论文部分内容阅读
采用化学气相沉积(CVD)法在不同密度的炭/炭复合材料表面原位生长碳纳米纤维(CNFs),探究不同工艺参数对CNFs微观形貌的影响规律,寻求最优化工艺。以原位生长CNFs改性C/C复合材料和纯C/C复合材料为研究对象,描述了CNFs的生长机制,并分别对2种试样进行石墨化度、力学性能和导热性能的检测分析,研究CNFs增强C/C复合材料性能的改性机理。结果表明:当催化剂前驱体Ni(NO_3)_2溶液的浓度为0.10 mol/L,裂解温度为650~700℃,反应时间为30~45 min时,所制备的CNFs直径细小均匀,一般为30~60 nm,长径比大,呈网状分布,分散性好。相同密度下,CNFs-C/C复合材料的弯曲强度达到166.29 MPa,比纯C/C复合材料(131.73 MPa)提高了26.2%,弯曲性能显著提升。原位生长CNFs改性C/C复合材料的室温z轴热导率为14.50 W/(m·K),是纯C/C复合材料的1.85倍。
Carbon nanofibers (CNFs) were grown in situ on different density carbon / carbon composites by chemical vapor deposition (CVD) method. The influence of different process parameters on the microstructure of CNFs was explored and the optimum process was sought. The CNFs-modified C / C composites and pure C / C composites were grown in situ and the growth mechanism of CNFs was described. The graphitization degree, mechanical properties and thermal conductivity of the two samples were analyzed respectively , To study the modification mechanism of CNFs to enhance the properties of C / C composites. The results show that when the concentration of catalyst Ni (NO_3) _2 is 0.10 mol / L, the pyrolysis temperature is 650 ~ 700 ℃ and the reaction time is 30 ~ 45 min, the diameter of CNFs prepared is small and uniform, usually 30 ~ 60 nm, large aspect ratio, reticular distribution, good dispersion. The flexural strength of CNFs-C / C composites reached 166.29 MPa at the same density, which was 26.2% higher than that of the pure C / C composites (131.73 MPa), and the flexural properties were significantly improved. The in-situ z-axis thermal conductivity of CNFs-modified C / C composites was 14.50 W / (m · K), which was 1.85 times that of pure C / C composites.