#### Effects of the speed ratio on the efficiency of planetary mills

Planetary ball mills provide high energy density due to the superimposed effect of two ... Early models were based on kinematic equations describing the trajectory and velocity of balls inside the vial. ... boron powder (9597% purity, amorphous, Fluka) and highpurity argon gas (H 2 O and O 2 < 3 ppm, Linde) were used in this work. All ...