Rare-Earth Magnet Spring-Back Suppression via Pressure Cooling
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Solution Overview
Problem
Rare-earth magnets produced through hot deformation processing often experience spring-back due to elasticity, which damages the oriented structure and reduces residual magnetization and coercive force.
Innovation Solution
Applying a predetermined pressure in the same direction during cooling after hot deformation processing to suppress spring-back, maintaining the shape and dimension of the rare-earth magnet precursor until the liquid phase component solidifies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hot deformation processing is performed to impart magnetic anisotropy, then magnetic properties are improved, but spring-back damages the oriented structure and deteriorates residual magnetization and coercive force
Solution Approach 1:
A predetermined pressure is applied in the same direction as the pressurization direction during cooling to counteract the spring-back force before it can damage the oriented structure. This preliminary counter-action prevents the elastic recovery that would otherwise deteriorate the magnetic properties by maintaining the oriented structure formed during hot deformation processing.
2Productivity
If pressure is released immediately after hot deformation processing, then production efficiency is improved, but spring-back becomes significant and damages the magnet structure
Solution Approach 1:
Instead of releasing pressure immediately after hot deformation processing, a predetermined pressure is maintained during the cooling process. This preliminary action of maintaining pressure prevents spring-back from occurring, ensuring the magnet structure remains intact while still allowing for efficient production by not requiring additional stabilization steps.
3Device complexity
If cooling is performed without applied pressure, then process simplicity is improved, but the spring-back force deteriorates residual magnetization and coercive force
Solution Approach 1:
The cooling process is modified by maintaining a predetermined pressure parameter during cooling, rather than cooling without pressure. This parameter change from zero pressure to predetermined pressure during cooling prevents spring-back while maintaining reasonable process simplicity, as the pressure application is automated and requires no additional complex equipment.
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 effectively prevents the deterioration of residual magnetization and coercive force by maintaining the magnetic anisotropy and orientation, resulting in improved magnetic properties.
Implementation Method 1
the sintered body is placed within a plastic processing mold and is pressurized in a predetermined direction so as to impart magnetic anisotropy to the sintered body
Implementation Method 2
spring-back is often generated by the spring-back force due to the elasticity of the rare-earth magnet slightly remaining therein
Implementation Method 3
performing cooling of the rare-earth magnet precursor while a predetermined pressure is kept being applied thereto... until the liquid phase component solidifies
Data Source
AI summary
Provided is a method for producing a rare-earth magnet that can resolve a problem of deterioration of the residual magnetization and coercive force of the rare-earth magnet due to spring-back in producing the rare-earth magnet through performing hot deformation processing of upsetting on a sintered body. The method includes a first step of producing the sintered body through press-forming of magnetic powder for a rare-earth magnet, and a second step of producing a rare-earth magnet precursor through hot deformation processing of upsetting in which the sintered body is placed within a plastic processing mold and is pressurized in a predetermined direction so as to impart magnetic anisotropy to the sintered body, and performing cooling of the rare-earth magnet precursor while a predetermined pressure is kept being applied thereto in the predetermined direction, so that the rare-earth magnet is produced.