WO2014153694A1

WO2014153694A1 - Electroplating and vapour deposition combined protection method for neodymium-iron-boron magnet

Info

Publication number: WO2014153694A1
Application number: PCT/CN2013/000433
Authority: WO
Inventors: 胡依群; 郑国芳; 鲍盈; 王应发; 徐治伟
Original assignee: 宁波韵升股份有限公司; 宁波韵升磁体元件技术有限公司; 宁波韵升特种金属材料有限公司; 宁波韵升高科磁业有限公司
Priority date: 2013-03-28
Filing date: 2013-04-15
Publication date: 2014-10-02
Also published as: CN103173763A

Abstract

Disclosed is an electroplating and vapour deposition combined protection method for a neodymium-iron-boron magnet, comprising the steps of: pre-treating the neodymium-iron-boron magnet, performing a vapour deposition treatment on the pre-treated neodymium-iron-boron magnet, and performing a surface electroplating treatment on the neodymium-iron-boron magnet after the vapour deposition treatment. The protection method has the advantages that the vapour deposition film layer formed firstly encloses the cellular structure on the surface of the neodymium-iron-boron magnet itself and does not cause any damage to the neodymium-iron-boron magnet that results in the reduction of the magnetic performance; thereby less or no heavy rare earth metals such as dysprosium and terbium or the strategic metal cobalt need to be added in the material formulation of the neodymium-iron-boron magnet, saving rare resources, and at the same time, the vapour deposition film layer can block the subsequent corrosion paths on the neodymium-iron-boron magnet caused by an electroplating solution, and also can overcome the pore defects of an electroplated coating, so that the external environment cannot contact the neodymium-iron-boron magnet through the pores of the electroplated coating. Therefore the corrosion resistance of the neodymium-iron-boron magnet is improved through the double protection of the vapour deposition film layer and the electroplated coating.

Description

Composite protection method for electroplating and vapor deposition of neodymium iron boron magnet

Technical field

The invention relates to a surface protection method for a neodymium iron boron magnet, in particular to a method for plating and vapor phase deposition composite protection of a neodymium iron boron magnet.

Background technique

NdFeB magnets have excellent magnetic properties and high cost performance. They are widely used in electronics, motors and communications. However, NdFeB magnets are very active and easily corroded, resulting in rust, chalking or Loss of magnetism and other issues greatly limits the service life and application areas of NdFeB magnets.

At present, the anti-corrosion performance is improved mainly by electroplating the surface of the neodymium-iron-boron magnet. Although the electroplating plating isolates the contact of the NdFeB magnet with the external environment to a certain extent and improves the corrosion resistance of the NdFeB magnet, due to the limitations of the electroplating process, the following problems exist: 1. Electroplating plating is more or less There are pores, and the external environment can contact the neodymium iron boron magnet through these pores, thereby corroding the neodymium iron boron magnet; 2. The neodymium iron boron magnet itself has a microporous structure, and directly plating the neodymium iron boron magnet, electroplating The liquid will infiltrate into the NdFeB magnet through the microporous structure to cause damage to the NdFeB magnet, causing a decrease in magnetic properties. In order to ensure that the magnetic properties of NdFeB magnets meet the design requirements, the corrosion resistance of NdFeB magnets is improved by adding heavy rare earth metals such as lanthanum and cerium or strategic metal cobalt in the material formulation of NdFeB magnets. , to resist the corrosion of electroplating liquid. As a result, China's expensive cesium, cesium and other heavy rare earth metals or strategic metal cobalt have been consumed, resulting in waste of resources.

Summary of the invention

The technical problem to be solved by the present invention is to provide a composite protection method for electroplating and vapor deposition of a neodymium iron boron magnet which can save rare resources such as heavy rare earth metal and strategic metal cobalt and has high corrosion resistance.

The technical solution adopted by the present invention to solve the above technical problems is as follows: A composite protection method for electroplating and vapor deposition of a neodymium iron boron magnet, comprising the following steps:

1 pretreating the neodymium iron boron magnet;

2 subjecting the pretreated NdFeB magnet to vapor deposition treatment;

3 The surface-plated treatment of the NdFeB magnet after the vapor deposition treatment.

The thickness of the vapor deposited film layer in the step 2 is at least. The thickness of the electroplated layer in the step 3 is 5 to 35; / _W. The pretreatment in step 1 described includes degreasing, descaling and activation treatment.

