Grain-Oriented Steel Coating Adhesion and Iron Loss
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Solution Overview
Problem
Grain oriented electrical steel sheets face challenges with high-cost ceramic coatings that are difficult to form and result in low productivity due to hardness, leading to poor adhesion and increased iron loss, especially when subjected to annealing.
Innovation Solution
A ceramic coating with a nitride and oxide structure, where the nitride contains elements like Cr, Ti, and Zr, and the oxide has a corundum type crystal structure, is applied to the steel sheet, along with an insulation tension oxide coating to enhance adhesion and tension imparting properties, using methods like Ark Ion Plating and sputtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a ceramic coating is formed to reduce iron loss, then magnetic properties are improved, but coating adhesion deteriorates during annealing
Solution Approach 1:
The patent applies a composite coating structure consisting of a ceramic coating layer (containing Cr, Ti, or Zr) combined with an insulation tension oxide coating layer. This composite structure allows the ceramic layer to reduce iron loss while the oxide layer maintains adhesion during annealing, resolving the contradiction between magnetic property improvement and coating reliability.
Solution Approach 2:
The patent optimizes the thickness of the ceramic coating to 0.01-0.30 μm and controls the Young's modulus to be 230 GPa or more. By changing these parameters, the coating achieves sufficient tension imparting effect for iron loss reduction while maintaining adhesion properties during thermal processing.
2Loss of energy
If a thick ceramic coating is applied to ensure sufficient tension imparting effect, then iron loss is reduced, but coating formation cost increases
Solution Approach 1:
The patent sets the ceramic coating thickness to 0.01-0.30 μm and Young's modulus to 230 GPa or more, optimizing these parameters to achieve the minimum necessary material quantity for sufficient tension imparting effect while minimizing cost.
Solution Approach 2:
The composite structure with insulation tension oxide coating allows the ceramic layer to be thinner while still achieving the required tension imparting effect, thereby reducing material quantity and cost.
3Loss of energy
If a thick ceramic coating is applied to ensure sufficient tension imparting effect, then iron loss is reduced, but productivity decreases due to severe shearing machine wear
Solution Approach 1:
By controlling the ceramic coating thickness to 0.01-0.30 μm, the patent reduces the coating thickness to a level that minimizes wear on shearing machine blades while maintaining sufficient tension imparting effect for iron loss reduction.
Solution Approach 2:
The composite coating structure with insulation tension oxide layer provides adequate functional performance with reduced ceramic material, thereby decreasing the adverse impact on shearing machine productivity.
4Loss of energy
If a phosphate-based high tension coating is formed on a smoothed steel sheet, then hysteresis loss is reduced, but coating adhesion deteriorates due to thermal expansion mismatch
Solution Approach 1:
The patent uses a composite structure where the ceramic coating layer (with different thermal expansion properties) is combined with an insulation tension oxide coating layer. This composite design mitigates the thermal expansion mismatch issue, allowing the coating to maintain adhesion during annealing while still reducing hysteresis loss.
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 achieves excellent coating adhesion and magnetic properties, reducing iron loss and improving workability by maintaining tension imparting effects even after annealing, while minimizing the thickness and cost of the ceramic coating.
Implementation Method 1
it has been disclosed that methods such as PVD (Physical Vapor Deposition) methods or CVD (Chemical Vapor Deposition) methods are applicable... when a tensile stress is applied to a steel sheet, eddy current loss can be reduced
Implementation Method 2
using methods like Ark Ion Plating and sputtering
Implementation Method 3
using methods like Ark Ion Plating and sputtering
Implementation Method 4
excellent coating adhesion and magnetic properties, reducing iron loss and improving workability by maintaining tension imparting effects even after annealing
Data Source
AI summary
Provided are: a grain-oriented electromagnetic steel sheet exhibiting excellent coating film adhesion and excellent magnetic characteristics; and a method for producing this grain-oriented electromagnetic steel sheet. This grain-oriented electromagnetic steel sheet is provided with a ceramic coating film arranged on a steel sheet, and an oxide insulating tension coating film arranged on the ceramic coating film. The ceramic coating film contains a nitride and an oxide; the nitride contains at least one element selected from the group consisting of Cr, Ti, Zr, Mo, Nb, Si, Al, Ta, Hf, W and Y; and the oxide has a corundum crystal structure. The Young's modulus of the ceramic coating film as determined by a nanoindentation method is 230 GPa or more; the average film thickness of the ceramic coating film is from 0.01 μm to 0.30 μm (inclusive); and the tension of the oxide insulating tension coating film is 10 MPa or more.