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Homogeneous Distribution of Sintering Additives in Liquid‐Phase Sintered Silicon Carbide
Author(s) -
Lidén Eva,
Carlstrom Elis,
Eklund Lars,
Nyberg Brita,
Carlsson Roger
Publication year - 1995
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.1151-2916.1995.tb08886.x
Subject(s) - sintering , materials science , silicon carbide , microstructure , chemical engineering , homogeneity (statistics) , colloid , adsorption , carbide , electron microprobe , silicon , mineralogy , composite material , metallurgy , chemistry , statistics , mathematics , engineering
The addition of sintering additives to silicon carbide particles by electrostatic adsorption of colloidal A1 2 O 3 and Y 2 O 3 sols has been studied as a way to achieve an optimum homogeneity in the microstructure. The adsorption behavior of the sol particles was examined by electrophoretic measurements and X‐ray fluorescence analysis. Both A1 2 O 3 and Y 2 O 3 sols could simultaneously be adsorbed on the SiC particle surfaces. Viscosity measurements showed that the colloidal sol particles had a stabilizing effect on the slip, and hence slips with relatively high solid loadings could be prepared without adding extra dispersing agent. Liquid‐phase‐sintered silicon carbide materials (LPS‐SiC) with 2 wt% A1 2 O 3 and 1 wt% Y 2 O 3 were prepared by freeze granulation/ pressing and sintering at 1880 deg; C for 4 h. The homogeneity of the green compacts was quantified using a spot analysis technique in an electron probe microanalyzer. It was clearly shown that the addition of sols gave a more homogeneous microstructure than the reference sample with Y 2 O 3 and A1 2 O 3 added as powders. The addition of sintering additives as sols also enhanced the sintering behavior.