Magnet Phosphate Coating Reduces Eddy Current Loss
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Solution Overview
Problem
Rare earth magnets used in motors experience eddy currents due to high conductivity, leading to heat loss, decreased efficiency, and demagnetization, which existing methods like dividing magnets with insulating layers do not fully address, especially as applications expand.
Innovation Solution
A magnet with a rare earth element, transition metal, and boron, coated with a manganese-containing phosphate layer of 0.5 μm or more, where the phosphate layer covers the main phase but not the grain boundary phase, enhancing the insulating properties and reducing eddy currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a magnet is divided and an insulating layer is provided on the surface, then eddy currents decrease, but device complexity increases and manufacturing becomes more complex
Solution Approach 1:
The invention changes the surface property parameter of the magnet by forming a phosphate layer through chemical conversion treatment. This layer has different electrical conductivity characteristics than the base magnet material, thereby reducing eddy currents without requiring physical division or additional insulating components
Solution Approach 2:
The phosphate layer is formed directly on the magnet surface through chemical conversion treatment, making the magnet itself provide the insulating function. This eliminates the need for separate insulating layers or divided structures, allowing the object to serve its own insulating needs
2Loss of energy
If a thick insulating layer is provided on the magnet surface, then insulating property increases, but manufacturing precision requirements increase
Solution Approach 1:
The chemical conversion treatment process allows the phosphate layer to form uniformly on the magnet surface through self-limiting chemical reactions. The layer thickness is controlled by the treatment conditions (time, temperature, solution concentration) rather than requiring precise mechanical or deposition control, enabling consistent insulating properties without stringent manufacturing precision requirements
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 phosphate layer significantly improves the insulating properties of the magnet's surface, reducing eddy current losses and maintaining superior magnetic properties, even in harsh environments, while eliminating the need for additional insulators, thus enhancing motor efficiency and durability.
Implementation Method 1
Since rare earth magnets have a high conductivity, eddy currents occur inside the magnet when used in a motor. When eddy currents occur inside the magnet, heat (loss) occurs due to the electrical resistance
Implementation Method 2
When eddy currents occur inside the magnet, heat (loss) occurs due to the electrical resistance
Data Source
AI summary
The present invention aims to provide a novel magnet, whose surface's insulating property can be increased, and a motor using the same. The present invention provides a magnet comprising a magnet element containing a rare earth element R, a transition metal element T and boron B, and a phosphate layer including manganese-containing phosphate, wherein the phosphate layer is provided on the surface of the magnet element, and the thickness of the phosphate layer is 0.5 μm or more.