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Processing of Concentrated Aqueous Silicon Nitride Slips by Slip Casting
Author(s) -
Albano María P.,
Garrido Liliana B.
Publication year - 1998
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.1151-2916.1998.tb02417.x
Subject(s) - sintering , dispersant , slurry , materials science , aqueous solution , calcination , silicon nitride , chemical engineering , slip (aerodynamics) , dispersion (optics) , composite material , mineralogy , silicon , metallurgy , chemistry , organic chemistry , physics , catalysis , optics , thermodynamics , engineering
The optimization of concentrated Si 3 N 4 powder aqueous slurry properties to achieve high packing density slipcast compacts and subsequent high sintered densities was investigated. The influence of pH, sintering aid powder (6% Y 2 O 3 , 4% Al 2 O 3 ), NH 4 PA dispersant, and Si 3 N 4 oxidative thermal treatment was determined for 32 vol% Si 3 N 4 slurries. The results were then utilized to optimize the dispersion properties of 43 vol% solids Si 3 N 4 ‐sintering aid slurries. Calcination of the Si 3 N 4 powder was observed to result in significantly greater adsorption of NH 4 PA dispersant and effectively reduced the viscosity of the 32 vol% slurries. Lower viscosities of the optimized dispersion 43 vol% Si 3 N 4 ‐sintering aid slurries resulted in higher slipcast packing density compacts with smaller pore sizes and pore volumes, and corresponding higher sintered densities.