True H The vapor deposition process in the step 2 is nickel plating, copper plating, titanium plating, nickel-plated iron, iron plating, aluminum plating, galvanization, silver plating, stainless steel plating and chrome plating or a combination of at least two of them.

The electroplating process in the step 3 is electroplated nickel, electrogalvanized, and electroplated copper or a combination of at least two of them. Compared with the prior art, the invention has the advantages that a vapor deposition coating layer is formed on the surface of the neodymium iron boron magnet by first performing a vapor deposition treatment on the neodymium iron boron magnet, and the vapor deposited film layer has a surface of the neodymium iron boron magnet itself. The microporous structure is closed and does not cause damage to the NdFeB magnet, which causes a decrease in magnetic properties. Therefore, it is possible to add little or no heavy rare earth metal or strategic metal in the material formulation of the NdFeB magnet. Cobalt saves rare resources and is electroplated on the vapor-deposited film. The vapor-deposited film can block the corrosion path of the electroplating solution to the NdFeB magnet, and on the other hand, it can overcome the pores of the electroplated coating. Defects, the external environment can not be contacted with the NdFeB magnet through the pores of the electroplated coating; the vapor deposited film layer and the electroplated coating form a double protection to the NdFeB magnet, which improves the corrosion resistance of the NdFeB magnet, and has been tested. The NdFeB magnet treated by the method of the invention has a higher temperature and high humidity resistance test time than the existing NdFeB magnet. 2-6 times, a strong corrosion resistance, long life, high reliability and wide field of application;

Due to the presence of the vapor deposited layer, the thickness of the electroplated coating can be as thin as 5 to 35 /, and the thin plating plating can shorten the plating time, save the plating anode material and the plating solution, and reduce the plating of heavy metal waste liquid. Emissions, economic and environmental protection.

detailed description

The invention is further described in detail below with reference to the embodiments.

Embodiment 1 A composite protection method for electroplating and vapor deposition of a neodymium iron boron magnet comprises the following steps:

1 Pretreatment of the neodymium iron boron magnet, wherein the pretreatment includes processes such as degreasing, derusting and activation, and the specific process is:

1 -1 alkaline degreasing (deoiling) of neodymium iron boron magnet at a temperature of 50 to 70 ° C for 5 to 15 minutes;

1 - 2 pairs of degreased NdFeB magnets were washed twice with pure water;

1 -3 is pickled at a concentration of 5% nitric acid pickling solution at room temperature for 1 to 3 minutes (rust removal);

1 - 4 for two pure water washes;

1 - 5 for ultrasonic washing;

1- 6 for pure water washing; 1 -7 using a solution of ammonium hydrogen fluoride at a concentration of 15 g / L for activation treatment, wherein the temperature is room temperature, the time is 30 seconds;

1- 8 is washed with pure water, and the pretreatment is completed;

2, the pretreated NdFeB magnet is subjected to vapor deposition treatment: a nickel film is used in the vapor deposition process, the target power is 300 W, the gas pressure is 0. 2Pa, and the thickness of the vapor deposited film layer is l~5 / m _;

3 Electroplating treatment of the vapor-deposited NdFeB magnet: Electroplating nickel on the surface of the vapor deposited film layer, the plating thickness is 10~25, the electroplating temperature is 55 °C, wherein the nickel plating solution is nickel sulfate solution, nickel sulfate solution It consists mainly of nickel sulfate with a concentration of 330g/l, nickel chloride with a concentration of 50g/l, boric acid with a concentration of 40g/l, sodium decyl sulfate and water with a concentration of 0.08g/l, nickel sulfate. 5。 The pH of the solution was 3.5.

The neodymium-iron-boron magnet treated by the method of the present embodiment and the neodymium-iron-boron magnet which is only subjected to the electroplating treatment are respectively subjected to a pressure vessel test (PCT) test and a magnetic property magnetic flux test, and the crucible treated by the method of the present embodiment is used. The ferro-boron magnet was subjected to a time of 240 hours, and only the neodymium-iron-boron magnet subjected to the electroplating treatment was subjected to a time of 72 hours.

