不同增强结构炭/炭复合材料力学及抗烧蚀性能

分别采用轴棒法编织、轴向穿刺以及无纬布/网胎针刺3种结构预制体,经致密化处理得到高密度C/C复合材料,研究了材料力学性能、抗烧蚀性能,并评价了3种增强结构材料的整体性能。结果表明,C/C材料轴向拉伸强度与预制体轴向纤维含量、纤维连续状态有关。轴向穿刺、轴棒法C/C材料轴向拉伸强度明显高于无纬布/网胎针刺C/C材料,但无纬布/网胎针刺C/C材料的径向压缩强度最高。经300 s氧-乙炔烧蚀后无纬布叠层针刺C/C材料的线烧蚀率和质量烧蚀率最低,抗烧蚀最好,烧蚀过程主要受热化学烧蚀和机械剥蚀共同作用。     

碳/碳复合材料SiC-HfSi_2抗烧蚀复合涂层(英文)

为改善碳/碳(C/C)复合材料的抗烧蚀性能,采用包埋技术在C/C复合材料表面制备了碳化硅-硅化铪(SiC-HfSi2)抗烧蚀复合涂层。采用氧乙炔火焰烧蚀试验评价了C/C复合材料样品的抗烧蚀性能。通过扫描电镜观察、能谱分析及X射线衍射分析研究了烧蚀前后C/C复合材料抗烧蚀涂层的表面和断面形貌、元素分布和相组成。结果表明:涂层C/C复合材料在烧蚀后其表面出现了丛生的氧化硅纳米线。同时,与未涂层C/C复合材料相比,SiC-HfSi2涂层使C/C复合材料的质量烧蚀率下降了85.6%。     

碳/碳复合材料SiC–HfSi_2–TaSi_2抗烧蚀复合涂层

采用包埋技术在碳纤维增强碳(carbon fiber reinforced carbon,C/C)复合材料表面制备了碳化硅-硅化铪-硅化钽(SiC-HfSi2-TaSi2)抗烧蚀复合涂层.采用氧已炔火焰烧蚀试验评价了. C/C复合材料样品的抗烧蚀性能.通过X射线衍射分析、扫描电镜观察及能谱分析研究了SiC-HfSi-TaSi2作为 C/C复合材料抗烧蚀涂层的表面和断面相组成、元素分布及形貌.结果表明:由于烧蚀过程中生成的Hf02,Ta205具有高温稳定性,使得该涂层表现 出良好的抗烧蚀性能,在3 000℃下烧蚀20s后,线烧蚀率为0.009 mm/s,质量烧蚀率为0.003 85 g/s.     

纳米改性碳/酚醛树脂基复合材料性能研究

针对碳/酚醛树脂基复合材料层间剪切强度低的缺点,采用纳米填料进行改性。测试了2种纳米填料(纳米碳纤维、碳纳米管)改性后酚醛树脂的热解性能,研究了纳米填料对复合材料力学性能、烧蚀性能以及高温炭化后力学性能的影响,并观察分析了复合材料测试后的微观形貌。研究结果表明,纳米填料改性后,复合材料的力学性能、烧蚀性能均有所改善。其中,纳米碳纤维改性后复合材料的常温层间剪切强度达到24.9 MPa,氧乙炔线烧蚀率为22.75μm/s,质量烧蚀率为23.58 mg/s。纳米碳纤维表面粗糙,与树脂基体的界面强度高,因此其改性后的力学性能和烧蚀性能优于碳纳米管。     

三维织物碳／碳复合材料中层间剪切强度的改进

碳纤维增强碳(C/C)复合材料是由沥青基碳纤维粗纱纺织的多层织物和煤沥青基体构成的,本次实验研究了两种C/C多层织物复合材料和一种平纹编织C/C布复合材料,测试了弯曲、剪切和压缩强度。根据不同跨距--高度比下的三点弯曲试验结果,表明C/C1多层织物复合材料具有高的剪切性能,多层织物复合材料的分层断裂比平纹编织C/C布复合材料具有更高的层间断裂韧性。     

