Fraunhofer Institute for Ceramic Technologies and Systems IKTS
Wear resistent transparent corundum balls.
Highly pure microstructure of sintered α-Al2O3 grinding balls. Average grain size 0.41 µm at relative density > 99.9 %.
Vickers hardness HV10 = 2090 ± 50
Perfect sub-µm micostructures reduce the wear of grinding balls in volume, particle size, and impurity content
Known grinding balls with low and sub-µm wear consist, e.g. of ZrO2 (detrimental in Al2O3 substrates for microelectronics or in alumina with high permeability for microwaves), balls of 85 % Al2O3 introduce silica impurities. Commercial high-purity Al2O3 grinding balls exhibit increased and coarser wear. The corundum balls developed here by IKTS Dresden avoid these disadvantages and enable highly pure ceramic processing for special use.
Advantages
- Highest purity > 99.9 % α-Al2O3.
- Minimum wear (1/4 of the typical wear of 85 % Al2O3 balls) due to sub-µm grain size < 0.5 µm at high relative density > 99.9%.
- High hardness HV10 > 2000.
- Small average particle size of wear (0.6 µm).
- Use in fast attrition mills enabled by high specific fracture stress (750 – 1000 MPa in compression).
Services offered
- License on know how. Upscaling. Contributions to the development of an industrial production of new grinding balls.
- Supply of new wear resistant corundum balls.
- Investigations of the performance in technical applications.
| Grade of grinding balls | Wear rate* [%/h] |
| New product from IKTS | 0.025 |
| commercial 85% Al2O3 | 0.09 |
| commercial ZrO2(TZ-3Y) | 0.02 |
* Wear of new sub-µm alumina grinding balls in an attrition mill (water, 1000 rev/min) in comparison with commercial grades.