The isothermal oxidation of the 200 face of HfC and TiC single crystals was carried out at 700 to 1500°C and at oxygen pressures of 0.08 to 80 kPa for up to 20 h. The oxide scale on the HfC crystal was found to consist of almostcompact and pore-free black scale (zone 1) and white/gray scale containing many pores (zone 2). Zone 1 containedabout unoxidized 25 at.% carbon and zone 2 6 to 11 at.% carbon. Oxidation of TiC produced a characteristic scalecomposed of inner dense lamella subscale with black and gray alternate strips (zone 1) and an outer region withlaminations separated by pores and cracks (zone 2). The carbon content in the inner scale ranged from 7 (1300°C) to 23 at.% (1500°C). The structure and morphology of carbon films obtained from zone 1 by the treatment of the oxidizedHfC by HF solution was characterized by Raman spectroscopy and transmission electron microscopy (TEM). Alloying of carbon formed by oxidation of the carbides (HfC, TiC, ZrC) was suggested on the basis of tentative C-Me-O nonequilibrium reaction path diagram.

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Planar specimens of graphite (Grafoil) and carbon materials (artificial graphite materials derived from petroleum cokes) with different heat-treatment temperatures (HTT) were brought into contact with IBr vapor at 20°C. The resistance of the carbon materials decreased by the contact with IBr vapor. The relative resistance, R/R₀, defined as the resistance of IBr-doped material divided by that of the starting carbon material was determined and minimum values were as follows: 0.095 for Grafoil, 0.116 for carbon material with HTT of 2800°C, 0.117 (HTT-2400), 0.167 (HTT-2200), 0.269 (HTT-2000), 0.862 (HTT-1750) and 0.838 (HTT-1000). The composition of the saturated compound was estimated to be approximately C₁₆IBr. By the desorption of IBr from the doped specimens, stable residue compounds were obtained. The nominal composition of the residue compounds estimated from weight change was in the range of about C₁₂₀IBr to C₂₈₀IBr, depending on the host material. Values of electric resistance of the residue compounds were about half as much as those of the host materials.

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The influence of H₂O and CO₂ gases on the high temperature oxidation of CVD-SiC was investigated under a condition of active oxidation for SiC. The SiO gas produced by the active oxidation of SiC was further oxidized to form SiO₂ protective scale against oxidation on the SiC surface at 1700°C. The SiO₂ scale growth rate was controlled by the diffusion rate of the oxidant gases in the SiO₂ scale. The oxidation protection ability of the CVD-SiC on the 3D-C/C surface was also improved by using a newly developed Si-polymer process. Poly-vinyl alcohol was more effective as the binder to obtain a dense SiC layer than phenolic resin. Although the CVD-SiC film was successfully formed on the side of the yarn exposed in the 3D-C/C surface, cracks were observedto form on the cross section of the yarn. The crack formation was attributable to the difference in the CTE between longitudinal and transverse direction of carbon fiber.

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The pyrolysis of Langmuir-Blodgett (LB) films of kapton-type polyamic acid N, N-dimethyloctadecylamine salt (PAO) has been studied to prepare ultra-thin carbon films. The deposition of PAO monolayers onto silicon-wafer substrate has been found to be performed well at 10°C under 35 mN/m. The structures of PAO 51 layered LB film and the heat-treated ones have been characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). XPS spectra indicate that the evolution of nitrogen starts at 600°C or lower and that the ultrathin carbon film is formed on the silicon-wafer substrate by the treatment at 1000°C. AFM results of heat-treated PAO LB films show that (1) the surface has many holes at 360°C, (2) island like structure is formed after heating up to 500 and 600°C, (3) the smoothness of the film surface increases with increasing the heat-treatment temperature, and (4) the carbon film with about 4nm thickness can be prepared by heating up to 1000°C.

