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Mesophase pitch-based carbon fibers (MPCF) have been prepared by a melt-brow method and applied to Li ion secondary battery. To improve the reversible capacity, B was doped in the fiber about 1 at% by adding B 4 C to the precarbonized milled fibers and then heat-treated up to 3000°C in Ar. The structure of the B-doped fibers was characterized and compared with that of non-doped standard fibers,...
High energy resolution XPS and high mass resolution TOF SIMS have been used to probe the surface chemistry of type A carbon fibres. Four components have been identified within the XPS N1s envelope through a range of ammonium bicarbonate electrolytic oxidation levels. These peaks were assigned to amide, aza, imide and protonated amine functionalities. The amide is identified as the major nitrogen...
Pyrocarbon materials containing various amounts of boron have been prepared by LPCVD from BCl 3 -C 3 H 8 -H 2 precursor mixtures. By increasing the BCl 3 /(C 3 H 8 + BCl 3 ) ratio up to 85%, the incorporation of boron can reach 33 at.%. A small amount of boron (e.g. 8 at.%) highly enhances the structural anisotropy of pyrocarbon, as...
In the present paper, various kinds of carbon fibers were studied in order to cover a wide range of crystallinity from disordered to highly graphitized materials. Poly-p-phenylene (PPP)-based granular carbon was also comparatively chosen as one of the highly disordered carbons against low crystalline carbon fibers. The discharge capacity of carbon fiber electrode was shown to depend on the crystallite...
Two activated carbon fibers supporting MnO particles (0.84 wt % Mn and 1380m 2 g -1 , 11.84wt % Mn and 2050m 2 g -1 ) were prepared from phenolic resins containing manganese acetate tetrahydrate and their deodorization abilities against H 2 S gas were examined. The former fiber contained finely dispersed MnO particles and exhibited a high deodorization...
Mesogenic and mesophase pitches were produced from Ashland A 240 pitch in a stirred tank reactor under various pyrolysis conditions. Isothermal experiments showed strongly different properties of the products as compared to results with an earlier lot of the same pitch. The products were characterized by their solubility in tetrahydrofuran and N-methyl-pyrrolidone, their mesophase content, glass...
A one-dimensional model was developed for the forced flow-thermal gradient chemical vapor infiltration of carbon/carbon composites. The infiltration time predicted by the model agreed very well with experiments, where propylene and propane were used as the hydrocarbon source. The model was also validated by interrupting the infiltration and comparing predicted with observed densities.
The surface of carbon black was modified with an oxygen plasma treatment. The initial increase and following reduction of carbon black weight due to the treatment were observed as the treatment time increased. The chemical structure of carbon black surfaces formed by the oxidation process has been characterized by X-ray photoelectron spectroscopy (XPS). The XPS O/C atomic ratio of the surfaces showed...
Composite materials were prepared using multi-layer fabric and epoxy resin matrix. The multi-layer fabric was woven from pitch-based carbon fiber rovings. The relationship between structure of the multi-layer fabric and the mechanical properties of the composites, measured by tensile and flexural tests, were investigated. The properties were compared with those of laminated fabric composites with...
In order to shorten the processing time for oxidative stabilization in pitch based carbon fibers, petroleum derived mesophase pitch fiber was oxidized in air containing 2% of NO 2 . Oxygen consumption by pitch fiber was determined under several conditions by measuring O 2 concentration of exit gas from the reactor. The change of elemental composition of oxidized pitch fiber was elucidated...
Unidirectional (UD) composites, fabricated with surface-oxidized HT carbon fibers (Magnamite AS4, Hercules) and with two mesogenic pitches and two mesophase pitches, were stabilized at 1 MPa oxygen pressure and 200°C to various amounts of oxygen uptake, carbonized and graphitization-treated at 2100°C. Dimensional changes and bulk densities of the composites, carbon yields of the matrix, and mechanical...
The stabilization of unidirectional (UD) composites fabricated with non-surface-oxidized and surface-oxidized HT carbon fibers, mesogenic pitches and mesophase pitches with oxygen was studied by variation of oxygen pressure (up to 2 MPa), temperature (160-200°C), and stabilization time (up to 36 hours). The oxygen uptake is diffusion controlled and can be described by Fick's second law. By stabilization,...
Diamond-like carbon (DLC) thin film deposition was examined by applying 13.56 Mhz of r.f. power to the substrate electrode. We tried to control deposition temperature by the plasma pulse deposition technique: repeated cycles of alternating 5 seconds deposition with 180 seconds of cooling, then we investigated the influence of the deposition temperature on the thin film characteristics and structure...
We tried to produce activated carbons with high specific surface area from bean-curd refuse by chemical activation using several alkali metal compounds such as K 2 CO 3 , NaOH and Na 2 CO and H 3 PO 4 as the reagent. The effects of carbonization temperature, holding time and impregnation ratio of reagent to dried bean-curd refuse on pore structure of the activated...
The projected probability function (PPF) for the first nearest neighbor carbon layer plane was calculated for the mesocarbon microbeads (MCMB) based on the theory proposed by Houska and Warren for the turbostratic nature. The degree of rotational misorientation was estimated from the displacement of the two peak tops on the PPF pattern, and the angle of misorientation decreased with increasing the...
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