Nd-Fe-B Magnet Anti-Corrosion via Multi-Arc Sputtering
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Solution Overview
Problem
Conventional anti-corrosion coatings for Nd-Fe-B permanent magnets, such as aluminum and epoxy resin, fail to meet the specific test requirements for use in wind power generators, particularly in damp environments where they are prone to rusting due to their composition of rare earth metals.
Innovation Solution
A multi-arc sputtering method is employed to deposit an aluminum layer followed by an epoxy resin coating on Nd-Fe-B permanent magnets, involving pre-treatment, vacuum processing, arc deposition, and heat treatment to achieve a durable anti-corrosive layer that enhances corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional aluminum coating or epoxy resin coating is applied on Nd-Fe-B permanent magnets, then the magnets are protected to some extent, but they fail to meet the specific test requirements for wind power generators in damp environments
Solution Approach 1:
The patent applies a composite coating system consisting of multiple layers: a pre-treatment layer, an aluminum alloy coating layer (containing elements like Si, Mg, Mn, Zn), and an epoxy resin top coat. This multi-layer composite structure provides superior corrosion resistance compared to single-layer coatings, meeting the stringent requirements for wind power generator applications in damp environments.
Solution Approach 2:
The patent modifies the composition parameters of the aluminum coating by incorporating specific alloying elements (Si: 3-15 wt%, Mg: 2-10 wt%, Mn: 1-5 wt%, Zn: 1-5 wt%) to enhance corrosion resistance. The controlled thickness parameters (aluminum layer: 5-20 μm, epoxy layer: 10-30 μm) are also optimized to achieve the required protection level.
2Reliability
If multi-arc sputtering is used to deposit aluminum layer and epoxy resin coating, then corrosion resistance is significantly improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent replaces conventional mechanical coating methods with multi-arc sputtering technology, which uses physical vapor deposition under vacuum conditions. This substitution enables precise control of coating composition and thickness, ensuring uniform and high-quality anti-corrosion layers that meet wind power generator requirements.
Solution Approach 2:
The multi-arc sputtering process is conducted in a vacuum environment with controlled atmosphere, preventing oxidation and contamination during coating deposition. This inert environment ensures the purity and quality of the aluminum alloy coating layer, contributing to enhanced corrosion resistance.
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 described method significantly improves corrosion resistance compared to single-layer coatings, meeting stringent test requirements like salt spray and pressure cooker tests, ensuring the longevity and performance of Nd-Fe-B magnets in harsh conditions.
Implementation Method 1
a multi-arc sputtering method is employed to deposit an aluminum layer
Implementation Method 2
it is a kind of surface coating technology that uses electric arc as the power of vaporizing
Implementation Method 3
Evacuating the multi-arc sputtering equipment with a vacuum system until the pressure reaches 1×10^-2
Implementation Method 4
it is a kind of surface coating technology that uses electric arc as the power of vaporizing
Implementation Method 5
step g) of heating the epoxy resin coating may be performed at 170°C for 30min
Data Source
AI summary
According to the present invention there is provided a method for disposing an anti-corrosion coating on Nd-Fe-B permanent magnets and an Nd-Fe-B permanent magnet including an improved anti-corrosion coating. The method includes the steps of: a) Performing a pre-treatment of the Nd-Fe-B permanent magnets; b) Fixing the Nd-Fe-B permanent magnets on a jig and placing the same in a multi-arc sputtering equipment; c) Evacuating the multi-arc sputtering equipment with a vacuum system until the pressure reaches 1×10-2Pa to 3×10-2Pa, then introducing argon gas until the pressure reaches 1×10-1Pa to 5×10-1Pa, starting bias voltage treatment of the Nd-Fe-B permanent magnets for 1 to 10 minutes at 800V to 1000V; d) Stopping bias voltage treatment and then evacuating the multi-arc sputtering equipment until the pressure reaches 1×10-3Pa to 8×10-3Pa, then refilling argon gas until the pressure reaches 3×10-1Pa to 5×10-1Pa, then starting arc deposition from a target source and maintain a DC current between 50A to 70A, turn on bias voltage and maintain voltage between 100V to 200V, and maintain coating the magnets for 0.1 to 2h; e) Cooling down on 20°C to 100°C and taking out the Nd-Fe-B permanent magnets from the multi-arc sputtering equipment; f) Spray coating of the Nd-Fe-B permanent magnets with an epoxy resin; and g) Placing the Nd-Fe-B permanent magnets into an oven and heat-treating the same at a treatment temperature between 100°C to 220°C for 10min to 120min.