法国碳／碳,陶瓷／陶瓷复合材料的现状与进展

根据法国Carbon’90国际会议提供的信息,介绍了法国碳/碳、陶瓷/陶瓷复合材料的现状和发展动态。重点报道了四维碳/碳整体喉衬入口段、三维超细编织碳/碳薄壁扩散段抗氧化碳/碳复合材料及碳化硅纤维/碳化硅复合材料。     

2.5D碳/酚醛模压复合材料的性能研究

采用真空浸胶技术和模压成型工艺研制2.5D编织碳纤维/酚醛新型树脂基防热复合材料,对材料的拉伸性能、烧蚀性能和热常数等进行了测试。结果表明:2.5D碳/酚醛模压复合材料拉伸强度为424 MPa、拉伸模量为66.4 GPa,氧-乙炔线烧蚀率为0.013 mm/s,质量烧蚀率为0.049 g/s,比热容大于1.1 J/(g·K),导热系数小于0.6 W/(m·K),与传统的短纤维、碳布增强的酚醛模压材料相比,2.5D碳/酚醛模压复合材料具有较好的综合性能,可作为结构防热一体化复合材料。     

先驱体浸渗裂解法制备C/C-SiC复合材料的烧蚀性能

用先驱体浸渗裂解法制备了碳纤维增强碳(carbon fiber reinforced carbon,C/C)-SiC复合材料,用H2-D2火焰法检测其烧蚀性能.结果表明:C/C-SiC复合材料的烧蚀率随复合材料中的Si含量的增加而呈下降趋势;经过5次浸渍,C/C-SiC复合材料的密度从1.46 g/cm3增加到1.75 g/cm3,Si含量从5.06%增加到13.8%,线烧蚀率和质量烧蚀率分别下降474%和34.5%.密度为1.75g/cm3的C/C-SiC复合材料,其线烧蚀率和质量烧蚀率分别为2.22 μm/s和1.289 mg/s,其线烧蚀率和质量烧蚀率分别为密度1.78 g/cm3的C/C复合材料的21.7%和78.6%.基体中SiC的引入明显提高了C/C复合材料的抗氧化烧蚀性能.     

薄型碳纤维织物预浸料及其复合材料研究

采用国产1k T300级薄型碳纤维织物和中温固化高性能树脂制备预浸料。测试了该预浸料及其复合材料性能,并与国产3k T300级碳纤维织物预浸料及其复合材料性能进行对比。研究结果表明:国产1k T300级薄型碳纤维织物的复合材料性能与国产3k T300级碳纤维织物的复合材料性能相当;该薄型碳纤维织物复合材料的树脂体系是改性增韧环氧树脂,韧性好,适用于轻质夹层结构复合材料,具有较高滚筒剥离强度;同时,该轻质复合材料耐热性好,玻璃化转变温度能达到200℃。     

固体火箭发动机炭/炭复合材料喉衬烧蚀行为研究

从固体火箭发动机炭/炭复合材料喉衬烧蚀后的形貌和结构特性出发,采用扫描电子显微镜、高分辨透射电子显微镜、元素分析仪等表征分析了炭/炭复合材料烧蚀后的微观结构形貌、纤维损伤程度、纤维和基体的界面结合状态、沉积粒子含量以及喉衬密度等,探究了烧蚀温度、压力及推进剂种类等因素对炭/炭复合材料烧蚀后微观结构的影响,并结合材料的构...     

碳/碳复合材料力学性能的研究进展

本文综述了碳/碳复合材料力学性能的研究进展,包括碳纤维、基体炭、界面性能、制备工艺及工艺参数等对碳/碳复合材料力学性能的影响。同时简单介绍了当今单向碳/碳复合材料力学性能的表征手段。希望对碳/碳复合材料力学性能的研究及应用提供帮助。     

Mechanical and thermophysical properties of carbon/carbon composites with hafnium carbide

Carbon/carbon (C/C) composites with addition of hafnium carbide (HfC) were prepared by immersing the carbon felt in a hafnium oxychloride aqueous solution, followed by densification and graphitization. Mechanical properties, coefficients of thermal expansion (CTE), and thermal conductivity of the composites were investigated. Results show that mechanical properties of the composites decrease dramatically when the HfC content is greater than 6.5 wt%. CTE of the composites increases with the increase of HfC contents. The composites with addition of 6.5 wt% HfC show the highest thermal conductivity. The high thermal conductivity results from the thermal motion of CO in the gaps and pores, which can improve phonon–defect interaction of the C/C composites. Thermal conductivities of the composites decrease when the HfC content is greater than 6.5 wt%, which is due to formation of a large number of cracks in the composites. Cracks increase the phonon scattering and hence restrain heat transport, which results in the decrease of thermal conductivity of the composites.     

