To tackle the challenges of high-temperature phase stability deterioration and sintering densification in zirconia-based thermal barrier coating ceramic materials during prolonged service at temperatures exceeding 1200 ℃, this study utilizes a highly efficient and cost-effective solid-phase synthesis process to fabricate La₂Zr₂O₇-SYSZ composite ceramics with a hypoeutectic composition. We conduct a comprehensive investigation into the impact of 1450 ℃ heat treatment on the high-temperature microstructural stability, evolution, and grain growth kinetics of these composite ceramics using field emission scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The experimental findings reveal that La₂Zr₂O₇-SYSZ composite ceramics, sintered at 1600 ℃ for 6 h, display equiaxed or near-equiaxed grain morphology, with an average grain size of (2.9±0.31) μm. Following heat treatment at 1450 ℃ for durations ranging from 50 h to 300 h, the grain size distribution curves exhibit a notable rightward shift and broadening, with the average grain size gradually increasing to (4.7±0.33) μm. Initially, the grain size distribution follows a single-peak normal distribution pattern; however, as the heat treatment time is extended to 150-300 h, it gradually evolves into a dual-peak normal distribution. The composite system demonstrates a grain growth activation energy of (351.79±19.21) kJ/mol and a growth exponent (n=2.3), suggesting that grain growth is predominantly governed by lattice-diffusion-controlled pinning effects. This research offers vital theoretical underpinnings and technical references for the development of next-generation anti-sintering thermal barrier coating materials.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |