Nanoparticle-Coated Rare Earth Magnet for Low Eddy Current Loss
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Solution Overview
Problem
Existing methods for manufacturing rare earth magnets result in increased eddy current loss due to the formation of electrical connections between magnet powder particles during hot plastic molding, leading to reduced magnetic properties.
Innovation Solution
A rare earth magnet with a coating of nanoparticles on its surface, specifically using alkali or alkaline earth metal fluorides, which prevents breaks in the coating and maintains high magnetic properties by ensuring the coating remains uniform and intact during molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the amount of insulating compound material is reduced to minimize deterioration of magnetic properties, then magnetic properties are improved, but the coating breaks during hot plastic molding causing electrical connections between particles
Solution Approach 1:
The patent changes the particle size parameter of the insulating material from conventional micrometer-scale particles to nanoparticles (1-100 nm). This parameter change allows the coating to remain intact during hot plastic molding while using minimal insulating material, thus reducing eddy current loss without compromising coating integrity.
Solution Approach 2:
The patent creates a composite coating structure by combining rare earth oxide particles with nanoparticle insulating material (alkali metal fluoride or alkaline earth metal fluoride). This composite approach enhances coating durability during molding while maintaining electrical insulation properties, resolving the contradiction between minimal material usage and coating integrity.
2Reliability
If conventional insulating compound material is used, then coating integrity is maintained, but eddy current loss increases due to larger amount of insulating material
Solution Approach 1:
The patent changes the particle size parameter from micrometer-scale to nanometer-scale (1-100 nm). This dramatic reduction in particle size allows achieving the same coating integrity with much smaller amounts of insulating material, thereby reducing eddy current loss while maintaining coating durability during hot plastic molding.
Solution Approach 2:
The patent applies nanoparticle insulating material that provides localized insulation at particle contact points. This localized quality approach ensures coating integrity where needed (at particle interfaces) while minimizing the total amount of insulating material, thus reducing eddy current loss.
3Quantity of substance
If flake-shaped magnet powder particles are stacked during densifying, then packing density is improved, but coating breaks during hot plastic molding forming electrical connections
Solution Approach 1:
The patent changes the size parameter of insulating particles to nanometer scale (1-100 nm). This parameter change enables the coating to withstand the mechanical stresses of hot plastic molding and particle stacking without breaking, maintaining coating integrity while allowing high packing density of flake-shaped magnet powder particles.
Solution Approach 2:
The patent applies a pre-formed nanoparticle coating that acts as a cushioning layer before hot plastic molding. This beforehand cushioning protects the magnet powder particles from direct contact and coating breakage during subsequent molding and stacking processes, maintaining both packing density and coating integrity.
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 use of nanoparticle coatings on rare earth magnets minimizes eddy current loss while maintaining high magnetic properties by preventing electrical connections between particles, thus enhancing motor efficiency.
Implementation Method 1
the insulating material contains nanoparticles, with which the rare earth magnet powder particle is coated
Implementation Method 2
a coating (4) of an insulating material on a surface of the rare earth magnet powder particle (2)
Data Source
AI summary
Provided are a rare earth magnet and a method for manufacturing the same, which achieve both high magnetic properties and low eddy current loss. The rare earth magnet comprises coated magnet powder particles, each comprising a rare earth magnet powder particle and a coating of an insulating material on a surface thereof, wherein the insulating material contains nanoparticles, with which the rare earth magnet powder particle is coated. The method of manufacturing the rare earth magnet comprises a coating operation which includes adding an insulating material to the rare earth magnet powder particles, such that each coated magnet powder particle comprises a rare earth magnet powder particle and a coating of the insulating material on a surface thereof, wherein the coating operation comprises spraying a nanoparticle dispersion solution containing the nanoparticles and a binding agent, to the rare earth magnet powder particles that are caused to be tumbling and flowing.