Optimization of chromium oxide nanopowders dispersion for spray-drying

The aim of this work is to produce spherical micron-sized granules by spray-drying. This technique requires stable and well-dispersed suspensions. The targeted application for such granules is the development of wear resistant Cr2O3 nanostructured coatings by plasma projection. The work reported in this paper was performed to develop and to optimize Cr2O3 nanopowders dispersion by a ball milling method for producing granules. al, structural and microstructural properties of Cr2O3 nanopowders were followed by XRD analysis, helium pycnometer density, gas adsorption (BET), SEM and TEM observations. oice of suitable dispersant was determined by zeta potential measurements. The dispersant amount has been optimized from the rheological behavior of slurries containing 30 wt.% nanopowders. Slip stabilization was investigated by sedimentation tests and zeta potential measurements. The influences of milling time, milling balls diameter and milling balls to powder ratio were studied by granulometric measurements. A well-dispersed and stable aqueous Cr2O3 slip, suitable for spray-drying, was achieved.