硼在碳／碳复合材料中的状态及其催化石墨化作用

以糖酮树脂作粘结剂，添加树脂碳微粉、硼类催化剂、短切ＰＡＮ基高强碳纤维，制得了含硼Ｃ／Ｃ复合材料。通过Ｘ射线衍射（ＸＲＤ）、Ｘ射线光电子（ＸＰＳ）等手段，检测了硼、氧化硼在Ｃ／Ｃ中的状态，研究了它们对Ｃ／Ｃ复合材料的催化石墨化作用，分析了石墨化温度、催化剂种类及其用量对石墨化度的影响。结果表明：硼以固溶体的形式存在Ｃ／Ｃ复合材料，通过吸电子断键、代替碳原子消除缺陷等机理形式，使最难石墨化的玻璃碳和     

聚丙烯腈基碳纤维石墨化过程的晶体结构分析(英文)

使用国产聚丙烯腈基碳纤维进行石墨化实验,制备高模量的碳纤维。使用X光衍射和拉曼光谱的方法对晶体结构进行了表征,讨论了石墨化工艺参数,包括石墨化温度以及牵引张力大小对晶体结构的影响。实验发现:高温石墨化辅助牵伸石墨化是有效的方法提高石墨化度制备得到石墨化碳纤维。本文使用国产碳纤维在2700℃以及牵伸为1.5%时制备得到了杨氏模量为356GPa的高模量碳纤维。     

石墨化对微螺旋炭纤维形貌和微观结构的影响

采用化学气相沉积法制备微螺旋炭纤维, 在氩气气氛, 2500℃下对其进行石墨化处理. 通过扫描电镜, 激光拉曼光谱和X射线晶体衍射对石墨化前后微螺旋炭纤维的形貌与微观结构进行了研究, 并初步探讨了石墨化机理. 结果表明: 石墨化处理对微螺旋炭纤维具有显著的纯化作用, 其螺旋形貌基本保持不变. 微观结构更加规整, 微螺旋炭纤维的晶面层间距d₀₀₂(0.3626～0.3378nm)减小, 晶粒尺寸L_c(1.6404～3.8590nm)和L_a(2.04～7.21nm)增大, 石墨化程度增强.     

Tuning Array Morphology for High‐Strength Carbon‐Nanotube Fibers

Vertically aligned carbon‐nanotube arrays are synthesized by chemical vapor deposition. Carbon‐nanotube fibers are directly spun from the obtained nanotube arrays and then tested mechanically. A strong correlation between the array morphologies and the mechanical properties of the fibers is observed: well‐aligned arrays yield fibers with much higher performance, while wavy and entangled arrays give poor fiber properties. More importantly, such array morphologies could be controlled by introducing hydrogen or oxygen during the nanotube synthesis. By simply switching the growth condition from 150 ppm oxygen addition to 2% hydrogen addition, the nanotube array changes from the wavy morphology to the well‐aligned morphology, and correspondingly the tensile strength of the resultant fibers could be increased by 4.5 times, from 0.29 GPa for the fibers spun from the oxygen‐assistance‐grown nanotube arrays to 1.3 GPa for the fibers spun from the hydrogen‐assistance‐grown nanotube arrays. The detailed effects of hydrogen and oxygen on the nanotube growth, especially on the growth rate and the array spinnability, are extensively studied. The formation mechanism of the different morphologies of the nanotube arrays and the failure mechanism of the nanotube fibers are also discussed in detail.     

Atomic‐Distributed Coordination State of Metal‐Phenolic Compounds Enabled Low Temperature Graphitization for High‐Performance Multioriented Graphite Anode

Continuous efforts have been made to achieve nanostructured carbon materials with highly ordered graphitic structures using facile synthetic methods. 3D graphite nanoballs (GNBs) are synthesized by the low‐temperature pyrolysis of a non‐graphitizable precursor, tannic acid (TA). Abundant phenol groups on TA bind to Ni²⁺ to form metal‐phenolic coordination, which renders each Ni cation to be atomically distributed by the TA ligands. Even at low temperatures (1000 °C), highly ordered graphitic structure is promoted by the distributed Ni nanoparticles that act as a graphitization catalyzer. The crystallinity of the GNB is fully corroborated by the intense 2D peak observed in Raman spectroscopy. In particular, the graphitic layers have orientations pointing toward multidirections, which are beneficial for the rapid transport of Li‐ions into graphite grains. The resulting materials exhibit outstanding electrochemical performance (120 mAh g^?1 at 5 C and 282 mAh g^?1 at 0.5 C after 500 cycles) when evaluated as a fast‐chargeable negative electrode for lithium ion batteries.     

