Expandable Sintered Neodymium-Iron-Boron Magnet Coating
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Solution Overview
Problem
Sintered neodymium-iron-boron magnets face corrosion issues due to high chemical activity, and existing epoxy resin coatings lack sufficient hardness and wear resistance, limiting their application and requiring lengthy assembly processes.
Innovation Solution
An expandable coating comprising water-soluble resin, foaming agent, and microspheres is applied to the magnet, expanding irreversibly to fix the magnet in place, offering improved hardness and wear resistance, and forming a honeycomb structure for enhanced bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If epoxy resin coating is used for surface protection, then corrosion resistance is improved, but hardness and wear resistance deteriorate
Solution Approach 1:
The patent applies a composite coating system consisting of an epoxy resin base coat providing corrosion resistance, and a polyurethane top coat providing enhanced hardness and wear resistance. This multi-layer composite structure allows each layer to perform its specialized function, resolving the contradiction between corrosion protection and mechanical durability.
2Strength
If resin adhesive filling is used for magnet assembly, then bonding strength is improved, but assembly time deteriorates
Solution Approach 1:
The patent modifies the chemical composition and curing characteristics of the resin adhesive to achieve faster curing kinetics. By adjusting parameters such as crosslinking density, gel time, and cure temperature, the adhesive achieves sufficient bonding strength in significantly reduced time, resolving the contradiction between bond strength and assembly speed.
Solution Approach 2:
The patent implements preliminary surface treatment and coating application before magnet assembly, creating a pre-prepared bonding surface that reduces the complexity and time of the final assembly process. The expandable microsphere coating is applied in advance, allowing optimized timing for the adhesive bonding step.
3Reliability
If epoxy resin coating is used, then corrosion protection is improved, but the coating is prone to damage in packaging and transportation
Solution Approach 1:
The patent employs a composite coating system where the epoxy resin base coat provides corrosion protection, while the polyurethane top coat provides superior mechanical strength, hardness, and resistance to physical damage during handling, packaging, and transportation. This layered composite approach allows simultaneous achievement of both corrosion protection and damage resistance.
4Device complexity
If conventional coating is used for magnet fixation, then assembly process is simplified, but bonding force and thrust force are insufficient
Solution Approach 1:
The patent utilizes expandable microspheres that undergo volume expansion upon heating, generating significant bonding force and thrust force through controlled expansion pressure. This thermal expansion mechanism provides sufficient holding force while maintaining a relatively simple assembly process, as the expansion occurs automatically during the heating cycle without requiring additional mechanical fastening steps.
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 expandable coating provides strong bonding force, reduces assembly time, and enhances corrosion and wear resistance, while using an environmentally friendly water-based material, ensuring high temperature and chemical resistance.
Implementation Method 1
comprising a sintered neodymium-iron-boron magnet and an expandable coating that coats on the surface of the sintered neodymium-iron-boron magnet
Implementation Method 2
The coating has a thickness of 15-30 μm, strong binding ability to a substrate
Implementation Method 3
injecting an resin adhesive, and heating and curing the resin adhesive to fix the magnet in the magnetic steel groove
Data Source
Figure 1~2
Figure 3~4
AI summary
Disclosed are an expandable sintered neodymium-iron-boron magnet, a preparation method, and an application. The magnet comprises a sintered neodymium-iron-boron magnet and an expandable coating coated on the surface of the sintered neodymium-iron-boron magnet. In the present disclosure, the sintered neodymium-iron-boron magnet coated with the expandable coating is used to replace a conventional assembly method of an epoxy resin adhesive coating magnet and potting resin glue, so that the magnet coated with the expandable coating may be inserted into a magnetic steel groove. The irreversible expansion of the coating itself is used to fix the magnet in the magnetic steel groove. Meanwhile, the use of the expandable coating of the present disclosure greatly shortens the assembly time of motors and improves the assembly accuracy of the motors. Moreover, the sintered magnet coated with the expandable coating of the present disclosure has excellent properties such as excellent high temperature resistance, anti-aging and corrosion resistance, and a strong bonding force.