The Influence of Mechanical Activation on the Structure of a ZrO2(MgO) Nanocrystalline Powder.

The influence of mechanical activation of a nanocrystalline ZrO₂ (3 wt. % of MgO) powder on its structure is studied. For mechanical activation a ball mill was used with a constant speed of 70 rpm. The duration of treatment was from 1 to 50 hours. It is shown that after mechanical activation of the powder for 5 hours, it begins aggregation of particles. A further treatment leads to the separation of particles into two fractions. After 25 hours of mechanical activation there was a complete breakdown of the aggregates and reaching a minimum of the particle average size in comparison with the initial powder. Further increasing of the activation duration did not lead to a noticeable decrease in the average size of individual particles, however, the morphology of the powder changed, and the particles began to group into large spherical formations. [ABSTRACT FROM AUTHOR]