Carbide ultra-high temperature ceramics have high melting point, high hardness, and can still maintain high strength at high temperatures. They have excellent properties such as low density, low thermal expansion, and linear expansion coefficient, and are widely used in functional coatings of C/C composites. Among them, commonly used carbide ultra-high temperature ceramics include ZrC, HfC, and TaC.    

Taking the most commonly used carbide ultra-high temperature ceramic ZrC as an example, for the ZrC/SiC coating of C/C composite materials, during the ablation process, the external ZrC coating first undergoes an oxidation reaction, as shown in reaction (1), reaction (2), reaction (3), and reaction (4); When the temperature is higher than the melting point of ZrO2, a reaction occurs (5). Due to the low viscosity of liquid ZrO2, it is more easily blown away by the airflow, and cracks appear in the ZrO2 film. Oxygen can enter the coating through the cracks, causing oxidation of the internal SiC coating and substrate. Therefore, carbide ultra-high temperature ceramics are generally used in the form of multiphase ceramics.

Room termperature curing polysilazane, pls check IOTA 9150, IOTA 9150A. 
High termperature curing polysilazane, pls check IOTA 9108, IOTA 9118.