Silane-Coated Dust Core Surface for Low-Temperature Corrosion Resistance
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Solution Overview
Problem
Current dust cores used in motors and coil devices face challenges in corrosion resistance, particularly when chromium is required, as it narrows material selection, and existing coatings like phosphate have low toughness or require high-temperature processing that can damage insulated copper wires.
Innovation Solution
A dust core comprising a metal magnetic material and resin with fine Si—O based particles attached to its surface, which enhances corrosion resistance through nano-scale unevenness and improved water repellency, using a manufacturing process involving alkoxysilane solutions and controlled firing conditions to bond the particles to the metal magnetic material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Cr is contained as a metal magnetic material to improve corrosion resistance, then corrosion resistance is improved, but the range of material selection is narrowed
Solution Approach 1:
The patent introduces a silane-based coating layer as an intermediary substance between the metal magnetic material and the corrosive environment. This coating layer, formed by applying a silane solution and heating, provides corrosion resistance without requiring chromium in the base metal magnetic material, thus maintaining material selection flexibility while achieving the desired protective function
Solution Approach 2:
The patent creates a composite structure consisting of the metal magnetic material core and a silane-based coating layer. This composite approach allows the base material to maintain its magnetic properties and selection flexibility, while the coating layer provides the corrosion resistance function, effectively separating the functional requirements
2Reliability
If phosphate coating is applied to improve corrosion resistance, then corrosion resistance is improved, but the coating film may be broken when molding pressure is increased due to low toughness
Solution Approach 1:
The patent changes the chemical composition and physical properties of the coating material from phosphate-based to silane-based. The silane coating exhibits different mechanical properties, specifically higher toughness and flexibility, which allows it to withstand molding pressures without breaking while still providing effective corrosion resistance
3Reliability
If ceramics and resin coating is applied to improve corrosion resistance, then corrosion resistance is improved, but the dust core must be heated at high temperature of 800° C. or more which may break the insulation of insulated copper wire
Solution Approach 1:
The patent modifies the curing temperature parameter from high temperature (800°C or more) to a lower temperature range (50-200°C). The silane-based coating system is designed to achieve proper cross-linking and protective properties at these reduced temperatures, thereby preventing damage to insulated copper wire while still providing effective corrosion resistance
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 significantly improves corrosion resistance, as demonstrated by reduced rust area ratios in saltwater spray tests, with optimal results achieved when fine particles have average sizes between 1.0 to 200 nm and standard deviations of 30 nm or less, maintaining high saturation magnetization and permeability.
Implementation Method 1
fine particles exist on a surface of the dust core... excellent in corrosion resistance... improved water repellency
Implementation Method 2
an oxide film comprising a Si—O based oxide exists on a surface of the metal magnetic material
Implementation Method 3
manufacturing process involving alkoxysilane solutions and controlled firing conditions to bond the particles
Data Source
AI summary
A dust core includes a metal magnetic material and a resin. Fine particles exist on a surface of the dust core.