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Surface Modification of Si 3 N 4 Powders by Coprecipitation of Sintering Aids
Author(s) -
Bertoni Fabrice,
Galassi Carmen,
Ardizzone Silvia,
Bianchi Claudia Letizia
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.tb02137.x
Subject(s) - coprecipitation , sintering , materials science , electrokinetic phenomena , coating , chemical engineering , aqueous solution , yttrium , metallurgy , solubility , mineralogy , composite material , chemistry , nanotechnology , organic chemistry , engineering , oxide
Two commercial Si 3 N 4 powders were coated with sintering aids by coprecipitation. Lanthanum and yttrium nitrates were used as sintering aid precursors. Electrokinetic sonic amplitude measurements and X‐ray photoemission spectroscopy analysis were used to investigate electrokinetic behavior and surface properties, respectively. Coprecipitation produced different effects on the composition of the coating layer depending on the actual features of the starting Si 3 N 4 powders. The electrokinetic behavior of aqueous suspensions with coated powders depended strongly on the additives, their solubility, and the rate of oxidation of the coated layer. The coprecipitation conditions had to be carefully controlled to obtain reproducible composition and morphology of the coating layers. Treatments of the starting powder, pH, and washing volumes were optimized to tailor the coating layer and improve the coprecipitation yield.