Annealing Separator Composition for Grain-Oriented Steel Coating Adhesion
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Solution Overview
Problem
Existing grain-oriented electrical steel sheets face challenges in maintaining excellent magnetic properties, adhesion of the primary coating, and rust resistance, particularly when using annealing separators with rare earth element compounds.
Innovation Solution
The grain-oriented electrical steel sheet is manufactured using a base metal steel sheet with a specific chemical composition and a primary coating containing Mg2SiO4, where the annealing separator includes MgO, Y, La, Ce, Ti, Zr, Hf, Ca, Sr, and Ba compounds, optimized in terms of content and particle size to achieve desired coating characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elements improving magnetic properties (Sn, Sb, Bi, Te, Pb, Se) are added to strengthen inhibitor action and raise magnetic flux density, then magnetic flux density is improved, but parts of the primary coating aggregate and the interface between steel sheet and primary coating becomes flattened, causing adhesion of primary coating to deteriorate
Solution Approach 1:
The patent introduces an annealing separator containing rare earth element compounds (Y, La, Ce) as an intermediary substance between the steel sheet and the primary coating. This separator prevents direct harmful interaction between magnetic property improvement elements and the primary coating, allowing both magnetic flux density enhancement and coating adhesion to be maintained simultaneously
Solution Approach 2:
The patent changes the chemical composition parameters of the annealing separator by specifying precise content ranges of rare earth element compounds (Y: 0.01-5.0 wt%, La: 0.01-5.0 wt%, Ce: 0.01-5.0 wt%). These parameter adjustments optimize the separator's ability to prevent coating aggregation while maintaining magnetic properties
2Manufacturing precision
If annealing separator contains rare earth element compounds (Y, La, Ce) to improve coating characteristics, then adhesion of primary coating is improved, but magnetic properties may deteriorate
Solution Approach 1:
The patent precisely controls the content parameters of rare earth element compounds in the annealing separator (Y: 0.01-5.0 wt%, La: 0.01-5.0 wt%, Ce: 0.01-5.0 wt%) to optimize both coating adhesion and magnetic properties, preventing deterioration of either characteristic
Solution Approach 2:
The annealing separator is designed as a composite material containing multiple rare earth element compounds (Y, La, Ce) combined with MgO and other oxides. This composite structure synergistically improves coating adhesion while maintaining magnetic properties through the combined effects of different rare earth elements
3Manufacturing precision
If annealing separator composition is optimized for coating adhesion, then adhesion of primary coating is improved, but rust resistance may be compromised
Solution Approach 1:
The annealing separator is formulated as a composite material containing rare earth element compounds (Y, La, Ce), MgO, and other metal oxides in specific proportions. This composite structure simultaneously achieves high coating adhesion through rare earth elements and superior rust resistance through the protective barrier formed by the composite coating system
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
This approach results in grain-oriented electrical steel sheets with improved magnetic properties, enhanced adhesion of the primary coating, and superior rust resistance, while also optimizing the manufacturing process.
Implementation Method 1
the MgO in the annealing separator and the SiO2 in the internal oxide layer formed on the surface of the cold rolled steel sheet at the time of decarburization annealing react whereby a primary coating having forsterite (Mg2 SiO4) as a main constituent is formed on the surface
Implementation Method 2
a peak position of Al emission intensity obtained when performing elemental analysis by glow discharge optical emission spectrometry from a surface of the primary coating in a thickness direction
Data Source
AI summary
An annealing separator used for manufacture of the grain-oriented electrical steel sheet according to the present invention contains MgO, at least one or more types of compounds of metal selected from a group comprised of Y, La, and Ce, at least one or more types of compounds of metal selected from a group comprised of Ti, Zr, and Hf, and at least one or more types of compounds of metal selected from a group comprised of Ca, Sr, and Ba, when a content of the MgO in the annealing separator is defined as 100% by mass %, a total content of the compounds selected from a group comprised of Y, La, and Ce converted to oxides is 0.8 to 8.0%, a total content of the compounds of metal selected from a group comprised of Ti, Zr, and Hf converted to oxides is 0.5 to 9.0%, and a total content of the compounds of metal selected from a group comprised of Ca, Sr, and Ba converted to sulfates is 0.5 to 8.0%, a mean particle size of the compounds of metal selected from a group comprised of Ca, Sr, and Ba is 12 μm or less, a ratio of the mean particle size of the compounds of metal selected from a group comprised of Ca, Sr, and Ba to the mean particle size of the compounds of metal selected from a group comprised of Y, La, and Ce is 0.1 to 3.0, a total of the total content of the compounds of metal selected from a group comprised of Y, La, and Ce converted to oxides and the total content of the compounds of metal selected from a group comprised of Ti, Zr, and Hf converted to oxides is 2.0 to 12.5%, a ratio of a sum of the numbers of Y, La, and Ce atoms to a sum of the numbers of Ti, Zr, and Hf atoms contained in the annealing separator is 0.18 to 4.0, still further a number density of particles of the compounds of metal selected from the group comprised of Y, La, and Ce which are particles of a spherical equivalent diameter based on volume of 0.1 μm or more is 2,000,000,000/g or more, still further a number density of particles of the compounds of metal selected from the group comprised of Ti, Zr, and Hf which are particles of a spherical equivalent diameter based on volume of 0.1 μm or more is 2,000,000,000/g or more, and still further a number density of particles of the compounds of metal selected from the group comprised of Ca, Sr, and Ba which are particles of a spherical equivalent diameter based on volume of 0.1 μm or more is 2,000,000,000/g or more.