Annealing Separator Composition for Uniform Forsterite Layers
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Solution Overview
Problem
Current annealing separators for grain-oriented magnetic steel production often suffer from issues such as depressed deformation, inadequate performance, and the inability to form uniform, dense forsterite layers, which are crucial for achieving excellent insulation and electromagnetic properties.
Innovation Solution
A method for producing an annealing separator involving the mixing of magnesium oxide and an ammonium salt solution to form a magnesium salt solution and ammonia, followed by high temperature and low temperature ageing of magnesium hydroxide precursors, and subsequent burning to obtain magnesium oxide with controlled properties for use as an annealing separator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If aggregated MgO microparticles are used to reduce water and O2 contents, then water and oxygen content is reduced, but trace amounts of water residue remain which is disadvantageous for high quality grain-oriented magnetic steel production
Solution Approach 1:
The invention changes the particle size parameter of MgO from aggregated microparticles to ultrafine particles with specific surface area of 3000-10000 m²/kg, and controls water content at 5-20 mass%, achieving both low water/oxygen content and high steel quality without water residue issues
Solution Approach 2:
The invention creates local quality differences by controlling the distribution and concentration of MgO particles in the annealing separator coating, ensuring optimal reaction zones for forming uniform forsterite layers while maintaining low water content throughout the structure
2Manufacturing precision
If an annealing separator with high reactivity is used to form forsterite layer, then forsterite layer formation is improved, but depressed deformation occurs on the steel sheet surface
Solution Approach 1:
The invention optimizes the particle size distribution and specific surface area of MgO particles within specific ranges (3000-10000 m²/kg), and controls the coating thickness and composition to achieve balanced reactivity that forms uniform forsterite layers without causing depressed deformation
Solution Approach 2:
The invention uses controlled amounts of MgO with high specific surface area to achieve sufficient reactivity for complete forsterite layer formation without excessive reaction that would cause surface depression, maintaining optimal balance between reaction completeness and surface integrity
3Stability of the object's composition
If the annealing separator has high dispersibility to form uniform coating, then coating uniformity is improved, but bonding strength with steel substrate decreases
Solution Approach 1:
The invention optimizes particle size distribution and surface characteristics of MgO particles to achieve simultaneous improvement in dispersibility for uniform coating and surface properties for strong bonding with steel substrate
Solution Approach 2:
The invention creates a composite structure in the annealing separator coating that combines dispersed MgO particles with binding components, achieving both uniform distribution and strong adhesion to the steel substrate
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 resulting annealing separator has high purity, excellent dispersibility, and strong bonding strength, enabling the formation of uniform, dense forsterite layers on grain-oriented magnetic steel surfaces, thereby enhancing the steel's insulation and electromagnetic properties.
Implementation Method 1
magnesium oxide and an ammonium salt solution are mixed and reacted to prepare a magnesium salt solution and ammonia
Implementation Method 2
one portion of the obtained magnesium hydroxide is subjected to high temperature ageing
Implementation Method 3
another portion of the obtained magnesium hydroxide is subjected to low temperature ageing
Implementation Method 4
the magnesium hydroxides aged under the different conditions are mixed and burned to obtain magnesium oxide
Data Source
AI summary
The invention provides a method of producing an annealing separator, an annealing separator and a grain-oriented magnetic steel. An annealing separator obtained by the method has high purity and excellent dispersibility and bonding strength, thus allowing formation of a uniform, dense forsterite layer on the surface of a grain-oriented magnetic steel. The method of producing an annealing separator comprises the following steps: step (1) in which magnesium oxide and an ammonium salt solution are mixed and reacted to prepare a magnesium salt solution and ammonia, and then the purified magnesium salt solution and the ammonia are reacted to obtain magnesium hydroxide, step (2) in which one portion of the obtained magnesium hydroxide is subjected to high temperature ageing at 155 to 230° C. while another portion of the obtained magnesium hydroxide is subjected to low temperature ageing at 10 to 100° C., and step (3) in which the magnesium hydroxides aged under the different conditions are mixed and burned to obtain magnesium oxide for use as an annealing separator.