Carbon materials graphite

Inagaki, M. and Kang, F. Structural development in carbon materials (graphitization). In Carbon Materials Science and Engineering, Beijing, China Tsinghua University Press, 2006 112. 

Carbon atoms crystallize in several forms. Graphite and diamond are well known carbon polymorphs. Fullerenes, which were discovered in the 1980 s, have also been well characterized. Carbon materials show a variety of different physical and chemical properties. Because of this the electronic structure of carbon materials has been investigated using a number of different experimental techniques, for example, XPS, UPS and XANES. Theoretical studies of carbon materials have been also performed. However, experimentally observed spectra are not always consistent with theoretical predictions. Recently, in order to understand the various kinds of observed electronic spectra, DV-Xa calculations have been performed on a small cluster model. [1] In the present paper, we report results of DV-Xa calculations performed on the carbon materials graphite, alkali graphite intercalation compounds (GIC), fullerene, and fluorinated fullerenes. 

Different carbon materials (graphite, graphene, activated carbons, carbon nanotubes, etc.) are described in Chapter 3. These materials are very interesting with respect to the interfacial phenomena because they have a maximum possible specific surface area (up to 3500-4000m /g), and some of them (such as graphenes and graphene oxides) represent one-two atomic layers, that is aU their atoms are surface atoms. 

See graphitic carbon, carbon material, graphite material... 

Carbon-Carbon Composites. Carbon—carbon composites are simply described as a carbon fiber reinforcement in one or many directions using a carbon or graphite matrix material (see Composite materials). 

Carbon nd Graphite. Carbon and graphite rendered impervious with 10—15% phenoHc, epoxy, or furan resia are among the most important materials for hydrochloric acid service up to 170°C. The most important appHcations of these materials for hydrochloric acid service are heat exchangers and centrifugal pumps. 

Among nonmetallic materials, glass, chemical stoneware, enameled steel, acid-proof brick, carbon, graphite, and wood are resistant to iodine and its solutions under suitable conditions, but carbon and graphite may be subject to attack. Polytetrafluoroethylene withstands Hquid iodine and its vapor up to 200°C although it discolors. Cloth fabrics made of Saran, a vinyHdene chloride polymer, have lasted for several years when used in the filtration of iodine recovered from oil-weU brines (64). 

High performance composites may be laminates wherein veils of carbon fiber ate treated with an epoxy resin, stacked up to the desired final product thickness, and then laminated together under heat and pressure (see Composite materials Carbon and graphite fibers). Simply mixing together carbon or glass fibers and polymeric resins to form a reinforced plastic leads to a composite material, but this is not a laminate if not constmcted from discrete phes. 

Carbon and Graphite. Carbon (qv) and graphite [7782 2-5] have been used alone to make refractory products for the lower blast furnace linings, and electrodes for steel and aluminum production. They are also commonly used in conjunction with other refractory raw materials. These materials are highly refractory nonwettable materials and are useful refractories in nonoxidizing environments. Carbon blacks are commercially manufactured, whereas graphite for refractory use has to be mined. 

Refractories, Glass, Ceramic Materials Carbon and Graphite Products," ASTM Annual Book ofASTM Standards, Vol. 15.01, ASTM, Philadelphia, Pa., 1992. 

J. D. Buckley, ed.. Advanced Materials, Composite Carbon, Preparation Symposium, American Ceramics Society, Inc., Columbus, Ohio, 1972. Papers on composite materials including carbon and graphite or nitride composites. 

Carbon Composites. Cermet friction materials tend to be heavy, thus making the brake system less energy-efficient. Compared with cermets, carbon (or graphite) is a thermally stable material of low density and reasonably high specific heat. A combination of these properties makes carbon attractive as a brake material and several companies are manufacturing carbon fiber—reinforced carbon-matrix composites, which ate used primarily for aircraft brakes and race cats (16). Carbon composites usually consist of three types of carbon carbon in the fibrous form (see Carbon fibers), carbon resulting from the controlled pyrolysis of the resin (usually phenoHc-based), and carbon from chemical vapor deposition (CVD) filling the pores (16). 

Carbon Composites. In this class of materials, carbon or graphite fibers are embedded in a carbon or graphite matrix. The matrix can be formed by two methods chemical vapor deposition (CVD) and coking. In the case of chemical vapor deposition (see Film deposition techniques) a hydrocarbon gas is introduced into a reaction chamber in which carbon formed from the decomposition of the gas condenses on the surface of carbon fibers. An alternative method is to mold a carbon fiber—resin mixture into shape and coke the resin precursor at high temperatures and then foUow with CVD. In both methods the process has to be repeated until a desired density is obtained. 

Standard Definitions ofiTerms Relating to Manufacturing Carbon and Graphite ASTM Standard C 709-90, Vol. 15.01 American Society for Testing and Materials, Philadelphia, Pa., 1991, p. 189. 

The raw materials used ia the production of manufactured carbon and graphite largely control the ultimate properties and practical appHcations of the final product. This dependence is related to the chemical and physical nature of the carbonization and graphitization processes. 

Low sulfur and ash levels are required for high GTE, isotropic cokes used for carbon and graphite specialty products. Highly isotropic cokes are also the filler materials for producing graphite for nuclear reactors. The purity, particularly the boron content, is critical in this appHcation. Properties of typical needle and isotropic (regular) cokes are summarized in Table 1. 

The principal binder material, coal-tar pitch, is produced by the distillation of coal tar. Coal tar is obtained primarily as a by-product of the destmctive distillation of bituminous coal in coke ovens during the production of metallurgical coke. Petroleum pitch is used to a much lesser extent as a binder in carbon and graphite manufacture. Because of its low sohds content, petroleum pitch is used as an impregnant to strengthen carbon artifacts prior to graphitization. 

Carbon—graphite materials employed for mechanical appHcations are prepared by mixing selected sizes and types of carbon and graphite with biader materials such as pitches and resias. The mixtures are formed iato compacts and baked to temperatures of ca 1000—3000°C. Specific raw materials and processiag techniques are employed to obtain desired properties for the finished carbon—graphite materials (24). 

Carbon—graphite materials do not gall or weld even when mbbed under excessive load and speed. Early carbon materials contained metal fillers to provide strength and high thermal conductivity, but these desirable properties can now be obtained ia tme carboa—graphite materials that completely eliminate the galling teadeacy and other disadvantages of metals. 

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