Electroplating technology

An electroplating process and electroplating solution technology, which is applied in the direction of electrolysis, electrolysis components, cells, etc., can solve the problems of the gap in the protective ability of the protective layer, the plating layer foaming and falling off, and the loss of protective effect, so as to improve the speed of electroplating film formation, The effect of uniform pH value and reducing the foaming phenomenon of the coating

Inactive Publication Date: 2020-07-14
EARTH PANDA ADVANCE MAGNETIC MATERIAL
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Problems solved by technology

Although the electroplating technology has been very mature in the iron and steel industry and has been used in the sintered NdFeB industry for many years, there are still some deficiencies in the electroplating technology on the surface of NdFeB magnets, which are mainly reflected in: (1) Sintered NdFeB produced by powder metallurgy process It is impossible for a boron magnet to be 100% dense. There must be certain holes inside the magnet, and some gas will remain in the holes. After electroplating, the gas remaining in the holes will be sealed in the magnet; (2) During the pretreatment process of magnet electroplating , especially during the pre-pickling process, due to the different corrosion rates of the grain boundary phase and the main phase, the grain boundary phase will corrode preferentially, and narrow and deep pits will be formed after the grain boundary phase is corroded, and these pits will also Residual gas, when the magnet is immersed in the electroplating solution, it is difficult for the electroplating solution to enter these pits completely due to capillary force, and the residual gas in the pit will also be encapsulated inside the magnet by the electroplating layer; (3) The electroplating solution is usually Being acidic, NdFeB magnets are very easy to react with it and release hydrogen gas. These gases will be adsorbed on the surface of the magnet and sealed inside the magnet by the electroplating layer formed later.
The gas encapsulated inside the magnet will be released gradually with the use of the magnet, especially when the temperature of the magnet rises, the gas will expand when heated, which will directly cause the coating to bubble and fall off, and then lose the protective effect
Existing experiments have shown that the failure of the protective layer on the surface of sintered NdFeB magnets is mainly due to internal reasons, that is, caused by the internal failure of the magnet, which directly leads to the fact that the protective ability of the same protective layer on the magnet surface is comparable to that on the pure metal surface. There is still a big gap

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] (1) Select N48 sintered NdFeB magnets with specifications of 40mm×40mm×3mm, and perform surface pretreatment on the magnets by grinding, pickling, and ultrasonic cleaning in order to remove impurities such as rust and oil stains remaining on the surface of the magnets ;

[0048] (2) Vacuumize the magnet, vacuumize to 5Pa and keep it for 3 hours, extract the residual gas on the surface of the magnet, and place the magnet on the figure 1 Immerse the electroplating device in the Zn electroplating solution. Before the magnet is completely immersed in the Zn electroplating solution, the vacuum degree of the space where the magnet is located is always maintained below 8Pa;

[0049] (3) Control the air pressure in the upper space of the electroplating tank to 800Pa, turn on the ultrasonic generator, the ultrasonic frequency is 30kHz, and start the pump at the same time to rush the Zn electroplating solution to the surface of the magnet at a speed of 0.2m / s. Turn on the electr...

Embodiment 2

[0055] (1) Select a sintered NdFeB magnet with a size of 50mm×40mm×2mm and a grade of 48M, and use sandblasting, pickling, and ultrasonic cleaning to perform surface pretreatment on the magnet to remove residual rust and oil on the surface of the magnet. impurities;

[0056] (2) Vacuumize the magnet, vacuumize to 8Pa and keep it for 5 hours, extract the residual gas on the surface of the magnet, and place the magnet on the figure 1 Immerse the electroplating device in the Zn-Co electroplating solution. Before the magnet is completely immersed in the Zn-Co electroplating solution, the vacuum degree of the space where the magnet is located is maintained below 10Pa;

[0057] (3) Control the air pressure in the upper space of the electroplating tank to 900Pa, turn on the ultrasonic generator, and the ultrasonic frequency is 40kHz; start the pump, and rush the electroplating solution to the surface of the magnet at a speed of 0.5m / s. Turn on the electroplating power supply, and el...

Embodiment 3

[0063] (1) Select a sintered NdFeB magnet with a size of 50mm × 25mm × 2mm and a grade of 48H, and use pickling, ultrasonic cleaning, and alcohol cleaning to perform surface pretreatment on the magnet to remove residual rust and oil on the surface of the magnet. impurities;

[0064] (2) Vacuumize the magnet, vacuumize to 4Pa and keep it for 6 hours, extract the residual gas on the surface of the magnet, and place the magnet on the figure 1 Immerse the electroplating device in the Zn-Fe electroplating solution. Before the magnet is completely immersed in the electroplating solution, the vacuum degree of the space where the magnet is located is maintained below 6Pa;

[0065] (3) Control the air pressure in the upper space of the electroplating tank to 500Pa; turn on the ultrasonic generators arranged on the bottom and side of the electroplating tank, and the ultrasonic frequency is 45kHz; start the pump, and rush the electroplating solution to the surface of the magnet at a spee...

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Abstract

The invention discloses an electroplating technology. The electroplating technology includes a pretreatment process, a vacuum sucking process and an electroplating process. In the pretreatment process, pretreatment is conducted on the surface of a magnet. In the vacuum sucking process, vacuum sucking is conducted on the pretreated magnet, and the vacuum sucking state is maintained. In the electroplating process, the magnet obtained after vacuum sucking is immersed into electroplating liquid, under the condition of negative pressure, ultrasonic waves and water flow impacts, a metal protection layer is electroplated on the surface of the magnet. By means of the electroplating technology, the bonding strength of the manufactured metal protection layer and the magnet is high, in addition, corrosion resistance is good, disengagement is not likely to happen, and in addition, the electroplating efficiency is high.

Description

technical field [0001] The invention belongs to the technical field of magnet surface protection, and in particular relates to an electroplating process. Background technique [0002] Sintered NdFeB magnets are the most magnetic permanent magnet materials so far. They are widely used in the automotive industry, electronic appliances, medical equipment, industrial motors and other fields. They are the fastest growing permanent magnets with the best market prospects in the world today. Material. Sintered NdFeB magnets have outstanding advantages such as high magnetic energy product, high coercive force, high energy density, high cost performance, and good mechanical properties, and have played an important role in the high-tech field. After more than 30 years of research and development, the production process of sintered NdFeB magnets has basically formed alloy smelting→hydrogen crushing→jet milling→forming→sintering→heat treatment, realizing the production of more than 100 ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D5/20C25D5/34C25D21/04C25D21/10C25D7/00
CPCC25D5/20C25D5/34C25D7/001C25D21/04C25D21/10
Inventor 刘友好查善顺王守春衣晓飞陈静武
Owner EARTH PANDA ADVANCE MAGNETIC MATERIAL
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