新型炭材料

QIU Jie-shan, LI Ping, LIU Gui-shan, ZHOU Ying

2005, 20(03): 193-197.

Abstract(4188)

PDF(3379)

Abstract:
Carbon foams with high performance have been successfully prepared from mesophase pitch in the presence of iron nitrite. The effect of iron nitrite on preparation of carbon foams was focused and addressed in detail. The decomposition behavior of mesophase pitch with and without Fe(NO3)3 or mixed with SiO2 were studied using TG, XRD techniques, and an NOx analyzer. The carbon foams were examined using SEM and XRD. The results indicate that the presence of Fe(NO3)3 is advantageous to the preparation of carbon foams with well-developed and uniform cell structures. During the carbonization treatment stage, several iron species were detected at different temperatures, of which iron carbides dominate as main iron species in carbon foams obtained at 1500℃. It is believed that iron species in carbon foams function, to some degree, as a catalyst for the graphitization of carbon foams.

通过再活化浸渍金属盐的活性炭来发展中孔结构(英)

QIAO Wen-ming, SONG Yan, Seong-Ho Yoon, Isao Mochida

2005, 20(03): 198-204.

Abstract(3237)

PDF(3197)

Abstract:
Commercial coconut shell based activated carbon (AC) was used to investigate the production of increased mesoporosity by impregnating with catalytic metal salts such as Fe(NO3)3 and Fe2(SO4)3 followed by CO2 gasification. The salts are found be effective in enlarging the pore size of AC and Fe(NO3)3 is the more effective one to increase pore size and surface area, up to 10nm and 1930m2/g, respectively. Modified AC shows a much larger adsorption capacity (5-8 times as large as that of as-received AC) and a more rapid adsorption rate for vitamin B12. Three mechanisms are proposed to modify the surface properties and pore size of AC: (1) NOx and SOx liberated from the impregnated salts burn the carbon wall to enlarge pore size; (2) Metal oxide reacts with the carbon wall to enlarge pore size, accompanied by reduction to the corresponding metal; and (3) Metal has a catalytic effect during CO2 gasification of the carbon wall of the AC. Graphitization of the carbon wall caused by metal is also observed. The present modification method is a promising, convenient and cheap way to modify AC to obtain mesopores.

添加多壁纳米碳管活性炭电极材料的电化学电容特性

LIU Chen-guang, FANG Hai-tao, WANG Da-wei, LI Feng, LIU Min, CHENG Hui-ming

2005, 20(03): 205-210.

Abstract(3170)

PDF(2066)

Abstract:
Multi-walled carbon nanotubes (MWNTs) were used as a conducting additive in activated carbon electrode materials instead of the commonly used carbon black and graphite powder conducting additive. It was found that MWNTs can greatly improve the capacitor performance. When 5 w/% MWNT conducting additive was used, the specific capacitance of activated carbon can be increased to 185 F/g compared with 130 F/g of activated carbon with 5 w/% carbon black conducting additive, and the frequency response characteristic of the MWNT added activated carbon electrochemical capacitor is much better than that of one with added carbon black. Moreover, some prototype electrochemical capacitors were fabricated on the basis of the research results. All these show that activated carbon with added MWNTs has a good capacitance performance and is suitable for application in electrochemical capacitors.

纳米SiO2改性上浆剂对炭纤维复合材料界面性能的影响

YANG Yu, LU Chun-xiang, WANG Xin-kui, LIU Hong-peng, HE Fu, LI Yong-hong, SONG Yan

2005, 20(03): 211-216.

Abstract(2552)

PDF(1685)

Abstract:
A single fiber fragmentation test, three-point bend test, scanning electron microscopy and dynamic mechanical thermal analysis (DMTA) were performed to study the influence of nano-SiO2 modified emulsion sizing on the interfacial properties of carbon fibers reinforced plastics (CFRP). As a comparison, CFRP with and without sizing but not modified by nanoSiO2 were also investigated. Results showed that the interfacial shear strength (IFSS) values of the CF with modified sizing and unmodified sizing were increased by 79% and 41%, respectively, compared to the CF without sizing. The interlaminar shear strength (ILSS) values of the CFRP with modified sizing and unmodified sizing were also increased by 14% and 9%, respectively compared to the CFRP without sizing. Furthermore, the loss tangent (tanδ) of CFRP with modified sizing declined to 18% and glass transition temperature (Tg) was increased by 5℃, compared to the CFRP with unmodified sizing in the DMTA chart. So the interfacial adhesion performance of the CFRP with modified sizing by nano-SiO2 was evidently increased.

