Strategic priorities in the field of hydrogen energy include the design of intermediate-temperature solid oxide fuel cells capable of highly efficient operation in the temperature range of 573–973 K. Consequently, attempts are being made to replace the widely applied cubic zirconia electrolyte with an electrolyte consisting of tetragonal zirconia. The rationale for this approach is that 3Y-TZP exhibits higher mechanical strength and higher electrical conductivity at temperatures below 973 K. The addition of Al2O3 in an amount that exceeds its solubility limit in 3Y-TZP has been found to result in increased electrical conductivity and improved mechanical properties. The aim of the study was to synthesize 3-YSZ powder via co-precipitation and use it to obtain composites with a 3Y-TZP matrix and 0.5 mol.% or 1.0 mol.% of Al2O3 inclusions. The correlation between these samples' electrical conductivity and resistance to brittle fracture and their phase composition and microstructure was investigated by means of X-ray diffractometry, scanning electron microscopy, electrochemical impedance spectroscopy and Vickers indentation tests. For comparison, the properties of composites with an 8-YSZ matrix and Al2O3 inclusions were also investigated. It was determined that the composite based on the 3Y-TZP matrix and containing 0.5 mol.% of Al2O3 inclusions can be considered a viable alternative for 8-YSZ electrolytes in IT-SOFC applications.
3Y-TZP sinters with 1, 5, 10, and 15 mol% of Al 2 O 3 were prepared using two different procedures from a 3-YSZ powder synthesized via the citrate process. In the first procedure, alumina was introduced during synthesis via the citrate method. In the second one, the 3-YSZ powder was impregnated with aluminum nitrate. All samples were sintered at 1773 K. The prepared composites were evaluated in terms of their microstructure, chemical and phase composition, and electrical properties. The total conductivity of the 3Y-TZP/Al 2 O 3 composite material, which contained primarily the tetragonal phase, was found to increase with temperature, and to decrease for reduced concentrations of alumina in 3Y-TZP. In the case of the samples which had alumina introduced via impregnation, its higher content was not associated with significantly lower electrical conductivity. These samples generally exhibited higher conductivity than the samples to which alumina had been added via chemical synthesis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.