Doping of alumina ceramics by manganese – Thermodynamical and experimental approach

0557931 - ÚFM 2024 RIV RS eng J - Journal Article
Svoboda, Jiří - Drdlíková, K. - Drdlík, D. - Kroupa, Aleš - Michalička, J. - Maca, K.
Doping of alumina ceramics by manganese – Thermodynamical and experimental approach.
Processing and Application of Ceramics. Roč. 16, č. 1 (2022), s. 13-21. ISSN 1820-6131. E-ISSN 2406-1034
R&D Projects: GA ČR(CZ) GA20-14237S
Research Infrastructure: CzechNanoLab - 90110
Institutional support: RVO:68081723
Keywords : alumina * doping * electron energy loss spectroscopy (EELS) * sintering * thermodynamics
OECD category: Thermodynamics
Impact factor: 1.1, year: 2022
Method of publishing: Open access
https://doiserbia.nb.rs/Article.aspx?ID=1820-61312201013S

The preparation of a transparent ultra-fine-grained doped ceramics requires a homogeneous dopant distribution in a matrix. In the present work, two thermodynamical phenomena allowing the preparation of such ceramics (the dissolution of the dopant and the formation of undesirable secondary phases) were experimentally and theoretically studied. A general thermodynamic-kinetic model was developed for dopant dissolution, which was verified for the experimental conditions used in this work. The model and experiment showed that Mn3O4 dopant with overall concentration of 1 at.% and particle size of 50 nm is dissolved and homogenized in a fine-grained alumina matrix within less than one hour at a temperature of 1220 °C. For the purposes of the study of the formation of undesired secondary phase, the phase diagram of the Al2O3-Mn3O4 system was calculated using the CALPHAD approach. Detailed STEM observations combined with EDX and EELS chemical analyses showed that the data used for the calculation of the phase diagram need some modifications because they overestimate the solubility of Mn in the alumina and underestimate the solubility of Mn in the MnAl2O4 spinel. © 2022 University of Novi Sad, Faculty of Technology. All rights reserved.
Permanent Link: https://hdl.handle.net/11104/0334359