Please note: For the Planetary Micro Mill PULVERISETTE 7 premium line, you require at least 2 grinding bowls of your choice and the corresponding number of grinding balls. The grinding bowl material must also be harder than the material to be ground. In normal cases, grinding bowls and balls of the same material are used. To shorten the grinding time, grinding bowls and balls with a higher density and correspondingly higher impact energy can be used. Please take note of the useful capacity, this is not identical with the bowl volume!
Please select 2 grinding bowls, which are offered in the sizes 20 ml, 45 ml and 80 ml to perfectly match your sample volume. The useful capacity of the grinding bowls can be found in the selection aid. All grinding bowls of the FRITSCH premium line are cased in stainless steel, have a label and the same inner diameter regardless of their volume.
For the best grinding results in each individual case, all grinding bowls are available in 7 different materials, thus directly preventing contamination of the samples as a result of undesired abrasion.
Grinding bowl with lid, seal ring and label
Grinding bowl volume: 20 ml
Useful capacity: 1 … 9 ml
Weight net: 1.410 kg
General material specification:
Material: stainless steel
Abrasion resistance: fairly good
Suitable for: medium-hard, brittle samples
Detailed information about the material you will find in the element analysis.
All grinding bowls for the Planetary Micro Mill PULVERISETTE 7 premium line are delivered - as a standard – with a silicone seal ring. Due to this seal ring, the lid and grinding bowl are so tightly sealed that even grinding in suspension is possible absolutely problem-free.
When grinding in solvents or dry grinding of slightly caustic samples, we recommend our seal rings made of Viton (Article No. 84.0341.15) because they have a much higher chemical resistance.
Planetary Micro Mill PULVERISETTE 7 premium line
(Selection Aid)
MATERIAL DATA FOR GRINDING BOWLS / BALLS
| Material | Main component of the material | Density g/cm³ | Abrasion resistance | Used for grinding material |
| Agate | SiO2 | 2.65 | good | soft to medium-hard samples |
| Sintered corundum | Al2O3 (99.7%) | 3.8 | fairly good | medium-hard, fibrous samples |
| Silicon nitride | Si3N4 | 3.25 | excellent | abrasive samples, metal-free grinding |
| Zirconium oxide | ZrO2 | 5.7 | very good | fibrous, abrasive samples |
| Stainless steel | Fe – Cr – Ni | 7.8 | fairly good | medium-hard, brittle samples |
| Hardened steel | Fe – Cr | 7.9 | good | hard, brittle samples |
| Hardmetal tungsten carbide | WC | 14.3 | very good | hard, abrasive samples |
RECOMMENDED NUMBER OF GRINDING BALLS PER BOWL
Grinding balls ≥ 5 mm
Recommended number of balls per bowl
| Grinding bowl/ Useful capacity (grinding material) |
20 ml 1 – 9 ml |
45 ml 3 – 20 ml |
80 ml 10 - 30 ml |
| Balls diameter | |||
| 20 mm | 5 | ||
| 15 mm | 7 | 10 | |
| 10 mm | 10 | 18 | 25 |
| 5 mm | 80 | 180 | 250 |
Grinding balls ≤ 3 mm
Recommended ball mass per bowl in grams
| Grinding bowl/ Useful capacity (grinding material) |
20 ml 1 – 9 ml |
45 ml 3 – 20 ml |
80 ml 10 - 30 ml |
| Material | |||
| Zirconium oxide | 30 g | 70 g | 100 g |
| Stainless steel / hardened steel | 40 g | 90 g | 150 g |
| Hard metal tungsten carbide | 80 g | 200 g | 300 g |
ADDITIONAL INFORMATION
Grinding balls with diameter 3 mm and smaller must be weighed out. The above table provides you with the necessary weight to be included per grinding bowl.
The quantity of grinding balls can be reduced by up to 15 %; however, increased wear can then be expected. The specified number/mass of balls per bowl is the minimum quantity; depending on the material behaviour, it may be necessary to increase this.
In normal cases, grinding bowls and balls of the same material are used. To shorten the grinding time, grinding bowls and balls with a higher density and correspondingly higher impact energy can be used.
