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Graphitation partielle de quelques carbones durs. Etude en microscopie et microdiffraction électroniques
Author(s) -
Oberlin A.,
Rousseaux F.
Publication year - 1968
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889868005376
Subject(s) - graphite , stacking , materials science , phase (matter) , crystallography , carbon fibers , spheres , conical surface , composite material , chemistry , physics , organic chemistry , astronomy , composite number
All the hard carbons are composed of three phases when they are heated above 2000°C: non‐graphitizable carbon, graphitizable carbon, and graphite (the latter two appearing only in very small amounts). When the heat treatment temperature is increased to 3000°C, these phases change in various ways. At low temperatures, the non‐graphitizable phase is formed by small turbostratic stacks of carbon layers which are oriented completely at random inside the carbon grains. Above 2000°, these stacks begin to undergo mutual rearrangement to produce small fibers by ordering roughly parallel to each other. The graphitizable phase is formed of spheres made up of conical rolled spirals, which are themselves made up by turbostratic stacking of the carbon layers. When heat treated, each sphere transforms to graphite very suddenly. The third phase is well crystallized graphite with stacking faults and twist defects.