MANUFACTURING AND EQUIPMENT
HIGH TEMPERATURE RESISTANT ENVIRONMENT-FRIENDLY
SILICA FIBERS AND MATERIALS
É. N. Zhurba,
I. A. Lavrinovich,
A. N. Trofimov,
and V. I. Shumskii
Translated from Novye Ogneupory, No. 12, pp. 51 – 53, December, 2004.
Original article submitted June 22, 2004.
Methods for the preparation of silica fibers by chemical leaching of glass fibrous are described. The materials
in question are composed of high-melting oxides (94 – 96 wt.% SiO
and 3.5 – 4.0 wt.% Al
) and display
superior properties: service temperature up to 1000°C, melting point 1650 – 1700°C, heat conductivity
0.082 – 0.11 W/(m × K) at 50°C. The materials are stable on exposure to water, hydrocarbons, ammonia hydr
oxide, hydrochloric, nitric and sulfuric acids, high temperature, pressure, and radiation. The silica materials
are commercially available as fabrics, gauzes, ribbons, filaments, fibers, and blankets.
Protection from effects due to high temperature and ag-
gressive media has been and continues to be an issue of ma-
jor concern in many sectors of research, technology, and na-
tional economy. In Russia, a route towards solving the prob-
lem is the use of silica materials of domestic production.
High temperature resistant silica fibers are produced us-
ing the property of oxides (components of silicate glasses of
different compositions) to dissolve (leach out) selectively un
der the action of acid solutions. The fiber becomes enriched
in silicon oxide in proportion depending on the glass compo
sition. The leachability of silicate glasses and fibers is con
trolled by the structural silicon-oxygen glass network that re
mains unchanged during extraction.
Silica fiber (with 96 – 99% SiO
able from foreign manufacturers is typically
prepared by treating alkali-free aluminoboro
silicate glass (of composition E) with aqueous
hydrochloric acid. Domestic manufacturers
deal in silica materials based on sodium alumi
nosilicate glasses treated by sulfuric acid. The
high temperature resistance of domestic mate
rials is due to the fact that they contain
high-melting oxides: SiO
, 94 – 96 wt.% and
, 3.5 – 4.0 wt.% (Table 1).
A comparison of domestic and foreign silica materials
has revealed a difference in porous structure and mechanical
strength; the difference in thermal physical properties (heat
capacity, heat diffusivity, temperature coefficient of linear
expansion, and heat conductivity) was less pronounced
Unleached E-type glass materials are known to exhibit
high mechanical strength. When treated with acid, their
strength decreased by a factor of 4 – 5, and the pore size
reached 0.9 – 1.1 nm. The decrease in strength was ex
plained by the passage of some 50% of oxides (B
) into solution. The least loss of strength was
observed in leached sodium aluminoborosilicate glasses. In
Refractories and Industrial Ceramics Vol. 46, No. 2, 2005
1083-4877/05/4602-0113 © 2005 Springer Science+Business Media, Inc.
Stekloplastik Research and Production Associa
tion, Andreevka, Moscow Region, Russia.
TABLE 1. Composition of Precursor Glasses and Silica Materials
Component concentration, %
O CaO MgO Na
silica materials 94 – 96 3.5 – 4.0 ––––
precursor glass (E-type) 52 – 56 12 – 16 5 – 10 16 – 26 0 – 6 0 – 1
silica materials 96 – 99 –––––