In this mill, the charge of the powder and milling tools are agitated in three perpendicular directions (Fig. ) at very high speed, as high as 1200 rpm. Figure Schematic drawing of a highenergy vibratory ball mill. (After Hashimoto et al.) [43] Another type of the vibratory ball mill, which is used at the van der WaalsZeeman Laboratory, consists of a stainless steel vial with a ...