Insulating Coating Processing Liquid for Grain Oriented Electrical Steel
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Solution Overview
Problem
Existing insulating coatings for grain oriented electrical steel sheets, particularly those containing phosphates and colloidal silica, often fail to provide sufficient iron loss reduction and basic physical properties such as adhesion and insulation when applied to metals with or without forsterite coatings.
Innovation Solution
A treatment solution comprising a phosphate and two or more types of colloidal silicas with different mean particle diameters, applied at specific ratios and concentrations, is used to form an insulating coating on metal surfaces, which is then baked at high temperatures to achieve improved physical properties like tension, iron loss reduction, and water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a phosphate and one type of colloidal silica are used to form an insulating coating, then the coating can be formed on the steel sheet surface, but the iron loss reducing effect is insufficient
Solution Approach 1:
The patent uses a composite coating system consisting of a phosphate base coat and a silicate top coat containing multiple types of colloidal silicas with different particle diameters. This composite structure combines the advantages of both material systems to achieve both adhesion and iron loss reduction properties that single-material coatings cannot provide
Solution Approach 2:
The patent applies different types of colloidal silicas with specific particle diameter ranges (first type: 5-20 nm, second type: 20-50 nm, third type: 50-150 nm) in specific proportions to the top coat. This creates local quality variations in the coating structure that optimize both the adhesion to the phosphate base coat and the tension exerted on the steel sheet for iron loss reduction
2Loss of energy
If the insulating coating is formed to exert tension on the steel sheet, then iron loss reduction is achieved, but the adhesion property may be compromised
Solution Approach 1:
The two-layer composite structure with phosphate base coat and multi-component silicate top coat allows the base coat to provide strong adhesion to the steel sheet while the top coat provides the tension-exerting function for iron loss reduction. The layered composite design separates the adhesion function from the iron loss reduction function, allowing each layer to optimize its specific role without compromising the other
Solution Approach 2:
The patent carefully controls the particle diameter parameters of the colloidal silicas used in the top coat, specifying three distinct size ranges (5-20 nm, 20-50 nm, 50-150 nm) with specific proportion requirements. This parameter optimization ensures the top coat can exert sufficient tension on the steel sheet while maintaining compatibility with the phosphate base coat for good adhesion
3Device complexity
If a single type of colloidal silica is used in the treatment solution, then the formulation is simple, but the physical properties of the insulating coating are insufficient
Solution Approach 1:
The patent formulates the top coat as a composite material containing three distinct types of colloidal silicas with different particle diameters in specific proportions. This multi-component composite formulation achieves optimal physical properties including adhesion, insulation, and iron loss reduction that cannot be obtained with single-type colloidal silica, while the total content is controlled at 10-30 mass% to maintain formulation manageability
Solution Approach 2:
The patent specifies particular particle diameter ranges for each type of colloidal silica (first type: 5-20 nm, second type: 20-50 nm, third type: 50-150 nm) and their respective proportions in the top coat. This creates local quality variations within the coating that optimize different functions: smaller particles for adhesion and larger particles for tension exertion, achieving superior overall performance
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 effectively enhances the physical properties of the insulating coating, including increased tension and iron loss reduction on grain oriented electrical steel sheets, and improves adhesion and insulation properties on various metal types, while maintaining excellent water resistance.
Implementation Method 1
forming an insulating coating on a surface of metal
Implementation Method 2
have a low coefficient of thermal expansion, and therefore serve to exert tension to the steel sheet owing to a difference in a coefficient of thermal expansion between the steel sheet and each coating when the temperature drops to room temperature
Data Source
Figure 1
AI summary
Provided is an insulative coating processing liquid with which an insulative coating having excellent physical properties can be obtained. The insulative coating processing liquid contains: at least one phosphate selected from the group consisting of Mg, Ca, Ba, Sr, Zn, Al, and Mn; and two or more types of colloidal silicas having different mean particle diameters, wherein the total contained amount of the colloidal silicas in terms of the SiO2 solid content is 50-120 parts by mass with respect to 100 parts by mass of the solid content of the phosphate, a mean particle diameter ratio expressed as ri+1/ri is not lower than 1.5 when the mean particle diameters of the colloidal silicas are represented as r1, ..., rn in an ascending order, and a mass ratio expressed as wi+1/(wi+1+wi) is 0.30-0.90 when the masses of the colloidal silicas in terms of the SiO2 solid content are represented as w1, ..., wn in an ascending order of the respective mean particle diameters. It should be noted that n represents an integer equal to or larger than 2, and i represents an integer of 1-n.