Embodiment 2: A composite protection method for electroplating and vapor deposition of a neodymium iron boron magnet, comprising the following steps: 1 pretreating a neodymium iron boron magnet, wherein the pretreatment includes a process of degreasing, derusting and activating, and a specific process for-

1 - 2 pairs of degreased NdFeB magnets were washed twice with pure water;

1 - 4 for two pure water washes;

1- 5 ultrasonic water washing;

1 -6 for pure water washing;

1- 7 is activated by a solution of ammonium hydrogen fluoride at a concentration of 15 g/L, wherein the temperature is room temperature and the time is 30 seconds;

1-8 is washed with pure water, and the pretreatment is completed;

2 The pretreated NdFeB magnet is subjected to vapor deposition treatment: an aluminum film is used in the vapor deposition process, the target power is 300 W, the gas pressure is 0.2 Pa, and the thickness of the vapor deposited film layer is l~5 m;

3 Electroplating the NdFeB magnet after vapor deposition: Electroplating nickel on the surface of the vapor deposited film, electricity The plating thickness is 5~15 / , and the electroplating temperature is 55 ° C. The electroplating nickel is nickel sulfate solution, the nickel sulfate solution has a main antimony concentration of 330 g/l of nickel sulfate, the concentration of 50 g/l of nickel chloride, and the concentration is 5。 The pH of the nickel sulfate solution is 3.8.

The neodymium iron boron magnet treated by the method of the present embodiment and the neodymium iron boron magnet only subjected to the electroplating treatment are respectively subjected to a pressure vessel test (PCT) test and a magnetic property magnetic flux test, and the ferroniobium iron treated by the method of the present embodiment is used. The boron magnet was subjected to a 216 hour stand time, and the NdFeB magnet subjected to only the plating treatment was subjected to a time of 36 hours.

Embodiment 3: A composite protection method for electroplating and vapor deposition of a neodymium iron boron magnet, comprising the following steps - 1 pretreating a neodymium iron boron magnet, wherein the pretreatment includes a process of degreasing, derusting and activating, and the specific process is :

1 - 2 pairs of degreased NdFeB magnets were washed twice with pure water;

1 - 4 for two pure water washes;

1 - 5 for ultrasonic washing;

1 -6 for pure water washing;

1- 8 is washed with pure water, and the pretreatment is completed;

2, the pretreated NdFeB magnet is subjected to vapor deposition treatment: a titanium film is used in the vapor deposition process, the target power is 300 W, the gas pressure is 0.2 Pa, and the thickness of the vapor deposited film layer is l~5 m _;

3 Electroplating treatment of the vapor-deposited NdFeB magnet: Electroplating nickel on the surface of the vapor deposited film layer, the plating thickness is 8~20, the plating temperature is 55 °C, wherein the nickel plating solution is nickel sulfate solution, nickel sulfate solution It consists mainly of nickel sulfate at a concentration of 330 g/l, nickel chloride at a concentration of 50 g/l, boric acid at a concentration of 40 g/l, sodium lauryl sulfate at a concentration of 0.08 g/l, and water, nickel sulfate. 0。 The pH of the solution was 4.0.

The neodymium iron boron magnet treated by the method of the present embodiment and the neodymium iron boron magnet only subjected to the electroplating treatment are respectively subjected to a pressure vessel test (PCT) test and a magnetic property magnetic flux test, and the ferroniobium iron treated by the method of the present embodiment is used. The boron magnet was subjected to a 144 hour stand time, and only the neodymium iron boron magnet subjected to the plating treatment was subjected to a time of 48 hours.

Embodiment 4: A composite protection method for electroplating and vapor deposition of a neodymium iron boron magnet, comprising the following steps: 1 Pretreatment of the NdFeB magnet, wherein the pretreatment includes processes such as degreasing, derusting and activation, and the specific process is:

1 - 2 pairs of degreased NdFeB magnets were washed twice with pure water;

1- 4 pure water washing;

1 - 5 for ultrasonic washing;

1- 6 for pure water washing;

1 -7 using a solution of ammonium hydrogen fluoride at a concentration of 15 g / L for activation treatment, wherein the temperature is room temperature, the time is 30 seconds;

1-8 is washed with pure water, and the pretreatment is completed;

2 The pre-treated NdFeB magnet is subjected to vapor deposition treatment: a stainless steel film is used in the vapor deposition process, the target power is 300 W, the gas pressure is 0.2 Pa, and the thickness of the vapor deposited film layer is 1 to 5 //« _;

3 Electroplating treatment of the vapor-deposited neodymium-iron-boron magnet: electroplating nickel on the surface of the vapor-deposited film layer, the plating thickness is 10~25 / , and the electroplating temperature is 55 ° C, wherein the nickel plating solution is nickel sulfate solution, nickel sulfate The solution is mainly composed of nickel sulfate having a concentration of 330 g/l, nickel chloride having a concentration of 50 g/l, boric acid having a concentration of 40 g/l, sodium t-decyl sulfate having a concentration of 0.08 g/l, and water, sulfuric acid. 5。 The pH of the nickel solution was 3.5.

