Sm-Fe-N Magnet Powder Orientation and Low-Temperature Densification
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Solution Overview
Problem
The existing methods for manufacturing Sm-Fe-N magnets, particularly through rolling, do not adequately enhance magnetic properties, which are crucial for applications in motors of mobile objects and rotating machines.
Innovation Solution
A method involving a sealing step with a metal sheath, magnetic field application, preliminary rolling, and pressurizing to densify the magnetically oriented Sm-Fe-N powder, ensuring a relative density of 52% to 88% and a degree of magnetic orientation of 0.72 to 0.87, with specific conditions such as tapping and varying temperatures to optimize magnetic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high temperature sintering is used to manufacture Sm-Fe-N magnets, then magnetic properties can be improved, but the Sm-Fe-N compound pyrolyzes and cannot be manufactured
Solution Approach 1:
The invention changes the temperature parameter from high temperature sintering to room temperature or low temperature pressing, and changes the pressure parameter to high pressure, thereby achieving densification without pyrolysis of the Sm-Fe-N compound
Solution Approach 2:
The invention replaces the thermal field (high temperature sintering) with a mechanical field (high pressure pressing), using mechanical energy instead of thermal energy to achieve densification and improve magnetic properties
2Device complexity
If rolling method is used to manufacture Sm-Fe-N magnets without sintering, then manufacturing complexity is reduced, but magnetic properties are insufficient
Solution Approach 1:
The invention applies a magnetic field in advance to orient the magnet powder particles before pressing, ensuring that the particles are aligned in the desired direction to maximize magnetic properties before the densification process
Solution Approach 2:
The pressing step serves multiple functions simultaneously: it densifies the green compact, maintains particle orientation, and improves magnetic properties, eliminating the need for separate sintering and orientation steps
3Productivity
If green compact is pressurized at high pressure without preliminary rolling, then manufacturing steps are reduced, but density and magnetic orientation are insufficient
Solution Approach 1:
The invention divides the densification process into two separate steps: preliminary rolling at low pressure to achieve initial densification and orientation, followed by high pressure pressing to achieve final densification, with each step serving a specific function
Solution Approach 2:
The invention maintains continuous magnetic field application during both preliminary rolling and pressing steps, ensuring continuous particle orientation throughout the densification process to maximize magnetic properties
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 significantly improves the magnetic properties of Sm-Fe-N magnets, resulting in enhanced residual magnetic flux density and degree of magnetic orientation, making them suitable for high-performance applications in motors and rotating machines.
Implementation Method 1
a sealing step of filling a metal sheath with magnet powder containing an Sm-Fe-N compound as a main component and sealing the metal sheath
Implementation Method 2
a magnetic field applying step of applying a magnetic field to the magnet powder sealed in the metal sheath and magnetizing the magnet powder by magnetically orienting the magnet powder and aligning a direction of magnetic orientation in one direction
Implementation Method 3
magnetizing the magnet powder by magnetically orienting the magnet powder
Implementation Method 4
a pressurizing step of pressurizing the green compact sealed in the metal sheath and densifying the green compact to form a magnet body
Data Source
Figure 1
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Figure 4~5
AI summary
A method of manufacturing an Sm-Fe-N magnet includes a sealing step (S10) of filling a metal sheath with a magnet powder including an Sm-Fe-N compound as a main component and sealing the metal sheath, a magnetic field applying step (S12) of applying a magnetic field to the magnet powder sealed in the metal sheath, and magnetizing the magnet powder by magnetically orienting the magnet powder and aligning a direction of magnetic orientation in one direction, a preliminary rolling step (S14) of preliminarily rolling the magnetically oriented magnet powder sealed in the metal sheath to make the magnetically oriented magnet powder into a green compact, and a pressurizing step (S16) of pressurizing the green compact sealed in the metal sheath and densifying the green compact to form a magnet body, wherein in the preliminary rolling step (S14), the preliminary rolling is performed by lightly rolling the magnetically oriented magnet powder sealed in the metal sheath with a pressure smaller than a pressure in the pressurizing step (S16).