THERMAL STABILITY OF HIGH-TEMPERATURE MATERIALS. PART 2
V. B. Kolomeitsev,
S. A. Suvorov,
E. F. Kolomeitseva,
and O. V. Kolomeitseva
Translated from Novye Ogneupory, No. 8, August, 2004, pp. 38 – 48.
Original article submitted April 19, 2004.
Experimental methods for determining thermal stability of high-temperature materials under dynamic and
static thermal loading conditions are considered. Experimentally, thermal stability is characterized by the de
structive temperature difference or critical (destructive) rate of change of the temperature field in the bulk or at
the surface of the material. It is shown that, with the observance of special conditions, the thermal-shock
method, based on sharp cooling of heated specimens in water, provides an acceptable destructive temperature
difference for a particular material, in agreement with theory. At present, however, no unique method for ex
perimental determination of the thermal stability of high-temperature materials has been developed. A route
towards standardizing static methods for determining the destructive temperature difference is proposed.
THERMAL STABILITY OF HIGH-TEMPERATURE
economic, and environmental conditions and the dynamics
of development of the leading research and industrial com-
plexes of the world community . While differing in chem-
ical and phase composition, structure and properties, manu
facturing technology, and application, these materials share
general characteristics of which the thermal stability is of
The high-temperature materials  are divided into the
1. Whisker-type single crystals.
2. Bulky single crystals.
3. High-density (with a density close to theoretical)
fine-grained polycrystalline materials.
4. Porous fine-grained polycrystalline materials.
5. Porous coarse-grained polycrystalline materials.
6. High-porosity polycrystalline materials.
7. Fibrous (filamentary) polycrystalline materials.
Except for materials of the 1st and 2nd groups (which are
single-phase), the rest of materials may be single- or multi
phase, quasi-homogeneous of heterogeneous.
Knowledge of the relations between fundamental proper
ties of materials, principles of design of engineering struc
tures intended for service under thermal shock conditions is
of importance both for theory and practice. A theory of ther
mal stability that has been developed within the framework
of the maximum stress theory and. quantum field theory of
thermal states provides an adequate description of the behav
ior of materials in a nonstationary temperature field [3, 4].
Thermal stability was substantiated as a physical property of
materials related to the fundamental properties of matter.
However, numerical analysis of the thermally stressed state
of high-temperature materials in a high-intensity nonstatio
nary temperature field and associated therewith technologi
cal implications is an arduous task; for this reason, experi
mental determination of thermal stability is frequently a pref
As an example of an approximate numerical analysis one
may refer to the determination of the critical heating rate of a
refractory lining by solving the nonstationary heat conduc
tion equation using destructive temperature gradients that
Refractories and Industrial Ceramics Vol. 45, No. 5, 2004
1083-4877/04/4505-0364 © 2004 Springer Science + Business Media, Inc.
St. Petersburg State Technological Institute (Technical Univer
sity), St. Petersburg; Moscow Technological College, Moscow,
High-temperature materials are called those for which the work
ing temperature is higher than the characteristic Debye tempera
ture for the elemental iron (~200°C); ultrahigh-temperature mate
rials are those for which the working temperature is higher than
the characteristic Debye temperature for the elemental carbon
(~1730°C). The elemental iron and carbon have been chosen as
references for the reason that iron is the base for structural steels
and heat-resistant alloys, and carbon – for high-temperature and
ultrahigh-temperature structural carbon-carbon materials. In what
follows, no distinction is made between “high-temperature” and