Abstracts of New Carbon Materials, 2010(3)

Effect of density and fibre orientation on the ablation behaviour

of carbon–carbon composites

Shameel Farhana, Ke-zhi Lia, Ling-jun Guoa, Quan-ming Guob,

Feng-tao Lana

a School of Materials Science, Northwestern Polytechnical University,

Xi’an 710072, Chinab Quality Testing Center, Jinxi Industries Group Corporation, Taiyuan

030027, China

Five carbon–carbon composites were prepared with different

fibre orientations in the preform and were densified by different

methods. Their ablation behaviour was examined by an oxy-acet-

ylene test and scanning electron microscopy. The densities of the

composites were in the range of 1.77–1.85 g/cm3. Fibres having an

angle of 30� with the oxy-acetylene flame turned into a sharp

wedge shape, whereas fibres parallel to the flame had a needle-

like shape with diameter up to 3.5–4.5 lm after ablation. The nee-

dled fibres were easily attacked and ultimately became blunt. Par-

tially filled macropores with sizes of 1.0–1.26 mm, needle pores,

interfacial cracks and gaps in non-woven cloth were easily

attacked by the flame, resulting in macroscopic ablation pits that

decreased with increasing density of the composites. The needled

fibres around pitch carbon layers were severely denuded due to

their discontinuity with the pyrolytic carbon matrix. A high den-

sity (1.85 g/cm3) composite had an excellent ablation resistance.

[New Carbon Materials 2010;25(3):161–67.]

doi:10.1016/j.carbon.2010.06.019

Growth of super long vertically aligned carbon nanotube arrays

from cyclohexane via floating catalyst method

Zhou Yang, Qiang Zhang, Guo-hua Luo, Rong Xiang, Wei-zhong

Qian, Yao Wang, Fei Wei

Beijing Key Laboratory of Green Reaction Engineering and Technology,

Department of Chemical Engineering, Tsinghua University, Beijing

100084, China

Vertically aligned carbon nanotube (VACNT) arrays were

obtained using the floating catalyst method with cyclohexane

as a carbon source. Results indicated that various factors, such

as growth temperature, ferrocene feed rate, feed rate of the solu-

tion (ferrocene dissolved in cyclohexane), and composition of car-

rier gases, had a great effect on the VACNT array growth. A

maximum growth rate of the VACNT array was obtained in a

quartz tubular reactor with a diameter of 25 mm when the growth

temperature was 820 �C, ferrocene feed rate 0.24 mg/min, feed

rate of the solution 0.12 mL/min, and the flow rate of the H2/Ar

(1:15) carrier gas 640 mL/min. A VACNT array with a height of

5.0 mm was obtained with a large aspect ratio (>105) and a high

purity (96.7%).

[New Carbon Materials 2010;25(3):168–74.]

doi:10.1016/j.carbon.2010.06.020

Helical multiwalled carbon nanotubes synthesized by catalytic

chemical vapor deposition

T. Somanathan, A. Pandurangan

Department of Chemistry, Anna University, Chennai 25, India

Helical multiwalled carbon nanotubes (h-MWCNTs) were syn-

thesized by a catalytic chemical vapor deposition method using

acetylene as a carbon source and FeMo/MgO catalyst as a tem-

plate, which was prepared by a combustion method using citric

acid as a foaming and combustion additive. The XRD pattern

revealed that the catalyst was crystalline. Furthermore, the syn-

thesized carbon materials were characterized by SEM, TEM, and

Raman spectroscopy, where SEM and TEM images showed the for-

mation of thin h-MWCNTs and the Raman spectrum confirmed

the crystalline characteristics of the CNTs. This is an easy and

simple method to synthesize h-MWCNTs with diameter of 20–

30 nm.

[New Carbon Materials 2010;25(3):175–80.]

doi:10.1016/j.carbon.2010.06.021

Synthesis of mesoporous carbon by catalytic activation using

rare earth elements

Yan-qiu Lia,b, Kai-xi Lia

a Key Laboratory of Carbon Materials, Institute of Coal Chemistry,

Chinese Academy of Sciences, Taiyuan 030001, China

doi:10.1016/S0008-6223(10)00421-5

C A R B O N 4 8 ( 2 0 1 0 ) 3 9 7 4 – 3 9 7 7

ava i lab le at www.sc iencedi rec t .com

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