Electrical Steel Sheet Oxide Layer for Coating Adhesion and Low Iron Loss
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Solution Overview
Problem
Grain oriented electrical steel sheets without a glass film face challenges in achieving stable adhesion of tension-insulation coatings, leading to fluctuating iron loss characteristics and poor magnetic performance.
Innovation Solution
A grain oriented electrical steel sheet comprising a base steel sheet with a specific chemical composition and a phosphate-silica mixed tension-insulation coating, where the coating is applied to an oxide layer formed through a process involving washing, pickling, and heat treatment, ensuring excellent adhesion and controlled layering structure to improve magnetic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a glass film is formed on the steel sheet surface through final annealing, then the adhesion of the tension-insulation coating is improved, but the magnetic characteristics deteriorate due to the non-magnetic nature of the glass film and intruding structure formation
Solution Approach 1:
The invention removes the glass film (forsterite film) from the steel sheet surface by suppressing its formation during final annealing. This extraction eliminates the harmful non-magnetic layer that causes intruding structure formation and deteriorates magnetic characteristics, while the patent subsequently applies alternative treatments to maintain coating adhesion.
Solution Approach 2:
The invention introduces an oxide layer as an intermediary between the steel sheet surface and the tension-insulation coating. This oxide layer, formed through controlled oxidation treatment, serves as a bonding interface that maintains coating adhesion without the harmful effects of the glass film, such as intruding structure formation.
2Object-generated harmful factors
If the glass film formation is suppressed to improve magnetic characteristics, then the domain wall motion is facilitated, but the coating adhesion is not ensured and tension imparting is insufficient
Solution Approach 1:
The invention introduces an oxide layer as an intermediary between the steel sheet surface and the tension-insulation coating. This oxide layer, formed through controlled oxidation treatment, serves as a bonding interface that maintains coating adhesion without the harmful effects of the glass film, such as intruding structure formation.
Solution Approach 2:
The invention changes the chemical composition and structure of the surface layer by controlling oxidation conditions. Instead of forming a glass film through MgO-SiO2 reaction, the patent creates an oxide layer with specific composition (Fe, Cr, Si oxides) that provides both adhesion and magnetic compatibility.
3Device complexity
If a phosphate-silica mixed coating is applied without a glass film, then the coating structure is simplified, but the adhesion stability is poor leading to fluctuating iron loss characteristics
Solution Approach 1:
The invention introduces an oxide layer as an intermediary between the steel sheet surface and the tension-insulation coating. This oxide layer, formed through controlled oxidation treatment, serves as a bonding interface that maintains coating adhesion without the harmful effects of the glass film, such as intruding structure formation.
Solution Approach 2:
The invention creates a composite structure consisting of the steel sheet, oxide layer, and phosphate-silica mixed coating. This multi-layer composite provides both simplified structure and stable adhesion, with each layer contributing specific properties: the steel sheet provides magnetic characteristics, the oxide layer provides bonding interface, and the coating provides tension and insulation.
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 enhanced adhesion of the tension-insulation coating, stable iron loss reduction, and improved magnetic performance by suppressing the formation of intruding structures and ensuring sufficient tension is imparted to the base steel sheet.
Implementation Method 1
an oxide layer arranged in contact with the base steel sheet
Implementation Method 2
a solution for forming a phosphate-silica mixed tension-insulation coating is applied to an oxide layer of the steel substrate and the solution is baked so as to form the tension-insulation coating
Data Source
AI summary
A grain oriented electrical steel sheet includes a base steel sheet, an oxide layer, and a tension-insulation coating. When a glow discharge spectroscopy is conducted in a region from a surface of the tension-insulation coating to an inside of the base steel sheet, a sputtering time Fe0.5 at which a Fe emission intensity becomes 0.5 times as compared with a saturation value thereof and a sputtering time Fe0.05 at which a Fe emission intensity becomes 0.05 times as compared with the saturation value satisfy (Fe0.5−Fe0.05)/Fe0.5≥0.35. A maximal point of a Cr emission intensity is included between the Fe0.05 and the Fesat. Moreover, a magnetic flux density B8 in a rolling direction of the grain oriented electrical steel sheet is 1.90 T or more.