Influence of Structural Distortion on Physical Properties of Yttria-Zirconia-Alumina Nanoparticles

Yttria-stabilized zirconia-alumina (YSZ/A) nanoparticles are materials with ionic conductivity. This is the main feature of YSZ/A solid electrolytes for solid oxide fuel cells (SOFCs) applications. Because of the adition of metal oxides in YSZ, it is posible to improve its ionic conductivity, mechanical strength and, thermal and chemical stability. In this work, YSZ/A with tetragonal structure (YSZ/A-t) and lattice parameters a = 5 09964 Å and c = 5 17488 Å; and YSZ/A with cubic structure (YSZ/A-c) with a = 5.13921 Å are analyzed. Fundamentally, the alumina (Al₂O₃) added in YSZ was able to create small lattice distortion and vacancies over the grain and grain boundary in concetration 3 mol% YSZ/A and 90/10 wt% for YSZ/A-t. This feature allows the ionic mobility through oxygen vacancies in the tetragonal lattice YSZ/A-t. Results of this material showed ionic conductivity, 0.118 S/cm with activation energy (E _a) equal to 0.912 eV and 1.011 eV in the grain and grain boundary respectively. Highlight, this response, which is associated to Al′_Zr–V··₀ defects at 1000 °C. As well as, the hardness properties of YSZ/A-t, which was increased keeping ionic conductivity with response reproducibility. Finally, these results were compared with YSZ/A-c structure identifying a the small structural distortion.