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炭基体结构状态对C/C复合材料抗烧蚀性能的影响 总被引:12,自引:2,他引:12
碳基体在C/C复合材料的组成中占有很大的比重,因此炭基体不同的结构状态往往对C/C复合材料的各项性能有显著的影响。本文利用不同的原料和加工工艺制备出了三种具有不同炭基体的C/C复合材料,这三种碳基体分别是热解炭,沥青炭以及解热炭-树脂炭混合炭基体。对这三种材料多项性能的测试结果表明,炭基体的结构状态如石墨化度,炭片层结构的取向度的不同对C/C复合材料的各项性能均有显著的影响;基本趋势是C/C材料的石墨化度越高,材料的导电性能,导热性能以及抗烧蚀性能越好,压缩强度越低。三种炭基体中沥青炭基体沿纤维轴向的取向度最低,其抗烧蚀性能最差。 相似文献
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采用轴棒法4D预制体、煤沥青为前驱体,经过常压、高压相结合的液相浸渍一炭化的致密工艺,制备出高密度轴棒法C/C复合材料。研究了轴棒法C/C复合材料的微观结构及其对轴向室温、高温(2800℃)拉伸破坏形式的影响。结果表明:轴棒法C/C复合材料轴向增强体采用炭棒,出现了一个特殊的界面,即炭棒与基体的“间隙”,主要原因是炭棒内部结合较强和纤维、基体的热膨胀系数不匹配而引起的;间隙的存在,使得轴棒法C/C复合材料的轴向室温、高温拉伸破坏形式出现较大差异,室温拉伸由于界面结合强度弱而引起的炭棒完整的拔出,未起到纤维应有的增强作用;高温拉伸却由于受热膨胀,间隙愈合,界面结合变强,试样从有效部位断裂,纤维增强作用明显提高。 相似文献
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以自制高成炭率氨酚醛树脂为基体炭源,采用溶剂分散铁、硼和铬催化剂、多次液相浸渍–炭化增密和石墨化处理的方法制备出密度为1.20~1.61g/cm3的碳/碳(C/C)复合材料。采用X射线衍射仪、扫描电子显微镜、四探针测试仪和弯曲强度测试等手段研究了催化剂种类对酚醛树脂基C/C复合材料结构和性能的影响。结果表明:硼、铁和铬等催化剂的引入可显著提高C/C复合材料的整体石墨化程度,降低其电阻率,催化石墨化效果按Fe,B,Cr的顺序依次降低;密度对电阻率及其分布有重要影响,体积密度较高的C/C复合材料的电阻率分布较均匀。催化剂的引入使得C/C复合材料的弯曲强度有所下降,但表现出明显的韧性断裂特征。 相似文献
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酚醛炭基C/C复合滑板材料的催化石墨化及其性能研究 总被引:1,自引:0,他引:1
通过溶剂分散法在酚醛树脂浸渍剂中引入催化剂,采用多次液相浸渍-炭化增密和催化石墨化处理的方法,制备出密度为1.60g·cm^-3左右、石墨化度大于77%的酚醛炭基C/C复合材料。对比考察了催化剂的引入和催化剂种类对酚醛炭基C/C复合材料石墨化度、电阻率、抗折强度和摩擦磨损性能的影响,探讨了酚醛炭基C/C复合材料用作受电弓滑板材料的可能性。结果表明:硼酸或二茂铁等催化剂的引入可显著提高酚醛炭基C/C复合材料的石墨化度,降低其电阻率和摩擦系数,改善其弯曲断裂韧性;添加硼酸催化剂的酚醛炭基C/C复合材料的导电性、抗折强度和摩擦磨损性能明显优于德国纯炭整体滑板材料,可望用作高速电力机车的受电弓滑板材料。 相似文献
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采用平均密度不同的预制体制备变密度预制体C/C复合材料,并对应制备了常用的恒密度预制体C/C复合材料.研究了不同结构和不同平均密度的预制体对C/C复合材料压缩性能的影响.实验结果表明,变密度预制体C/C复合材料的压缩强度远远大于相同平均预制体密度的恒密度预制体C/C复合材料,并且随预制体平均密度的增大呈先增大后下降的趋势.由于预制体内部纤维含量的不同分布状态,变密度预制体C/C复合材料的压缩破坏同时呈现出压溃和剪切破坏模式. 相似文献
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结合化学气相沉积(CVD)和前驱体浸渍裂解工艺,分别以丙烯、糠酮树脂和煤沥青为前驱体制备了密度在1.85g/cm3以上的三维炭/炭(C/C)复合材料,对比研究了沥青炭、热解炭+沥青炭以及热解炭+树脂炭结构(分别为A、B、C组)的等三种不同炭基体C/C复合材料的增密效率与力学性能,采用排水法表征C/C复合材料的孔隙率及密度,利用扫描电镜进行炭基体的微观结构表征,采用万用电子力学试验机进行拉伸强度、压缩强度、剪切强度等力学性能表征。结果表明,在热解炭质量含量相同的前提下,树脂浸渍裂解增密速率低于沥青浸渍裂解工艺,树脂炭基体孔隙率低于沥青炭基体。不同炭基体结构的C/C复合材料力学性能次序为:热解炭+树脂炭双元炭基体最高,纯沥青炭基体次之,热解炭+沥青炭双元炭基体最低,分析原因为热解炭与树脂炭双元炭基体的界面结合强度高,而沥青炭为混乱无序碳结构,热解炭和沥青炭双元炭基体界面结合强度弱,因此力学强度最低。 相似文献
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采用碳布层叠然后用化学气相渗方法制备了C/SiC复合材料,这种材料纤维与基体间的界面是决策材料力学行为的重要因素,带有热解碳作为界面层的C/SiC材料,在断裂进表现出大范围的脱粘,纤维与周围的基体不同发生断裂,有大量的纤维拨出,断口类似毛刷,无界央层材料表现为脆性平面断口,裂纹直接通过纤维和基体向前扩展,没有发生脱粘。 相似文献
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C/C多孔体对C/C-SiC复合材料微观结构和弯曲性能的影响 总被引:2,自引:0,他引:2
以4种纤维含量相同(32%,体积分数,下同),用化学气相渗透(chemical vapor infiltration,CVI)法制备了4种密度的碳纤维增强碳(carbon fiber reinforced carbon,C/C)多孔体,基体炭含量约20%~50%.利用液相渗硅法(liquid silicon infiltration,LSI)制备了C/C-SiC复合材料,研究了C/C多孔体对所制备的C/C-SiC复合材料微观结构和弯曲性能的影响.结果表明:不同密度的C/C多孔体反应渗硅后,复合材料的物相组成均为SiC,C及单质Si;随着C/C多孔体中基体炭含量的增加,C/C-SiC复合材料中SiC含量逐渐减少而热解炭含量逐渐增加.C/C-SiC复合材料弯曲强度随着材料中残留热解炭含量增加而逐渐增加,热解炭含量为约42%的C/C多孔体所制备的C/C-SiC复合材料的弯曲强度最大,达到320 MPa. 相似文献
