NdFeB Magnet Demagnetization Detection by Pole Distribution
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Solution Overview
Problem
Current methods for evaluating the demagnetization state of grain boundary diffusion NdFeB magnets are inefficient, damaging the magnets, and require significant resources, as they involve cutting the magnets into layers and using large equipment, making it difficult to assess internal demagnetization without damaging the product.
Innovation Solution
A method involving the application of a reverse magnetic field to a saturation-magnetized grain boundary diffusion NdFeB magnet, observing the magnetic pole distribution on non-diffusion faces, which allows for the identification of irreversible demagnetization without damaging the magnet, using devices like magnetic field distribution visualization tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the magnet is cut into layers for detection, then the demagnetization state can be evaluated, but the magnet is damaged and detection efficiency is low
Solution Approach 1:
The patent replaces the mechanical cutting method with a magnetic field-based detection method. By applying a reverse magnetic field and observing magnetic pole distribution changes on the magnet surface, the demagnetization state can be evaluated without physically cutting or damaging the magnet. This substitutes mechanical destruction with a non-contact magnetic field measurement approach.
Solution Approach 2:
The patent uses magnetic pole distribution as an intermediary indicator to assess the internal demagnetization state. Instead of directly measuring internal properties through destructive means, the method observes the external magnetic field distribution pattern, which serves as a mediator reflecting the internal magnetic state and grain boundary conditions.
2Measurement precision
If large equipment such as VSM, PPMS, MPMS is used for detection, then detection results can be obtained, but resource consumption is high
Solution Approach 1:
The patent employs simple, inexpensive detection tools such as Gauss meters or magnetic developing films instead of expensive large-scale equipment like VSM, PPMS, or MPMS. These low-cost tools can effectively detect magnetic pole distribution changes and provide sufficient information for demagnetization evaluation, significantly reducing resource consumption while maintaining practical detection capability.
3Measurement precision
If the magnet is cut into layers for detection, then each layer's coercivity can be measured, but the magnet cannot be used further
Solution Approach 1:
The patent replaces the destructive mechanical cutting process with a non-contact magnetic field application method. By applying a reverse magnetic field and detecting magnetic pole distribution changes on the surface, the method evaluates the demagnetization state without physically altering or damaging the magnet, thereby preserving its integrity and usability after detection.
4Measurement precision
If multiple detection times are conducted on small samples, then detection results can be obtained, but detection efficiency is low
Solution Approach 1:
The patent creates a universal detection method that can evaluate the overall demagnetization state of the entire magnet in a single operation. The magnetic field-based approach simultaneously assesses the magnetic state across different regions by observing the overall magnetic pole distribution pattern, eliminating the need for multiple sequential measurements on different layers or sections.
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
This method provides accurate, non-destructive assessment of demagnetization, is not affected by magnet size or temperature, and allows for the continued use of the magnet if no demagnetization is detected, with results obtainable using various devices like Gauss meters or magnetic developing films.
Implementation Method 1
applying a reverse magnetic field to a saturation-magnetization grain boundary diffusion NdFeB magnet, and, if a number of magnetic poles on a non-diffusion face of the grain boundary diffusion NdFeB magnet is increased and divided into layers
Implementation Method 2
saturation-magnetization grain boundary diffusion NdFeB magnet
Data Source
AI summary
The present application relates to a technical field of determining an irreversible demagnetization of a grain boundary diffusion NdFeB magnet, and more particularly, to a method for identifying an irreversible demagnetization of a grain boundary diffusion NdFeB magnet by magnetic field distribution. After applying a reverse magnetic field to a saturatedly magnetized grain boundary diffusion NdFeB magnet, if a number of magnetic poles on a non-diffusion face of the grain boundary diffusion NdFeB magnet is increased, it is determined that there is an irreversible demagnetization in the grain boundary diffusion NdFeB magnet.