CLVI原位共沉积制备碳纳米线增韧C/C-SiC-ZrC复合材料及烧蚀性能研究

The introduction of ultrahigh temperature ceramics (UHTCs) into carbon matrix modified C/C composites is a wonderful way to solve the problems of high temperature oxidation and ablation failure of C/C composites. Aim to alleviate the shortcoming of long preparation and mechanical property loss, this project was proposed to co-deposition carbon nanowires, ZrC and SiC components to modify pyrolytic carbon matrix by chemical liquid vapor infiltration method (CLVI) . On the basis of the precursor cleavage transformation temperature, further adjustments of deposition temperature, deposition time, precursor ratio and et al were made. And the effect on the nanowire growth, densification behavior of C/C composite and precursor distribution uniformity were analyzed. As a result，carbon nanowire toughen C/C composites modified by ZrC-SiC were got. The phase composition, microstructure and the matrix phase interface compatibility were.analyzed in detail. Clarifying the co-deposition mechanism, toughening modification mechanism and ablation mechanism can provide theory support for the preparation of C/C composites of high toughness and good ablation property applied in the high-speed abrasion environments at ultrahigh temperature.

将超高温陶瓷引入碳基体改性C/C复合材料是解决C/C复合材料高温氧化和烧蚀失效最有效的方法。针对常规引入方法制备周期长、对碳纤维有性能损伤等缺点，本项目提出采用化学液气相沉积方法(CLVI)原位共沉积引入碳纳米线、ZrC和SiC组分改性热解碳基体的新思路，即首先获得各前驱体裂解转化的温度，在此基础上进一步调整沉积温度、沉积时间、前驱体配比等工艺参数，分析工艺参数的改变对碳纳米线的生长特点、C/C复合材料致密化行为以及前驱体分布均匀性的影响，实现热解碳、碳纳米线、ZrC和SiC组分的一体化共沉积。系统分析所制备材料的相组分、基体微观结构和各相界面相容性等特点，明确各组元的共沉积机理，阐明碳纳米线的增韧机制，揭示改性烧蚀组元协同抗烧蚀的机理，为进一步制备出应用于航空航天防氧化抗烧蚀环境下的高韧性、烧蚀性能好的超高温陶瓷改性C/C复合材料奠定理论基础。

本项目围绕抗烧蚀 C/C 复合材料基体改性常规方法引入超高温陶瓷存在周期长、损伤碳纤维的问题，从提高C/C复合材料耐烧蚀性能和改善复合材料性能角度出发，提出了一种共沉积制备ZrC-SiC 超高温陶瓷改性 C/C 复合材料的快速制备方法。采用化学液气相沉积工艺，通过二甲苯、聚碳硅烷和有机锆的共沉积，获得了C、ZrC、SiC 多种前驱体的 CLVI 共沉积工艺规律，实现了较快制备ZrC-SiC超高温陶瓷改性 C/C 复合材料，明确了 C、ZrC、SiC 多种前驱体的液相共沉积机理；获得了共沉积前预制体密度、SiC和ZrC前驱体加入量对制备的C/C-SiC-ZrC复合材料微观结构、力学性能、烧蚀性能的影响规律；通过在沉积前期引入碳纳米线，实现了基体相的二次增强，探明了碳纳米线增强 C/C-SiC-ZrC 复合材料的增强机制，以及ZrC和SiC陶瓷组元在烧蚀过程的协同抗烧蚀机制，为扩大C/C复合材料作为热结构件的制备提供了新思路。