The neodymium iron boron magnet treated by the method of the present embodiment and the neodymium iron boron magnet only subjected to the electroplating treatment are respectively subjected to a pressure vessel test (PCT) test and a magnetic property magnetic flux test, and the ferroniobium iron treated by the method of the present embodiment is used. The boron magnet was subjected to a 144 hour stand time, and only the neodymium iron boron magnet subjected to the plating treatment was subjected to a time of 72 hours.

Embodiment 5: A composite protection method for electroplating and vapor deposition of a neodymium iron boron magnet comprises the following steps: 1 pretreating a neodymium iron boron magnet, wherein the pretreatment includes a process of degreasing, derusting and activation, and a specific process for-

1- 1 at the temperature of 50~70 ° C for alkaline degreasing (deoiling) of the neodymium iron boron magnet, the time is 5~15 minutes;

1 - 2 pairs of degreased NdFeB magnets were washed twice with pure water;

1 - 4 for two pure water washes; 1- 5 ultrasonic water washing;

1- 6 for pure water washing;

1- 8 is washed with pure water, and the pretreatment is completed;

2, the pretreated NdFeB magnet is subjected to vapor deposition treatment: a nickel-iron film is used in the vapor deposition process, the target power is 300 W, the gas pressure is 0.2 Pa, and the thickness of the vapor deposited film layer is 1 to 5 / _W;

3 Electroplating treatment of the NdFeB magnet after vapor deposition: electroplating nickel on the surface of the vapor deposited film layer, the plating thickness is 8-20; m, the plating temperature is 55 °C, wherein the nickel plating solution is nickel sulfate solution, sulfuric acid The nickel solution has a main strontium concentration of 330 g/l of nickel sulfate, a concentration of 50 g/l of nickel chloride, a concentration of 40 g/l of boric acid, and a concentration of

0. 08 _g / twelve alkyl with sodium and water i composition, ra of nickel sulfate solution is 3.5.

The neodymium iron boron magnet treated by the method of the present embodiment and the neodymium iron boron magnet only subjected to the electroplating treatment are respectively subjected to a pressure vessel test (PCT) test and a magnetic property magnetic flux test, and the ferroniobium iron treated by the method of the present embodiment is used. The boron magnet was subjected to a 168 hour stand time, and only the neodymium-iron-boron magnet subjected to the plating treatment was subjected to a time of 48 hours.

Embodiment 6: A composite protection method for electroplating and vapor deposition of a neodymium iron boron magnet, comprising the following steps: 1 pretreating a neodymium iron boron magnet, wherein the pretreatment includes a process of degreasing, derusting and activating, the specific process For:

1 - 2 pairs of degreased NdFeB magnets were washed twice with pure water;

1- 3 is pickled at a concentration of 5% nitric acid pickling solution at room temperature for 1 to 3 minutes (rust removal);

1- 4 pure water washing;

1 - 5 for ultrasonic washing;

1 -6 for pure water washing;

1-8 is washed with pure water, and the pretreatment is completed;

2 The pre-treated NdFeB magnet is subjected to vapor deposition treatment: a copper film is used in the vapor deposition process, the target power is 300 W, the gas pressure is 0.2 Pa, and the thickness of the vapor deposited film layer is 1 to 5 / _W; 3 Electroplating treatment of the NdFeB magnet after vapor deposition: Electroplating nickel on the surface of the NdFeB magnet, the plating thickness is 17-35 m, the electroplating temperature is 55 °C, and the nickel plating solution is nickel sulfate solution, sulfuric acid The nickel solution is mainly composed of nickel sulfate having a concentration of 330 g/l, nickel chloride having a concentration of 50 g/l, boric acid having a concentration of 40 g/l, sodium lauryl sulfate having a concentration of 0.08 g/l, and water. 5。 The pH of the nickel sulfate solution was 3.5.

