Nanocomposites and nanomaterials
Properties of ceramic nanocomposites based on zirconia and manganite
A.O. Novokhatska, G.Ya. Akimov
Donetsk Institute for Physics and Engineering named after O.O.Galkin, Natl. Acad. of Sci. of Ukraine. Prospect Nauki, 46, Kiev-03039, Ukraine. 
E-mail: a.novokhatska@gmail.com

This paper presents the results of studying the effect of excess manganese on the structure and conductivity of nanocomposite ceramic materials consisting of manganite (Nd0.67Sr0.33)1–xMn1+xO3 (x=0 and 0.2) and electrolyte 10 mol% Sc + 1 mol% (NSMO-SCSZ) used as the cathode for the medium-temperature solid oxide fuel cell (SOFC). To obtain composites, nanosize powders of manganites and electrolytes were mixed in equal mass fractions and sintered at 1000 °C. 
According to the research results of NSMO-SCSZ (х=0; 0.2) nanocomposites the excess manganese (x=0.2) promotes the formation of the microstructure which appropriated requirements for cathode materials [1], namely a porous microstructure (open porosity of 20-30%) with necks formed between manganite grains (grain size of 200-300 nm) and an electrolyte, but also the preservation of phase composition of both materials, which is a completely new result in the studies of these composite cathodes. The results of the study of the electric transport properties presented in the figure showed that the conductivity of composites with excess manganese is two times higher than the conductivity of samples without excess manganese.
Thus, it is found that excess manganese in manganites significantly influences the formation of the structure and conductivity of nanocomposite cathode materials, namely it ensures the formation of the necessary grain size and porosity, the preservation of phase composition and high conductivity of the nanocomposite.

1.	 Gauckler L. J.; Beckel D.; Buergler B. E.; Jud E.; Muecke U. R.; Prestat M.; Rupp J. L. M.; Richter, J. Solid oxide fuel cells: Systems and materials // CHIMIA International Journal for Chemistry. – 2004. - 58. – P. 837-850.