NdFeB Magnet Grain Boundary Diffusion for Higher Coercive Force

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Solution Overview

Problem

Current methods for enhancing the coercive force of neodymium iron boron magnets, such as doping with heavy rare earth elements, face high costs due to expensive materials and low utilization rates, and require costly production equipment, while traditional processes like sputtering and coating methods consume large amounts of heavy rare earths, limiting their effectiveness and increasing production costs.

Innovation Solution

A treatment method involving electrochemical deposition of a diffusion water-based solution containing chloride salts of heavy rare earths, copper sulfate, aluminum chloride, and other components, followed by heat treatment, to enhance the coercive force of neodymium iron boron magnets, utilizing cheaper heavy rare earth compounds and a simpler process that allows for uniform deposition and improved grain boundary diffusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional sputtering or coating methods are used to add heavy rare earth elements, then the coercive force of the magnet can be improved, but the utilization rate of heavy rare earth elements is extremely low and production cost is high

Engineering Contradiction:
Improvecoercive forceVSAvoidutilization rate of heavy rare earth elements
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent replaces traditional mechanical/physical methods (sputtering, coating) with an electrochemical method. The heavy rare earth elements are introduced through electrochemical deposition from a water-based solution containing chloride salts, allowing precise control of element distribution and significantly improving utilization rate while reducing material consumption and production cost

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the chemical form of heavy rare earth elements from metallic or oxide forms used in traditional methods to chloride salt forms in an electrochemical solution. This parameter change enables efficient electrochemical deposition and diffusion, improving both utilization rate and cost-effectiveness

Inventive Principle:
Principle #35Parameter changes

2Reliability

If heavy rare earth doping is used to improve coercive force, then the magnetic properties can be enhanced, but rare earth resources are greatly consumed

Engineering Contradiction:
Improvecoercive forceVSAvoidconsumption of heavy rare earth elements
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies partial action by introducing heavy rare earth elements only where needed - specifically through grain boundary diffusion from the surface inward. This targeted approach uses minimal amounts of heavy rare earth elements (small additions) to achieve the desired coercive force enhancement without excessive resource consumption

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent uses an electrochemical solution containing chloride salts of heavy rare earth elements as an intermediary medium. This solution enables controlled delivery and diffusion of heavy rare earth elements into the magnet structure, achieving efficient resource utilization with minimal consumption

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If conventional grain boundary diffusion processes are used, then coercive force can be improved with small amounts of heavy rare earth, but the process requires complex production equipment and high production cost

Engineering Contradiction:
Improvecoercive forceVSAvoidproduction equipment requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex thermal field equipment and vacuum systems required by conventional grain boundary diffusion with a simpler electrochemical system. The electrochemical deposition process uses basic electrochemical cells and water-based solutions, eliminating the need for expensive and complex production equipment while achieving the same grain boundary diffusion effect

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses a water-based electrochemical solution containing chloride salts as a disposable or easily replaceable medium. This simple, inexpensive solution can be prepared in basic containers and applied through straightforward electrochemical deposition, eliminating the need for expensive, complex, and difficult-to-maintain production equipment

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 effectively increases the coercive force of neodymium iron boron magnets by nearly 30% without significantly reducing residual magnetism, while reducing production costs and expanding the adaptation range of substrate shapes, with a simpler and safer process that does not require specialized equipment.

Implementation Method 1

subjecting the neodymium iron boron magnet to electrochemical deposition in a diffusion water-based solution to obtain a neodymium iron boron magnet containing heavy rare earth

Methodology Applied
Scientific EffectElectrochemical deposition: Electrodeposition

Implementation Method 2

by adding small amounts of heavy rare earth elements into a magnet, the coercive force of a material is greatly improved

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 3

subjecting the neodymium iron boron magnet containing heavy rare earth to heat treatment to complete enhancement of the coercive force

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentUS20250246367A1Treatment method for enhancing coercive force of neodymium iron boron magnet
Publication Date: 2025.07.31 CHINA JILIANG UNIV

AI summary

A treatment method for enhancing coercive force of neodymium iron boron magnet includes the following steps: subjecting the neodymium iron boron magnet to electrochemical deposition in a diffusion water-based solution to obtain a neodymium iron boron magnet containing a heavy rare earth; and subjecting the neodymium iron boron magnet containing the heavy rare earth to heat treatment to complete enhancement of the coercive force of the neodymium iron boron magnet. The raw material used in the present invention is cheap heavy rare earth compounds which increases the selection of diffusion sources and lowers costs. Metal alloy particles are mainly obtained in a nanoscale size and can effectively enter crystal grains, and low-melting-point metal alloy components can enhance a demagnetizing coupling effect between main phase grains. According to the present invention, the coercive force of the magnet is increased by nearly 30%, and residual magnetism is almost not changed.