Cerium (IV) oxide synthesis and sinterable powders prepared by the polymeric organic complex solution method

• Published in: Journal of the European Ceramic Society 2002-09, Vol.22 (9), p.1711-1721
• Main Authors: Durán, Pedro, Capel, Francisco, Gutierrez, Dionisio, Tartaj, Jesús, Moure, Carlos
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; CeO 2; Ceramic industries; Chemical industry and chemicals; Chemistry; Colloidal state and disperse state; Elements and non-metal compounds (oxides, hydroxides, hydrides, sulfides, carbides, ...); Exact sciences and technology; General and physical chemistry; Inorganic chemistry and origins of life; Microstructure-final; Miscellaneous; Powders; Powders-chemical preparation; Precursors-organic; Preparations and properties; Sintering; Technical ceramics
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/S0955-2219(01)00483-6

Three processing methods making use of different cations complexant as citric acid (CA), polyvinylalcohol (PVA) or polyethylene glycol (PEG) have been used to prepare high purity fine CeO 2 powder with different particle size and agglomeration degrees. Green compacts prepared from the differently agglomerated powders were studied by Hg-porosimetry, and pore-size distribution curves were taken to compare the uniformity of the green compacts microstructure. The citrate-based prepared powders could be sintered to densities of 98% of theoretical at 1250 °C for 10 h, and to nearly fully dense (99.5% theoretical) at 1380 °C for 1 h. Otherwise, sintering temperatures of 1380 °C and ⩾1650 °C were necessary to obtain densities of ≈98% theoretical when using PEG and PVA as complexant, respectively. The different shrinkage-rate behavior was assumed to be closely related to differences in the pore-size distribution in the green compacts. Pore-size evolution was taken into account to study the microstructural development during sintering. Moderate grain growth (grain size ≈200 nm) was observed until densities lower than about 90% theoretical, while it considerably increases for higher densities. Grain size and microstructure uniformity could be related to the green compacts uniformity, i.e. the pore-size distribution and the agglomeration degree.