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The C/C composites made by laying up the sheets of carbon fibers using a pitch matrix were used as startingmaterials. After cutting the composites in the parallel (PA) and the perpendicular (PE) directions to the sheets ofcarbon fibers, the surface of PA and PE substrates obtained were reacted with MoSi₂, at 1450°C in argon gas. From XRDmeasurements, the four phases of graphite, MoSi₂, MoO₃ and α-SiC were observed at the surface of the substrates treatingfor 3 and 6h, irrespective of the direction to carbon fiber sheets. A concentration gradient of SiC in the as-prepared substrates was observed in both directions parallel and perpendicular; the concentration of SiC decreases along the depthfrom the surface of substrate. In the results of line analysis by EDX measurements, it was found that the reaction betweenC/C substrates and MoSi₂ occurred in the portion of matrix in the substrates. The thermal conductivity of PA substratesdecreased with the increase of the treating time and was lower than that of PA substrate without treatment. However, the thermal conductivity of the PE substrates treating for 6h was higher than that of the PA substrtes treating below3h and without treatment.

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Carbonaceous thin films were prepared from ethylene, argon and nitrogen trifluoride (NF₃) by plasma assisted chemical vapor deposition (PCVD). The carbon thin films were characterized by scanning electron microscope (SEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) and then their electrochemical properties were studied by cyclic voltammetry and charge and discharge.measurements. From SEM image carbon thin films were flat and pin-hole free. XPS spectra indicate that nitrogen and fluorine atoms are not contained in carbon thin films. Crystallinity of the films are affected by the NF₃ flow rate from Raman spectra. The difference of the NF₃ flow rates also affected the results of cyclic voltammetry and charge and discharge measurements. Correlation of the NF3 flow rate and the electrochemical properties of carbon thin films was discussed.

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Nano-composite films consisting of nano-sized BN and C have been prepared by plasma enhanced CVD usingtrimethylamine-borane. Inductively coupled plasma generated by a power supply with 4 MHz was used.The films weredeposited on silicon substrates at 110 Pa for 30 min. BN and C were confirmed in the film by the XPS and FT-IR spectra, when the deposition was performed at 800°C with a substrate position of 40 mm below the lower end of the inductioncoil. The films were consisted of h-BN nano crystals and amorphous C, which were confirmed by the XRD and TEDpatterns.

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Various carbon fibers with different microstructures were irradiated in the Japan Materials Testing Reactor (JMTR). Tensile tests were conducted and the microstructures were also examined before and after neutron irradiation. Clear correlations between the tensile properties and the microstructures were found before and after irradiation.
The data obtained here will be useful for the development of C/C composite materials that have higher resistanceto radiation damage.

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The microstructure of the C₆₀/carbon nanotube composite produced at a pressure of 5.5GPa at 1073K wasexamined by X-ray diffraction (XRD) and high resolution electron microscopy (HRTEM). The XRD profile froma compaction surface indicated that C₆₀ matrix changed into a polymerized phase which can be indexed as fcc structure (a =1.31 nm). On a cross-sectional area of the specimen and the crushed specimen, however, the XRD profiles andthe HRTEM observation suggested that the polymerized structure was approximated as the rhombohedral structure. The structural orientation of the bulk specimen and handling of the specimen (bulk or powder) should be taken intoaccount in structural characterization of high pressure polymerized C₆₀. In the nanotubes, no obvious change in the structureis observed even after high-pressure compaction except for a partial collapse.

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Hybrid Gel Precursors for SiC fine particles were synthesized from the liquid mixtures composed of tetraethylorthosilicate, triethyl borate and phenol resin. After the addition of catalyst, the turbid dispersion was converted intothe transparent solution and was gelled under continuous stirring. The synthesized gels with various compositions weredried under vacuum, crushed and pyrolyzed with an appointed conditions to yield the precursors for SiC powder.NMR study of the synthesized precursors indicates the formation of Q₂ and Q₃ units in the dried precursors, which would correspond to the low dimensional Si-O-Si networks. After the pyrolysis at 1273K, the single signal assigned to Q₄ is observed, which corresponds to three-dimensional Si-O-Si network. The SiC precipitation process in these precursorsat 1873K was investigated in terms of X-ray diffraction analysis and powder morphology. The composition of the startingmixture hardly influenced the mixture transparency during the gelation process and the silicon environments in theobtained precursors. The morphology and the size of the resulting powders, however, strongly depend on the resin and borate content in the starting mixtures.

