You need JavaScript to view this

Contribution to the study of hard, low-density pyrolytic carbons; Contribution a l'etude des carbones pyrolytiques de variete dure et de faible densite

Abstract

Apparent contradictions in the properties of pyrolytic carbons obtained at 1600 deg C (hardness and graphitization) are studied. It is shown that structure of the deposit is turbostratic with high internal stresses ({delta}{sup -2}), and it graphitizes (by thermal treatment over 2000 deg C) in a similar manner to graphitisable carbon. Because the deposit forms lamellar compounds, it is presumed that the structure is similar to that of graphitisable carbon. Since it is not structure dependant, the hardness originates from the 'growth texture' and is not comparable with the hardness of a non-graphitisable carbon. The pyrolytic carbon studied is composed of regions, on the overage a few microns across, formed by the stacking of small carbon platelets, interlocked and showing a preferred orientation. The mis-orientation of the various regions produces general disorientation. We estimate that the introduction of the particles of some material such as thermal black which are observed in the electron microscope are responsible for the mis-orientation. The density and hardness of the deposit are a result of the interlocking of platelets, which creates a closed porosity and prevents any sliding of the atomic planes. (author) [French] On etudie les proprietes apparemment contradictoires du pyrocarbone 1600 deg C,  More>>
Authors:
Boutin, F R [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1967
Product Type:
Thesis/Dissertation
Report Number:
CEA-R-3110
Resource Relation:
Other Information: TH: These docteur es-sciences appliquees; 61 refs; PBD: 1967
Subject:
36 MATERIALS SCIENCE; CHEMICAL PREPARATION; CRYSTAL STRUCTURE; GRAPHITIZATION; HARDNESS; MICROSTRUCTURE; OXIDATION; PHYSICAL PROPERTIES; PYROLYTIC CARBON; TEXTURE; X-RAY DIFFRACTION
OSTI ID:
20626198
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France); Faculte des Sciences de l'Universite de Paris - 75 (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR05R3110069311
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
68 pages
Announcement Date:

Citation Formats

Boutin, F R. Contribution to the study of hard, low-density pyrolytic carbons; Contribution a l'etude des carbones pyrolytiques de variete dure et de faible densite. France: N. p., 1967. Web.
Boutin, F R. Contribution to the study of hard, low-density pyrolytic carbons; Contribution a l'etude des carbones pyrolytiques de variete dure et de faible densite. France.
Boutin, F R. 1967. "Contribution to the study of hard, low-density pyrolytic carbons; Contribution a l'etude des carbones pyrolytiques de variete dure et de faible densite." France.
@misc{etde_20626198,
title = {Contribution to the study of hard, low-density pyrolytic carbons; Contribution a l'etude des carbones pyrolytiques de variete dure et de faible densite}
author = {Boutin, F R}
abstractNote = {Apparent contradictions in the properties of pyrolytic carbons obtained at 1600 deg C (hardness and graphitization) are studied. It is shown that structure of the deposit is turbostratic with high internal stresses ({delta}{sup -2}), and it graphitizes (by thermal treatment over 2000 deg C) in a similar manner to graphitisable carbon. Because the deposit forms lamellar compounds, it is presumed that the structure is similar to that of graphitisable carbon. Since it is not structure dependant, the hardness originates from the 'growth texture' and is not comparable with the hardness of a non-graphitisable carbon. The pyrolytic carbon studied is composed of regions, on the overage a few microns across, formed by the stacking of small carbon platelets, interlocked and showing a preferred orientation. The mis-orientation of the various regions produces general disorientation. We estimate that the introduction of the particles of some material such as thermal black which are observed in the electron microscope are responsible for the mis-orientation. The density and hardness of the deposit are a result of the interlocking of platelets, which creates a closed porosity and prevents any sliding of the atomic planes. (author) [French] On etudie les proprietes apparemment contradictoires du pyrocarbone 1600 deg C, durete et graphitabilite. On montre que le pyrocarbone possede la structure d'un carbone turbostratique a fort taux de distorsion et qu'il subit, par traitement a des temperatures superieures a 2000 deg C, une transformation de graphitation comparable a celle que l'on observe sur les cokes graphitables. Comme le pyrocarbone forme de plus des composes d'insertion, sa structure est comparable a celle d'un carbone graphitable. La durete, qui n'a pas d'origine structurale, est donc liee a la 'texture de croissance' du depot et ne peut etre comparee a celle d'un coke dur et non graphitable. Le pyrocarbone etudie est constitue de domaines, dont les dimensions sont de l'ordre de quelques microns, formes par un empilement de lamelles de carbone de faible dimension, enchevetrees les unes dans les autres et presentant entre elles une orientation preferentielle. C'est la diversite d'orientation des domaines qui determine la desorientation generale du depot. Nous pensons qu'elle est provoquee par l'introduction de particules, peu differentes d'un noir thermique, dont la presence a ete mise en evidence a l'aide du microscope electronique. La densite et la durete du depot sont liees a l'enchevetrement des lamelles, enchevetrement qui cree une porosite fermee et un blocage du glissement des couches atomiques. (auteur)}
place = {France}
year = {1967}
month = {Jul}
}