Weigang ZHANG
,
Huiming CHENG
,
Ge SU
,
Yueying FAN
,
Feng LI
,
Zuhong SHEN
,
Benlian ZHOU
材料科学技术（英文）
A mechanism for the catalytically growth of vapor grown fibrous carbon (VGFC)preparing from the floating catalyst method has been proposed, in which liquid diffusion-determined diffusion of carbon atoms through catalyst particles is described mathematically, and the physical and chemical properties of the catalyst particles during the growth process are taken into account. From the model the growth rate and grown length of VGFC are calculated theoretically which coincides with the experimental data; and the necessity of reducing gas such as hydrogen in preparing VGFC is explained as to reduce Fe3C, which acts as intermediate catalyst shown by the model. Fe3C formed on the surface of γ-Fe will stop the growth of carbon fiber if they can not be reduced at once. Additionally, the growth temperature and diameter of VGFC are also discussed in the paper.
关键词:
Mingfen WEN
,
Lian CHEN
,
Min TONG
,
Demin CHEN
,
Huiming CHENG
,
Yuchun ZHAI
,
Yanwen TIAN
材料科学技术（英文）
Zr0.9Ti0.1(Ni,Co,Mn,V)(2.1) as-cast alloy was prepared by melting under Ar atmosphere; and then, four composite alloys were prepared by ball-milling after hydrogen absorbing agent was added. The initial discharge capacity was as high as 430 mAh .g(-1) for composite alloy electrode c discharged at 60 mA .g(-1) current density and its maximum capacity reached 505 mAh .g(-1). All composite alloy electrodes have good activation behavior, being fully activated in one or two cycles. At 300 mA .g(-1) current density, the composite alloy electrode c was found to have good cycle stability.
关键词:
Xin TONG
,
Yong CHEN
,
Huiming CHENG
材料科学技术（英文）
Carbon nanofiber (CNF)-reinforced polypropylene (CNF/PP) composites with different CNF contents were prepared by melt mixing, and the mechanical properties and crystallization behavior of the CNF/PP composites obtained were investigated. It was found that the tensile modulus of the composites was increased with the addition of CNFs, but their elongation at break and fracture strain energy were decreased, while the tensile strength of the composites was firstly increased and then decreased due to the agglomeration of CNFs at higher loading. Nonisothermal crystallization analysis showed that the CNFs played a role as nucleating agent in PP matrix, which led to increment in the crystallization rate and the degree of crystallinity of PP. Moreover, X-ray diffraction studies showed that the CNFs incorporated in the PP matrix favored the growth of (040)-oriented PP crystals. With the increase in the CNF content, the nucleating and orientation roles of the CNFs were obviously enhanced.
关键词:
Carbon nanofibers
,
null
,
null
,
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