碳纤维-铝多层结构胶接质量的超声检测

采用宽带窄脉冲超声换能器对树脂基碳纤维与铝板胶接质量进行检测,通过对采集的回波信号幅值、声时以及相位等因素的分析,找出回波信号与胶接缺陷形态的对应关系,提出针对树脂基碳纤维与铝多层结构胶接结构的超声检测方法。本文还通过对试块上预埋缺陷的检测确定了该检测方法的准确性,并运用红外热成像检测技术对检测结果的可靠性予以验证。     

从炭纤维的发展看石墨烯产业化进程

简要介绍了碳家族的两种重要的材料——炭纤维和石墨烯的发展历史、结构、性能及制备方法,深入剖析了两种材料的产业化发展特点和区别,探讨了石墨烯产业化进程中的问题,最后从炭纤维的产业化进程得出未来石墨烯要走务实的产业化道路。     

Wide‐Range Tunable Dynamic Property of Carbon‐Nanotube‐Based Fibers

A carbon nanotube (CNT) fiber is formed by assembling millions of individual tubes. The assembly feature provides the fiber with rich interface structures and thus various ways of energy dissipation, as reflected by the nonzero loss tangent (>0.028–0.045) at low vibration frequencies. A fiber containing entangled CNTs possesses higher loss tangents than a fiber spun from aligned CNTs. Liquid densification and polymer infiltration, the two common ways to increase the interfacial friction and thus the fiber's tensile strength and modulus, are found to efficiently reduce the damping coefficient. This is because the sliding tendency between CNT bundles can also be well suppressed by a high packing density and the formation of covalent polymer cross‐links within the fiber. The CNT/bismaleimide composite fiber exhibits the smallest loss tangent, nearly the same as that of carbon fibers. At a higher level of the assembly structure, namely a multi‐ply CNT yarn, the interfiber friction and sliding tendency obviously influence the yarn's damping performance, and the loss tangent can be tuned within a wide range, similar to carbon fibers, nylon yarns, or cotton yarns. The wide‐range tunable dynamic properties allow new applications ranging from high quality factor materials to dissipative systems.     

High Temperature‐Stable Perovskite Solar Cell Based on Low‐Cost Carbon Nanotube Hole Contact

Mixed ion perovskite solar cells (PSC) are manufactured with a metal‐free hole contact based on press‐transferred single‐walled carbon nanotube (SWCNT) film infiltrated with 2,2,7,‐7‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,90‐spirobifluorene (Spiro‐OMeTAD). By means of maximum power point tracking, their stabilities are compared with those of standard PSCs employing spin‐coated Spiro‐OMeTAD and a thermally evaporated Au back contact, under full 1 sun illumination, at 60 °C, and in a N₂ atmosphere. During the 140 h experiment, the solar cells with the Au electrode experience a dramatic, irreversible efficiency loss, rendering them effectively nonoperational, whereas the SWCNT‐contacted devices show only a small linear efficiency loss with an extrapolated lifetime of 580 h.     

碳纤维增强碳化硅陶瓷复合材料的研究

使用ＣＶＤ技术提高纤维增强陶瓷基复合材料的密度是很困难的,因为它很难使反应气体完全渗入到基体里面,这是由于“瓶颈”效应所致,即ＣＶＤ过程阻塞了基体表面的小气孔,进而封闭了通向大气孔的入口,为此提出了一种新的方法位控ＣＶＤ（ＰＣＣＶＤ）,来克服上述通过控制反应气体通道位置试样的加热位置,从而达到控制沉积位置,使沉积界面始终处于开孔状态,使用ＰＣＣＶＤ技术制造的Ｃ／ＳｉＣ复合材料,实际密度可达到其理论