Design and fabrication of ceramic beads by the vibration method

The purpose of this of study was to investigate the confined vibration method to produce alumina beads for the study of stress wave propagation in granular media. The method produces beads with desirable shape (i.e. oblate, prolate, and tri-axial ellipsoid), microstructure (level of porosity), and size (5 mm to 3 cm in diameter). This environmentally friendly approach to process beads involves preparing a slurry with a small amount of PVA binder and dispersant. After drying, the pre-formed material is a shear-reversible soft-solid, which flows under applied stress with limited strain recovery. This rheological behavior is sufficient for the alumina paste to be processed into rounded shapes with a confined shaker table and to maintain the shape for sintering of the alumina beads.