LAYERED HEAT-INSULATING REFRACTORIES
BASED ON OXIDE MATERIALS
T. P. Salikhov,
T. T. Riskiev,
V. V. Kan,
É. M. Urazaeva,
and T. V. Savatyugina
Translated from Ogneupory i Tekhnicheskaya Keramika, No. 10, pp. 27 – 30, October, 2002.
Experimental data on laminated materials with layers of different density intended for heat-shielding, ero
sion-resistant, and refractory applications are reported. Two-layer specimens based on oxide materials with
different macroporous structure (granulated, containing burn-out additions, and chemically swollen based on
a phosphate binder) are considered. Test results for a pilot batch of two- and three-layer components for re
fractory lining (200 ´ 100 mm plates) based on phosphate-bonded corundum are given.
When selecting ceramics with special structural, refrac-
tory, heat-insulating, and strength properties for demanding
applications, one must frequently combine a range of physi-
cochemical characteristics in a single individual material.
Different approaches have evolved to creating multilayer
composites. Some of them are based on an optimum combi-
nation of chemically and compositionally different materials
[1, 2], and others — on the selection of chemically homoge-
neous materials that may differ in macrostructure, porosity,
and density [3, 4].
Our goal in this study was to see which chemically ho
mogeneous oxide materials of different density can be used
for developing heat-shielding, erosion-resistant, refractory-
lining structural components.
In developing multilayer structures, the following issues
were of major concern:
— combining porous components based on fractionated
powders of different grain size;
— combining a heat-insulating porous layer containing
burn-out additions (polystyrene, sawdust, etc.) with a com
pact refractory layer;
— combining a heat-insulating chemically swollen layer
with a compact layer containing phosphate binders.
The precursor materials were chamotte powders of dif
ferent grain size based on a calcined kaolin (from the
Angrenskoe deposit) and variously heat-treated Al
ders. The laminated components were fabricated using a con
ventional technology for refractory heat insulators.
The granulated refractory materials were molded using
a sequential semidry pressing technique under pressures of
10 – 20 MPa .
The heat-insulating components containing burn-out ad-
ditions were prepared by vibratory pressing with or without
additional loading .
The technology for laminated components based on
phosphate binders  was developed using experience
gained in the molding of homogeneous specimens with alter-
nating compact and porous layers .
The tests were conducted using laboratory-made speci
mens with dimensions of 50 ´ 50 ´ 50 mm. Materials show
ing optimum test results were used to prepare plates with di
mensions of 200 ´ 100 mm.
Conditions at the interface of layers differing in density
were inspected visually and under a microscope.
Combinations of compact layers with chemically identi
cal porous structures — granulated (a, b ), containing burn-
out additions (c, d ), and chemically swollen phosphate-
bonded (e, f ) — are shown schematically in Fig. 1.
The schemes sketched in Fig. 1 suggest that, in develop
ing such structures, one is confronted with a range of prob
lems, in particular those that bear on the different shrinkage
and density of layers, which may cause strain (b ) or even
cracking (c, d ) in the specimens. In quantitative terms, the
bounds of existence of layered structures are evaluated as
Refractories and Industrial Ceramics Vol. 43, Nos. 9 – 10, 2002
1083-4877/02/0910-0303$27.00 © 2002 Plenum Publishing Corporation
Physics – Sun Institute for Materials Science Research and Pro
duction Association, Academy of Sciences of the Republic of
Uzbekistan, Tashkent, Uzbekistan.