Industrial Carbon and Graphite Materials. Группа авторов
See: GRAPHENE LAYERS, GRAPHITE.
Notes
If there is, due to misalignment of the layers caused by their bending, no three‐dimensional stacking order as in GRAPHITE, the term CARBON WHISKERS should be used. GRAPHITE WHISKERS and CARBON WHISKERS should be distinguished from more disordered FILAMENTOUS CARBON.
See: CARBON WHISKERS, FILAMENTOUS CARBON, GRAPHITIC CARBON.
GRAPHITIC CARBON
Description
GRAPHITIC CARBONS are all varieties of substances consisting of the element carbon in the allotropic form of GRAPHITE irrespective of the presence of structural defects.
See: GRAPHITE.
Notes
The use of the term GRAPHITIC CARBON is justified if three‐dimensional hexagonal crystalline long‐range order can be detected in the material by diffraction methods, independent of the volume fraction and the homogeneity of distribution of such crystalline domains. Otherwise, the term NON‐GRAPHITIC CARBON should be used.
See: NON‐GRAPHITIC CARBON.
Graphitizable Carbon
Description
GRAPHITIZABLE CARBON is a NON‐GRAPHITIC CARBON that upon GRAPHITIZATION HEAT TREATMENT converts into GRAPHITIC CARBON.
See: GRAPHITIC CARBON, GRAPHITIZATION HFAT TREATMENT, NON‐GRAPHITIC CARBON.
Notes
If it is preferred to define the characterizable state of material instead of its behavior during subsequent treatment, the term “pregraphitic carbon” could be considered.
Graphitization
Description
GRAPHITIZATION is a solid state transformation of thermodynamically unstable NON‐GRAPHITIC CARBON into GRAPHITE by means of heat treatment.
See: GRAPHITE, NON‐GRAPHITIC CARBON.
Notes
GRAPHITIZATION is also used for the transformation of metastable DIAMOND into GRAPHITE by heat treatment, as well as in metallurgy for the formation of GRAPHITE from thermodynamically unstable carbides by thermal decomposition at high temperatures. Such uses of the term GRAPHITIZATION are in line with the above definition. The use of the term GRAPHITIZATION to indicate a process of thermal treatment of CARBON MATERIALS at T > 2500 K regardless of any resultant crystallinity is incorrect.
See: CARBON MATERIALS, DIAMOND, GRAPHITE, GRAPHITIZATION, GRAPHITIZATION HEAT TREATMENT.
Graphitization Heat Treatment
Description
GRAPHITIZATION HEAT TREATMENT is a process of heat treatment of a NON‐GRAPHITIC CARBON, industrially performed at temperatures in the range between 2500 and 3300 K, to achieve transformation into GRAPITIC CARBON.
See: GRAPHITIC CARBON, GRAPHITIZATION, NON‐GRAPHITIC CARBON.
Notes
The term GRAPHITIZATION HEAT TREATMENT does not include information as to the crystallinity achieved by the heat treatment, that is, the extent of transformation into GRAPHITIC CARBON or the degree of GRAPHITIZATION.
Only for such a transformation into GRAPHITIC CARBON should the term GRAPHITIZATION be used. Consequently, the common use of the term GRAPHITIZATION for the heat treatment process only, regardless of the resultant crystallinity, is incorrect and should be avoided.
See: GRAPHITIC CARBON, GRAPHITIZATION.
Graphitized Carbon
Description
GRAPHITIZED CARBON is a GRAPHITIC CARBON with more or less perfect three‐dimensional hexagonal crystalline order prepared from NON‐GRAPHITIC CARBON by GRAPHITIZATION HEAT TREATMENT.
See: GRAPHITIC CARBON, GRAPHITIZATION HEAT TREATMENT, NON‐GRAPHITIC CARBON.
Notes
NON‐GRAPHITIZABLE CARBONS do not transform into GRAPHITIC CARBON on heat treatment at temperatures above 2500 K and therefore are not GRAPHITIZED CARBONS.
See: GRAPHITIC CARBON, NON‐GRAPHITIZABLE CARBON.
Green Coke
Description
GREEN COKE (RAW COKE) is the primary solid CARBONIZATION product from high‐boiling hydrocarbon fractions obtained at temperatures below 900 K. It contains a fraction of matter that can be released as volatiles during subsequent heat treatment at temperatures up to approximately 1600 K. This mass fraction, the so‐called volatile matter, is in the case of GREEN COKE between 4 and 15 wt%, but it depends also on the heating rate.
See: CARBONIZATION, RAW COKE.
Notes
RAW COKE is an equivalent term to GREEN COKE although it is now less frequently used. The so‐called volatile matter of GREEN COKE depends not only on the temperature and time of coking but also on the method for its determination.
See: RAW COKE.
Hard Amorphous Carbon Films
Description
HARD AMORPHOUS CARBON FILMS is a synonym for DIAMOND‐LIKE CARBON FILMS.
See: DIAMOND‐LIKE CARBON FILMS.
Hexagonal Graphite
Description
HEXAGONAL GRAPHITE is the thermodynamically stable form of GRAPHITE with an ABAB stacking sequence of the GRAPHENE LAYERS. The exact crystallographic description of this allotropic form is given by the space group D46h‐P63/mmc (unit cell constants: ao = 245.6 pm, co = 670.8 pm). HEXAGONAL GRAPHITE is thermodynamically stable below approximately 2600 K and 6 GPa.
See: GRAPHENE LAYERS, GRAPHITE.
Notes
The use of the term GRAPHITE instead of the more exact term HEXAGONAL GRAPHITE may be tolerated in view of the minor importance of RHOMBOHEDRAL