Synthesis and thermal stability of zirconia and yttria-stabilized zirconia microspheres
| Autor: | Elisabeth W. Leib, Ulla Vainio, Robert M. Pasquarelli, Jonas Kus, Andreas Schreyer, Martin Müller, Horst Weller, Rolf Janssen, Christian Czaschke, Nils Walter, Tobias Vossmeyer |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Materials science
Ingenieurwissenschaften [620] Ceramic Phase transformation Thermal barrier coating Grain size Microspheres Surfaces Coatings and Films Electronic Optical and Magnetic Materials Biomaterials Tetragonal crystal system Grain growth Condensed Matter::Materials Science Colloid and Surface Chemistry YSZ Chemical engineering Particle Zirconia Cubic zirconia Thermal stability ddc:620 Yttria-stabilized zirconia |
| Zdroj: | Journal of colloid and interface science (448): 582-592 (2015-06-15) |
| ISSN: | 1095-7103 |
| Popis: | Hypothesis Zirconia microparticles produced by sol–gel synthesis have great potential for photonic applications. To this end, identifying synthetic methods that yield reproducible control over size uniformity is important. Phase transformations during thermal cycling can disintegrate the particles. Therefore, understanding the parameters driving these transformations is essential for enabling high-temperature applications. Particle morphology is expected to influence particle processability and stability. Yttria-doping should improve the thermal stability of the particles, as it does in bulk zirconia. Experiments Zirconia and YSZ particles were synthesized by improved sol–gel approaches using fatty acid stabilizers. The particles were heated to 1500 °C, and structural and morphological changes were monitored by SEM, ex situ XRD and high-energy in situ XRD. Findings Zirconia particles (0.4–4.3 μm in diameter, 5–10% standard deviation) synthesized according to the modified sol–gel approaches yielded significantly improved monodispersities. As-synthesized amorphous particles transformed to the tetragonal phase at ∼450 °C with a volume decrease of up to ∼75% and then to monoclinic after heating from ∼650 to 850 °C. Submicron particles disintegrated at ∼850 °C and microparticles at ∼1200 °C due to grain growth. In situ XRD revealed that the transition from the amorphous to tetragonal phase was accompanied by relief in microstrain and the transition from tetragonal to monoclinic was correlated with the tetragonal grain size. Early crystallization and smaller initial grain sizes, which depend on the precursors used for particle synthesis, coincided with higher stability. Yttria-doping reduced grain growth, stabilized the tetragonal phase, and significantly improved the thermal stability of the particles. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect