is a solid high in content of the element CARBON and structurally in a NON‐GRAPHITIC state.
See: CARBON, NON‐GRAPHITIC CARBON.
Notes
The use of the term CARBON as a short term for a material consisting of NON‐GRAPHITIC CARBON is incorrect. The use of the term CARBON without a second noun or a clarifying adjective should be restricted to the chemical element carbon. The term CARBON can be used in combination with other nouns or clarifying adjectives for special types of CARBON MATERIALS (CARBON ELECTRODE, CARBON FIBERS, PYROLYTIC CARBON, GLASS‐LIKE CARBON, and others).
See: CARBON, CARBON ELECTRODE, CARBON FIBERS, GLASS‐LIKE CARBON, NON‐GRAPHITIC CARBON, PYROLYTIC CARBON.
Carbon Mix
Description
CARBON MIX is a mixture of FILLER COKE, e.g. grains and/or powders of solid CARBON MATERIALS, and a carbonaceous BINDER and selected additives prepared in heated mixers at temperatures in the range of 410–445 K as a preliminary step for the formation of shaped green bodies.
See: BINDER, CARBON MATERIAL, FILLER COKE.
Carbon Whiskers
Description
See: GRAPHITE WHISKERS.
Carbonaceous Mesophase
Description
CARBONACEOUS MESOPHASE is a liquid‐crystalline state of PITCH, which shows the optical birefringence of disklike (discotic) nematic liquid crystals. It can be formed as an intermediate phase during thermolysis (pyrolysis) of an isotropic molten PITCH or by precipitation from PITCH fractions prepared by selective extraction. Generally, the spherical mesophase precipitated from a pyrolyzing PITCH has the BROOKS AND TAYLOR STRUCTURE. With continuous heat treatment the CARBONACEOUS MESOPHASE coalesces to a state of BULK MESOPHASE before solidification to GREEN COKE with further loss of hydrogen or low‐molecular‐weight compounds.
See: BROOKS AND TAYLOR STRUCTURE IN THE CARBONACEOUS MESOPHASE, BULK MESOPHASE, GREEN COKE, PITCH.
Notes
In the formation of CARBONACEOUS MESOPHASE by thermolysis (pyrolysis) of isotropic molten PITCH, the development of a liquid‐crystalline phase is accompanied by simultaneous aromatic polymerization reactions. The reactivity of PITCH with increasing heat treatment temperature and its thermosetting nature are responsible for the lack of a true reversible thermotropic phase transition for the BULK MESOPHASE in most PITCHES. Due to its glass‐like nature, most of the liquid‐crystalline characteristics are retained in the supercooled solid state.
See: BROOKS AND TAYLOR STRUCTURE IN THE CARBONACEOUS MESOPHASE, BULK MESOPHASE, PITCH.
Carbonization
Description
CARBONIZATION is a process by which solid residues with increasing content of the element carbon are formed from organic material usually by pyrolysis in inert atmosphere.
Notes
As with all pyrolytic reactions, CARBONIZATION is a complex process in which many reactions take place concurrently such as dehydrogenation, condensation, hydrogen transfer, and isomerization. It differs from COALIFICATION in that its reaction rate is faster by many orders of magnitude. The final pyrolysis temperature applied controls the degree of CARBONIZATION and residual content of foreign elements, e.g. at T ∼1200 K the carbon content of the residue exceeds a mass fraction of 90 wt%, whereas at T ∼ 1600 K more than 99 wt% carbon is found.
See: CALCINED COKE, COALIFICATION.
Catalytic Graphitization
Description
CATALYTIC GRAPHITIZATION refers to a transformation of NON‐GRAPHITIC CARBON into GRAPHITE by heat treatment in the presence of certain metals or minerals.
See: GRAPHITE, GRAPHITIZATION, NON‐GRAPHITIC CARBON.
Notes
CATALYTIC GRAPHITIZATION gives a fixed degree of GRAPHITIZATION at lower temperature and/or for a shorter heat treatment time than in the absence of the catalytic additives (or a higher degree of GRAPHITIZATION at fixed heat treatment conditions). Often it involves dissolution of CARBON and precipitation of GRAPHITE at the catalyst particles so that NON‐GRAPHITIZING CARBONS can be graphitized by this procedure.
See: CARBON, GRAPHITE, GRAPHITIZATION, NON‐GRAPHITIZABLE CARBON.
Char
Description
CHAR is a solid decomposition product of a natural or synthetic organic material.
Notes
If the precursor has not passed through a fluid stage, CHAR will retain the characteristic shape of the precursor (although becoming of smaller size). For such materials the term “pseudomorphous” has been used. Some simple organic compounds, e.g. sugar, melt at an early stage of decomposition and then polymerize during CARBONIZATION to produce CHARS.
See: CARBONIZATION.
Charcoal
Description
CHARCOAL is a traditional term for a CHAR obtained from wood, peat, coal, or some related natural organic materials.
See: CHAR.
Notes
CHARCOAL has highly reactive inner surfaces and low sulfur content. It has or has had, therefore, a variety of uses, e.g. in ferrous metallurgy and for gunpowder (minor uses: medical purpose and paint materials).
Coal‐Derived Pitch Coke
Description
