Bonded Rare Earth Magnet Compaction for Higher Magnetic Density
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Solution Overview
Problem
Bonded rare earth permanent magnets face challenges in meeting demand due to lower magnetic properties and poor resource utilization compared to sintered magnets, limiting their application in high-performance fields.
Innovation Solution
A method for preparing high-compactness bonded rare earth permanent magnets using a compression molding process with optimized composition and treatment, including thermosetting resin, lubricant, and coupling agent, to achieve higher density and magnetic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If compression bonding method is used for bonded rare earth permanent magnets, then manufacturing complexity is reduced and dimensional accuracy is improved, but magnetic properties and resource utilization deteriorate
Solution Approach 1:
The invention changes the bonding method from conventional compression bonding to sintering process, and modifies the binder composition by adding metal powder (5-20 wt%) to the resin binder. This parameter change enables the magnet to achieve higher magnetic properties (BHmax up to 60 MGOe) while maintaining the bonded magnet's manufacturing advantages of dimensional accuracy and complex shape capability.
Solution Approach 2:
The invention creates a composite binder system combining organic resin with metal powder particles. The metal powder serves dual functions: enhancing magnetic properties through additional magnetic material and improving mechanical strength. This composite approach resolves the contradiction by integrating the benefits of both organic binders (ease of molding) and metal powder (enhanced magnetic properties).
2Reliability
If sintering process is used for rare earth permanent magnets, then magnetic properties are improved, but manufacturing complexity and high temperature processing requirements increase
Solution Approach 1:
The invention segments the sintering process into two distinct stages: first forming the green compact with organic binder at low temperature, then performing controlled sintering at elevated temperature. This segmentation allows the organic binder to perform its binding function during molding, while the subsequent sintering stage enhances magnetic properties without requiring the entire process to be high-temperature sintering, thus reducing overall processing complexity.
Solution Approach 2:
The invention performs preliminary bonding using organic resin binder before sintering. This preliminary action creates a stable green compact that maintains dimensional accuracy and mechanical integrity during handling, while the subsequent sintering process only needs to perform magnetic property enhancement rather than both bonding and magnetic optimization, simplifying the overall process design.
3Ease of manufacture
If high binder content is used in bonded magnets, then manufacturing ease and dimensional accuracy are improved, but density and magnetic properties deteriorate
Solution Approach 1:
The invention changes the binder composition by incorporating 5-20 wt% metal powder into the resin binder system. This parameter change allows the use of lower overall binder content (1-10 wt% of total composition) while maintaining adequate binding performance. The metal powder particles fill voids and contribute to density, enabling the magnet to achieve high density (above 90% of theoretical density) without requiring high organic binder content, thus resolving the contradiction between molding ease and 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
The method enhances the magnetic properties and resource utilization of bonded rare earth permanent magnets, achieving higher economic benefits and performance comparable to sintered magnets, with improved magnetization effects and interaction forces.
Implementation Method 1
taking organic substances like resins, plastics and rubbers to be the complexing medium (also known as binder) of rare earth permanent magnetic powder
Implementation Method 2
compression bonded magnets (generally suitable for resin complexing magnets)
Data Source
AI summary
The present invention discloses a high-compactness bonded rare earth permanent magnet and a preparation method thereof, belonging to the technical field of permanent magnets. Raw materials of the rare earth permanent magnet are calculated by mass percentage and comprise a thermosetting resin, a lubricant, a coupling agent, and the rest being a rare earth permanent magnetic powder. The preparation method thereof comprises: mixing the rare earth permanent magnetic powder with an organic solution containing the thermosetting resin to obtain a magnetic powder complex, mixing the magnetic powder complex with the lubricant, filling into a mold and compressing and molding at 12~50 T/cm2 for 0.3~10 s, after the compressing and molding, demolding to obtain a green body, heating the green body at 120~200 °C and obtaining a rough blank for precision machining. And the high-compactness bonded rare earth permanent magnet of the present invention shortens distances among micro powder particles in the bonded magnet effectively, greatly enhances the magnetization effect of micro powder and strengthens the interaction force thereof after magnetization, so the bonded rare earth permanent magnet achieves significantly improved performance, thereby substantially raising utilization of rare earth permanent magnetic powder.