Ring-Shaped NdFeB Magnet Coating for Uniform Coercivity Improvement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods fail to effectively and efficiently improve the coercivity of ring-shaped NdFeB magnets due to difficulties in uniformly applying heavy rare earth diffusion, leading to uneven magnetic properties and reduced motor performance.
Innovation Solution
A device and method involving a sealed chamber with retractable rollers and spray guns to apply a heavy rare earth slurry coating on both inner and outer surfaces of ring-shaped NdFeB magnets, followed by heat treatment to enhance coercivity, ensuring uniform coverage and improved magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electroplating method is used to apply heavy rare earth coating, then coercivity can be improved, but coating thickness uniformity deteriorates due to corner effect
Solution Approach 1:
The patent replaces the electroplating method with a spray coating method. Instead of using electrical fields and electrochemical reactions, the invention uses mechanical spraying technology to deposit heavy rare earth slurry onto the magnet surface. This substitution eliminates the corner effect inherent in electroplating and achieves uniform coating thickness across the entire surface including corners and edges.
Solution Approach 2:
The patent changes the physical state and application method of the heavy rare earth material. Instead of applying it as a metal salt solution through electroplating, the invention uses a slurry form that is sprayed onto the surface. The slurry is then dried and sintered to form the coating, fundamentally changing the application parameters from electrochemical deposition to thermal processing.
2Ease of manufacture
If heavy rare earth salt solution electroplating is used, then heavy rare earth can be deposited on magnet surface, but the solution oxidizes easily causing process instability
Solution Approach 1:
The patent fundamentally changes the chemical form and stability of the heavy rare earth source. Instead of using unstable salt solutions that oxidize easily, the invention uses stable slurry formulations containing heavy rare earth compounds dispersed in a carrier medium. The slurry is applied and then processed through drying and sintering, eliminating the oxidation problem entirely.
Solution Approach 2:
The patent introduces an intermediary carrier medium in the form of slurry. The heavy rare earth compounds are dispersed in this carrier medium, which protects them from direct exposure to oxidizing environments during application. The slurry acts as an intermediary that delivers the heavy rare earth material without suffering from oxidation issues.
3Reliability
If conventional diffusion methods are used on ring-shaped magnets, then some coercivity improvement can be achieved, but uniform diffusion to inner and outer surfaces is difficult
Solution Approach 1:
The patent segments the coating application process into two distinct stages: first coating the outer surface, then coating the inner surface. This segmentation allows each surface to receive optimized coating coverage independently, ensuring uniform diffusion throughout the ring structure. The process divides the complex task of simultaneous multi-surface coating into manageable sequential steps.
Solution Approach 2:
The patent addresses the three-dimensional geometry of ring-shaped magnets by applying coating from multiple spatial dimensions. The spray coating method can access and uniformly coat both the outer cylindrical surface and the inner cylindrical surface, as well as the top and bottom faces, ensuring comprehensive and uniform heavy rare earth distribution throughout the entire magnet structure.
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 achieves significant improvement in coercivity with uniform heavy rare earth coating and controlled thickness, outperforming existing methods like electroplating and electrophoresis by maintaining remanence while increasing coercivity substantially.
Implementation Method 1
a layer of heavy rare earth coating is sprayed on the inner and outer surfaces of the ring-shaped NdFeB magnet
Implementation Method 2
the ring-shaped NdFeB magnet sprayed with the heavy rare-earth coating is subjected to diffusion treatment
Data Source
Figure 1~2
AI summary
The invention belongs to the technical field of NdFeB magnet processing, and mainly relates to a device and method that can be used to improve the coercivity of ring-shaped NdFeB magnet. A layer of heavy rare earth coating is sprayed on the inner and outer surfaces of the ring-shaped NdFeB magnet by the device, and then the ring-shaped NdFeB magnet sprayed with the heavy rare-earth coating is subjected to diffusion treatment to improve the coercivity of the ring-shaped NdFeB magnet. The invention uses heavy rare earth slurry as the diffusion source, combined with spraying technology, can quickly and uniformly cover a layer of heavy rare earth coating on the inner and outer surfaces of the ring-shaped NdFeB magnet, and the coercivity of the ring-shaped NdFeB magnet is improved after heat treatment.