Author(s)

Ian P. Maher, Richard A. Haber

Department of Materials Science and Engineering, Rutgers University, Piscataway, NJ, USA.

Slurry parameters were controlled prior to spray-drying to visualize and govern an understanding of which parameters govern hollow coring and granule morphology during spray-drying. An aqueous alumina using a polyvinyl alcohol binder (PVA) system was analyzed and granules were processed by altering the slurry specific gravity and viscosity value prior to spray-drying. Spray-dried granules were uniaxial dry-pressed at varying moisture contents to show the plasticizing effects of moisture during compaction. A novel characterization method using a field emission electron microscope (FESEM) was implemented to image the green microstructures of the granules and compacted samples. Slurries with a higher specific gravity and viscosity resulted in denser granules with spherical shapes. Viscosity affected the binder segregation during the spray-drying process. Granules stored at higher moisture contents resulted in denser compacts with fewer intergranular pores and cracks along granule boundaries. Using a FESEM resulted in higher resolution for green microstructural characterization.

Spray-Dried Alumina, Uniaxial Dry-Pressing, SEM, Green Microstructural Imaging

Maher, I. and Haber, R. (2018) Green Microstructural Visualization of Dry-Pressed Spray-Dried Alumina (Al₂O₃). Materials Sciences and Applications, 9, 936-948. doi: 10.4236/msa.2019.912067.