RFeB Magnet Grain Boundary Diffusion Nozzle System
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Solution Overview
Problem
Existing methods for applying a grain boundary diffusion process to RFeB-based magnets with nonplanar surfaces, such as those used in motors, face challenges in achieving uniform thickness and efficient distribution of heavy rare earth elements, leading to uneven coercive force and increased resource consumption.
Innovation Solution
A method involving a nozzle-based system to non-contactly attach a mixture of heavy rare earth element-containing powder and organic solvent to the magnet surface, allowing for uniform application on arbitrary shapes and adjustable thickness, with silicone grease as the solvent to enhance adhesion and prevent peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods (dip coating, screen printing) are used to apply RH-containing powder to magnet surfaces, then the process is simple to implement, but uniform thickness cannot be achieved on nonplanar surfaces and resource consumption increases
Solution Approach 1:
The patent replaces conventional mechanical application methods (dip coating, screen printing) with a spray application system. The spray system uses fluid dynamics to deliver the mixture uniformly across complex surfaces, achieving consistent thickness without the material waste associated with conventional methods that cannot conform to nonplanar geometries
Solution Approach 2:
The patent changes the physical state and delivery parameters of the RH-containing powder by mixing it with organic solvent to create a sprayable mixture. This parameter change enables precise control of application thickness and uniform distribution across nonplanar surfaces, directly addressing the uniformity and resource consumption issues
2Manufacturing precision
If screen printing method is used, then the mixture can be applied in uniform thickness on planar surfaces, but it cannot be applied uniformly on nonplanar surfaces and the process becomes complex
Solution Approach 1:
The patent replaces the screen printing mechanical system with a spray application system. The spray system uses aerosol or mist delivery mechanisms that can conform to three-dimensional surfaces, maintaining uniform thickness control while achieving versatility across planar and nonplanar geometries
Solution Approach 2:
The spray application system is designed to be universally applicable to both planar and nonplanar surfaces. By using a delivery mechanism that relies on fluid dynamics rather than mechanical contact or screen constraints, the system achieves multi-functionality across different surface geometries while maintaining uniform application quality
3Strength
If RH-containing powder is applied to increase coercive force, then the coercive force is improved, but the residual magnetic flux density decreases and production cost increases
Solution Approach 1:
The spray application system enables precise local delivery of the RH-containing mixture to specific regions of the magnet surface. This local quality control ensures that RH is applied only where needed to enhance coercive force, minimizing the total amount of expensive rare earth material required while avoiding unnecessary additions that would reduce residual magnetic flux density
Solution Approach 2:
The patent implements a feedback mechanism where the application process is controlled to achieve the desired coercive force enhancement with minimal RH content. By monitoring and controlling the spray parameters and mixture composition, the system optimizes the balance between coercive force improvement and material consumption, preventing over-application that would harm residual magnetic flux density
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
Enables uniform and efficient attachment of the mixture to nonplanar surfaces, maintaining magnetic properties similar to those achieved on planar surfaces, while reducing resource consumption and ensuring consistent coercive force across the magnet.
Implementation Method 1
silicone grease as the solvent to enhance adhesion and prevent peeling
Implementation Method 2
a process (grain boundary diffusion process) of diffusing at least one element selected from the group consisting of Dy, Tb and Ho to the vicinity of surfaces of main phase grains through a grain boundary of the main phase grains
Implementation Method 3
the RFeB-based magnet is heated. According to this, the RH penetrates to the inside of the magnet through the grain boundary of the RFeB-based magnet, and thus atoms of the RH are diffused only in the vicinity of the surface of the crystal grains
Data Source
AI summary
Provided is a method for producing an RFeB-based magnet, the method including: disposing a nozzle so as to be opposed to an attachment surface of a base material that is a sintered magnet or hot-plastic worked magnet composed of an RFeB-based magnet containing a light rare earth element RL that is at least one element selected from the group consisting of Nd and Pr, Fe, and B; ejecting a mixture, from the nozzle, obtained by mixing an organic solvent and an RH-containing powder containing a heavy rare earth element RH that is at least one element selected from the group consisting of Dy, Tb and Ho so as to attach the mixture to the attachment surface; and heating the base material together with the mixture.