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Effect of Acid Cleaning and Calcination on Rheological Properties of Concentrated Aqueous Suspensions of Silicon Nitride Powder
Author(s) -
Dai JianQing,
Huang Yong,
Xie ZhiPeng,
Xu XingLi,
Yang JinLong
Publication year - 2002
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.1151-2916.2002.tb00087.x
Subject(s) - calcination , aqueous solution , materials science , chemical engineering , slurry , rheology , inorganic chemistry , chemistry , organic chemistry , composite material , catalysis , engineering
The powder characteristics of two types of Si 3 N 4 (referred to as FD1 and FD2), as well as the rheological properties of their aqueous suspensions, were studied in this paper. There are distinctive differences in size distribution, soluble counterions, and surface groups. Highly concentrated aqueous slurries could not be prepared from these two as‐received powders. Acid cleaning and calcination improved the solids loading of their aqueous slurries, but the improvement varied with the powder. For the as‐received FD1 powder, poor dispersibility was caused by high‐valence counterions, which can be eliminated through acid‐cleaning. However, for the as‐received FD2 powder, it was the surface group of amine structures and carbon‐hydrogen bonding that limited the dispersibility. The calcination of FD2 can remove the amine structure and carbon‐hydrogen bonding and improve the slurry's rheological properties almost perfectly. For acid‐cleaned and calcined FD1, and calcined FD2, the solids loading of their aqueous suspensions reached 50 vol% with a viscosity below 300 mPa·s.