Open AccessPreparation and Characterization of Si3N4-BN Ceramic Composites by Gelcasting
Author(s) -
Nagaveni Thallapalli,
K. Kishore Kumar,
C. S. P. Rao
Publication year - 2016
Publication title -
material science research india
Language(s) - English
Resource type - Journals
eISSN - 2394-0565
pISSN - 0973-3469
DOI - 10.13005/msri/130105
Subject(s) - dispersant , materials science , slurry , boron nitride , silicon nitride , ceramic , composite material , dispersion (optics) , microstructure , composite number , aqueous solution , polyethylenimine , fabrication , tape casting , casting , chemical engineering , chemistry , layer (electronics) , organic chemistry , medicine , transfection , biochemistry , physics , alternative medicine , pathology , optics , gene , engineering
In this work, a novel method for the preparation of colloids has been studied for the fabrication of silicon nitride –Boron nitride composites. In the present work, the dispersion of mixed silicon nitride –Boron nitride powders in aqueous media was studied with the changes dispersant concentration, solution pH etc. Polyethylenimine (PEI) additive as a dispersant were used for Si3N4 and BN powders in aqueous media. Well-dispersed Si3N4 and BN powders in aqueous media were attained at the 1 wt% PEI and pH 9. 40 vol% covered Si3N4/BN slurries with varying BN content was adapted for gel casting. The gel casted material was preheated at normal room temperature, debindered at 6000C and sintered at 17000C. The sintered composite material composed mainly of alpha-Si3N4, beta-Si3N4, and h-BN. The prepared composite material shows uniform microstructure with faceted particles, a-Si3N4 and abundant pores.
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