常压干燥制备炭气凝胶及其电化学行为的研究

LI Wen-cui, HU Hao-quan, ZHU Yu-dong, ZHU Sheng-wei

2005, 20(03): 217-222.

Abstract(2537)

PDF(2331)

Abstract:
Carbon aerogel was synthesized via a sol-gel process from the polycondensation of cresol and resorcinol with formaldehyde catalyzed by NaOH, followed by drying at ambient pressure and pyrolysis at 900℃ under inert atmosphere. Results show that this carbon aerogel has a BET surface area higher than 500m2/g and a fairly uniform pore size distribution in the range of 8-20nm. The electrochemical behavior of such a carbon aerogel used as electrode material for an electrical double-layer capacitor was investigated by impedance spectroscopy. It is found that this carbon aerogel exhibits nearly ideal double-layer capacitance characteristics. The volume specific capacitance and the mass specific capacitance in 1mol/L sulfur acid solution can reach as high as 70F/cm3 and 97F/g.

中间相沥青不熔化纤维自烧结制备高传导性炭材料研究

MA Zhao-kun, SHI Jing-li, LIU Lang, SONG Jin-ren, GUO Quan-gui, ZHAI Geng-tai

2005, 20(03): 223-227.

Abstract(2713)

PDF(1873)

Abstract:
Mesophase pitch was melt-spun with a spinneret of ribbon-shaped section followed by oxidative stabilization; then the mesophase ribbon-shaped oxidized fibers were self-sintered by hot-pressing without using a binder. The effect of ultimate oxidation temperature for mesophase-based ribbon shaped fibers under the same heating rate and oxidation time on the functional groups of the fibers, and the formability and properties of the resulting carbon materials were investigated by infrared spectroscopy (IR) and scanning electron microscopy. Results showed that the ribbon-shaped mesophase fibers oxidized at a moderate range of ultimate temperature can be self-sintered into carbon materials with high conductivity, density and bend strength. As an example, the electrical resistivity, thermal conductivity, bend strength and density of carbon materials formed by self-sintering of ribbon shaped fibers oxidized at an ultimate temperature of 260℃ are 0.56μΩm, 830W/(m•K), 125.9MPa and 2.16g/cm3, respectively.

热丝CVD大面积金刚石薄膜的生长动力学研究

WANG Ai-ying, KE Pe-ling, SUN Chao, HUANG Rong-fang, WEN Li-shi

2005, 20(03): 229-234.

Abstract(2427)

PDF(1996)

Abstract:
For the easier scaling up and better growth behavior of diamond films, hot-filament CVD (HFCVD) is considered as the most promising deposition technique compared with the other CVD techniques. However, inhomogeneous nucleation and low growth rate of diamond films are two main barriers to industrial applications for the HFCVD technique. When the relative deposition parameters are fixed at optimized values, the spatial distributions of substrate temperature and gas temperature are calculated by a developed two-dimensional mathematical model based on previous results. In addition, the growth kinetics of diamond films over a large area deposited on silicon (100) is discussed in terms of the simulated results. X-ray diffraction, scanning electron microscopy and Raman spectroscopy were used to characterize the structure and morphology of the films. It is found that under the simulated homogeneous distributions of substrate temperature and gas temperature, the diamond films, although with residual stress, are continuous and uniform with good crystallinity and high quality, the average growth rate is up to 1.8mm/h. Simultaneously, the dominant morphology of the films is very sensitive to substrate temperature and radical concentrations, which agree well with the earlier simulated results.

焦炭颗粒的平均细度对沥青基炭复合材料性能的影响

GUO Ling-jun, LI He-jun, XUE Hui, LI Ke-zhi, SUN Guo-ling

2005, 20(03): 235-239.

Abstract(2725)

PDF(1717)

Abstract:
Granular coke reinforced pitch-based carbon composites (CRPCC) with high density and low cost were fabricated by a new mould pressing and semi-carbonization technology. The effect of the average particle size of the granular pitch coke on the density and compressive strength of CRPCC materials was studied in detail. The rules about the effect of the density on the compressive strength of CRPCC materials were mathematically analyzed. Results show that the density and the compressive strength increase with an increase of the average particle size of granular pitch coke. In the experiment, the density and compressive strength increase from 1.28g/cm3 to 1.77g/cm3 and from 10.1MPa to 55.0MPa respectively when the average particle size of the granular pitch coke as reinforcement rises from 44.2 to 206.3mesh.