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A low-density carbon/carbon (C/C) composite/silane coupling agent/hexagonal boron nitride (h-BN) hybrid reinforcement was prepared by grafting polyethyleneimine (PEI)-encapsulated modified h-BN fillers onto a carbon fiber surface using 3-aminopropyltriethoxysilane (APS) as the connection to improve the distribution uniformity of h-BN fillers in quasi-three-dimensional reinforcements and the interfacial properties between the fibers/pyrocarbon (PyC) in the C/C-BN composites obtained after densification by chemical vapor infiltration (CVI). The microstructure and chemical components of the hybrid reinforcement were investigated. The transmission electron microscopy (TEM) sample was prepared using a focused-ion beam (FIB) for the h-BN/PyC interfacial zone. The interlaminar shear strength (ILSS) and impact toughness were analyzed to inspect the composites’ interfacial properties. The results show that APS and h-BN are uniformly grafted on the fiber surface in the chopped fiber web inside the C/C composite without a density gradient, and agglomeration occurred and significantly increasing the fiber surface roughness. The highly ordered h-BN basal plane may affect the order degree of PyC near the h-BN/PyC interface. The addition of h-BN reduces the PyC texture near it, causing the annular cracks to disappear gradually. The lower PyC texture and the rougher fiber surface strengthen the interfacial bond of the fiber/matrix. Consequently, the ILSS strength of the C/C-BN composites first increases and then decreases as the h-BN filler content increases and is always higher than that of the C/C composite, while the addition of h-BN fillers weakens its impact toughness. When the h-BN content in the C/C-BN composite is 10 vol%, the ILSS of the C/C-BN composites was 15.6% higher than that of the C/C composites. However, when the h-BN content is excessive (15 vol%), the densely grafted h-BN will bridge each other, reducing the subsequent CVI densification efficiency to form a loose interface, causing a decrease in the shear strength. 相似文献
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《Journal of the European Ceramic Society》2023,43(14):5972-5985
The purpose of the work was to determine the conditions of CF preparation to obtain carbide composites with favorable mechanical response. The relationships between the interfacial properties of fiber/polymethylsiloxane composite, and mechanical properties of the resulting fiber/carbide composites were investigated. The CF/resin interfacial strength was modified by oxidation of CF surface with nitric acid, silanization, and depositing CNT or a pyrolytic carbon layer (PyC). The study of composite interphases (ILSS and SEM) and surface tests of the modified CF (XPS, FT-IR, wettability measurements) showed different nature of the bonding occurring at the fiber/resin and fiber/ceramics boundary. The CF silanization significantly improved the ILSS between CFs and resin by 38.5%, while reduced flexural properties of carbide composites. The most promising treatment method of CF for PIP-based ceramic composites was modification with PyC, which provided 2 times higher ILSS, 1.5 times higher flexural strength and improved work to fracture (WF) as compared to unmodified CF. 相似文献
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研究了不同燃气流作用时间对玻璃钢层间剪切强度的影响。研究结果表明:随着燃气流作用时间的延长,玻璃钢表面碳化失效层数呈增加趋势;未烧蚀部分复合材料层间剪切强度虽有降低,但是降低幅度不大,说明表面的玻璃布层碳化失效对深层复合材料层间剪切强度影响不大;烧蚀后复合材料断裂模式由韧性转变为脆性。该研究结果为玻璃钢在燃气流环境中的应用提供了重要的数据支撑。 相似文献
