Zirconium oxide

With a start size of ~ 100 µm, a direct grinding with smallest grinding balls is not possible. We recommend using 5 mm Ø grinding balls for a pre grinding step as shown in this trial.

We added 14 ml of water to maintain motor oil like viscosity for an optimum grinding effect.

To avoid over pressure, we ground the sample in steps of 5 minutes, followed by a programmed pausing time of 15 minutes. After several cycles, the outside temperature of the bowl should be checked (remain below 80°C); grinding time or programmed pausing time might be readjusted afterwards. This is counting for following grinding trials too.

We checked the fineness after a grinding time of 10 minutes with a Laser Particle Sizer ANALYSETTE 22 NanoTec plus. A d50 < 440 nm with 100 % < 10 µm has been reached.

A change of grinding balls might be possible, but we wanted to check what final fineness can be achieved with 5 mm Ø grinding balls. For this, we proceeded grinding for a total of 30 minutes. With an equal d50 < 440 nm and only a slight improvement in the range of coarsest particles (max. 6 µm), we recommend to change grinding balls to 0,5 mm Ø after 10 minutes (for this, see result 2).

Because there was no significant improvement compared between 10 and 30 minutes of grinding with 5 mm Ø grinding balls, we changed to a ball diameter of 0,5 mm in this trial.

We also added further 18 ml of water to maintain motor oil like viscosity again. Because of the higher amount of particles which have been formed during grinding, more water will be needed.

We proceeded grinding for a total of 90 minutes and checked the present fineness again. With a d50 < 63 nm, the desired fineness has been fulfilled already. The sample has been packed and will be returned with this report.

We also like to mention that standard Mie parameters for zirconium oxide do not seem to fit properly. If more suitable Mie parameters can be provided, a more precise grinding result can be recalculated.