are so-called agglomerate-free products. Agglomerates that are present after the calcination process are broken up using a special process, so that the precision aluminum oxides of the SEPP series are extremely fineness and a carefully controlled, narrow grain size distribution.

Technical Data

SEPP 1.0 SEPP 0.3 SEPP 0.05
Crystal shape hexagonal hexagonal kubisch
Crystal structure Alpha Alpha Gamma
Hardness (acc. Mohs) 9 9 8
pH (in distilled water) 7 - 8 7 - 8 7 - 8
Particle size distribution (sedigraph)
d20 (μ) 0,35 0,2 0,1
d50 (μ) 0,6 0,4 0,3
d90 (μ) 1,4 1 0,8

Chemical Structure

SEPP polishes are available in three different grades of purity whereas our standard product contains 99.98% aluminium oxide. The following impurities can occur:

element Share in ppm element Share in ppm
Fe 2 K 22
Na 13 Ca 3
Si 13 Mg, Ti, Cr, Mn < 1 (each)
Ni, Cu, Zn < 1 (each)

If higher purity is requested please contact us.


Our SEPP Precision Aluminum Oxides are extremely well-suited to polishes that demand the highest quality. The individual particles, a high degree of deagglomeration as well as the special and extremely precisely controlled hardness of the material lead to almost absolute scratch resistance of the surface. Below are a few key areas where our SEPP Precision Aluminum Oxides are used:

  • Infrared optics, silicon, germanium, cadmium sulfide
  • Single crystal materials
  • Fiber optics
  • Soft Materials, Aluminum, Lead, Copper
  • Hardmetal Alloys
  • Cast Iron
  • Alloys
  • ferrite
  • Precision Ball Bearing


1 kg container
5 kg container