Ammonium polyacrylate adsorption on "aluminium hydroxides and oxyhydroxide" coated silicon nitride powders

Citation
Mp. Albano et al., Ammonium polyacrylate adsorption on "aluminium hydroxides and oxyhydroxide" coated silicon nitride powders, CERAM INT, 26(5), 2000, pp. 551-559
Citations number
12
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
CERAMICS INTERNATIONAL
ISSN journal
02728842 → ACNP
Volume
26
Issue
5
Year of publication
2000
Pages
551 - 559
Database
ISI
SICI code
0272-8842(2000)26:5<551:APAO"H>2.0.ZU;2-1
Abstract
Si3N4 powders coated with pseudoboehmite, Al hydroxide with a OH/Al mol rat io (R) lower than 3 and bayerite, were prepared from different coating solu tions and dispersed in water with an ammonium polyacrylate (NH(4)PA) to pro duce 11.8 vol% slips. The coated powders showed isoelectric points at pH 7, 7.5 and 7.5 close to that of the precipitate coatings of pseudoboehmite, A l hydroxide (R < 3) and bayerite, respectively, indicating that the surface coverages were almost complete. The bayerite coated powders had the lowest specific surface area values. The coatings on Si3N4 particles were shown t o improve the adsorption of NH(4)PA dispersant on Si3N4 The maximum adsorpt ion of the polyelectrolyte at pH 9.5 increased from 0.01 for the uncoated p owder to 0.03, 0.055 and 0.08 mg/m(2) for the coated powders with pseudoboe hmite, Al hydroxide (R < 3) and bayerite, respectively. (C) 2000 Elsevier S cience Ltd and Techna S.r.l. All rights reserved.