采用温控电弧装置，以Co, Ni 合金粉未作为崔化剂，放电电流为80A，电压为32V，放电时间为5min，研究了不同气氛、压力及温度对制取非晶碳纳米管的影响，确定了优化参数。在环境温度为600°C时，氢气气氛，真空度约为6.6×104 Pa，非晶碳纳米管的产量和纯度质量分数都分别达到了6.5g/h和80%以上，其管径为7~20nm.

Two non-stoichiometric low-Co AB5 alloys, Ml0.95Mg0.05Ni3.8Co0.3Mn0.3Al0.4 (AB4.8) and Ml0.95Mg0.05Ni3.6Co0.3Mn0.3Al0.4 (AB4.6), were designed to reduce the cost ofAB5 alloys. The maximum discharge capacities of the two low-Co alloys can reach 307 mAh/g forAB4.8 alloy and 298 mAh/g for AB4.6 alloy, respectively. After 300 cycles, the capacity decay is 23% for AB4.8 alloy and 19.1% for AB4.6 alloy. XRD patterns and the microstructure, examined by optic microscope and SEM, show that both of the two low-Co alloys are composed of three phases, LaNi5 matrix phase, AlMnNi2 secondary phase and LaNi tertiary phase. For the two low-Co alloys, the microhardness (HV) of the secondary phase are only half of that of the matrix phase, which could resist the crack propagating and make the alloys not amenable to pulverization. The small amount of Mg promotes to form the soft secondary phase, which is believed to be the reason for improving the cycling stability.

Large amounts of amorphous carbon nanotubes (ACNTs) were prepared with Co–Ni alloy powders as catalyst in hydrogen gas atmosphere by a modified arc discharging furnace which can control temperature during the electric arcing process. The experimental results indicate that the cooperative function of temperature and catalyst plays an important role in the soot production rate and the relative ACNT purity. When temperature increases from 25°C to 700°C, the soot production rate increases from around 1 g/h to 8 g/h, the best relative ACNT purity at 600°C can reach up to 99% compared to the room temperature sample. Without catalyst, only plate graphite is formed at 25°C and very few carbon nanotubes are found when temperature increases to 600°C. TEM, SEM, HRTEM and XRD analysis showed that the as-prepared carbon nanotubes are almost amorphous. The soot production rate is 8 g/h and diameter range of amorphous carbon nanotubes is about 7–20 nm, respectively. © 2005 Elsevier Ltd. All rights reserved.

The effects of gas, pressure and temperature on the production of amorphous carbon nanotubes were investigated using an arc discharging furnace at controlled temperature. Co/Ni alloy powder was used as catalyst. The discharge current was 80 A and voltage was 32 V. The optimal parameters were obtained: 600 temperature, hydrogen gas and 500 torr pressure. The productivity and purity of amorphous carbon nanotubes are 6.5 gram per hour and 80%, respectively. The diameter of the amorphous carbon nanotubes is about 7 20 nm.

The effect of oxygen on the growth of single-walled carbon nanotubes was studied with Ni–Co alloy powder as catalyst under helium atmosphere of 500 Torr by electric arc discharge. The oxygen included in nickel or (and) cobalt oxides was added in catalyst. The content of oxygen in atmosphere was controlled by changing vacuum degree inside furnace before inputting buffer gas. The examinations of TEM and Raman scattering showed that oxygen in metal oxide as catalyst promotes the nucleation of SWCNT by taking effect on the metal catalyst particles. However, O2 in atmosphere has the role of oxidizing amorphous particles along with nanotubes. When its molar proportion is higher than 0.22 ppm (Parts per million), the carbon nanotubes produced are oxidized and their purity decreases. The diameter of single-walled carbon nanotube obtained under different condition has a narrow distribution around 1.28 nm.

Single-walled carbon nanotubes (SWCNTs) were prepared by a modified arc discharging furnace using Fe-Ni-Mg powders as catalyst at 600◦C. The effects of catalyst composition and content on the production rate and purity of SWCNTs are investigated in this paper. When the Fe-Ni-Mg catalyst composition is 2 : 1 : 2 wt% and the catalyst content is 5 wt%, the experimental results indicate that the production of SWCNTs is 12 grams per hour, and the purity and diameter of SWCNTs are 70% and 1.22~1.38 nm, respectively. The results indicate that the cooperative function of catalyst composition and content plays an important role in the production of SWCNTs. The aim of this work is to control the production process of SWCNTs efficiently.