The neodymium iron boron magnet treated by the method of the present embodiment and the neodymium iron boron magnet only subjected to the electroplating treatment are respectively subjected to a pressure vessel test (PCT) test and a magnetic property magnetic flux test, and the ferroniobium iron treated by the method of the present embodiment is used. The boron magnet was subjected to a time of 360 hours, and only the neodymium-iron-boron magnet subjected to the plating treatment was subjected to a time of 96 hours.

In all of the above embodiments, the material formula of the NdFeB magnet is not added with a heavy rare earth metal such as ruthenium or osmium or a strategic metal cobalt.

In each of the examples, a neodymium iron boron magnet sample (example sample) treated by the method of the embodiment and a neodymium iron boron magnet sample (example comparative sample) treated only by the plating method in the present embodiment were used. Select 20 measurements of the maximum, minimum and average values of the magnetic flux, and select the non-surface treated NdFeB magnet sample 20 to measure the maximum, minimum and average values of the magnetic flux, and then obtain The magnetic attenuation of each of the example samples and the comparative samples of the respective examples with respect to the non-surface-treated NdFeB magnet samples, the magnetic attenuation indicates the average magnetic flux decay rate of each of the example samples and the comparative samples of the respective examples, and the magnetic flux test The results are shown in Table 1, where the magnetic flux unit is 10 - ³ mvb:

Table 1: Magnetic flux test table

Magnetic

Sample

Maximum flux minimum flux average flux magnetic attenuation 365 355 361 without surface treatment

NdFeB magnet sample

Example 1 Sample 363 342 355 1.66% Example 1 Comparative Sample 340 331 335 7.20% Example 2 Sample 362 342 356 1.39% Example 2 Comparative Sample 338 331 335 7.20% Example 3 Sample 365 345 358 0.83% Example 3 Comparative sample 343 330 336 6.93% Example 4 sample 361 341 354 1.94% Example 4 Comparative sample 340 330 334 7.48% Example 5 sample 363 340 355 1.66% Example 5 Comparative sample 345 333 337 6.65% Example 6 sample 364 344 357 1 .1 1 % Example 6 Comparative sample 340 335 337 6.65% As can be seen from Table 1, after the surface composite protection treatment of the sintered NdFeB magnet according to the method of the present invention, the sintered NdFeB magnet The magnetic attenuation is small, and the magnetic properties of the sintered NdFeB magnet before the surface protection treatment are substantially maintained. The surface composite protection method of the invention has little damage to the sintered NdFeB magnet, and the surface protection treatment method only by electroplating significantly reduces the damage to the sintered NdFeB magnet; thus, it can save 镝 and 铽Rare rare earth metals and strategic metals such as cobalt.

In the present invention, the vapor deposition process may be nickel plating, copper plating, titanium plating, nickel-plated iron, iron plating, aluminum plating, galvanization, silver plating, stainless steel plating, and chrome plating, or a combination of at least two of them. The electroplating process can also be electroplated nickel, electrogalvanized, and electroplated copper or a combination of at least two of them.

Claims

Rights request

A method for resistive plating and vapor deposition of a neodymium iron boron magnet, comprising the steps of:

1 pretreating the neodymium iron boron magnet;

2 subjecting the pretreated NdFeB magnet to vapor deposition treatment;

2. The method of plating and vapor phase deposition composite protection of a neodymium iron boron magnet according to claim 1, wherein the vapor deposited film layer in the step 2 has a thickness of at least l / .

The method for resisting electroplating and vapor phase deposition of a neodymium iron boron magnet according to claim 1 or 2, wherein the thickness of the electroplated layer in the step 3 is 5 to 35 /w.

4. A method of electroplating and vapor phase deposition composite protection of a neodymium iron boron magnet according to claim 1, wherein the pretreatment in the step 1 comprises degreasing, descaling and activation treatment.

The method of protecting and plating a neodymium-iron-boron magnet according to claim 1, wherein the vapor deposition process in the step 2 is nickel plating, copper plating, titanium plating, nickel plating. Iron, iron, aluminized, galvanized, silver plated, plated stainless steel and chrome or a composite of at least two of them.

6 . The method of plating and vapor phase deposition composite protection of a neodymium iron boron magnet according to claim 1 , wherein the plating process in the step 3 is electroplating nickel, electrogalvanizing and electroplating copper or among them. At least two complex