THE SINTERING PROCESS OF QUARTZ CERAMICS
E. I. Suzdal’tsev
Translated from Ogneupory i Tekhnicheskaya Keramika, No. 4, pp. 46 – 52, April, 2003.
It is shown, based on the available evidence, that the heating and cooling rates in the heat-treatment regimes of
quartz ceramics and its commercial products are of minor importance for the properties of the material and are
limited only by the process equipment potentialities. Still, the use of higher heating and cooling rates makes
the production of quartz ceramics more cost-effective.
Quartz ceramics (QC) combining a ranges of unique
properties such as high heat resistance, low heat conducti-
vity, temperature stability of dielectric constants, and suffi-
cient mechanical strength have gained acceptance in many
areas of science and technology.
Sintering is the most responsible and labor-intensive step
in the production of quartz ceramics and QC-based compo-
nents: In this process, discrete particles of finely ground
quartz glass are built into a cohesive framework, and the ma-
terial acquires its specific physicomechanical properties.
This issue has been given sufficient attention in the literature
[1 – 7]. However, the available data have never been syste-
matized or properly classified, which creates difficulties for
improving the existing QC production technologies and ne
cessitates additional research efforts in the field.
Our goal in this study was to generalize QC sintering
data, to analyze the effect of various heat treatment regimes
on QC properties, and to suggest recommendations on the
sintering technology of ceramic products and materials based
on quartz glass.
In this study we present the results obtained on material
specimens and components prepared from QC treated by
various thermal regimes.
The QC sintering is a time-consuming and energy-inten
sive process at all steps of preparation of materials and prod
ucts with specified physical and technical properties. Heat
treatment of molded preforms and components should be
carried out with due regard for glass quality and properties of
the slip and precursor materials. Therefore in our analysis we
used the QC processing parameters that were typical of an
established production technology backed up by appropriate
The quartz glass-based slips we have selected for our
study in their casting properties were suited for making com-
ponents of different shape and size (see Table 1). Specimens
and preforms were shaped by casting slip in plaster molds.
The QC sintering was carried out using laboratory fur-
naces equipped with SiC rod heaters that provided heating
rates up to 1000 K/h and industrial batch-operated electric
shaft furnaces with a heating rate of up to 600 K/h . To
provide conditions for higher heating (cooling) rates and to
avoid non-isothermal sintering regime effects, the dried
specimens were placed in a furnace heated to the terminal
temperature, held for a specified time, and cooled in air. The
specimens for testing were cast from slips of the same com
position (Table 2). To control the properties of QC speci
mens, the sintering at selected regimes was run in replicate
using laboratory and industrial furnaces. The sintering at es
tablished heating regimes and cooling at the inertial (in-fur
nace) regime made it possible to prepare QC specimens with
high-quality characteristics (Tables 3 and 4).
Refractories and Industrial Ceramics Vol. 44, No. 4, 2003
1083-4877/03/4404-0236$25.00 © 2003 Plenum Publishing Corporation
Tekhnologiya Research and Production Association Federal State
Unitary Enterprise, Obninsk, Kaluga Region, Russia.
TABLE 1. Properties of Precursor Slips and Cast Preforms
slip cast preform
1.87 – 1.90 1.93 – 1.96
Moisture content, % 14 – 17 12 – 15
Viscosity, °E 4.0 – 7.5 –
pH 4.0 – 7.5 –
Particle percentage, %:
up to 5 mm
63 – 500 mm
Porosity, % – 12.0 – 14.5