摘要
采用浸渍-炭化、等温及薄膜沸腾CVI法,分别以煤沥青、糠酮树脂、天然气和二甲苯为前驱体制备了密度为1.75~1.81 g/cm^3的炭/炭(C/C)复合材料,对比研究了4种材料的力学与导热性能。结果表明,基体为天然气热解炭(PyC)时材料的弯曲和层间剪切强度较高,分别达到208.7和26.4 MPa,沥青炭为基体时弯曲(125.8 MPa)和层间剪切强度(20.1 MPa)较低。天然气和二甲苯PyC为基体的材料韧性较好。二甲苯PyC呈粗糙层结构,材料具有高的石墨化度、表观微晶尺寸及热导率,其平行和垂直方向的热导率分别达到148.2和75.4 W/(m·K),约为树脂炭基体材料的1.5倍。天然气PyC可作为高强度要求的材料基体,二甲苯PyC有利于提高材料导热与力学性能。
Four carbon/carbon composites with densities of 1.75-1.81 g/cm^3 were produced with matrix carbons derived from(a)coal tar pitch and furfural acetone resin by impregnation-carbonization,(b)natural gas by isothermal chemical vapor infiltration and(c)xylene by film-boiling chemical vapor infiltration.Their mechanical properties and thermal conductivities(TC)were compared and correlated to the matrix carbon microstructures.Results showed that the strength of the composites decreased as the carbon matrix changed from natural gas pyrocarbon(PyCN),to resin-derived carbon,to xylene PyC(PyCX),and to pitch-derived carbon.The highest flexural and interlaminar shear strengths of 208.7 and 26.4 MPa,respectively,were obtained for the PyCN matrix.The large amount of fiber pull-out and step-like matrix fracture contributed to a high toughness of composites with PyCN and PyCX matrices.Relatively low strength and toughness were obtained for the pitch-derived carbon.The change of TC with the matrix type was consistent with the graphitization degree and apparent crystallite height.The highest in-plane and out-of-plane TC reached 148.2 and 75.4 W/(m·K),respectively,for the PyCX matrix,which was due to its carbon layers having the highest preferred orientation.The chaotic structure and large number of defects of the resin-derived carbon produced a relatively low TC.PyCN was the most suitable matrix for composites with excellent mechanical properties.PyCX should be used to improve the TC and toughness of the low-cost composites.
作者
刘霞
邓海亮
郑金煌
孙茗
崔红
张晓虎
宋广生
LIU Xia;DENG Hai-liang;ZHENG Jin-huang;SUN Ming;CUI Hong;ZHANG Xiao-hu;SONG Guang-sheng(College of Electromechanical Engineering,Xi'an Polytechnic University,Xi'an 710048,China;School of Materials Science and Engineering,Anhui University of Technology,Maanshan 243002,China;Xi'an Aerospace Composite Research Institute,Xi'an 710025,China)
出处
《新型炭材料》
SCIE
EI
CAS
CSCD
北大核心
2020年第5期576-584,共9页
New Carbon Materials
基金
国家自然科学基金资助项目(51972002)
装备预研基金(JZX7Y20190262004901).
关键词
C/C复合材料
基体结构
力学性能
热导率
Carbon/carbon composites
Matrix microstructure
Mechanical strength
Thermal conductivity
