Controlling the sintering of ceria by shape-controlled synthesis of nanoparticles
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2019
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INTERNATIONAL CONFERENCE ON HIGH-PERFORMANCE CERAMICS, 11th
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The influence of surface energy of Gd-doped CeO2 nanometric crystals with different
morphologies on mass diffusion mechanisms is studied. Depending on the starting morphology
(nanocubes, nanorods, and random nanoparticles) extremely different microstructures, ranging
from rapidly densified to thermodynamically stable porous structures. We investigate Gd-doped
ceria (10% molar, GDC) both for its relevance in several chemical, environmental and energy
technologies, and because the extensive knowledge on diffusion effects ruling this compound. We
synthesized GDC as nanocubes (NC) and nanorods (NR) by a hydrothermal method whereas
randomly oriented nanoparticles (RD) were obtained by co-precipitation. All samples were
measured as single phase GDC powders with narrow nanoparticle size distributions. The high
surface area NR exhibit lower green density as compared to NC. Dilatometric analyses revealed
that NR have a pronounced linear retraction starting at low temperatures (~200°C) with maximum
sintering activity at ~1100°C. High surface energy in NRs leads to a rapid rod to sphere
transformation as well as to a rapid densification despite relatively low green density. On the other
hand, the solid state diffusion in NCs is significantly inhibited, as confirmed by the highly porous
microstructure of sintered samples. The results indicated the possibility of controlling
microstructure of GDC by defining the shape of nanoparticles for different application in which
dense or stable pores are required.
Como referenciar
FONSECA, FABIO C.; MACHADO, MARINA F.S.; MORAES, LETICIA P.R.; RODRIGUES, THENNER S.; KABIR, AHSANUL; MARANI, DEBORA; VAN NONG, NGO; ESPOSITO, VINCENZO. Controlling the sintering of ceria by shape-controlled synthesis of nanoparticles. In: INTERNATIONAL CONFERENCE ON HIGH-PERFORMANCE CERAMICS, 11th, May 25-29, 2019, Kunming, China. Abstract... Disponível em: http://repositorio.ipen.br/handle/123456789/32206. Acesso em: 26 Apr 2024.
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