Scandia Stabilized Zirconia

While particles of a height of ~ 50 µm will pass the grinding chamber of a Disk Mill PULVERISETTE 13 premium line, the length and width of particles can be up to ~ 300 µm when the gap is adjusted properly (always depending on sample properties).

Test wise, we used the Disk Mill PULVERISETTE 13 and ground a sample amount of 125 grams with 0,05 mm gap setting. Surely also other grinding disks (e.g. zirconium oxide as desired) can be used for comminution. After feeding of the sample, the typical grinding sound vanished within 20 seconds.

Typically about 10 ± 3 grams of sample remains loose inside the grinding chamber afterwards. Also here, a few grams remained, easily to remove by vacuuming with a soft brush.

An aliquot of ground sample was sieved with a test sieve of 50 µm; about 14 % of sample was successfully ground < 50 µm while 86 % of sample output is still larger than 50 µm. Both fractions was packed separately for demonstration.

We estimate that this grinding result can be improved, when the used disks are warn in correctly and the 0-gap will be readjusted. We don’t expect that much more than 30 % of sample would be ground as desired. Majority of output might be about 100-200 µm when a sample will be sieved out.

Test wise, we used a second batch of sample, 100 grams and tried grinding with our Planetary Mono Mill PULVERISETTE 6 classic line.

For a start size up to ~ 3 mm thickness, we recommend using grinding balls of 15 mm Ø minimum. With 500 ml bowls and 70x 15 mm Ø grinding balls, up to ~ 200 grams of sample might fit into the bowl. For only batches of 100 grams, also 250 ml bowls should be fulfilling.

Without knowing the properties of sample, we reduced the main disk speed of the mill to only 450 rpm to check grinding behavior. After only one minute of comminution, the sample was compressed harder to grinding bowl and balls. A longer dry grinding is not recommended.

The found result is indicating that the sample provided might contain mainly compressed primary particles of very fine size. We checked the start size of original sample material, using our Laser Particle Sizer ANALYSETTE 22 NanoTec (static light scattering). As expected, the majority of particles are already < 2 µm. Because of this level of fineness, a dry ground sample is sticking almost instantly.

The basic task might not be a comminution of particles, only deagglomeration of compressed (dried material). We recommend comminuting the sample in suspension for a short while and using a speed evaporator to remove the solvent quickly, so agglomerates should become softer and forming powder should become much smaller.