石油焦系超级活性炭的孔结构控制(英)

SUN Xin, ZHA Qing-fang, GUO Yan-sheng, LI Zhao-feng

2005, 20(03): 240-244.

Abstract(2251)

PDF(1653)

Abstract:
采用KOH活化法从大庆石油焦制得超级活性炭，而后对其进行微孔和中孔的调控。中孔调控采用热处理法，所得超级活性炭的中孔率在85%以上，比表面积大于1500m2/g。同时对热处理后的超级活性炭进行表面硝酸氧化，引入部分含氧官能团。60min酸处理效果明显，羧基的增加量是20min酸处理的9倍。处理后的超级活性炭更适合作催化剂载体。微孔的控制采用化学气相炭沉积法（以苯为碳源），所得超级活性炭的微孔率从51%增加到87%。对CO2和CH4的分离能力从30mg/g提升到47mg/g，具有良好的筛分效果。

高温热处理对C/C-SiC复合材料制备与力学性能的影响

WANG Lin-shan, XIONG Xiang, XIAO Peng, YAN Zhi-qiao, ZHANG Hong-bo, LIU Gen-shan

2005, 20(03): 245-249.

Abstract(3197)

PDF(1987)

Abstract:
C/C preforms were prepared by densification of carbon fiber felts, using furan resin impregnation, carbonization, CVD and an initial high temperature treatment (HTT) at 2000-2400℃ followed by a second resin impregnation and carbonization. The C/C-SiC composites were manufactured by molten silicon infiltration of the as-obtained C/C preforms at 1650℃ with or without a second HTT. The effect of the first HTT on the density, porosity, mechanical properties and fracture mode of the C/C-SiC composites was studied. Results show that the first HTT results in C/C-SiC composites with a “pesuo-plastic” fracture mode and better general mechanical properties. The second HTT of the C/C preforms results in carbon with open porosity, which is favorable for molten silicon infiltration, leading to a C/C-SiC composite with high density and low porosity, but the mechanical properties decrease while the fracture mode is unchanged.

等离子体射流辅助双催化剂原位催化法合成碳纳米管

LIANG Xin-yu, WANG Hao-jing, LIU Yin, CHAO Bin, ZHOU Li-gong

2005, 20(03): 250-254.

Abstract(2416)

PDF(2019)

Abstract:
Carbon nanotubes were synthesized in a methane plasma by using Fe2O3/Ni as catalysis. Methane is pyrolyzed efficiently into nano-carbon and H2 by the plasma jet under atmospheric pressure, during which Fe2O3 is reduced by H2 to form nanometer sized metallic particles, which together with Ni are used as bimetallic catalysts for the preparation of nanotubes. The carbon nanotubes were examined using TEM and chemical element analysis, etc. Results show that the carbon nantotubes present an appearance of entangled morphologies with outer diameters of 10-30nm, length of several hundred nanometers, and the yield is about 75%. Compared with the single catalyst, the bimetallic catalyst is advantageous for the mass production of carbon nanotubes.

有机硅添加剂对热处理粘胶纤维结构和性能的影响

LI Xin-lian, WEN Yue-fang, YANG Yong-gong

2005, 20(03): 255-260.

Abstract(2753)

PDF(1814)

Abstract:
Rayon fibers were impregnated by an organosilicone additive followed by heat treatment and the structure and properties were investigated. Results show that strength of the heattreated rayon fibers impregnated by the organosilicone was improved The number of pores in the resulting carbon fibers was decreased and the separability of filaments was improved because the organosilicone may protect the surface of the fibers during heat-treatment by virtue of its heat-resistant, non-conglutination, hydrophobic nature and chemical inertness. When the loading of the organosilicone additive on the rayon fibers was 4.79 w/%, the tensile strength of the resulting carbon fibers was increased by 126.3%. The organosilicone additive was decomposed to form SiO2 after heat treatment.

燃料和基板对火焰法制备一维碳纳米材料的影响

CAO Feng, YANG Han, FU Qiang, PAN Chun-xu

2005, 20(03): 261-269.

