STUDY OF THE EFFECT OF HIGH-TEMPERATURE TREATMENT
ON CARBON-CARBON COMPOSITE MATERIAL OXIDATION RESISTANCE
M. Yu. Bamborin
and S. A. Kolesnikov
Translated from Novye Ogneupory, No. 6, pp. 46 – 49, June, 2014.
Original article submitted March 19, 2014.
The change in oxidation reaction rate for specimens of four-dimensional reinforced carbon-carbon composite
material with an identical level of apparent density and different graphitizing temperature is studied. Ranking
of factors governing material oxidation reaction rate is established. X-ray structural properties are determined
for carbon-carbon composites with a different oxidation reaction rate.
Keywords: high-temperature treatment, carbon-carbon composites, oxidation reaction rate, structural proper-
ties, flame bench tests.
Carbon-carbon composite materials (CCCM) are a heter-
ogeneous structure consisting of fibers, matrix, and pores. A
change in the structure of carbon material occurs under ac-
tion of high temperature and isothermal soaking, and is re-
flected in changes in physical and chemical properties.
High-temperature treatment (HTT) of billets is technological
version of regulating not only porosity, true density, and elec-
trical conductivity of carbon materials, but also oxidation
rate and other chemical properties [1, 2].
High-temperature treatment under certain processing
conditions and billet isothermal soaking time, and subse-
quent billet carbonization, are important processing stages
affecting subsequent structural, physical, and chemical prop-
erties of carbon composites [3 – 5].
The aim of this work is to study the effect of high-tem-
perature treatment on level of CCCM oxidation resistance.
The object studied was a composite of four-dimensional rein-
forcement based on carbon thread of polyacrylonitrile (PAN)
fiber and carbon matrix of coal-tar pitch coke. Carbonization
was carried in furnaces under pressure. The fundamental pro-
cessing scheme for CCCM manufacture has been described
previously [6, 7]. It should be noted that after the final im-
pregnation and carbonization cycle under pressure billets
were given HTT at 2170°C, which is sufficient for achieving
the true density of carbon material (up to 2.1 g/cm
billets were given final HTT at different temperatures and
isothermal soaking time.
Treatment temperature. High-temperature treatment of
CCCM specimens was performed in a chamber (diameter 40
and length 1300 mm) of a water-cooled graphitizing furnace
(temperature range from 30 to 3000°C by a regime: heating
from (2170 ± 30) to 2900°C, isothermal soaking from 1 to
17 h. Temperature within the furnace working chamber was
measured by means of a Promin’ optical pyrometer, and
readings were recorded from the surface of a graphite heater
through a quartz glass viewing port. Deviation from the true
temperature value, caused by such factors individual opera-
tor sensitivity, absorption of the atmosphere and glass in the
measuring port, inaccuracy of considering the degree of body
blackness, and other less significant factors, was from –40 to
+10°C of the nominal value.
Apparent density. Density and open porosity were de-
termined hydrostatically. The method has been proven within
the limits values of open porosity from 5 to 35%.
Graphite crystal lattice parameters. X-ray phase anal-
ysis was performed by the procedure MI 00200851-
343–2011 in a Bruker D8 Advance powder diffractometer in
“back-scatter” geometry, fitted with a n x-ray tube with a
copper anode. Specimens were pulverized to a fraction less
than 80 mm and laid as a thin layer on a flat amorphous
quartz cuvette. Silicon powder was added to a specimen as
an internal standard. Recording of diffraction patterns was
performed with a step of 0.02° and exposure at a point of
11 sec. Data processing was carried out by means of a
Refractories and Industrial Ceramics Vol. 55, No. 3, September, 2014
1083-4877/14/05503-0244 © 2014 Springer Science+Business Media New York
OAO NIIgrafit, Moscow, Russia.