Pre-plating process of chemically-plated Ni-P alloy

An alloy process and electroless plating technology, which is applied in the direction of liquid chemical plating, metal material coating process, magnetic materials, etc., can solve the problems of poor bonding between the coating and the magnet, affecting the close combination of the coating and the substrate, and peeling of the coating.

Inactive Publication Date: 2011-05-04
SANVAC BEIJING MAGNETICS +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Electroless plating of Ni-based alloys on the surface of sintered permanent magnets is prone to peeling and peeling of the coating. It can be said that the problem of poor bonding between the coating and the magnet is the problem of affecting the surface of electroless Ni-based alloys. In the actual NdFeB magnet anti-corrosion technology Obstacles in application promotion
[0004] The poor bonding force of the Ni-P electroless coating prepared on the surface of the sintered NdFeB magnet is mainly due to the following three reasons: (1) Since the sintered NdFeB magnet is prepared by powder metallurgy, there will be uneven surface quality, many pores, and loose and many other defects
In the process of material processing and substrate pretreatment, it is easy to appear oil stains, residual liquid and other impurities on the surface, which will affect the combination of the coating and the substrate; It is very easy to interact with other metal ions in the solution such as Ni during the treatment or during the plating process. 2+ When a replacement reaction occurs, the replaced metal Ni itself has a high self-catalytic activity, but due to the rich Nd, it will also react in an aqueous solution to produce a large amount of H 2 , so that the replacement layer becomes loose, which will also affect the bonding force of the coating; (3) Since the sintered NdFeB magnet has a porous surface structure, it has a large surface area and has a strong oxophilicity in the environment. The surface can produce a layer of oxide film in a short period of time, and the oxide film itself is not active, which affects the tight combination of the coating and the substrate
[0005] There are some reports both at home and abroad for the method of electroless plating that adopts the ultrasonic wave to assist, as Mallory studied the influence of different ultrasonic frequencies (25kHz and 40kHz) on the electroless Ni layer (Malloy G O et al, plating and surface Finishing, 1985, 72 (9 ): 64-68, Park et al. also studied the effects of different ultrasonic frequencies (28kHz, 40kHz and 68kHz) and different pH values ​​(4.3-5.7) on the deposition amount, P content and surface finish of the coating (ParkY S etal, surface and coating Technology, 2002, 153(2 / 3): 245-251), but no technology has been found to improve the bonding force between the coating and the substrate by means of ultrasonic assistance

Method used

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  • Pre-plating process of chemically-plated Ni-P alloy
  • Pre-plating process of chemically-plated Ni-P alloy
  • Pre-plating process of chemically-plated Ni-P alloy

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Prepare sample D10.5*2.5, where 2.5 is the direction of magnetization, and the density of the sample is 7.4g / cm 3 , using the conventional process for pre-plating for 20 minutes and ultrasonic pre-plating for 20 minutes, wherein the frequency of ultrasonic pre-plating is 40kHz, the power of ultrasonic pre-plating is 110W, and the temperature of ultrasonic pre-plating is 56°C. After 45 minutes, the finished product was evaluated by thermal shock test and knife engraving test, and the results are shown in Table 1

[0026] Table 1

[0027]

[0028] From the results, after 20 minutes of ultrasonic pre-plating, the bonding force between the substrate and the coating can be improved.

Embodiment 2

[0030] Prepare sample D12.5*2.5, where the 2.5 direction is the magnetization direction, and the density of the sample is 7.5g / cm 3 , using the conventional process for pre-plating for 30 minutes and ultrasonic pre-plating for 30 minutes respectively, wherein the frequency of ultrasonic pre-plating is 50kHz, the power of ultrasonic pre-plating is 90W, and the temperature of ultrasonic pre-plating is 60°C. After plating for 45 minutes, thermal shock and knife engraving tests were used to evaluate the bonding strength of the finished product. The results are shown in Table 2:

[0031] Table 2

[0032]

Embodiment 3

[0034] Prepare sample D12.5*2.5, where the 2.5 direction is the magnetization direction, and the density of the sample is 7.5g / cm 3 , using the conventional process for pre-plating for 25 minutes and ultrasonic pre-plating for 25 minutes, wherein the frequency of ultrasonic pre-plating is 45kHz, the power of ultrasonic pre-plating is 100W, and the temperature of ultrasonic pre-plating is 57°C. After 45 minutes of plating, the finished product was evaluated by thermal shock and knife engraving experiments, and the results are shown in Table 3:

[0035] table 3

[0036]

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Abstract

The invention relates to a pre-plating process of a chemically-plated Ni-P alloy, in particular to an ultrasonic pre-plating process of the chemically-plated Ni-P alloy. Ultrasonic pre-plating frequency is between 40 and 50 kHz, ultrasonic pre-plating power is 100W+ / -10, ultrasonic pre-plating temperature is between 56 and 60 DEG C and ultrasonic pre-plating time is between 20 and 30 minutes. A pre-plated layer obtained by the process is uniform and dense and is tightly bonded with a substrate, and the bonding force between the substrate and the plated layer can be enhanced remarkably.

Description

technical field [0001] The invention relates to a magnet surface treatment process, in particular to a pre-plating process for electroless Ni-P alloy plating. technical background [0002] The bonding force between the coating and the substrate is a very important process index for NdFeB sintered magnets, and it is also one of the important indicators to measure the quality of the coating. [0003] Electroless plating of Ni-based alloys on the surface of sintered permanent magnets is prone to peeling and peeling of the coating. It can be said that the problem of poor bonding between the coating and the magnet is the problem of affecting the surface of electroless Ni-based alloys. In the actual NdFeB magnet anti-corrosion technology Obstacles in application promotion. [0004] The poor bonding force of the Ni-P electroless coating prepared on the surface of the sintered NdFeB magnet is mainly due to the following three reasons: (1) Since the sintered NdFeB magnet is prepared...

Claims

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Application Information

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IPC IPC(8): C23C18/18C23C18/32H01F1/057
Inventor 赵玉刚姜兵宋琪杨雁孙立柏王浩颉
Owner SANVAC BEIJING MAGNETICS
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