A surface coating process for sintered NdFeB magnets

A technology of neodymium iron boron and magnets, which is applied in the direction of metal material coating process, coating, liquid chemical plating, etc., can solve the problems of poor bonding force, no essential improvement of salt spray resistance, large porosity, etc., to achieve Effects of reducing impact, good surface protection performance, and improving binding ability

Active Publication Date: 2018-03-02
EARTH PANDA ADVANCE MAGNETIC MATERIAL
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the surface protection treatment of sintered NdFeB permanent magnets is mainly carried out through the surface coating process. The surface coating process specifically includes electro-galvanizing, electro-nickel plating, electrophoresis, electroless nickel plating and other technologies. Poor, so that the current sintered NdFeB permanent magnets treated with surface coating can only keep the surface intact for 48 to 96 hours in the neutral salt spray test.
In addition, the electroless nickel-phosphorus alloy known in the prior art has improved mechanical properties and corrosion resistance compared with the above-mentioned conventional surface coating process, but its porosity is still relatively large, and the salt spray resistance is still not substantially improved.
As the application range of NdFeB magnetic materials continues to expand to technical fields such as automobile manufacturing and aerospace materials, it is difficult to meet the needs of the existing surface coating process for the surface protection of NdFeB magnetic materials; again, the surface of the existing technology Chloride ions present in the coating process have a greater negative impact on the magnetic properties of NdFeB magnetic materials, so the surface coating process of sintered NdFeB permanent magnets in the prior art needs to be improved urgently

Method used

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Examples

Experimental program
Comparison scheme
Effect test

specific Embodiment 1

[0024] ①. Sintered NdFeB magnet black sheet, performance 45H, size 50×15×8, after chamfering for 8 hours, clean it with ultrasonic frequency of 20000 Hz for 2 to 3 minutes, then degrease and wash with water ; Put the NdFeB product washed with water into nitric acid with a concentration of 3 to 6 degrees Baume for pickling, and then wash with water and then immerse it in the surface adjustment solution.

[0025] Wherein the degreasing liquid comprises the following components: sodium hydroxide 3 g / L, sodium carbonate 60 g / L, trisodium phosphate 60 g / L, sodium silicate 20 g / L and the water of balance; The temperature is 75-95° C., the pH value is 10-13, and the degreasing treatment time is 10-20 minutes.

[0026] The pickling solution includes the following components: nitric acid with a concentration of 3 to 6 Baume degrees and an inhibitor, and the inhibitor is 10 g / L urea; the time of pickling treatment is controlled until the NdFeB product is washed.

[0027] The surface ad...

specific Embodiment 2

[0035] ①. The sintered NdFeB magnet black sheet, performance 45H, specification R40.2×10×5.05×50, after chamfering for 6 hours, clean it with ultrasonic frequency of 30000 Hz for 1 to 2 minutes, and then remove Cleaning with oil and water; put the NdFeB product after water cleaning into nitric acid with a concentration of 3 to 6 degrees Baume for pickling, then wash with water and then immerse it in the surface conditioning solution.

[0036]Wherein the degreasing liquid comprises the following components: sodium hydroxide 15 g / L, sodium carbonate 90 g / L, trisodium phosphate 80 g / L, sodium silicate 15 g / L and the water of the balance; and the degreasing liquid The temperature is 75-95° C., the pH value is 10-13, and the degreasing treatment time is 10-20 minutes.

[0037] The pickling solution includes the following components: nitric acid with a concentration of 3 to 6 Baume degrees and an inhibitor, and the inhibitor is 20 g / L urea; the time of pickling treatment is controll...

specific Embodiment 3

[0046] ①. The sintered NdFeB magnet black sheet, performance 45M, specification φ8.3~φ4.5×15, chamfered for 5 hours, cleaned with ultrasonic frequency of 40000 Hz for 0.5 minutes, followed by degreasing and Washing with water: put the NdFeB product after washing with water into nitric acid with a concentration of 3-6 degrees Baume for pickling, then wash with water and then immerse in the surface conditioning solution.

[0047] Wherein the degreasing liquid comprises the following components: sodium hydroxide 10 g / L, sodium carbonate 30 g / L, trisodium phosphate 70 g / L, sodium silicate 10 g / L and the water of the remainder; and the degreasing liquid The temperature is 75-95° C., the pH value is 10-13, and the degreasing treatment time is 10-20 minutes.

[0048] The pickling solution includes the following components: nitric acid with a concentration of 3-6 Baume degrees and an inhibitor, and the inhibitor is 30 g / L urea; the time of pickling treatment is controlled until the Nd...

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Abstract

The invention discloses a sintered Nd-Fe-B magnet surface coating technology. The sintered Nd-Fe-B magnet surface coating technology comprises the following steps that firstly, oil removing, acid pickling and surface conditioning treatment are carried out on a sintered Nd-Fe-B magnetic black wafer in sequence; secondly, activation treatment is carried out on the Nd-Fe-B product treated through the first step; thirdly, nickel electroplating treatment is carried out on the Nd-Fe-B product treated through the second step; fourthly, chemical nickel tungsten phosphorus alloy plating treatment is carried out on the Nd-Fe-B product treated through the third step; and fifthly, baking treatment is carried out on the Nd-Fe-B product treated through the fourth step. According to the sintered Nd-Fe-B magnet surface coating technology, the nickel plating surface coating technology and the chemical nickel tungsten phosphorus alloy plating surface coating technology are combined to control the invasion of chloride ions to a Nd-Fe-B matrix, and the influence on the magnetic performance can be effectively reduced; and the bonding capability of a protective coating and the Nd-Fe-B matrix is improved, and good surface protection performance is achieved on Nd-Fe-B magnetic materials.

Description

technical field [0001] The invention relates to a surface coating process of a sintered NdFeB magnet, belonging to the technical field of surface protection treatment of NdFeB magnetic materials. Background technique [0002] NdFeB magnetic material is called "Magnetic King" because of its excellent magnetic properties. It is widely used in many fields such as electronics, electrical appliances, instruments, medical equipment, motors, sensors, automobiles, and wind power. However, due to the particularity of the preparation process of sintered NdFeB permanent magnets, sintered NdFeB permanent magnets have disadvantages such as poor corrosion resistance and serious self-powdering phenomenon. NdFeB magnets are mainly composed of three phases, namely the main phase, neodymium-rich phase and boron-rich phase, in which the neodymium-rich phase and boron-rich phase are generally distributed at the grain boundary, the neodymium-rich phase is easily oxidized, and the neodymium-rich ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23F17/00C23C18/32C25D3/12
Inventor 张强王守春陈静武田朋衣晓飞熊永飞
Owner EARTH PANDA ADVANCE MAGNETIC MATERIAL
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