NANODISPERSE SILICA AND SOME ASPECTS
OF NANOTECHNOLOGIES IN THE FIELD
OF SILICATE MATERIALS SCIENCE. PART 2
Yu. E. Pivinskii
Translated from Novye Ogneupory, No. 12, pp. 28 – 38, December, 2007.
Original article submitted August 14, 2007.
Methodological problems connected with the study of grain size distribution of polyfraction suspensions bearing
nanoparticles are considered. Some technological problems of the use of nanoparticles are analyzed. Examples
of effective use of nanodisperse kinds of silica for fabricating various silicate materials are presented.
In Part 1 of the paper
we considered the general con
cepts of nanosystems and generalized recent data on various
kinds of silica used in the technology of silicate materials.
In Part 2 we will analyze the characteristic features of
nanosystems that are determining in the technology of mate-
rials that include such systems. An example of silica HCBS
will be used for a detailed consideration of general problems
connected with the methods of determination of the size dis-
tribution of nanoparticles.
COMPLEX ESTIMATION OF DISPERSITY
AND GRAIN DISTRIBUTION IN HCBS
Dispersity and grain distribution of particles of the solid
phase play an exceptional role in the technology of materials
based on HCBS and especially of quartz ceramics and
refractories. This is connected with the fact that in this tech
nology the effect of superclose packing of particles of the
solid phase in shaped semiproducts has been implemented
for the first time in world practice. Whatever the method of
shaping of these materials with the use of cast molding sys
tems (slip casting, electrophoretic or centrifugal shaping,
vibration casting of ceramic concretes), it seems possible to
obtain a semiproduct with porosity or relative density un
attainable in the technologies of other materials. To a great
extent this is a result of optimum dispersity and grain distri
bution of solid-phase particles in the corresponding molding
systems. This concerns ceramic materials shaped on the basis
of suspensions and ceramic concretes. Molding systems for
fabricating ceramic concretes contain a considerable volume
fraction of granular or coarse-grained filler (in the form of
fused quartz or scrap of quartz ceramics or refractories).
In Fig. 1, the data of  are used to plot the grain distri-
bution of HCBS and ceramic concretes characterized by dif-
ferent grain sizes of the fillers. The range of particle sizes in
the fillers involves about eight decimal exponents from a
fraction of a micron for the colloid component to 10 mm for
the filler. At the same time, the main contribution to the spe-
cific surface of both the solid phase of the HCBS (curve 1¢)
and of ceramic concretes (curves 2¢ and 3¢) is made by the
very insignificant amount of very fine (highly dispersed) par-
ticles (at the level of nanoparticles). The filler ensures only
1 – 2% of the specific surface of the solid phase. The corre
sponding role in the formation of properties of materials
based on HCBS (quartz ceramics) and ceramic concretes is
played by the reactive colloid component (nanoparticles).
The minimum size d
of HCBS particles amounts to
~5 – 10 nm (nanoparticles), whereas the maximum size d
attains 100 – 200 mm for HCBS used in the technology of
quartz ceramics [7, 35] and 300 – 400 mm in the technology
of quartz refractories [27, 36]. In this connection, objective
difficulties arise in the study of the fully disperse composi
tion of solid-phase particles in such systems. Therefore, it is
expedient to use a complex method consisting of a combina
tion of several individual methods. The study is begun with a
wet sieve analysis of a sample of the suspension (commonly
from 100 to 200 ml). In the production of both quartz cera
mics and refractories the sieved fraction is estimated in terms
of a generalizing characteristic, i.e., the content of particles
with size exceeding 63 mm (the residue on a sieve with cells
0.063 mm in size). As applied to suspensions of quartz glass
in the production of ceramics this parameter is equal to
Refractories and Industrial Ceramics Vol. 48, No. 6, 2007
1083-4877/07/4806-0435 © 2007 Springer Science+Business Media, Inc.
“NVF KERAMBET-OGNEUPOR” Company, Russia.
Published in Novye Ogneupory, No. 11, 2007.