FORMATION OF SOLID ELECTROLYTE FILM STRUCTURES
E. A. Korableva,
M. A. Maizik,
and N. N. Savanina
Translated from Novye Ogneupory, No. 10, pp. 47 – 50, October 2014.
Original article submitted September 9, 2014.
Dependence of the effect of highly efficient milling on preparation of dense solid electrolytes in the form of
films of chemically deposited zirconium dioxide powder is studied on the example of the system
+ 8 mol.% Y
. Changes in ZrO
particle morphology and composition occurring during milling affect
sintered ceramic properties. During sintering there is inheritance of the powder structure. A reduction in the
degree of agglomeration during milling of chemically precipitated powders in a bead mill (to 2 mm) makes it
possible to obtain a more compact nanostructure (to 50 nm) during sintering compared with the structure of
specimens from powders after milling in a ball mill. Optimum properties are determined for starting powders
in order to prepare high quality dense films up to 170 mm thick by pouring on to a moving substrate.
Keywords: solid oxide fuel cells, solid electrolytes, film pouring, nanocrystalline zirconium dioxide powder,
powder grain size composition, nanostructure, milling in ball and bead mills.
Currently transition from unrenewable to renewable en-
ergy sources is a task of state importance. Promising energy
sources with high efficiency (up to 70%) exhibiting good
ecological efficiency, noise-free, and prolonged continuous
operation (decades), are power generation installations
founded on direct conversion of chemical fuel energy into
electrical energy based on solid oxide fuel cells (SOFC).
Solid electrolytes for SOFC are prepared from ceramic mate
rials made of zirconium dioxide.
In Japan, Germany, and Australia development of power
generation installations based on SOFC have achieved the
commercialization stage [1, 2]. Within Russia creation and
introduction of SOFC is held back by high cost of manufac
turing test power generation installations, which in particular
is due to use of technology not providing high output of fin
ished solid electrolytes and electrochemical cells based on
Solution of the problem is possible using new molding
technology making it possible to obtain assembly-line solid
electrolytes in the form of film structures 100 – 200 mm
thick. By reducing thickness and a preparing a dense struc
ture of conducting ceramic it is possible to improve conduc-
tion properties of solid electrolytes and reduce the SOFC op-
erating temperature from 950 – 1000°C to 850 – 700°C.
A reduction in SOFC operating temperature by 100 – 150°C
provides a marked increase in power generation installation
operating life as a result of a reduction in unit ceramic and
metal component degradation.
Preparation of a film by pouring is a process of feeding
slip through a slot, prescribed by a metal wiper, on to a sub
strate moving with controlled speed. The main slip compo
nents are ceramic powder and organic temporary production
binder (TPB). TPB for film pouring is multicomponent, and
each component fulfils its own function:
– a binder supports the level of strength during molding;
– a dispersant is a spatial barrier between particles and
– a plastifier provides slip rheological properties and
gives poured ceramic ductility;
– a solvent serves as a TPB base;
– a surface-active substance increases ceramic powder
wetting capacity by means of reducing surface tension.
Film thickness and quality depend on many factors: orig
inal powder and slip composition, rate of feed of moving
substrate, rate of air supply and removal of gases of elimi
nated solvents during subsequent drying, and also on drying
temperature. Slip composition should provide a sufficient
level of ductility for a “green” film, in order that combination
Refractories and Industrial Ceramics Vol. 55, No. 5, January, 2015
1083-4877/15/05505-0419 © 2015 Springer Science+Business Media New York
GNTs RF OAO ONPP Tekhnologiya, Obninsk, Kaluga Region,