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High-density isotropic graphite substrates with and without a notch produced at the surface were contactedwith metallic silicon and heated at 1350 and 1450°C. The contribution of open pores in the substrates for the formationof SiC-gradient was discussed. At 1350°C, no SiC-gradient was observed at the surface of the substrate without thenotch, but the gradient in the substrate was formed at 1450°C. On the substrates with notch, fibers were formed on thenotch wall of the substrate heated at 1350°C. By heating at 1450°C, however, SiC was detected at the portion beyondthe nose of notch. In present study, it was expected that small amount of 0₂ are enclosed in the open pores and in thenotch. Based on the expected reactions among silicon, carbon and oxygen, the formation of SiC-gradient in thesubstrate at 1450°C was found to be possibly formed due to the reaction between carbon on the wall of pores and SiOgas through the open pores from the surface of the substrate.

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After a single crystal of ZrC was dissolved in a HF/H₂SO₄ solution for about one year, single crystals of ZrF₄ and soot were formed. The soot was found to be amorphous carbon by Raman spectroscopy and contain a very smallamount of fluorine by X-ray photoelectron spectroscopy (XPS). Transmission electron microphotograph (TEM) revealed that the soot is flaky in an irregular shape of 0.1 to 7μm size, insidewhich fine particles in a size of 20 to 100 nm are included. The particles were confirmed to be 2H-WC by energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD). The surface area of the soot was measured to be about 30 m²/g.

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High power ultrasonic wave was applied through the curing process of furfuryl alcohol condensate (furanresin) by using an ultrasonic homogenizer at the frequency of 20 kHz and the intensity of 50 W/cm². Thestructuralproperties of cured furan resin prepared with and without sonication were examined. Combining the resultsfrom GPCmeasurement, FTIR spectroscopy, elemental analysis and XRD, it was cleared that the sonication was effective forthe increase of curing rate in furan resin, however, the structural change of the cured furan resin did not occur with and without sonication.

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Glass-like carbon material essentially has such excellent attributes as isotropicand non-contaminativeproperties, compared with other carbon materials. Though glass-like carbon material was only applied within arestricted field in the beginning of its developement, it has been used as a essential material for components in the silicon wafer treatment process in the manufacture of semiconductor devices, for example, LSI, and other apllications as fuel cells' components, electrochemical electrodes and so on due to its excellent poperties in resent years. In future, it will be in great demand in many fields through further improvements of its properties, for example, the improvement of oxidation resistance equivalent to some rival materials as silicon, silicon carbide and silicon dioxide, and the development of new apllications.

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This is a review of cement-matrix composites containing short carbon fibers. These composites exhibit attractivetensile and flexural properties, low drying shrinkage, high specific heat, low thermal conductivity, high electricalconductivity and high corrosion resistance. Moreover, they facilitate the cathodic protection of steel reinforcement inconcrete, and have the ability to sense their own strain, damage and temperature. Fiber surface treatment can improve numerous properties of the composites.

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Diamond-like carbon (DLC) films have received much attention owing to their attractive properties which areclose to those of diamond: extreme hardness, high thermal conductivity, abrasion resistance, corrosion resistance against chemicals, good biocompatibility and uniform flat surface. Furthermore, DLC films can be easily depositedon many substrates at room temperature. Due to their interesting advantages, DLC films have been developed forapplication as biomedical materials (e.g. coatings on contact lenses). In the presented study we have utilized DLCfilms as coatings of diaphragms (polyurethane) in artificial hearts.
For evaluation of the diffusion between the solutions (silicone oil and blood) a special two-chamber apparatuswas developed. Physiological saline solution and distilled water were used for these experiments. In case of the uncoatedpolyurethane diaphragm diffusion of Na ions through the diaphragm leads to an enrichment (diffusion) of Na on theother side of the diaphragm at the ppm level. In case of DLC coated diaphragms such an enrichment could not beobserved.
The Epifluorescent Video Microscopy (EVM) system measured the platelet adhesion onthe DLC film surface, using whole human blood containing Mepacrine-labeled platelets perfused at a wall shear rate of 100s^-1 at 1-min intervals for a period of 20 min. Based on these results, it is recommended that for use in implantable blood contactingdevice as coat materials. This DLC appear to be promising candidate for biomaterials application and merit furtherinvestigation. Finally, it should be mentioned that these DLC films also show a good biocompatibility.

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