Electrical Steel Insulating Coating With Smooth Phosphate Interface
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Solution Overview
Problem
Conventional grain-oriented electrical steel sheets face challenges in maintaining excellent adhesion with tension coatings while preserving magnetic characteristics, as the formation of intermediate layers containing metal phosphates can lead to uneven structures that suppress magnetic flux flow and reduce the space factor of transformers.
Innovation Solution
A grain-oriented electrical steel sheet with an intermediate layer containing crystalline metal phosphate, formed using a specific chemical treatment solution with controlled ratios of metal ion, phosphate ion, and nitrate ion, ensures smooth interfaces and maintains adhesion with a tension coating, thereby enhancing magnetic characteristics without reducing the space factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an intermediate layer containing metal phosphate is formed to improve adhesion with tension coating, then coating adhesion is improved, but the interface becomes uneven which suppresses magnetic flux flow and deteriorates magnetic characteristics
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentrations of metal ions (1.0-10.0 g/L), phosphate ions (2.0-25.0 g/L), and nitrate ions (2.0-40.0 g/L) in the treatment liquid, along with temperature (20-85°C) and immersion time (5-150 seconds). These parameter optimizations enable the formation of an intermediate layer with controlled thickness and uniform interface, achieving both good coating adhesion and smooth magnetic flux flow paths
Solution Approach 2:
The intermediate layer itself acts as an intermediary between the base steel sheet and the tension coating. By controlling its formation through specific treatment liquid composition, the layer provides adequate adhesion functionality while maintaining a smooth interface that does not hinder magnetic flux flow, thus mediating between the conflicting requirements of adhesion and magnetic performance
2Reliability
If the interface between base steel sheet and intermediate layer is made smooth to improve magnetic characteristics, then magnetic flux flow is improved, but coating adhesion may be reduced
Solution Approach 1:
The patent resolves this contradiction through parameter changes by optimizing the treatment liquid composition and processing conditions. The specific concentration ranges of metal ions, phosphate ions, and nitrate ions, combined with controlled temperature and time parameters, produce an intermediate layer that forms a smooth interface for magnetic flux flow while simultaneously providing sufficient adhesion strength for the tension coating
3Ease of manufacture
If conventional treatment liquid composition is used to simplify manufacturing, then manufacturing process is simplified, but adhesion and magnetic characteristics cannot be simultaneously optimized
Solution Approach 1:
The patent applies parameter changes by establishing specific concentration ranges for metal ions (1.0-10.0 g/L), phosphate ions (2.0-25.0 g/L), and nitrate ions (2.0-40.0 g/L) in the treatment liquid. These parameter specifications provide clear manufacturing guidelines that balance process simplicity with the ability to simultaneously achieve good coating adhesion and magnetic characteristics through controlled intermediate layer formation
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 solution provides a grain-oriented electrical steel sheet with improved adhesion and magnetic properties, ensuring effective tension coating application without compromising the transformer's space factor.
Implementation Method 1
a treatment liquid containing a metal phosphate, an oxidizing agent, and an iron ion... an intermediate layer that is formed on a side of the base steel sheet and contains a crystalline metal phosphate
Implementation Method 2
the ratio of an interface length L to an width W of analyzing image is 100.0 to 120.0%
Implementation Method 3
a treatment liquid containing a metal phosphate, an oxidizing agent, and an iron ion
Implementation Method 4
a tension coating layer forming step of applying a coating liquid containing a metal phosphate and colloidal silica... drying the steel sheet, and then holding the steel sheet at a sheet temperature of 700 to 950°C for 10 to 120 seconds
Data Source
Figure 1~2
AI summary
The 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 that is formed on a side of the base steel sheet and contains a crystalline metal phosphate; and a tension coating layer formed on a surface side of the insulating coating, and when an interface between the base steel sheet and the intermediate layer is observed with a scanning electron microscope at a magnification of 5000 in a cross section along a thickness direction of the intermediate layer, the ratio of an interface length L to a width W of analyzing image is 100.0 to 120.0%.