Effect of boron-catalyzed graphitization on the mechanical properties and microstructure of carbon fibers

CARBON

9 3 ( 2 0 1 5 ) 1 0 8 1 –1 0 8 4

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ScienceDirect journal homepage: www.elsevier.com/locate/carbon

New Carbon Materials Abstracts 2015(2) Advances in the ablation resistance of C/C composites

engineering applications. Research efforts need to be focused

Qian-gang Fu, Jia-ping Zhang, He-jun Li

on the fine structure and gradient design of preforms and the

State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China

optimum combination of different carbon matrices for the improvement of C/C composites. [New Carbon Materials 2015, 30(2): 106–114]

Carbon/carbon (C/C) composites are considered the most promising materials for high-temperature structural applications

http://dx.doi.org/10.1016/j.carbon.2015.04.068

owing to their excellent properties at high temperature. However, oxidation and ablation limits their applications in oxygen-con-

Preparation and characterization of a polyimide coating on the

taining environments at ultrahigh temperatures and high-speed

surface of carbon fibers

gas flows. How to improve oxidation and ablation resistance of

Hao-jie Yuana,b, Chun-xiang Lua, Shou-chun Zhanga, Gang-ping

the C/C composites has become a critical issue. The methods

Wua

for improving oxidation and ablation resistance of the C/C composites are reviewed, which mainly focus on optimizing the carbon fiber weave structure, controlling the pyrolytic carbon texture, modifying the matrix, and coating with anti-ablative

a

National Engineering Laboratory for Carbon Fiber Technology, Institute

of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China b

University of Chinese Academy of Sciences, Beijing 100049, China

ceramic layers. Matrix modification and coating technology have been proved to be the two effective ways of dealing with the problem. Development directions on producing oxidation and ablation resistive C/C composites are concentrated on decreasing preparation cost, controlling pyrolytic carbon texture, optimizing compositions of the doped ceramics used in the matrix and the coating layer, and combining matrix modification with an anti-ablation coating.

Organic, solvent-free polyamic acid sizing was coated onto T300 grade carbon fibers (3 k) to prepare a polyimide (PI) coating having a high thermal stability and oxidative resistance. The surface of PI-coated carbon fibers was characterized by FTIR and SEM. The mechanical strength of the carbon fibers, thermal stability and oxidative resistance of the coating were also investigated. Results indicate that a continuous and uniform PI coating

[New Carbon Materials 2015, 30(2): 97–105]

is formed on the surface of the carbon fibers. Compared to a carbon fiber coating with epoxy, the PI coating produces excellent

http://dx.doi.org/10.1016/j.carbon.2015.04.067

thermal stability with onset decomposition and a 5% weight-loss temperatures of 567 and 619 °C, respectively. The tensile strength

A

review

of

carbon–carbon

composites

for

engineering

applications Jun-ming Sua,b, Shao-jian Zhoua, Rui-zhen Lia, Zhi-chao Xiaoa,b, Hong Cui

a

a

Xi’an Aerospace Composites Research Institute, Xi’an 710025, China

b

Xi’an Chaoma Technology Co. Ltd, Xi’an 710025, China

Five kinds of carbon–carbon composites used in aerospace, aircraft, photovoltaics, powder metallurgy and high temperature furnaces are reviewed, whose preforms were fabricated by needle piercing, orthogonal three-direction weaving, radial weaving,

of PI-coated carbon fibers after thermal oxidation in air at 400 °C for 1 h has only a slight decrease of 6%, which is significantly lower than the decrease of 22% for epoxy-coated fibers. [New Carbon Materials 2015, 30(2): 115–121]

http://dx.doi.org/10.1016/j.carbon.2015.04.069

Effect of boron-catalyzed graphitization on the mechanical properties and microstructure of carbon fibers Hui-qi Wanga,b, Quan-gui Guob, Zhan-jun Liub, Tao Hana, Zhi-hai Fengc, Lang Liub

axial weaving and puncture. The physical, mechanical, thermal,

a

ablation, and wear properties and service life were compared with

Taiyuan 030051, China

corresponding

b

materials

from

overseas

manufacturers.

Correlations between the performance, type of preform and car-

School of Materials Science and Engineering, North University of China, Key Laboratory of Carbon Materials, Institute of Coal Chemistry,

Chinese Academy of Sciences, Taiyuan 030001, China

bon matrix, and interfacial bonding state was obtained. These

c

analyses and comparisons can lay a foundation for the construc-

Materials, Aerospace Research Institute of Material and Processing

tion of a database-sharing platform for C/C composites in

Technology, Beijing 100076, China

National

Key

Laboratory

of

Advanced

Functional

Composites

1082

CARBON 93 (2015) 1081– 1084

Boron-catalyzed graphitization of carbon fibers was conducted

c

School of Chemical and Environmental Engineering, North University of

in a boron-doped graphite crucible at 2000 °C, in which boron dif-

China, Taiyuan 030051, China

fused from the crucible to the carbon fibers to act as the catalyst.