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采用6K炭纤维无纬布/网胎交替叠层及12K炭纤维无纬布/网胎交替叠层,在针刺工艺,致密化、热处理工艺完全相同的情况下,制备了密度为1.8g/cm3的热解炭/树脂炭双元基体的两种C/C复合材料产品,考察了针刺预制体结构单元对C/C复合材料性能的影响.结果表明,两种C/C复合材料的热学(垂直方向导热系数)、电学性能及石墨化度基本相当;而针刺6K炭纤维无纬布/网胎预制体C/C复合材料的拉伸、弯曲、压缩、层间剪切强度分别为127MPa,189MPa,263MPa,24.6MPa;其平行方向导热系数为54.6W/m·K,比常规针刺12K炭纤维无纬布/网胎预制体C/C复合材料相应提高了38%,32.2%,32.8%,38.9%,21%,彰显了细化针刺预制体结构单元对C/C复合材料力学性能的显著影响. 相似文献
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采用有限元方法对炭纤维/树脂复合材料的导热性能进行了数值模拟,分别建立一维结构和二维结构炭纤维/树脂复合材料计算分析模型,研究炭纤维含量、界面接触热阻、以及炭纤维直径对复合材料有效热导率的影响。研究结果表明炭纤维作为复合材料增强相,其含量越高复合材料的热导率越高;界面的接触热阻在10-3~10-5(m2 K)/W范围内对复合材料有效热导率有较大的影响,超出范围之后改变接触热阻对材料热导率的影响可以忽略;接触热阻比较大时,炭纤维的直径对复合材料的热导率有较大的的影响,当接触热阻比较小时,炭纤维的直径对于复合材料热导率的影响非常小。 相似文献
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为了改善碳纤维/环氧树脂(CF/EP)层合板层间断裂韧性较差的问题,采用预浸料层间涂层和模压工艺制备聚醚醚酮(PEEK)层间增韧CF/EP层合板。探究PEEK含量对CF/EP层合板Ⅱ型层间断裂韧性和冲击强度的影响。结果表明:PEEK的加入有效提高CF/EP层合板的Ⅱ型层间断裂韧性和冲击强度。当PEEK含量为2%,层合板的断裂韧性和冲击强度分别达到1 253 J/m2和259 kJ/m2,与纯层合板相比分别提高61.5%和32.8%。实验分析PEEK增韧机理,为研究高附加值复合材料产品提供参考。 相似文献
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The poor interlaminar properties restrict the application of carbon fiber reinforced polymer (CFRP) composites. In this work, a novel method for fabricating a graded interface structure is developed to improve the through-thickness thermal conductivity of CFRP composites. High-strength graphene nano-plates (GnP) and phenolic resin (PF) were selected to deposit on the surface of carbon fiber to design a novel CF/Epoxy laminates, where a simultaneous improvement of interlaminar shear strength (ILSS) and through-thickness thermal conductivity was observed. With addition of 1 wt % of GnP-PF in CF, 37.04% increase of the ILSS, and 16.67% enhancement of thermal conductivity compared to the original CFRP. The mechanism for improvement of both ILSS and thermal conductivity was studied by scanning electron microscopy and nano-indentation, where a better interface formed by GnP-PF has been clearly observed. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47061. 相似文献
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Effects of quasi‐3D stacking architecture on interlaminar shear strength and void content of FRP
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To improve the interlaminar shear strength (ILSS) of composite laminate, three different quasi‐3D stacking architecture (q‐3DSA) laminates were fabricated by using automated fiber placement process and a traditional 2D stacking architecture (2DSA) laminate was fabricated as the control sample. The distribution of voids, the density, and the ILSS of four types of laminates were tested. The results indicated that the void content of the different q‐3DSA laminates was approximately 0.71%–3.07% greater than that of the 2DSA laminate, but the ILSS of q‐3DSA laminates was 5.49%–12.54% better than that of the 2DSA laminate. The microstructure images showed that the cracks spread along the interface between the adjacent layers in the 2DSA laminate, while the cracks cross two or more layers in the q‐3DSA laminates. This behavior indicated that the q‐3DSA improved the ILSS by dispersing the interlaminar load through the bended and interlaced tows in the laminate. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41076. 相似文献