AN ELECTROPHORETIC METHOD FOR SHAPING PREFORMS
FROM AQUEOUS SLIPS OF INORGANIC MATERIALS
E. I. Suzdal’tsev
and D. V. Kharitonov
Translated from Novye Ogneupory, No. 10, pp. 18 – 23, October, 2004.
Original article submitted August 26, 2004.
Traditional ceramic technology and an electrophoretic method for forming large-size complex-shaped pre
forms are discussed and compared. The superior of ceramic products prepared by the electrophoretic method
The shaping of preforms occupies a special place in ce-
ramics technology since this operation is critical for the
properties, shape, and dimensions of an engineering compo-
nent. Quite a number of techniques for shaping ceramic pre-
forms have been proposed; still, complex-shaped, large-size
components can be prepared just using slip casting technol-
ogy. The slip casting method, for its all merits, has shortcom-
ings, of which one is the eventual variation of physicomecha-
nical properties over the volume of the component [1, 2].
Our goal in this work was to see which ways can be used to
improve performance characteristics of large-size com
plex-shaped ceramic preforms prepared from aqueous slips
of inorganic materials.
As is known, the shaping of preforms treated by slip
casting occurs owing to the capillary suction in the material
of the mold as the fluid phase (water) is drawn up across the
walls of the mold. The solid particulates are entrained by the
fluid towards the walls of the mold and become deposited so
as to build up a gradually increasing layer on the walls. The
slip casting of complex-shaped large-size is a lengthy pro
cess which involves also the deposition of larger particles
In the course of deposition of larger particles , a solid
layer builds up on the inner surface of the mold in the
top-to-bottom direction. The preform buildup rate is con
trolled, among other conditions, by the angle of tilt of the
mold, for example, during the molding of preforms for radio
transparent fairings with a complex conic shape (Fig. 1),
which may result in a nonuniform buildup of the preform. To
see if this is a real fact, we studied the shaping of large-size
components — plates with dimensions of 23 ´ 70 ´ 650 mm
— from slips based on lithium aluminosilicate glass.
For this purpose, a device was used that allowed one to
follow the buildup rate throughout the height of the preform.
The procedure was as follows. A slip prepared from lithium
aluminosilicate glass (with properties: density, 2.00 g/cm
screenings remained on a 0.063 mm mesh sieve, 7%;
pH = 8.3) was poured through a pouring gate in the cavity
formed by a plaster mold with solid walls and a core (Fig. 2a).
The buildup process was controlled through a sight glass that
served as a wall for the cavity on one side. The buildup pro
cess throughout the height and across the thickness of the
preform is illustrated by the curves in Fig. 3a.
Refractories and Industrial Ceramics Vol. 45, No. 6, 2004
1083-4877/04/4506-0392 © 2004 Springer Science+Business Media, Inc.
Tekhnologiya Research and Production Enterprise, Obninsk,
Kaluga Region, Russia.
Fig. 1. Schematic diagram illustrating the shaping of a large-size
complex-shaped ceramic preform (of a radio transparent shell type)
by slip casting in plaster molds: 1 ) core; 2 ) slip mix; 3 ) deposited
layer; 4 ) plaster mold.