Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 11, pp. 1969
Pleiades Publishing, Ltd., 2007.
Original Russian Text ©
A.V. Zaichuk, V.V. Koleda, Ya.I. Belyi, 2007, published in Khimicheskaya Promyshlennost’, 2007, Vol. 84, No. 4, pp. 186
TECHNOLOGY OF ORGANIC
AND INORGANIC CHEMISTRY
On the Synthesis of Glass and Glass-Crystalline Black-Blue Facing
on Thin Ceramic
A. V. Zaichuk, V. V. Koleda, and Ya. I. Belyi
Ukrainian State Chemical Technological University, Dnepropetrovsk, Ukraine
Received June 28, 2007
Abstract—By x-ray phase analysis the optimal temperature is established for the spinel formation in the oxide
at the producing ceramic black-blue pigment and the phases playing the role of basic
chromophores. The synthesized pigments provide the glass facing with black-blue color and strong flashing (up
to 86%) and with semi-dull fine crystalline facture based on the developed unfritted glaze characterized by strong
and stable color in a wide range of roasting temperature.
The consumers’ demand of ceramic products, those
of everyday use in particular, is defined in much by their
appearance which in turn depends on the color and quality
of glaze facing. Producing the exclusive strong drinks
induces necessity in development of special ceramic
bottles with high aesthetic and decorative characteristics.
Therewith significant is the process of glazing, that is,
formation on surface of glass layer either flashing or of
semi-dull fine-crystalline facture. Developing research
in this direction is very actual. Therefore the purpose of
this work is development of compositions and investiga-
tion of pigment-containing black-blue glaze covers.
The blue and black pigments, as is known , should
be synthesized as a rule at high temperature (up to
1300°C), predominantly from the cobalt, iron, manganese
and chromium oxides.
Earlier investigations  showed that it is reasonable
to use two-component oxide system CoO–Fe
synthesis of black ceramic pigments, in part, for high
melting unfritted glazes. The basic chromophores in this
system providing formation of required color of glass
layer are cobalt ferrite (CoFe
) and free cobalt oxide.
Taking above into account, at the synthesis of such
pigments we studied the compositions that include cobalt
and iron oxides with Co
ratio in the range from
1.40 to 2.38. Their thermal treatment initially was carried
out in laboratory roasting furnace at maximal temperature
1000°C with isothermal 1 h exposure.
From the data of x-ray phase analysis (Fig. 1) follows
that the experimental pigments besides cobalt ferrite also
contain cobalt oxide, the latter in much bigger amount
than necessary for stoichiometric spinel CoFe
higher values of Co
ratio the intensity of dif-
fraction maxima corresponding to cobalt oxide (Co
d = 2.43; 2.86; 1.43) increases considerably. The phase com-
position of the pigment also includes gematite (α-Fe
appearing due to incomplete spinel formation.
The studied pigments were ground in a ball mill to
the particle size 5–10 m and were added in amount up to
8 wt. fraction above 100 wt % into unfritted transpaent
glaze containing pegmatite, sand, chalk, kaolin and
microvollastonite. The obtained dross with 38% moisture
was applied by pulverization on the ceramic samples
that after drying were roasted at maximum temperature
1200°C for 2 h. Properties of the glazes obtained are
listed in the table.
The data obtained show that including the syn-
thesized by us ceramic pigmets into the mixture for
producing unfritted transparent glaze allows obtaining
after roasting the glass layer of strong black-blue color,
as seen visually and as follows from spectral wavelength
of the cover which is related to purple region (575–
579 nm), as well as from low values of color purity (1–
2%) and CDR (coefficient of diffuse reflection) in the
range 3.20–3.69% inherent in black color. The most
intense black-blue color has the glaze containing pigment
n-8 with maximum Co
rate. The CDR of such
glass coating material is minimal, being equal to 3.20%,
and flash is 87%.
Formation of cobalt ferrite at the thermal treatment
of the pigment mixture leads to black colorization of
glaze cover. Appearance of blue color is stipulated by