Gradient Nd-Fe-B Magnet Coercivity Layout for Edge Demagnetization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing diffusion processes for enhancing the coercivity of Nd—Fe—B magnets result in poor controllability and inefficient use of heavy rare earth elements, leading to inadequate demagnetization resistance, especially in the edge regions.
Innovation Solution
A gradient Nd—Fe—B magnet is created by depositing heavy rare earth element films on the periphery of Nd—Fe—B magnet blocks, which are then diffused into the magnet, dividing it into edge, transition, and central regions with controlled coercivity gradients, reducing the amount of heavy rare earth elements used and improving demagnetization resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the conventional diffusion process applies heavy rare earth elements to two sides or all sides parallel to the magnetization direction, then the overall coercivity of the Nd-Fe-B magnets is enhanced, but the amount of heavy rare earth elements used is relatively large and the controllability of the high coercivity zone is poor
Solution Approach 1:
The patent applies heavy rare earth element films only to the edge regions of the magnet surfaces perpendicular to the magnetization direction, rather than uniformly coating all surfaces. This localized application creates a gradient distribution where the edge regions receive heavy rare earth elements while the central region does not, thereby reducing the total amount of heavy rare earth elements used while still achieving the desired coercivity enhancement in the critical edge regions where demagnetization occurs
Solution Approach 2:
The patent divides the magnet into distinct regions (edge region and central region) with different coercivity characteristics through selective diffusion. The edge region is treated with heavy rare earth elements to achieve high coercivity, while the central region maintains its original properties, creating a segmented functional structure that optimizes both performance and material usage
2Reliability
If the diffusion process is used to increase coercivity, then the demagnetization resistance is improved, but the direction of diffusion is perpendicular to the magnetization direction making it difficult to adjust the size range of the high coercivity zone
Solution Approach 1:
The patent applies the heavy rare earth element films to the surfaces before the diffusion process begins, positioning the material precisely where it is needed (edge regions). This preliminary placement allows subsequent diffusion to proceed in a controlled manner from the surface inward, enabling precise control over the depth and spatial distribution of the high coercivity zone, thereby improving manufacturing precision while maintaining reliable demagnetization resistance
3Strength
If heavy rare earth elements are diffused from grain boundary to Nd2Fe14B phase, then the magnetic anisotropy is improved and coercivity is increased, but the coating area is large resulting in inefficient use of heavy rare earth elements
Solution Approach 1:
The patent implements localized quality enhancement by applying heavy rare earth element films specifically to the edge regions rather than the entire surface area. This creates a spatially differentiated structure where only the critical edge regions undergo the diffusion process and develop enhanced magnetic anisotropy, while the central region retains its original composition. This approach dramatically reduces the total quantity of heavy rare earth elements consumed while still achieving the necessary magnetic property improvements in the regions where demagnetization resistance is most critical
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 effectively enhances the coercivity of the edge region while optimizing the use of heavy rare earth elements, resulting in improved demagnetization resistance and better alignment with actual application environments.
Implementation Method 1
The first film and the second film are diffused into the Nd—Fe—B magnet block dividing the Nd—Fe—B magnet block into an edge region, a transition region, and a central region
Data Source
AI summary
A gradient Nd—Fe—B magnet includes an Nd—Fe—B magnet block extending along a magnetization direction and having a plurality of surfaces perpendicular to the magnetization direction. A first film, is disposed on one of the surfaces. A second film is disposed on another one of the surfaces, opposite of the one of the surfaces. The first film and the second film are diffused into the Nd—Fe—B magnet block dividing the Nd—Fe—B magnet block into an edge region, a transition region, and a central region along a plane perpendicular to the magnetization direction wherein the edge region has a coercivity that remains constant in a direction perpendicular to the magnetization direction, and the coercivity, along said magnetization direction, gradually decreases from the one of the surfaces and the another one of the surfaces towards a point located therebetween. A method of making the gradient Nd—Fe—B magnet is disclosed herein.