NdFeB Magnet Grain Boundary Diffusion With Patterned Rare Earth Deposition
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Solution Overview
Problem
Current methods for applying rare earth metals to sintered type NdFeB permanent magnets through grain boundary diffusion suffer from low utilization rates, high production costs, and inefficiencies in adhesion and mass production, particularly due to the use of expensive equipment and volatile organic solvents.
Innovation Solution
A method involving the preparation of an organic film with a predetermined thickness on the magnet surface, creation of holes in the film, filling these holes with metal powders such as Dy and Tb, and performing a thermally induced grain boundary diffusion process, which includes compacting and heat treating the powders to achieve precise control over the weight and distribution of rare earth metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum coating or thermal spraying is used to attach rare earth metal, then adhesion quality is improved, but equipment cost increases and rare earth metal utilization rate decreases
Solution Approach 1:
The patent replaces expensive vacuum coating or thermal spraying equipment with simple, low-cost coating equipment. The organic suspension is applied as a disposable coating layer that is subsequently removed, eliminating the need for complex and costly vacuum or thermal spraying systems while maintaining effective rare earth metal attachment.
Solution Approach 2:
The patent introduces an organic suspension as an intermediary medium to facilitate the attachment of rare earth metal powder to the magnet surface. This organic carrier enables simple coating processes while ensuring proper adhesion, replacing the need for complex vacuum or thermal spraying equipment.
2Reliability
If vacuum coating or thermal spraying is used to attach rare earth metal, then adhesion quality is improved, but rare earth metal utilization rate decreases
Solution Approach 1:
The patent uses a simple organic suspension coating that can be precisely controlled and uniformly distributed, reducing waste of rare earth metal. The organic carrier allows for complete coverage with minimal excess material, and any unused suspension can be recovered and reused, significantly improving metal utilization rates compared to vacuum coating or thermal spraying.
Solution Approach 2:
The organic suspension acts as a mediator that enables uniform distribution of rare earth metal powder across the magnet surface. This intermediary approach ensures that metal powder is delivered exactly where needed, minimizing deposition on surrounding surfaces and improving overall utilization rate.
3Productivity
If coating or electrophoresis method is used to attach rare earth metal, then production cost decreases and production efficiency increases, but coating uniformity deteriorates due to organic solvent volatility and metal powder precipitation
Solution Approach 1:
The patent applies the organic suspension coating immediately before the diffusion process without allowing time for solvent evaporation or metal powder precipitation to occur. This preliminary action ensures that the coating is applied in its uniform, suspended state, capturing the metal powder in its evenly distributed form before any degradation can happen.
Solution Approach 2:
The patent maintains the organic suspension in a continuous, stable state from application through to the diffusion process. By keeping the organic carrier present and avoiding interruption that would cause evaporation or precipitation, the useful action of uniform coating distribution is maintained continuously throughout the process.
4Ease of manufacture
If screen mesh coating method is used, then production process is simplified, but coating material contact is insufficient and diffusion source is wasted
Solution Approach 1:
The patent extracts the metal powder from the organic suspension and directly deposits it onto the magnet surface through a simple coating process. By taking out the metal powder delivery from complex diffusion setups and using direct coating, the method ensures complete contact between coating material and magnet surface, eliminating waste of diffusion source.
Solution Approach 2:
The organic suspension serves as an intermediary that ensures complete and uniform contact between metal powder and magnet surface. This intermediary approach allows the coating material to be applied as a continuous layer with full surface contact, preventing the insufficient contact and material waste associated with screen mesh methods.
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 enhances the coercivity of NdFeB permanent magnets by improving the utilization efficiency of rare earth metals, allowing for precise control over their weight and distribution, simplifying the process, reducing costs, and enabling the production of special-shaped magnets with improved diffusion efficiency.
Implementation Method 1
performing a thermally induced grain boundary diffusion process
Implementation Method 2
followed by a heat treatment at 50°C to 180°C for solidifying the compacted metal powder
Data Source
Figure 1~3
Figure 4~5
AI summary
The invention relates to a method of increasing the coercivity of a sintered type NdFeB permanent magnet. The method comprises the following steps: a) preparing of an organic film with a predetermined thickness on a surface of the sintered type NdFeB permanent magnet; b) creating holes in the organic film according to a given pattern with the holes extending to the surface of the sintered type NdFeB permanent magnet; c) filling the holes with a metal powder, the metal powder including or consisting of at least one of Dy and Tb; and d) performing a thermally induced grain boundary diffusion process.