Microstructure Evolution During the Sintering of Freeze-Cast Alumina
Abstract:
Reports on freeze-cast ceramic materials frequently focus on the study of the organized
macroporosity and the properties of the materials. This study aims to describe the microstructure
evolution of freeze-cast alumina during the sintering process, analyzing grain growth, densification,
pore elimination and crystal structure at different sintering temperatures (1300-1500 °C). Aqueous
suspensions with 20 vol% alumina were freeze-cast in liquid N2 and sintered. The microstructure was
analyzed by stereological analysis, N2 adsorption and X-ray diffraction. Grain sizes varied within
237-500 nm, and the intergranular porosity decreased from 8.8% at 1300 °C to 1.4% at 1500 °C. N2
isotherm analysis revealed pore shrinking from the region of macro and mesopores (20-80 nm), to
smaller residual mesopores (3.7-15 nm) at temperatures above 1400 °C. Rietveld refinement of the
XRD diffractograms confirmed increased crystallite size and decreased lattice strain at higher sintering
temperatures. This comprehensive description of microstructural evolution of the freeze-cast alumina
contributes to understanding the sintering of highly porous ceramics produced via freeze-casting.
macroporosity and the properties of the materials. This study aims to describe the microstructure
evolution of freeze-cast alumina during the sintering process, analyzing grain growth, densification,
pore elimination and crystal structure at different sintering temperatures (1300-1500 °C). Aqueous
suspensions with 20 vol% alumina were freeze-cast in liquid N2 and sintered. The microstructure was
analyzed by stereological analysis, N2 adsorption and X-ray diffraction. Grain sizes varied within
237-500 nm, and the intergranular porosity decreased from 8.8% at 1300 °C to 1.4% at 1500 °C. N2
isotherm analysis revealed pore shrinking from the region of macro and mesopores (20-80 nm), to
smaller residual mesopores (3.7-15 nm) at temperatures above 1400 °C. Rietveld refinement of the
XRD diffractograms confirmed increased crystallite size and decreased lattice strain at higher sintering
temperatures. This comprehensive description of microstructural evolution of the freeze-cast alumina
contributes to understanding the sintering of highly porous ceramics produced via freeze-casting.
| Zugehörige Institution(en) am KIT | Institut für Funktionelle Grenzflächen (IFG) |
| Publikationstyp | Zeitschriftenaufsatz |
| Publikationsdatum | 26.02.2024 |
| Sprache | Englisch |
| Identifikator | ISSN: 1980-5373, 1516-1439 KITopen-ID: 1000175593 |
| HGF-Programm | 43.33.11 (POF IV, LK 01) Adaptive and Bioinstructive Materials Systems |
| Erschienen in | Materials Research |
| Verlag | Associação Brasileira de Metalurgia e Materiais (ABM); Associação Brasileira de Cerâmica (ABC); Associação Brasileira de PolÃmeros (ABPol) |
| Band | 27 |
| Seiten | Art.-Nr.: 20230380 |
| Nachgewiesen in | Web of Science OpenAlex Dimensions Scopus |