Electrical steel sheet with a layer improving the electrical insulation and method for the production thereof

Abstract

The invention relates to an electrical steel sheet (11) with a layer (14) improving the electrical insulation. According to the invention, this layer is formed from tantalum oxide or titanium oxide, wherein a diffusion zone (15) that is enriched with tantalum or titanium adjoins toward the interior of the electrical steel sheet (11). This has the advantage that the layer adheres better on the electrical steel sheet (11). Furthermore, the tantalum or titanium of the diffusion zone (15) can also be used as a depot, which has the effect of spontaneously passivating impairments of the layer (14). Therefore, corrosion protection is ensured even when there are impairments of said layer (14). The invention also relates to a method for producing an electrical steel sheet in the way described.

Description

technical field [0001] The invention relates to an electrical steel sheet with a layer for improved electrical insulation. Background technique [0002] According to the prior art, such electrical steel sheets are used for electric drives, for example, in the manufacture of stators. The materials used are regulated by the standard EN10106 (since 1995). The materials mentioned in this standard result in a wide variety of product ranges, whereby the requirements of different applications can be met. The materials that can be used range from low-alloy steels with excellent magnetic permeability, good thermal conductivity and stampability to high-alloy steels with very low remagnetization losses also at higher frequencies. The standard alloy contains copper (<=0.02%), manganese (<=1.2%), silicon (0.1-4.4%), aluminum (0.1-4.4%), phosphorus (<=0.15%), zinc (<=0.2 %) and antimony (<=0.2%) as alloy components in which the sum of the silicon content and twice the al...

AI Technical Summary

Problems solved by technology

[0004] However, as shown, the electrical steel sheets and their coatings available in the above standards are not suitable for all fields of use

In particular, electrical steel sheets are at risk of being strongly corroded when they are exposed to strongly corrosive media such as sour gas (high hydrogen sulfide content)

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