. Thus, our study demonstrates that polysilazanes are potential alternative choices as resin adhesives for high-temperature-resistant coatings rather than silicone-based resins, in extremely harsh conditions.