具有微米-亚微米增强结构的ZrB2-ZrC-SiC涂层的烧蚀机理与性能

Ablation Mechanism and Properties of ZrB-ZrC-SiC Coating with Micro-Submicron Reinforced Structure

通过真空浸渗和反应熔渗在C/C复合材料上制备了具有微米-亚微米增强结构的ZrB2-ZrC-SiC涂层。微米-亚微米增强结构由微米级的碳化硅为骨架,亚微米级的超高温陶瓷颗粒(UHTCs)为填充料组成。采用等离子火焰对复合材料进行了烧蚀试验。结果表明,在烧蚀过程中由聚集的碳化硅颗粒和超高温陶瓷颗粒组成的微米-亚微米增强结构在烧蚀气流的侵蚀下易于形成较大的缺陷。已形成的较大缺陷容易与缺陷周围的裂纹相连形成较大的凹坑,从而导致部分涂层脱落,并导致整个涂层系统失效。

ZrB2-ZrC-SiC coating with micro-submicron reinforced structure was prepared on the C/C composites by vacuum infiltration and reactive melt infiltration. The micro-submicron reinforced structure consisted of micron-sized SiC as the skeleton and submicron-sized ultra-high temperature ceramic particles(UHTCs) as the filler. The ablation resistance of the composites was tested by plasma flame. Results show that during ablation, the micro-submicron reinforced structure composed of concentrated SiC particles and UHTCs is prone to form larger defects under the erosion of ablative airflow. The defects induce ablation gaps that are connected with the surrounding cracks to form larger pits, which cause part of the coating to fall off, and the failure of the whole coating system.