Preparation of Agglomerate-Free Starting Powders for TiCp-Reinforced β-Sialon Nanocomposites

Abstract

By changing the molecular weight and concentration of dispersant, PH value of dispersion solution and treat process, this paper focuses on the optimization parameters of the TiCp-reinforced ß-sialon nanocomposites suspensions. Zeta potentials, sedimentation tests have been carried out to prepare a well reagglomerated and uniform suspensions. The optimum molecular weight of PEG is 1540 for Al2O3 powder and 4000 for others, while the concentration is 0.5wt% to 0.8wt% with the pH values range from 9.5 to 10. After addition of dispersant, PEG (polyethylene glycol), the surfaces of the TiC particles and Sialon contents were selectively covered with long organic molecular chains by soaking within solution. The resulting powders not only resisted reagglomeration, but were also readily dispersible within the mixed solution. Optimum dispersion conditions, i.e. the surfactant molecular weight and the concentration, the PH value of the suspens ions and the soaking time were determined.