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Transparent Alumina/Ceria Nanocomposites By Spark Plasma Sintering
Author(s) -
AlvarezClemares Isabel,
MataOsoro Gustavo,
Fernández Adolfo,
LopezEsteban Sonia,
Pecharromán Carlos,
Palomares Javier,
Torrecillas Ramón,
Moya José Serafín
Publication year - 2010
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201000176
Subject(s) - materials science , spark plasma sintering , crystallite , microstructure , nanoparticle , chemical engineering , sintering , nanocomposite , grain boundary , grain growth , composite material , metallurgy , nanotechnology , engineering
The influence of oxides (such as MgO, TiO 2 , CaO, etc.) on the transparency of polycrystalline alumina compacts are widely studied in the literature. In this work, a completely different approach is developed, consisting of precipitating 0.5 wt.‐% CeO 2 nanoparticles (< 5 nm) on the surface of the starting alumina nanopowder (d 50 approximately 170 nm) using cerium(III) acetate as precursor. It is shown that the ceria nanoparticles strongly enhance the transparency of the spark plasma sintered compacts due to: i) the ceria nanoparticles acting as powder lubricant, increasing by around 15% the initial density of the powder in the SPS die, and, ii) the CeO 2 nanoparticles, having a very low solid solubility in the alumina grains, locating at grain boundaries, hindering alumina grain growth by pinning during SPS sintering at 1 430 °C, 80 MPa for 2 min. This effect is found to be effective only under SPS vacuum conditions. In order to explain the light scattering behavior in the near‐infrared and visible range, a light scattering model under the Rayleigh‐Gans‐Debye approximation for polycrystalline alumina is used. This model offers an additional and simple tool for a completed bulk evaluation of the SPS compacts microstructure.