Vereschak V.
State Higher Education Institution “Ukrainian State University of Chemical
Engineering”, Dnepropetrovsk, Ukraine.
Pasenko O.
State Higher Education Institution “Ukrainian State University of Chemical
Engineering”, Dnepropetrovsk, Ukraine
Bykov I.
The Institute for Problems of Materials Science, Kyiv, Ukraine
CO-PRECIPITATION METHOD IN NANOSCALE SCANDIA
STABILIZED ZIRCONIA POWDERS TECHNOLOGY
FOR CERAMIC FUEL CELLS
Introduction. Scandium stabilized zirconia is used in SOFC application as solid
electrolyte and anode [1]. To manufacture these SOFC elements powders with different
disperse and phase composition are needed. Therefore technology for zirconia powders
production must be predictable and controlled.
The commonly used method that allows to actively control the process of oxides
solid phase formation is coprecipitation method. One of the disadvantages of the
method is extremely high activity of activity of intermediate zirconium compounds
(zirconium hydroxide) which leads to aggregation and agglomeration of precipitation
products and consequently the finished powders which in turn leads to a wide range in
sizes both primary particles and their agglomerates. In other words this method in its
classical application does not allow to prepare non-agglomerated nano-sized powders.
To solve these problems systematical studies of physicochemical processes and
phenomena that accompany the formation of zirconia solid phase throughout the entire
formation sequence: "Solution → Zirconium hydroxide precipitate → Amorphous
zirconium hydroxide → Crystalline zirconium dioxide" are needed.
The paper deals with physicochemical processes of the nanostructure formation
in stabilized zirconia powders while obtaining it from aqueous solutions of zirconium
salts containing soluble additives of stabilizing elements by coprecipitation method.
Experimental technique. 8-aqueous zirconium oxychloride (ZrOCl
2
·8H
2
O),
scandium chloride (ScCl
3
), ammonia (10% aqueous solution), n-butanol, distilled
water were used as original substances. All of these reagents were of CP grade.
Process solutions of zirconium oxychloride were prepared by dissolving
ZrOCl
2
·8H
2
O in distilled water up to concentration of 0.5mol/l Zr(IV). Stabilizing
additive (ScCl
3
) was introduced directly into zirconium oxychloride solution.
Precipitation of zirconium oxychloride was performed by adding an aqueous
solution of ammonia to the solution of zirconium oxychloride with stabilizer while
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