The mechanical and repair behavior of damaged carbon/carbon composites

With the aim of understanding the effect of defect types on the mechanical performance of carbon/carbon (C/C) composites, three kinds of defects such as circle arc, square, and triangle shapes were prefabricated on their surfaces. The results show that the prefabricated defects damage the flexural strength of C/C composites compared to the pristine sample (101 ± 6 MPa). The flexural strength of C/C decreased by 30.84%, 45.84%, and 42.58% corresponding to the circle arc, square, and triangle type defects respectively. The defect-repair method with Ni-based solder as the additive was employed to repair the damaged C/C composites. After repair, the stress concentration of C/C composites decreases, and there is a good connection between carbon fiber and the repaired solder so that the load can be transferred continuously, therefore the flexural strength of C/C composites can be improved by 20–28%.     

C/C复合材料SiC-SiO_2/ZrO_2-SiC复合抗氧化涂层

为了提高C/C复合材料在高温有氧环境的抗氧化性,在SiC抗氧化涂层防护的基础上,采用气相沉积法及溶胶凝胶吸附冷凝热蒸汽法在C/C复合材料表面制备出了SiC-SiO2/ZrO2-SiC复合涂层。利用扫描电镜、能谱质谱测试及X射线衍射等检测方法对涂层各层进行了分析。结果表明,溶胶吸附ZrCl4蒸汽法制备ZrO2涂层,不仅能够在高温自动修复单层SiC涂层的裂纹缺陷,还起到了在制备外层SiC涂层过程中缓冲应力的作用。这种多层复合涂层在高温下具有良好的抗氧化性,在1 800℃等离子焰动态空气氧化120 s后,计算得出该涂层失重速率仅为0.4 g/(m2·s),表明该涂层具有卓越的抗氧化性。     

High temperature oxidation resistance of Y2O3 modified ZrB2-SiC coating for carbon/carbon composites

To protect carbon/carbon (C/C) composites from oxidation at high temperature, Y₂O₃ modified ZrB₂-SiC coating was fabricated on C/C composites by atmospheric plasma spraying. The microstructure and chemical composition of the coatings were characterized by SEM, EDS, and XRD. Experiment results showed that the coating with 10 wt% Y₂O₃ presented a relatively compact surface without evident holes and cracks. No peeling off occurred on the interface between the coating and substrate. The ZSY10 coating underwent oxidation at 1450 °C for 10 h with a mass loss of 5.77%, while that of ZS coating was as high as 16.79%. The existence of Y₂O₃ played an important role in inhibiting the phase transition of ZrO₂, thus avoiding the cracks caused by the volume expansion of the coating. Meanwhile, Y₂SiO₅ and ZrSiO₄ had a similar coefficient of thermal expansion (CTE), which could relieve the thermal stress inside the coating. The ceramic phases Y₂SiO₅, Y₂Si₂O₇ and ZrSiO₄ with high thermal stability and low oxygen permeability reduced the volatilization of SiO₂.     

炭化压力对编织C/C复合材料致密过程及结构的影响

通过浸渍/高压炭化工艺在不同炭化压力下制备了高温煤沥青炭块及沥青基炭/炭（C/C）复合材料,并研究了不同炭化压力环境下对其密度和孔隙的影响.结果表明,随着炭化压力增大,沥青炭体积密度明显增加,孔隙填充效果明显改善;在编织C/C材料的致密过程中,压力越大其孔隙越小,分布越均匀,故产品致密效果越好.     

碳纳米材料制备技术的进展

综述了C60、碳纳米管、纳米石墨、纳米金刚石、煤基碳纳米材料的制备方法,考虑到我国煤炭资源丰富,认为以煤为原料制备碳纳米材料不失为最佳选择。