Oxides
A wide selection, even water-free
For final polishing of certain materials, especially for metals, silica suspensions have replaced alumina suspensions. This is mainly due to the chemical-mechanical material removal that results in nearly deformation free surfaces.
We offer a wide selection of silica suspensions manufactured for different requirements and for polishing different materials.
- Various grain structures
- Acidic and basic reacting suspensions with pH ranging from 3.5 to 10
- Grain size distribution from 0.2 µm to 0.050 µm (120 to 50 nm)
- Unique system to prevent crystal formation
- Water-free suspensions
Silica suspensions were originally developed to polish silicon wafers. The action is chemical-mechanical. The sample surface is etched, and the resulting layer is removed by means of the soft silica leaving the surface almost without deformation.
As in wafer polishing, this is best achieved by adding an oxidation agent to the suspension just before application. Hydrogen peroxide or acids/bases combined with a salt are frequently used.
The etching agent applied is often the same as that used for etching of the finished specimen. The oxidation or etching agent must be added just before application, since it may otherwise cause changes such as flocculation or coagulation in the silica suspension.
On to grain structure