Abstract: The adhesion of insulation coating is an important index to measure the surface quality and applicability of grain oriented silicon steel, and low adhesion will reduce the qualified rate and applicability of products. In this paper, the typical phase and structure characteristics of the surface layer were examined by SEM and EDS, and the influencing factors of insulation coating adhesion was analyzed to provide theoretical basis for improving the adhesion. The results showed that the adhesion level is corelated with the structure of glass layer, and the surface layer of high adhesion samples is mainly composed of continuous layer structure (insulating layer and glass layer) with a total thickness of about 3 μm and spinel particles of 0.5~4 μm.Besides, the glass layer with continuous and uniformly distribution in the matrix and fine embedded spinel particles can improve the adhesion.

Key words: grain oriented silicon steel, adhesion, glass layer, insulating layer, spinel particles