Wear resistance characteristics of micro-sized ceramic beads in a vertical bead mill

Abstract

To investigate the wear resistance characteristics of micro-sized ceramic beads, wear tests reflecting real milling conditions were performed on yttrium-stabilized zirconia beads with diameters of approximately 100 μm. And a novel method for monitoring of wear state is proposed to obtain the wear rate of micro-sized beads using the change in size of beads with time. A vertical bead mill was employed to simulate the milling environment of the beads. The size change of the ceramic beads as a function of milling time was monitored using a particle size analyzer and plotted to determine their wear rate. The wear rate of each ceramic bead was derived from the slope obtained through linear regression analysis: 0.0215 μm/h, 0.0058 μm/h, and 0.0075 μm/h for Beads #1, #2, and #3, respectively. The Vickers hardness, phase fraction, and grain size of the ceramic beads were analyzed and compared to find out the cause of the difference in the wear rate. Vickers hardness was measured in the central, intermediate, and outer regions of the cross-sections of the ceramic beads. The wear rate of the ceramic beads was largely dependent on the hardness of the outer region, rather than those of the central and intermediate regions. Bead #2, which had the lowest wear rate, exhibited the highest hardness of 1371 HV (measured in the outer region). Bead #2 had more tetragonal phase and smaller grain sizes than those of Beads #1 and #3.