Novel protection technique for plating multilayer coating on surface of sintered Nd-Fe-B permanent magnet

A NdFeB, multi-layer plating technology, applied in metal material coating process, liquid chemical plating, superimposed layer plating, etc., can solve problems such as poor bonding force and plating solution penetrating into the magnet

Inactive Publication Date: 2009-05-27
CHINA JILIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In order to solve the problems of poor bonding force and the penetration of the plating solution into the interior of the magnet in direct electroplating on the surface of NdFeB, so as to make it have good anti-corrosion performance and bonding force, and reduce the effect of being corroded during the electroplating process, the present invention provides a A new process for surface protection of NdFeB permanent magnets with simple operation and easy industrialization, that is, a protection technology for sintered NdFeB surface coated with multi-layer coatings

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] [Example 1] At 50°C, in 100g / L NaOH and 80g / L NaOH 2 CO 3 Degrease and decontaminate the surface of sintered NdFeB magnets in the mixed solution of sintered NdFeB magnets; soak in 30g / L degreaser F solution at room temperature for 30 minutes at 40°C; 80g / L Na 3 PO 4 12H 2 Ultrasonic decontamination at room temperature in O solution for 10 minutes; in HCl and H 2 SO 4 In the mixed solution of pH = 4.0, acid wash at room temperature for 10 seconds. Zinc sulfate 200g / L, nickel sulfamate 100g / L, sodium hypophosphite 60g / L, additive glycolic acid 5ml / L, pH value 10, temperature 50°C, chemically plate NiZnP alloy on the surface of sintered NdFeB magnet for 20 minutes . After taking out the sample after electroless plating, in 80g / L nickel sulfate, 60g / L nickel chloride, 20g / L sodium hypophosphite, 130g / L sodium tungstate, 200g / L triamine citrate, 2g / L Additive HEDP solution for electroplating.

[0025] The temperature is 30°C and the pH value is 9.0. The current adop...

Embodiment 2

[0027] [Example 2] At 65°C, in 140g / L NaOH and 50g / L NaOH 2 CO 3 Degrease and decontaminate the surface of sintered NdFeB magnets in the mixed solution of sintered NdFeB magnets; soak in 50g / L degreaser F solution at room temperature for 25 minutes at 20°C; 100g / L Na 3 PO 4 12H 2 Ultrasonic decontamination at room temperature in O solution for 10 minutes; in HCl and H 2 SO 4 In the mixed solution of pH = 4.0, acid wash at room temperature for 5 seconds. Zinc sulfate 110g / L, nickel sulfamate 160g / L, sodium hypophosphite 40g / L, additive glycolic acid 10ml / L, pH value 10, temperature 70°C, chemically plate NiZnP alloy on the surface of sintered NdFeB magnet for 30 minutes . After taking out the sample after electroless plating, in 60g / L nickel sulfate, 40g / L nickel chloride, 30g / L sodium hypophosphite, 130g / L sodium tungstate, 230g / L triamine citrate, 5g / L Additive HEDP solution for electroplating. The temperature is 30°C and the pH value is 9.0. The current adopts a tri...

Embodiment 3

[0029] [Example 3] Carry out pre-plating treatment and electroless plating according to Example 1, and the formula of the electroplating solution is the same as Example 1. The temperature is 30°C and the pH value is 9.0. The control potential is a square wave, the upper limit of the potential is -2.0V, the lower limit is -0.8V, and ten cycles are used. The potential scanning speed is 0.4V / min.

[0030] After plating, the samples were washed with water and dried with hot air. The coating is bright and has good bonding force, and there is no white rust in the neutral salt spray test for 360 hours.

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PUM

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Abstract

The invention relates to a protective technology for plating a plurality of plating layers on the surface of sintered neodymium iron boron. The technology is characterized in that firstly the surface is subjected to pretreatment before plating; secondly, NiZnP alloy is chemically plated on the surface; and finally, a plurality of NiWP alloy (at least three layers) are plated on the surface through controlling potential or current. The technology adopts the following specific steps: A, pretreatment before plating; B, chemical plating of the NiZnP alloy; and C, electroplating of a plurality of NiWP alloy layers. The technology has the following advantages: (1) the plating layer resists neutral salt mist corrosion; (2) a moist heat resistant test of the plating layer: in a moist heat box, the temperature is 85 DEG C; the humidity is between 80 and 90 DEG C; the testing time is 360 hours; after testing, the plating layer has no bubble, rust spot or stain; and (3) the bonding force of the plating layer: a scratch method: scratch of 1*1mm<2> is scratched to a basal body from the plating layer by a knife; and the plating layer does not fall off.

Description

technical field [0001] The invention relates to the surface protection technology of sintered NdFeB permanent magnets, in particular to a protection technology for coating the surface of sintered NdFeB permanent magnets with multi-layer coatings. Background technique [0002] Since its inception, sintered NdFeB has been favored for its excellent magnetic properties and high cost performance, and its application has gradually expanded to industries such as electronics, military, electrical, aerospace, automobiles and home appliances. Since the NdFeB magnet is made by powder sintering technology, its structure is loose and porous, it is a non-single-phase solid solution, and its corrosion resistance is poor, so its surface must be protected. As the anti-corrosion decoration treatment of metal and non-metal, there are many mature methods at present. "Wet" plating includes electroplating and chemical plating; "dry" plating includes: vacuum evaporation, sputtering, thermal spray...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C28/02C23C18/48C25D3/12
Inventor 卫国英葛洪良赵震蒋岚余云丹
Owner CHINA JILIANG UNIV
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