PORES: THEIR CLASSIFICATION AND ROLE
IN ACTUAL REFRACTORY MATERIAL STRUCTURES
I. G. Maryasev,
L. M. Mikhailovskaya,
L. D. Bocharov,
E. F. Chaika,
D. A. Tereshchenko,
A. A. Platonov,
and G. R. Platonova
Translated from Novye Ogneupory, No. 6, pp. 99 – 109, June 2011.
Original article submitted April 22, 2011.
Summarized material is presented, characterizing the pore space of refractories, whose analysis makes it pos-
sible to make recommendations for controlling production parameters in order to prepare refractories with a
desired pore structure. The results obtained are based on known research of the pore space, different pore clas-
sifications, and also the authors’ industrial and experimental experience.
Keywords: refractories, pores, classification.
The importance (role) of pores in materials science and
in the production of refractories is very considerable, which
many researchers have been devoted to studying: K. K. Stre-
lov, Ya. E. Geguzin, V. A. Perepelitsyn, and others, and state-
ment of the problem, caused by a requirement for drawing
new materials and technologies into production, for example
nanotechnology, reinforces interest in this theme.
Refractory objects are a common case of a solid with
pores, which serve as a source of valuable information about
many material and object properties. Present in practically all
structural elements (in coarse grains, in a binder, and be-
tween coarse grains and binder), pores may occupy from
90% to an extremely small volume of a refractory. Since dif-
ferent forms of pores have a favorable or negative effect on
the wear resistance of refractories, an important question of
pore genesis and their classification remains. As an argument
here we provide an example when in refractories with identi-
cal open porosity there may a different amount and configu-
ration, and consequently, they may behave differently during
operation under the same production conditions.
PORE CLASSIFICATION AND GENESIS
Several pore classifications have been presented in rela
tion to different features (size, shape, position, origin).
According to the permeability principle all pores (gen-
eral porosity) are separated into two categories: open and
closed (Fig. 1). Closed pores are those isolated and inaccessi-
ble for filling by any liquid. In refractories these pores are
normally in the minority . The shape of closed pores
mainly depends on the genesis and the nature of a chemical
bond in a solid. In many metals with a cubic lattice their
shape is close to spherical. Under specific conditions there is
formation of slot-like or acicular closed pores, for example in
crystals subjected to thermal action with a significant tem-
perature gradient. Pores, which communicate with each
Refractories and Industrial Ceramics Vol. 52, No. 3, September, 2011
1083-4877/11/05203-0202 © 2011 Springer Science+Business Media, Inc.
OOO Gruppa Magnezit, Satka, Chelyabinsk Region, Russia.
Fig. 1. General classification of porosity according to a permeabil