SURFACTANT EFFECTS IN THE MECHANICAL ACTIVATION
OF ULTRAFINE ALUMINA POWDERS MADE BY
I. V. Antsiferova,
V. B. Kul’met’eva,
and Yu. A. Biryukov
Translated from Novye Ogneupory, No. 6, pp. 29 – 33, June, 2009.
Original article submitted November 7, 2008.
Studies have been made on the effects of mechanochemical activation with the addition of surfactants on the
characteristics of the pneumocirculation grinding product from alumina powder and the properties of the co
rundum ceramic based on it. Processing the powder in an aqueous solution of polyvinyl alcohol and methyl
cellulose with concentration up to 1% has a marked effect on the detailed crystal structure of the particles and
improves the technological properties of the powder. Activation produces defects at the particle surfaces,
which tend to intensify the consolidation of the powder up to high sintering temperatures.
Keywords: alumina, corundum ceramic, mechanochemical activation, surfactants.
Corundum ceramic has a unique combination of proper-
ties: high hardness, wear resistance, chemical inertness, ther-
mal conductivity, and so on, and this is responsible for its
general use in areas from electronics to medicine. Aluminum
oxide at present occupies the leading position by volume of
production for technical ceramics .
Ultrafine powders meeting the following requirements
are required to make high-grade ceramic materials with sta
ble properties: controlled chemical and phase compositions,
appropriate particle morphology and size distribution, ag
glomeration level, sintering activity, and so on . To make
fewer finely divided powders one uses various methods of
chemical synthesis, whose main shortcoming is the low yield
of target product. The pneumocirculation method is a reliable
and highly productive method of making and processing
ultrafine powders, in which the particle grinding is provided
by the interaction between high-speed gas jets and a dense
layer of circulating material .
Mechanical activation in various media is used to im
prove the pressability and raise the activity of aluminum ox
ide powder, which is combined with chemical processing and
the addition of surfactants (SA) [4 – 7]. Aqueous solutions of
polyvinyl alcohol (PVA) and methyl cellulose (MC) are
fairly widely used as temporary bonding agents in ceramic
technology . It has been shown  that adding dry PVA at
the level of 5 wt.% has a favorable effect on the specific sur-
face and crystal structure parameters in the activation of
We have examined the effects of surfactants on the char-
acteristics of alumina powder made by pneumocirculation
grinding for mechanochemical activation and on the corun-
dum ceramic based on it.
We used a-Al
powder of grade M0.3 made by
pneumocirculation grinding as developed at the Innovation
and Technological Scientific Education Center of Tomsk
State University . The main fraction in the powder had a
particle size less than 0.3 mm and constituted 60%.
The powder was activated in a Sand planetary grinder for
1 h with a rotation speed of 160 rpm, with a ratio between the
mass of powder and that of the grinding bodies of 1:2. The
alumina was activated in a liquid, for which we used distilled
water with added SA: methyl cellulose and polyvinyl alcohol
at various concentrations. The specimens were pressed in a
steel mold at 200 MPa with the addition of a 4% solution of
PVA, with sintering in air at temperatures from 1100 to
1600°C, hold times ranging from 0 to 2 h.
The specific surface S
was measured with a GKh-1 gas
system by the BET method from the low-temperature ad
sorption of argon. The structure parameters (size of coherent
scattering regions (CSR) and microdistortions) were deter
Refractories and Industrial Ceramics Vol. 50, No. 3, 2009
1083-4877/09/5003-0227 © 2009 Springer Science+Business Media, Inc.
Powder Material Science Center, Perm’ State Technical Univer
Tomsk State University, Russia.