Sintered platelet-like randomly shaped abrasive particles and method of making same
The present invention relates to sintered platelet-like randomly shaped abrasive particles based on alpha alumina having a hardness H V of at least 20 GPa and a crystal structure with an average crystal size between 100 nm and 300 nm, whereby the abrasive particles comprise a body having a first surface and a second surface opposite to the first surface, both surfaces are separated from each other by a randomly shaped sidewall having a thickness (T) between 20 μm and 500 μm.
1. Sintered abrasive particles comprising a platelet-like body having a first surface and a second surface opposite to the first surface, wherein
the first and second surfaces are separated by a randomly shaped sidewall having a thickness (T) between 20 μm and 500 μm,
the abrasive particles have a crystal structure with an average crystal size between 100 and 300 nm,
the crystal structure comprises α-alumina crystals and zirconia crystals, the abrasive particles have a chemical composition comprising between 1% and 20% by weight zirconia,
at least 50% by weight of the zirconia is present in the tetragonal modification,
the crystal structure comprises a dominant continuous phase of α-alumina crystals and a secondary phase of intergranular oriented zirconia crystals, and
the crystal size of the zirconia crystals is less than 100 nm.
2. The abrasive particles of claim 1 , wherein the chemical composition additionally comprises between 0.5% and 5% by weight MgO.
3. The abrasive particles of claim 1 , wherein the chemical composition comprises between 1% and 10% by weight zirconia.
4. The abrasive particles of claim 1 , wherein at least 75% by weight of the zirconia is present in the tetragonal modification.
5. The abrasive particles of claim 1 ,
wherein the average crystal size of the alumina and zirconia crystals is below 250 nm.
6. The abrasive particles of claim 1 ,
wherein the abrasive particles have a circularity (C) of more than 0.60.
7. The abrasive particles of claim 1 ,
wherein the abrasive particles have an unevenness factor (UE) between 10 and 17.
8. The abrasive particles of claim 1 ,
wherein the abrasive particles have an average perimeter randomness factor (APRF) of more than 15%.
9. The abrasive particles of claim 1 ,
wherein the randomly shaped sidewall has a thickness (T) between 100 μm and 450 μm.
10. The abrasive particles of claim 1 ,
wherein the abrasive particles have an aspect ratio (AR) between 1.20 and 1.90.
11. The abrasive particles of claim 1 , wherein the abrasive particles have an aspect ratio of less than 1.60.
12. The abrasive particles of claim 1 ,
wherein the abrasive particles have a length-to-thickness ratio ranging from 2 to 10.
13. The abrasive particles of claim 1 , wherein at least one surface is homogeneously structured with structural elements, such as knobs, waves, teeth, saw-teeth, pyramids, cones and/or other indentations or protuberances.