Arc-Shaped NdFeB Magnet Coating for High-Coercivity Diffusion
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Solution Overview
Problem
Existing methods for improving the coercivity of arc-shaped NdFeB magnets are inefficient due to low utilization rates of heavy rare earth elements, leading to high production costs and limitations in applying diffusion technologies to curved surfaces.
Innovation Solution
A method involving a flexible film with a heavy rare earth coating, comprising Dy or Tb, is used to coat the arc-shaped NdFeB magnet, where the coating is applied via screen-printing and then subjected to a thermally induced grain boundary diffusion process with ceramic bodies of complementary shape, ensuring uniform and stable supply of heavy rare earth elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If evaporation, sputtering, or ion plating processes are used to deposit heavy rare earth layers on the surface of Nd-Fe-B magnets, then coercivity is improved, but the utilization rate of heavy rare earth elements is low, resulting in high production costs
Solution Approach 1:
The heavy rare earth elements are pre-loaded into the organic solvent before coating, allowing the magnet to absorb the elements during the coating process itself, rather than requiring separate diffusion steps. This preliminary preparation of the coating solution enables direct impregnation of heavy rare earth elements into the magnet's grain boundaries during coating, improving utilization efficiency
Solution Approach 2:
The patent changes the physical and chemical parameters of the coating process by using organic solvents with specific boiling points and chemical properties. The coating is applied at ambient or elevated temperatures without requiring vacuum conditions, and the organic solvent evaporates to leave behind the heavy rare earth elements embedded in the magnet structure, achieving high utilization rates
2Adaptability or versatility
If thermally spraying heavy rare earth layers on the surface of Nd-Fe-B magnets is used to improve coercivity, then the method is suitable for magnets of any shape, but the utilization rate of Dy and Tb is low, resulting in high cost production costs
Solution Approach 1:
The heavy rare earth elements are pre-dissolved or suspended in the organic coating solvent before application. This preliminary preparation allows the magnet to absorb the elements directly during the coating process through capillary action and diffusion, rather than requiring subsequent high-temperature diffusion steps that waste material
Solution Approach 2:
The patent replaces the mechanical thermal spraying process with a chemical coating process using organic solvents. The coating is applied through brush, spray, or dip methods at ambient or elevated temperatures, allowing the magnet to passively absorb heavy rare earth elements through diffusion into the grain boundaries without requiring external energy input for material deposition
3Loss of substance
If screen-printing process is used to coat heavy rare earth slurry on the magnet surface, then the utilization rate of heavy rare earth materials is very high, but the technical solution cannot be used for coating curved surface of arc-shaped magnets
Solution Approach 1:
The patent employs a flexible coating approach where the organic-based heavy rare earth coating can conform to curved and arc-shaped magnet surfaces. The coating solution is applied in a liquid or paste form that can flow and adhere to complex geometries, then dries to form a uniform coating layer that matches the magnet's surface shape
Solution Approach 2:
The patent replaces the rigid screen-printing mechanical system with a flexible chemical coating process using organic solvents. The coating can be applied by brush, spray, or dip methods that accommodate curved surfaces, and the organic-based formulation allows the coating to conform to complex geometries while maintaining high heavy rare earth element utilization rates
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 significantly increases the coercivity of arc-shaped NdFeB magnets while maintaining remanence and squareness ratio, with high production efficiency and low material usage, reducing production costs and accommodating various magnet shapes.
Implementation Method 1
performing a thermally induced grain boundary diffusion process
Data Source
AI summary
The disclosure relates to a method for improving the coercivity of an arc-shaped Nd—Fe—B magnet. A method for increasing the coercivity of an arc-shaped Nd—Fe—B magnet is provided. Said method comprises the steps of:a) providing of a flexible film with a heavy rare earth coating thereon, wherein the heavy rare earth coating comprises at least one of Dy and Tb;b) arranging the arc-shaped Nd—Fe—B magnet and the flexible film such that a first curved surface of the arc-shaped Nd—Fe—B magnet and the heavy rare earth coating on the flexible film are facing each other;such that a curved surface of the first ceramic body lies on the side of the flexible film opposite the arc-shaped Nd—Fe—B magnet, then pressing the first ceramic body and the magnet together; andd) performing a thermally induced grain boundary diffusion process.