In paints and coatings, white corundum increases the scratch and abrasion resistance of the often sensitive surfaces. White corundum is ultra-high temperature aluminium oxide, which has a Mohs hardness of 9, which is close to a diamond hardness of 10. There are few industrially suitable and yet affordable abrasive materials that are so hard and enable this high scratch resistance. Precious corundum is modified by organic surface treatment so that it is better embedded and anchored in the binder or coating agent. In order to make corundum more compatible with different binders, i.e. to optimize its embedding and anchoring, Wester Mineralien, a refiner of white corundum, works with customers to determine the suitable organic agent for surface modification and tests its effectiveness. Coating systems into which corundum can be easily incorporated are - due to their 100 percent solvent-free composition and rapid applicability - UV coatings. Precious corundum is white, very pure with over 99 percent Al2O3, absolutely inert, non-flammable and melts at 2040 °C. Its refractive index matches that of lacquers well. Its hardness (Mohs 9) is among the highest for a mineral product, which is industrially affordable and sensible. This profile determines its numerous application possibilities. A special variant are the flake corundums, especially PLK 800, which are much gentler on the processing machines due to their geometry (aspect ratio 1:4) and smoother structure and have a high transparency.
Wester Mineralien is specialized in the refinement of untreated white corundum. Grain sizes from very coarse (1 mm) to very fine (1 μm) can be supplied and rounded as well as organically treated particles can be tailor-made. They are classified according to the FEPA classification (Fédération Européenne des Fabricants de Produits Abrasifs) into macro and micro particle size distributions.