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2019
Journal Article
Titel
Alumina-Doped Zirconia Submicro-Particles: Synthesis, Thermal Stability, and Microstructural Characterization
Abstract
Zirconia nanoceramics are interesting materials for numerous high-temperature applications. Because their beneficial properties are mainly governed by the crystal and microstructure, it is essential to understand and control these features. The use of co-stabilizing agents in the sol-gel synthesis of zirconia submicro-particles should provide an effective tool for adjusting the particles' size and shape. Furthermore, alumina-doping is expected to enhance the particles' size and shape persistence at high temperatures, similar to what is observed in corresponding bulk ceramics. Dispersed alumina should inhibit grain growth by forming diffusion barriers, additionally impeding the martensitic phase transformation in zirconia grains. Here, alumina-doped zirconia particles with sphere-like shape and average diameters of similar to 300 nm were synthesized using a modified sol-gel route employing icosanoic acid and hydroxypropyl cellulose as stabilizing agents. The particles were annealed at temperatures between 800 and 1200 degrees C and characterized by electron microscopy, elemental analysis, and X-ray diffraction. Complementary elemental analyses confirmed the precise control over the alumina content (0-50 mol%) in the final product. Annealed alumina-doped particles showed more pronounced shape persistence after annealing at 1000 degrees C than undoped particles. Quantitative phase analyses revealed an increased stabilization of the tetragonal/cubic zirconia phase and a reduced grain growth with increasing alumina content. Elemental mapping indicated pronounced alumina segregation near the grain boundaries during annealing.
Author(s)
Dahl, Gregor Thomas
Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
Döring, Sebastian
Institute of Physical Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
Krekeler, Tobias
Electron Microscopy Unit, Hamburg University of Technology, Eißendorfer Straße 42 (M), 21073 Hamburg, Germany
Janssen, Rolf
Institute of Advanced Ceramics, Hamburg University of Technology, Denickestraße 15 (K), 21073 Hamburg, Germany
Ritter, Martin
Electron Microscopy Unit, Hamburg University of Technology, Eißendorfer Straße 42 (M), 21073 Hamburg, Germany
Weller, Horst
Institute for Physical Chemistry, University of Hamburg, Martin‐Luther‐King Platz 6, 20146, Hamburg, Germany The Hamburg Centre for Ultrafast Imaging, 22761, Hamburg, Germany Fraunhofer Center for Applied Nanotechnology CAN, Grindelallee 117, 20146, Hamburg, Germany