Ring-Shaped NdFeB Magnet Coating for Uniform Coercivity Diffusion
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Solution Overview
Problem
Current methods fail to effectively and efficiently improve the coercivity of ring-shaped NdFeB magnets due to their special shape, leading to non-uniform heavy rare earth diffusion and oxidation issues in electroplating processes.
Innovation Solution
A device and method involving a sealed chamber with retractable rollers and spray guns for atomizing and drying heavy rare earth slurry on both inner and outer surfaces of ring-shaped NdFeB magnets, followed by diffusion and aging under vacuum or inert gas to enhance coercivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If electroplating method is used to deposit heavy rare earth coating, then coercivity improvement is achieved, but film uniformity deteriorates due to nip and edge effects
Solution Approach 1:
The patent replaces the electroplating process with a spray coating process. Instead of using electrical fields and electrochemical reactions, the invention uses mechanical spray guns to deposit heavy rare earth slurry onto the magnet surface. This substitution eliminates the nip and edge effects inherent in electroplating, achieving uniform coating thickness across the entire surface including complex geometries.
Solution Approach 2:
The patent employs spray guns that utilize pneumatic or hydraulic mechanisms to atomize and deposit the heavy rare earth slurry. The spray coating system uses controlled fluid dynamics to achieve uniform distribution of the coating material, replacing the electrical field-based electroplating method with a fluid-based deposition process that provides better uniformity.
2Ease of manufacture
If electroplating solution is used for heavy rare earth deposition, then coating is formed, but oxidation occurs making the solution unstable
Solution Approach 1:
The patent changes the fundamental parameters of the deposition process by switching from an electrochemical system (electroplating solution) to a mechanical spray system. The heavy rare earth is applied as a slurry or suspension rather than an ionic solution, eliminating the oxidation problem that plagues electroplating solutions while maintaining effective coating formation.
Solution Approach 2:
The patent introduces a slurry or suspension as an intermediary medium to deliver the heavy rare earth material. Instead of using ionic solutions that are prone to oxidation, the invention uses a stable particulate suspension that can be mechanically sprayed, serving as a stable intermediary between the heavy rare earth powder and the magnet surface.
3Strength
If conventional diffusion methods are used for ring-shaped magnets, then some coercivity improvement is achieved, but diffusion uniformity deteriorates due to special shape
Solution Approach 1:
The patent applies the heavy rare earth coating uniformly across the entire surface of the ring-shaped magnet before the diffusion process. By pre-coating all surfaces including inner and outer circumferences with uniform thickness, the subsequent diffusion process achieves uniform coercivity improvement throughout the magnet, eliminating the shape-related non-uniformity problems of conventional methods.
Solution Approach 2:
The patent ensures that different regions of the ring-shaped magnet receive appropriate coating through the spray process. The spray coating method can uniformly deposit material on complex geometries, providing consistent heavy rare earth distribution across the inner surface, outer surface, and edges, which then diffuse uniformly to achieve homogeneous coercivity enhancement 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 uniform and controllable heavy rare earth coating, significantly improving coercivity while minimizing remanence loss, outperforming existing methods like electroplating in terms of film uniformity and thickness control.
Implementation Method 1
the first spray gun and the second spray gun are air pressure atomizing spray gun, the heavy rare earth slurry in the pressure mixing barrel is atomized and sprayed by spray gun and spray gun
Implementation Method 2
a second spray gun and a hot air drying spray gun disposed on one side of the roller
Implementation Method 3
a grain boundary diffusion technology is developed
Data Source
AI summary
Some embodiments of the invention belongs to a technical field of NdFeB magnet processing, and mainly relates to a device and method for improving 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.