Sodium Silicate Coating for Magnetic Powder Core Loss Reduction

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Solution Overview

Problem

Conventional magnetic powder cores coated with phosphoric acid and organic adhesives suffer from uneven coating, high energy losses, poor DC bias performance, and poor weatherability, especially under high frequency conditions and varying environmental conditions.

Innovation Solution

A method for coating magnetic powder cores with sodium silicate, involving pretreatment of sodium silicate and metal magnetic powder, followed by uniform mixing and baking, and finally adding inorganic insulating adhesives and lubricants for improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If phosphoric acid and organic adhesives are used for coating magnetic powder cores, then the coating process is simple, but the coating is uneven and energy losses are high

Engineering Contradiction:

Improvecoating process simplicityVSAvoidenergy loss

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent changes the chemical composition parameters of the coating material from phosphoric acid and organic adhesives to sodium silicate-based inorganic coating material. This parameter change achieves uniform coating distribution on magnetic powder particles while reducing energy losses by at least 15%, resolving the contradiction between manufacturing simplicity and energy efficiency.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite inorganic coating materials consisting of sodium silicate as the base material, combined with specific additives to form a multi-component coating system. This composite approach ensures uniform coating coverage and improves magnetic core performance, reducing energy losses while maintaining coating effectiveness.

Inventive Principle:

Principle #40Composite materials

2Reliability

If organic adhesives are added for coating, then the coating has good initial adhesion, but the adhesive ages easily and weatherability is poor

Engineering Contradiction:

Improveadhesive performanceVSAvoidweatherability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent replaces expensive organic adhesives with inorganic sodium silicate-based coating materials that do not suffer from aging. Although inorganic materials may have different initial adhesion characteristics, they provide long-term durability and weather resistance, effectively resolving the contradiction between initial adhesion and long-term weatherability.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent fundamentally changes the material parameter from organic to inorganic coating composition. Sodium silicate and its derivatives provide inherent resistance to aging and environmental degradation, maintaining coating integrity and magnetic core performance under varying weather conditions over extended periods.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional coating materials are used, then the coating process is straightforward, but DC bias performance is poor

Engineering Contradiction:

Improvecoating process simplicityVSAvoidDC bias performance

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the chemical composition parameter to sodium silicate-based inorganic materials, which provide superior electrical insulation properties compared to conventional organic coatings. This parameter change directly improves DC bias performance by at least 2% while maintaining a relatively simple coating process, resolving the contradiction between manufacturing simplicity and performance precision.

Inventive Principle:

Principle #35Parameter changes

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 method achieves a reduction in magnetic core losses by at least 15% and improves DC bias performance by at least 2%, while enhancing weatherability and reducing costs compared to conventional organic-based coatings.

Implementation Method 1

adding the sodium silicate solution obtained in step 1 to the metal magnetic powder obtained in step 2, and stirring for 10-30 minutes

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

baking the powder obtained in step 3 at a temperature 120-150° C. for 60-120 minutes to obtain a coated powder

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

keeping the magnetic powder core molded in step 6 under the protection of a N2 or H2 atmosphere at a temperature of 600-800° C. for 30-90 minutes to obtain a sodium silicate coated magnetic powder core

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentUS12283415B2Method for coating magnetic powder core with sodium silicate

Publication Date: 2025.04.22 JIANGXI EVERTECH NEW MATERIAL CO LTD

AI summary

The present disclosure discloses a method for coating a magnetic powder core with sodium silicate, including: using polyoxyethylene laurylether phosphate as a dispersant for sodium silicate and lignosulfonate as a dispersant for a metal magnetic powder, mixing a dispersed sodium silicate solution and a dispersed metal magnetic powder, coating the dispersed metal magnetic powder, and drying: adding an insulating adhesive and a lubricant, subjecting the resulting mixture to a compression molding, and finally, carrying out a high-temperature annealing treatment to obtain a sodium silicate coated magnetic powder core.