When functionalising fused alumina, a very thin layer of a silane adsorption group is applied to the fused alumina particles. This organic surface coating has the effect of better embedding and increased scratch resistance in a melamine resin matrix, for example. Fused alumina has a high refractive index (n = 1.76). “Greying” would occur in transparent coatings, such as varnishes and melamine resin, without additional coating. The coating adjusts the refractive index to that of the varnish, thereby improving the latter’s transparency.
What is the grit type?
Grit type is either aluminum oxide (white, pink, ruby red, brown, grey, etc.) silicon carbide (black or green), ceramic (blue and pink) or any combination of these. Grit types are sometimes mixed in combination for achieving certain cutting characteristics.