Fe基高温合金涂层封填C/C-ZrC-SiC复合材料的制备及抗烧蚀机制

《复合材料学报》优先在线发表论文。

摘  要：为了改善C/C-ZrC-SiC复合材料在高超声速飞行器热防护领域的使用性能，采用低压悬浮浸渗法制备出Fe基高温合金涂层封填C/C-ZrC-SiC复合材料。利用XRD、SEM、EDS等手段研究氧乙炔焰烧蚀前后Fe基高温合金涂层封填C/C-ZrC-SiC复合材料表层微观结构演变规律，阐明了Fe基高温合金涂层对C/C-ZrC-SiC复合材料烧蚀行为的影响。结果表明：C/C-ZrC-SiC复合材料在1650℃的大气环境下并通过低压悬浮浸渗法浸渗2h后，其表层形成一层均匀、致密、且结合紧密的Fe基高温合金涂层。在2500℃下烧蚀180s后，改性后的C/C-ZrC-SiC复合材料表面出现较小的烧蚀坑，质量烧蚀率相比未表面改性的试样降低了35%，线烧蚀率降低了8%。并且表面生成一层均匀致密的Fe2O3-ZrO2复合氧化物保护层，大大降低了表面裂纹、孔洞等缺陷的产生，从而降低了氧的扩散速率以及缺陷带来的应力集中。最终Fe基高温合金覆盖层提高了C/C-ZrC-SiC复合材料的高温抗氧化性和抗机械剥蚀性能。

关键词：C/C-ZrC-SiC复合材料；Fe基高温合金涂层；低压悬浮浸渗；烧蚀；复合氧化物

Abstract: C/C-ZrC-SiC composites filled with Fe-based superalloy coating was prepared by low pressure suspension impregnation to improve C/C-ZrC-SiC composites use in the field of hypersonic flight vehicle’s thermal protective performance. The evolution rule of the surface microstructure of C/C-ZrC-SiC composites filled with Fe-based superalloy before and after oxy-acetylene flame ablation were studied by means of XRD, SEM and EDS. And the effect of the Fe-based superalloy coating on the ablation behavior of C/C-ZrC-SiC composites was clarified. The results show that C/C-ZrC-SiC composites are infiltrated by low pressure suspension infiltration at 1650℃ for 2h, and a uniform, dense and tightly bonded Fe-based superalloy coating is formed on the surface. After the ablation at 2500℃ for 180s, the surface of the modified C/C-ZrC-SiC composites generates a smaller ablation pit, and the mass and linear ablation rate are reduced by 35% and 8% respectively than the unmodified sample. And a uniform and dense protective layer of Fe2O3-ZrO2 composite oxides is formed on the surface, which greatly reduces the occurrence of surface cracks, holes and other defects, thereby reducing the diffusion rate of oxygen and the stress concentration caused by defects. The Fe-based superalloy coating improves the high temperature oxidation resistance and mechanical corrosion resistance of C/C-ZrC-SiC composites.

Keywords: C/C-ZrC-SiC composites; Fe-based superalloy coating; low pressure suspension impregnation; ablation; composite oxides

作者：田甜等，中南大学 粉末冶金研究院，湖南

通讯作者：孙威，中南大学 粉末冶金研究院，湖南

全文详见中国知网学术期刊优先数字出版。