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Dispersion of Alumina and Silicon Carbide Powders in Alumina Sol
Author(s) -
Yang Quanzu,
Troczynski Tom
Publication year - 1999
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.1151-2916.1999.tb02019.x
Subject(s) - materials science , ceramic , dispersion (optics) , agglomerate , zeta potential , particle size , silicon carbide , dispersant , sol gel , particle (ecology) , particle size distribution , chemical engineering , composite material , suspension (topology) , mineralogy , nanotechnology , nanoparticle , chemistry , optics , oceanography , physics , mathematics , engineering , homotopy , geology , pure mathematics
Dispersion of Al 2 O 3 and SiC particles in an alumina sol has been investigated through determination of particle‐size distribution, zeta potential, and agglomerate morphology. The particle size of Al 2 O 3 and SiC (as determined by the particle‐size analyzer) is strongly affected by the presence of alumina sol in the solution. The average agglomerate size is decreased by at least 50%. The zeta potential of Al 2 O 3 in 1 M alumina sol increases slightly, whereas that of SiC reverses its sign over a wide range of pH values. It is proposed that these effects are caused by AlO 4 Al 12 (OH) 24 (H 2 O) 7+ 12 sol clusters (1‐2 nm in size) that are absorbed on the surface of the large (1‐5 µm) ceramic particles. The electrostatic and steric effects of the cluster absorption help to control the dispersion and stabilize the suspension of ceramic particles in the alumina sol during wet processing. It is expected that the alumina‐sol clusters can be used as an efficient, clean dispersant for single‐phase and composite ceramic powders.