Silicon Nitride Ceramic Prepared by Colloidal Process

Abstract

Advanced silicon nitride ceramic compact was prepared by colloidal process. The rheological behaviors of the Si3N4 powders were emphatically investigated. At the same time, the effects of the dispersant, pH value and ball milling time on the silicon nitride slurry were discussed. The results showed that the addition of the dispersant could shift the value of Zeta potential and improve the fluidity of silicon nitride slurries. The well fluidity can be achieved when the amount of the dispersant was 1.2wt%. Besides, a ball milling time of 8h was appropriate. Statistic pattern recognition was used to predict the processing parameters. Then the high density of green compact could be attained while the volume fraction of solid powders was up to 40%, and the fracture toughness of the sintered body reached 7.2MPa·m1/2. The microstructure of final sintered ceramic was observed by scanning electron microscope (SEM).

Spark Plasma Sintered Si3N4/TiN Nanocomposites Obtained by a Colloidal Processing Route

“…The standard procedure to obtain TiN-Si 3 N 4 composites is usually based on sintering of mechanically mixed powders, but this method does not allow homogeneous dispersion of TiN nanoparticles into the Si 3 N 4 matrix. Alternatively, the colloidal route has already demonstrated its potential to process ceramic oxides and/or nonoxide/oxide mixtures [9][10][11][12][13][14]. It is important to distinguish that among colloidal processing routes there are included processes based only on wet mixing of nanopowders and processes in which the nucleation of a second phase onto the surface of starting powders working with precursors in solution is promoted.…”