Messi’s MgO are high purity, micronized electrical steel grades of magnesium oxide that are used in the manufacture of silicon grain-oriented steel for high efficiency distribution transformer cores, specialty ceramics, and coatings.

electrical steel grades of magnesium oxide
In the annealing process, MgO react with the silicon steel to form a glass-like film during the high temperature anneal, which then acts as an electrical insulator between core laminations in an electrical transformer.
Magnesium oxide coating for electrical steels and the method of coating.PDF