Grain-Oriented Steel Insulating Coating with Etch Pit Adhesion Layer
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Solution Overview
Problem
Existing methods for manufacturing grain-oriented electrical steel sheets without inorganic coatings face challenges such as high treatment costs, inferior workability, and difficulties in securing sufficient adhesion and tension for insulating coatings, which affect magnetic characteristics and iron loss performance.
Innovation Solution
A grain-oriented electrical steel sheet with an etch pit structure and an intermediate layer of crystalline metal phosphate between the base steel sheet and a tension coating layer, where the intermediate layer contains metal phosphate and silica, enhancing coating adhesion, tension, and magnetic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a forsterite-based coating is applied to reduce iron loss, then coating adhesion is improved, but magnetic domain wall movement is hindered and iron loss increases
Solution Approach 1:
An intermediate layer comprising metal phosphate and silica is introduced between the base steel sheet and the tension coating layer. This intermediate layer acts as a mediator that provides sufficient adhesion for the tension coating while preventing the coating from directly contacting and hindering the magnetic domain wall movement on the steel sheet surface, thereby resolving the contradiction between coating adhesion and iron loss reduction.
2Loss of energy
If an inorganic coating is removed to improve magnetic characteristics, then iron loss is reduced, but coating adhesion and tension are insufficient
Solution Approach 1:
The intermediate layer comprising metal phosphate and silica serves as an intermediary that enables the tension coating layer to adhere sufficiently to the steel sheet without requiring a forsterite-based coating. This allows the steel sheet surface to remain free for optimal magnetic domain wall movement while providing the necessary adhesion through the intermediate layer.
Solution Approach 2:
The insulating coating is designed as a composite structure with an intermediate layer (metal phosphate and silica) and a tension coating layer. This composite material approach allows each layer to perform its specific function: the intermediate layer provides adhesion and the tension coating layer provides tension, achieving both requirements without using forsterite-based coating.
3Shape
If pickling and chemical polishing are performed to remove surface formations, then a mirror surface state is achieved, but treatment cost increases
Solution Approach 1:
Instead of using expensive and time-consuming pickling and chemical polishing processes to create a mirror surface, the invention uses a more economical approach by forming an intermediate layer comprising metal phosphate and silica. This intermediate layer can be applied through simpler processes and provides the necessary surface properties for coating adhesion without requiring a perfect mirror finish, thereby reducing treatment costs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution achieves excellent coating adhesion, tension, and magnetic characteristics while avoiding the drawbacks of forsterite-based coatings, improving iron loss performance and manufacturing efficiency.
Implementation Method 1
an intermediate layer which is formed on a base steel sheet side and comprises a crystalline metal phosphate... excellent coating adhesion
Implementation Method 2
the surface of the base steel sheet has an etch pit structure... excellent coating adhesion, tension, and magnetic characteristics
Implementation Method 3
a tension coating layer which is formed on a surface side of the insulating coating... excellent coating adhesion, tension, and magnetic characteristics
Data Source
AI summary
This grain-oriented electrical steel sheet includes: a base steel sheet; and an insulating coating formed on a surface of the base steel sheet, in which the insulating coating includes an intermediate layer formed on a base steel sheet side and containing a crystalline metal phosphate, and a tension coating layer formed on a surface side of the insulating coating, the surface of the base steel sheet has an etch pit structure, an average thickness of the intermediate layer is 0.2 to 10.0 μm, an average thickness of the insulating coating is 2.0 to 10.0 μm, the tension coating layer contains a metal phosphate and silica, and an amount of the silica in the tension coating layer is 20 to 60 mass %.