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Preparation of High Solids Content Nanozirconia Suspensions
Author(s) -
Santacruz Isabel,
Anapoorani Ketharam,
Binner Jon
Publication year - 2008
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2007.02164.x
Subject(s) - dispersant , materials science , yttria stabilized zirconia , suspension (topology) , sintering , ceramic , chemical engineering , cubic zirconia , economies of agglomeration , shear rate , slip (aerodynamics) , grain size , viscosity , composite material , mineralogy , dispersion (optics) , chemistry , engineering , physics , mathematics , homotopy , pure mathematics , optics , thermodynamics
A new colloidal route leading to the production of ∼99% dense 3‐mol% yttria‐stabilized zirconia nanostructured ceramics, while retaining a final average grain size of ∼75 nm, has been developed. The process was based on the production of stable, homogeneous nanosuspensions with solids contents of up to 28 vol% (70 wt%), but viscosities <0.05 Pa·s at any shear rate in the range of study were obtained. The suspensions were formed by the concentration and optimization of precursor, dilute (5.0 vol%) commercial nanosuspensions, the approach requiring a change of pH, from the 2.4 of the as‐received suspension to 11.5, and the use of an appropriate anionic dispersant. Exposure of the nanosuspensions to ultrasound also helped to reduce the viscosity further, although it only worked when the dispersant was optimized. The nanosuspension was slip cast to form homogenous green bodies with densities of ∼55% of the theoretical without agglomeration in the nanostructure; these were subsequently densified using a two‐step sintering technique.