Research on Thermal Stability and Properties of Ca3ZrSi2O9 as Potential T/EBC Materials

In this study, a new coating material for thermal barrier coating (TBC) or environment barrier coating (EBC) application, Ca3ZrSi2O9 (CZSO), was synthesized and prepared by atmospheric plasma spray (APS) technology. The evolution of the phases and microstructures of the coatings with different thermal-aged were characterized by XRD, XRF, EDS and SEM, respectively. The thermal stability was measured by TG-DTA and DSC. The mechanical and thermal properties, including Vickers hardness (H-V), fracture toughness (K-IC), thermal conductivity (kappa) and coefficient of thermal expansion (CTE) were focused on. It was found that the as-sprayed CZSO coating contained amorphous phase. Crystalline transformation happened at 900-960 degrees C and no mass changes took place from room temperature (RT) to 1300 degrees C. The phenomena of microcrack self-healing and composition uniformity were observed during thermal aging. The kappa of coating was very low at about 0.57-0.80 W center dot m(-1)center dot K-1 in 200-1200 degrees C. The combined properties indicated that the CZSO coating might be a potential T/EBC material.

Automated summary

The study found that CZSO coating synthesized by APS technology showed good thermal stability and exhibited phenomena of microcrack self-healing and composition uniformity during thermal aging. The coating had a very low thermal conductivity, suitable for high-temperature environments ranging from 200 to 1200 degrees Celsius.