Functionalization of Intergranular Regions inside Alkaline Earth Oxide Nanoparticle derived Ceramics

Publikation: KonferenzbeitragAbstract

Abstract

The physico-chemical properties of functional nanocrystalline ceramics are determined by the combination of constituent grains and the intergranular regions in between them. One effective approach to tailor structural and functional material properties is the engineering of grain boundaries that can be performed on the basis of previously established structure-property-processing relationships. Whereas related approaches have to some extent been performed for nanocrystalline metals, they have gained only recently increasing interest in the field of ceramics, where a fundamental understanding of segregation of admixed species is needed for an efficient grain boundary engineering. [1, 2]
In the present study we addressed the impact of gas adsorption during nanoparticle processing [3, 4] in view of the formation and compositional development of particle-particle interfaces and grain boundaries. For this purpose, we used nanocrystalline powders of MgO with defined concentrations of impurities such as Ba2+-ions as starting material for ceramic processing studies. The transformation of particle surfaces, which were previously functionalized with Ba-segregates, into grain boundaries, was achieved by uniaxial dry pressing and sintering (1373 K).
Using complementary structure analysis techniques (X-ray Diffraction and Transmission Electron Microscopy) we addressed an apparent grain growth effect that occurs at room temperature and can be explained by the size dependent dissolution behavior of Ba-admixed MgO nanoparticles in the presence of water vapor. Electron microscopy measurements on ceramic samples proved both, the annealing induced growth and reorganization of particles and grains during the formation of a granular microstructure. Residual porosity was characterized and identified as sinks of photoluminescent and BaO rich segregates. Characteristic photoluminescence emission features that are specific for the surface excitonic properties of highly dispersed alkaline earth oxides could have been retained during consolidation and sintering.
Literature: [1] P. Wynblatt, J. Eur. Cerm. Soc. 2003, 23, 2841-2848. [2] J. Han, Prog. Mater. Sci. 2018, 98, 386-476. [3] R. Castro, Am. Ceram. Soc. Bull. 2018, 97, 32. [4] D. Thomele, J. Am. Ceram. Soc. 2018, 101, 4994-5003.
OriginalspracheDeutsch
Seiten269
PublikationsstatusVeröffentlicht - 30 Mai 2019
VeranstaltungBunsentagung 2019: 118th General Assembly of the German Bunsen Society for Physical Chemistry - Jena, Jena, Deutschland
Dauer: 30 Mai 20191 Jun 2019
https://veranstaltungen.gdch.de/tms/frontend/index.cfm?l=8502

Konferenz

KonferenzBunsentagung 2019
LandDeutschland
OrtJena
Zeitraum30/05/191/06/19
Internetadresse

Systematik der Wissenschaftszweige 2012

  • 107 Andere Naturwissenschaften
  • 210 Nanotechnologie

Schlagwörter

  • Exsolution
  • Ceramics
  • Spectroscopy
  • Segregation

Zitieren