Composite Magnetic Core Oxidation Resistance via Sodium Boron Oxide
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Solution Overview
Problem
Conventional composite-type magnetic cores face challenges in achieving high oxidation resistance and compactness due to limitations in resin coating thickness and uneven inductance caused by organic material inconsistencies, which affect their ability to handle large electrical currents.
Innovation Solution
A composite-type magnetic core comprising soft magnetic metal powder and an insulating binder with specific concentrations of sodium oxide and boron oxide, concentrated in an inner layer near the surface, along with a manufacturing method involving molding, hardening, and heat treatment with a solution containing boron and sodium, to enhance oxidation resistance and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the resin coating is increased to improve oxidation resistance, then the oxidation resistance is improved, but the size of the magnetic core increases which reduces compactness
Solution Approach 1:
The patent changes the chemical composition parameters of the binder material, specifically incorporating sodium oxide (1-50 wt%) and boron oxide (1-50 wt%) to form a glass-like coating that provides oxidation resistance without requiring increased coating thickness. This parameter change in material composition allows achieving the same protective function with reduced dimensional impact.
Solution Approach 2:
The patent uses a composite binder material combining organic resin with inorganic components (sodium oxide and boron oxide). This composite formulation creates a glass-like coating structure that integrates both the adhesion benefits of organic materials and the oxidation resistance of inorganic glass, enabling thin-film protection with enhanced performance.
2Manufacturing precision
If masking is used to coat only non-contact surfaces with resin, then the inductance uniformity is improved, but the oxidation resistance of contact surfaces decreases
Solution Approach 1:
The patent makes the binder material itself serve multiple functions simultaneously: it provides electrical insulation, structural binding, and oxidation protection. The glass-like coating formed by sodium oxide and boron oxide delivers oxidation resistance to all surfaces including contact surfaces, eliminating the need for selective masking while maintaining inductance uniformity.
Solution Approach 2:
The patent applies the oxidation-resistant glass-like coating uniformly across all surfaces of the magnetic core particles, including those that will form contact surfaces. This local application of protective quality to previously exposed areas ensures consistent oxidation resistance throughout the assembled core structure without creating inductance variations.
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 oxidation resistance and allows for a more compact design, maintaining magnetic properties while accommodating larger electrical currents, as demonstrated by reduced rust area and improved surface coverage with boron and sodium oxides within specified concentration ranges.
Implementation Method 1
the sodium oxide and the boron oxide concentrated in an inner layer near the surface of the magnetic core
Implementation Method 2
a method of manufacturing a composite-type magnetic core comprises the steps of: molding a mixture of soft magnetic metal powder and an insulating binder; hardening the molded body; contacting the hardened body with a solution containing an inorganic compound including boron and sodium; and heating the body having boron and sodium
Implementation Method 3
an insulating binder having a lower electrical conductivity than such soft magnetic metal powder
Implementation Method 4
In order to give the above-described composite-type magnetic core itself high oxidation-resistant properties, a coating method is employed in which the magnetic core is coated with a resin
Data Source
AI summary
Present inventions relate to a composite-type magnetic core and a method of manufacturing same. The composite-type magnetic core is made of a soft magnetic metal powder and an insulating binder having a lower electrical conductivity than the soft magnetic metal powder. The composite-type magnetic core has 10 parts per million (ppm) or more but 500 ppm or less of sodium oxide and 50 ppm or more but 3000 ppm or less of boron oxide. The sodium oxide and the boron oxide are concentrated in an inner layer near the surface of the magnetic core.