Hydrolysis-assisted solidification of alumina slurry dispersed in silica sol without de-airing process

This work reports a novel hydrolysis-assisted solidification (HAS) casting technology without de-airing process developed to prepare mullite-based ceramics. Concentrated alumina slurry dispersed in silica sol with high solid volume loading but low viscosity was successfully prepared at about pH 2.0. Based on effect of pH values on stabilization behavior of the slurry, in situ consolidation was realized utilizing the self-hydrolysis of formamide to shift the pH value from 2.0 to above pH 2.8. High compact and uniform green body was obtained without entrapped air by HAS casting technology without de-airing process.