Neodymium-iron-boron magnet with composite coating and preparation process thereof

A composite coating, neodymium-iron-boron technology, applied in the manufacture of permanent magnets, magnets, magnetic objects, etc., can solve the problems of large influence of thermal demagnetization of magnets, poor bonding force of the substrate, etc., to achieve outstanding substantive characteristics, good bonding force, The effect of improving corrosion resistance

Inactive Publication Date: 2018-04-20
YANTAI DONGXING MAGNETIC MATERIALS INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The invention mainly solves the problems that the existing NdFeB magnet nickel plating process has a great influence on the thermal demagnetization of the magnet and relatively poor bonding force with the substrate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] Embodiment 1, taking the method of barrel plating as an example, first grind and chamfer the product to R0.2-0.3mm with a centrifugal finishing machine, and grind the chamfer for 3 hours; Use degreasing powder solution to remove the oil on the surface of the product, and wash the surface of the product with spray water for 1-2 minutes; then pickle with 3% nitric acid for 60 seconds to remove the oxide layer and corrosion layer on the surface of the product; use ultrasonic equipment Clean the surface of the product for 3 minutes to completely remove the hanging ash on the surface of the product; then use nitric acid with a mass fraction of 1% for 15 seconds, and clean the product with tap water and pure water for 60 seconds; then put the processed product into a hexagonal drum for rolling Galvanizing, using 20-120g / L zinc chloride, 120-320g / L potassium chloride, 10-100g / L boric acid and 0.1-50g / LHT-MB acid zinc additive and acid zinc brightener, PH3.0- 6.0 electrogalvani...

Embodiment 2

[0033] Example 2, for products with larger sizes, the method of rack plating is adopted. Taking the method of rack plating as an example, the product is first ground and chamfered to R0.4-0.5mm with a vibration polishing machine, and the chamfer is ground for 10 hours ; After chamfering, use 40g / L hot-soaked universal degreasing powder solution to remove the oil on the surface of the product, and wash the surface of the product with spray water for 1-2 minutes; then pickle with 1-10% nitric acid for 90 seconds , remove the oxide layer and corrosion layer on the surface of the product; clean the surface of the product with ultrasonic equipment for 5 minutes to completely remove the hanging ash on the surface of the product; then activate it with nitric acid with a volume concentration of 0.1-1% for 30 seconds, and clean the product with tap water and pure water respectively 60 seconds; then hang galvanized the treated product, using 20-120g / L zinc chloride, 120-320g / L potassium ...

Embodiment 3

[0034]Embodiment 3, with embodiment 1, difference, grinding chamfering 1 hour; Pickling 30 seconds, removes the oxidation layer and corroded layer of product surface; Cleans product surface with ultrasonic equipment 1 minute, removes hanging ash on product surface completely ; Then activate with nitric acid with a volume concentration of 0.1-1% for 5 seconds, and wash the product with tap water and pure water for 60 seconds; after electroplating copper, activate with hydrochloric acid or sulfuric acid with a volume concentration of 1-5% for 10 seconds.

[0035] A composite coating process for NdFeB magnets of the present invention adopts a composite coating structure of "zinc + zinc-nickel alloy + copper + nickel". , Electro-galvanizing after activation can obtain a galvanized layer that is very firmly combined with the substrate and has no effect on the thermal demagnetization of the magnet; based on the galvanized layer, electro-galvanized zinc-nickel alloy and copper are use...

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Abstract

The invention discloses a neodymium-iron-boron magnet with a composite coating and a preparation process thereof. The neodymium-iron-boron magnet comprises a neodymium-iron-boron matrix, and is characterized in that the neodymium-iron-boron matrix is provided with the composite coating which structurally comprises a zinc layer, a zinc-nickel alloy layer, a copper layer and a nickel layer. The preparation process comprises the steps of grinding and chamfering, oil removal, acid pickling, ultrasonic cleaning, activation, zinc electroplating, zinc-nickel alloy electroplating, copper electroplating, nickel electroplating and drying. The composite coating being complete, dense, uniform and bright can be obtained. The composite coating has a quite small influence on the performance of the magnetand greatly lowers the thermal demagnetizing rate of the magnet; the binding force between the coating and the matrix is firm, and the test requirements for grinding, thermal vibration, falling, thepushing and drawing force and the like can be met; the corrosion resistance is great, and the neutral salt spray test can be up to 96 hours; and the process is simple in procedure control and easy toapply and popularize.

Description

Technical field: [0001] The invention relates to the technical field of surface treatment of NdFeB magnets, in particular to a NdFeB magnet with a composite coating and a preparation process thereof. Background technique: [0002] New NdFeB magnets are the third generation of rare earth materials, usually made of Nd 2 Fe 14 Composed of B main phase and neodymium-rich phase at the grain boundary, it is a magnetic functional material with poor corrosion resistance and its magnetic structure is easily affected by temperature. The composite coating process can form a coating on the surface of the NdFeB magnet that has excellent corrosion resistance and has little effect on the thermal demagnetization of the magnet. [0003] At present, the types of coatings commonly used for NdFeB magnets are zinc plating, double nickel plating, nickel copper nickel plating, aluminum plating, and epoxy plating. Although each has its advantages, it also has its shortcomings. Among them, doubl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D5/14C25D3/22C25D3/38C25D3/56C25D3/12H01F1/057H01F41/02
CPCC25D3/12C25D3/22C25D3/38C25D3/56C25D5/14H01F1/0572H01F41/026C25D3/565C25D5/12C25D7/001H01F1/057H01F7/0221
Inventor 解长波陈德金
Owner YANTAI DONGXING MAGNETIC MATERIALS INC
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