d

The microstructures, boron contents and mechanical properties

University of Technology, Taiyuan 030024, China

Research Center of Materials Science and Technology, Taiyuan

of the resulting carbon fibers were characterized by Raman spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and mechanical tests. Results indicate that boron has a significant impact on the fiber microstructure. Raman spectra indicate the presence of distortions in the graphitic layers. The tensile modulus of boron-doped carbon fibers obviously increases with boron content and the tensile strength is also higher than that of the original carbon fibers at boron concentrations between 0.58 and 0.68 at.%. [New Carbon Materials 2015, 30(2): 122–127]

Graphene oxide (GO) prepared by the Hummers method was hydrothermally reduced for 5 and 10 h to obtain 5-RGO and 10RGO, respectively. The GO and RGOs reacted with phenyl isocyanate to obtain three solution-processable functionalized graphenes (SPFGO, 5-SPFRGO and 10-SPFRGO), which were used as electron acceptors to prepare composite films with poly 3hexylthiophene (P3HT) as an electron donor in polymer solar cells. Results indicate that GO consists of about 3–5 layers, and the RGOs still have some oxygen-containing functional groups such as –COOH and C@O after the reduction. Functionalized

http://dx.doi.org/10.1016/j.carbon.2015.04.070

GOs have good dispersibility in dichlorobenzene and exhibit energy levels matching P3HT, indicating that they can be used

A graphene/carbon black hybrid material: A novel binary con-

as the electron acceptor materials of polymer solar cells. A5-

ductive additive for lithium-ion batteries

SPFRGO/P3HT composite film exhibits good compatibility, strong

Yong Lia, Xiao-hui Lub, Fang-yuan Sua,c, Yan-bing Hea, Bao-huaLia,

light absorption and obvious fluorescence quenching, suggesting

Quan-hong Yanga,b, Fei-yu Kanga

that 5-SPFRGO is an excellent electron acceptor material.

a

Shenzhen

Key

Laboratory

for

Graphene-based

Materials

and

Engineering Laboratory for Functionalized Carbon Materials, Graduate

[New Carbon Materials 2015, 30(2): 133–140] http://dx.doi.org/10.1016/j.carbon.2015.04.072

School at Shenzhen, Tsinghua University, Shenzhen 518055, China b

School of Chemical Engineering and Technology, Tianjin University,

Tianjin 300072, China

Nanoporous carbons from oxidized green needle coke for use in

c

high performance supercapacitors

Key Laboratory of Carbon Materials, Institute of Coal Chemistry,

Chinese Academy of Sciences, Taiyuan 030001, China A novel graphene(GN)/carbon black(CB) binary conductive

Jiu-zhou Wang, Li-qun Wang, Ming-ming Chen, Cheng-yang Wang, Cui Zhang, Fei He

additive has been developed, which is characterized by a unique

Key Laboratory for Green Chemical Technology of Ministry of Education,

microstructure and excellent performance for lithium ion batter-

School of Chemical Engineering and Technology, Tianjin University,

ies (LIBs). It was fabricated using a hydrothermal process, fol-

Tianjin 300072, China

lowed by heat treatment. The introduction of CB particles prevents GN from agglomerating and hence improves the elec-

Green needle coke was oxidized by a mixture of HNO3 and

tronic conductivity of the resulting additive. CB particles can also

H2SO4 (3:7 vol/vol) acids. The resultant oxidized coke was sepa-

enhance the Li+ ion diffusion, owing to a reduction of the GN frac-

rated into water dispersible and non-dispersible fractions, which

tion and an increase in electrolyte adsorption. Therefore, the rate

were then activated by KOH using the same KOH/coke weight

performance of the LIB is improved to some extent. Experimental

ratio to obtain two kinds of nanoporous carbons with different

data shows that the specific capacity of LiFePO4 containing 5 wt%

pore structures. The oxidized coke and the nanoporous carbons

of this binary conductive additive (after 900 °C treatment) is

were characterized by XPS, XRD, TEM, N2 adsorption and electro-

73 mAh/g at 10 °C, which is superior to that of LiFePO4 with

chemical tests. Results indicate that, at the same KOH/coke

10 wt% of CB (62 mAh/g). Compared with the latter, the former

ratios, the nanoporous carbons derived from the water-dis-

has a specific capacity increase of 25% based on the mass of the

persible oxidized coke have higher mass specific capacitances

whole electrode and shows superior cycle stability.

and capacitance retention ratios, and lower resistances than

[New Carbon Materials 2015, 30(2): 128–132]

those from the non-dispersible ones when used as an electric double layer capacitor electrode in 6 M KOH, but the former have

http://dx.doi.org/10.1016/j.carbon.2015.04.071

a lower volumetric specific capacitance than the latter. [New Carbon Materials 2015, 30(2): 141–149]

Structure and optical property of functionalized reduced gra-

http://dx.doi.org/10.1016/j.carbon.2015.04.073

phene oxides as electron acceptors in polymer solar cells La-qin Qua,b,c, Wei-jia Yanga,d, Ya-min Haoa,d, Yong-zhen Yanga,d, Xu-guang Liua,b a

Spontaneous reduction of palladium chloride on surface of carbon materials to produce electrochemical catalysts for ethanol

Key Laboratory of Interface Science and Engineering in Advanced

Materials, Ministry of Education, Taiyuan University of Technology,

oxidation Li-zhi Sun, Qing-feng Yi

Taiyuan 030024, China b

College of Chemistry and Chemical Engineering, Taiyuan University of

Technology, Taiyuan 030024, China

School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201, China