Zirconia-Alumina Nanoparticles Prepared by Laser Evaporation: Powder Characterisation by TEM and 27Al MAS NMR

Dissolution kinetics of nanodispersed γ-alumina in aqueous solution at different pH: Unusual kinetic size effect and formation of a new phase

“…Without a doubt, the running processes at the interfacial surface have a great influence on the dissolution process itself. Additionally, appropriate methods have to be applied in the characterization of the powder material [35]. Nevertheless, the common opinion may still be that aluminum oxide is practically insoluble in aqueous solution under ambient conditions.…”

Fabrication of Macro-Mesoporous Zirconia-Alumina Materials with a One-Dimensional Hierarchical Structure

“…In agreement with some literature reports, this indicates that Zr ions could be accommodated into the alumina structure. In contrast, the lattice constant of the tetragonal zirconia seemed to remain constant as the Zr percentage varied from 15% to 50%; however, when compared with pristine zirconia, the cellages of the as-synthesized nanocomposites do exhibit a decrease in tetragonality ( c / a ratio), which shows the impregnation of aluminum atoms is not possible past an initial amount …”

“…In contrast, the lattice constant of the tetragonal zirconia seemed to remain constant as the Zr percentage varied from 15% to 50%; however, when compared with pristine zirconia, the cellages of the as-synthesized nanocomposites do exhibit a decrease in tetragonality (c/a ratio), which shows the impregnation of aluminum atoms is not possible past an initial amount. 31 It is well-known that monoclinic ZrO 2 is stable from room temperature up to 1000 °C, with it transforming into the tetragonal phase above 1170 °C. 32 Stabilized tetragonal zirconia can exist at ambient temperature, when prepared using certain methods, such as adding divalent or trivalent oxides into the pristine oxide, or simply preparing it by the low temperature calcination of zirconyl nitrate or precipitating it from zirconium aqueous solution under alkaline conditions.…”

New ZrO2/Al2O3 Nanocomposite Fabricated from Hybrid Nanoparticles Prepared by CO2 Laser Co-Vaporization

“…At higher alumina concentrations - in our case 43 mol% - the exceeding alumina might form an amorphous shell around these defect crystals 23 . Due to the significantly higher melting and vaporization temperatures of zirconia compared with alumina, ZrO 2 should condense and nucleate first from the gas phase followed by Al 2 O 3 24 25 . The pre-condensed zirconia crystals subsequently act as nuclei for the heterogeneous nucleation of alumina.…”