Electrochemical Synthesis of Precursors of Al2O3-ZrO2 Ceramic Stabilized with Cerium Oxide and Magnesium Aluminate

Abstract

This article presents a new approach to preparing the precursors of complex oxide systems Al2O3-ZrO2-MXOY (M = Mg, Ce). The approach is based on the electrogeneration and interaction of reagents with electrolyte components in a coaxial electrochemical reactor. The design of the electrolyzer provides the suspension homogenization due to the turbulence induced by the intensive hydrogen bubbles and electrolyte movement in opposite directions relative to the central electrode in a closed space. Hydrogen evolution leads to the mixing of the solution. The transfer of OH− ions generated at the cathode into the electrolyte and interaction with metal ions (Zr, Al, Ce, Mg) leads to the formation of hydroxoaqua complexes of these metals. They participate in the polycondensation reaction, forming polymerized hydroxides and oxyhydroxides, which are the basis of the primary particles. The process of hydroxylation of nanoparticle surface of the formed precursors of oxide systems stabilizes the dispersion and prevents particle aggregation. The stabilized tetragonal t-ZrO2 was obtained by sintering the precursor of the synthesized oxide system at 1100 °C with the formation of an alumina phase (γ-Al2O3, or an aluminum–magnesium spinel MgAl2O4) with a low CeO2 content (2–3 wt%).