Abstract(3137)

PDF(2238)

Abstract:
One-dimensional carbon nanomaterials involving carbon nanotubes (CNTs) and novel solid-cored carbon nanofibers (CNFs) were synthesized from flames by using methanol, ethanol and liquefied petroleum gas as fuels, and low carbon mild steel and Ni-contained alloys as substrates. The nanomaterials were characterized by field emission high resolution scanning electron microscopy, transmission electron microscopy and laser Raman spectroscopy. It was found that the morphologies of the nanomaterials were determined mainly by the substrates. A substrate containing Fe tended to produce the solid-cored CNFs on low carbon mild steel substrates, whereas a substrate containing Ni tended to produce hollow-cored CNTs. This was because Fe has a stronger affinity for carbon than Ni. The fuels also influenced the morphologies of the nanomaterials due to the differences in carbon content and combustion energy, etc.

用EA-CVD方法制备的大尺寸金刚石厚膜的品质和膜厚均匀性的研究

LU Xian-yi, JIN Zeng-sun, YANG Guang-liang

2005, 20(03): 270-273.

Abstract(2089)

PDF(2133)

Abstract:
An electron assisted chemical vapor deposition (EA-CVD) method was used to synthesize a uniform diamond thick film. The factors that influence the uniformity of quality and thickness of diamond thick films are methane concentration, gas pressure, bias current and the distance between filament and substrate. Results show that state of the glow discharge plasma plays an important role in the uniformity of quality and thickness of the diamond films. A larger filament-substrate distance, bigger bias current and lower gas pressure in the reactor can improve the state of the glow discharge plasma, resulting in an optimized uniform diamond thick film with diameter of 80mm, thickness of 1mm, and with a non-uniformity of thickness and thermal conductivity less than 5% and 10%, respectively. The abrasiveness ratio, defined by the abrasive weight loss of a standard grinding wheel divided by the abrasive weight loss of the resultant diamond film, is about 1.5×105, which is same in the middle and edge of the sample.

PAN基炭纤维中sp2杂化的C—C原子键距与结构参数之间关系

HUA Zhong, WANG Yue-mei, XIAO Li, QIN Zheng-kun, FAN Ji-wen

2005, 20(03): 274-277.

Abstract(2831)

PDF(2050)

Abstract:
PAN-based carbon fibers with different carbonization temperatures were characterized by Raman scattering and X-ray diffraction. The length of the sp2 hybrid C—C bond was obtained on the basis of Fitzer’s C—C bond length formula. Structural parameters (La, Lc, d002) of graphite were obtained by X-ray diffraction measurements. The dependences of sp2 hybrid C—C bond length with structural parameters (La, Lc, d002) were obtained. It was found that sp2 hybrid C—C bond length increases with La, Lc and decreases with d002.

碳质中间相形成机理研究

LI Tong-qi, WANG Cheng-yang

2005, 20(03): 278-285.

Abstract(2222)

PDF(2741)

Abstract:
Carbonaceous mesophase is an excellent precursor for the production of high-performance carbon materials which have been successfully applied in high-performance composites, ultra-high power graphite electrodes and anodes of rechargeable lithium ion batteries. The complicated structures and various forms of carbonaceous mesophase make the raw materials and production process involved more complicated. It is important to have a good understanding of the mesophase formation mechanism in order to predict the performance of mesophase based carbon materials prepared under different conditions and to determine further their applications. A review of the formation process and mechanism of carbonaceous mesophase is given based on explanations in previous papers and a new Building from Granular Basic Units (BGBU) theory is proposed. It is found that there are many unreasonable explanations in traditional theory that cannot clarify some experimental facts. Microdomain building theory made great progress in explaining the formation of carbonaceous mesophase, but the introduction of the non-existent stacking units of molecules is a defect of the theory. BGBU theory was brought forward based on the former theories and can explain the formation process of carbonaceous mesophase very well. In addition, some applications of BGBU theory are discussed.

从第13届国际插层化合物大会看插层化合物的最新发展趋势

LI Xin-lu, KANG Fei-yu

2005, 20(03): 286-288.

Abstract(2076)

PDF(1920)

Abstract:
This report briefly introduces the 13th intercalation symposium on intercalation compounds held in Clermont-Ferrand in France, 6-9 June, 2005. More than 170 experts from 23 nations presented 216 contributions of the updated development in the field of intercalation compounds. Presentations covered a wide range of issues, including graphite intercalation compounds (GICs), fullerenes, nanotubes, clays and modified clays, layered metal oxides and hydroxides, hybrid and nanocomposite materials, zeolites, phosphates and other related materials. Issues in nano-GICs, organic-inorganic nanocomposites, fullerene intercalations, lithium intercalation compounds and nanoscale hydrides for hydrogen storage represent future development for intercalation compounds.

2005 Vol. 20, No. 03

Classified CollectionMORE

Information Notice MORE MORE

DownloadMORE

LinksMORE