阅读说明：本技术 用于提高钕铁硼磁体镀层均匀分布性的电镀镍溶液配方及其方法 (Formula and method of nickel electroplating solution for improving uniform distribution of neodymium iron boron magnet coating ) 是由 陈国新 许式袍 翁浩洲 胡嘉炜 于 2019-09-05 设计创作，主要内容包括：本发明公开了一种用于提高钕铁硼磁体镀层均匀分布性的电镀镍溶液配方及其方法,配方包括的各组分及其浓度为：氯化镍70～150g/L、氯化钾或硫酸钠导电盐80～300g/L、硼酸35～55g/L、邻磺酰苯酰亚胺0.1～0.9mg/L,PH4.0-4.8。本发明的电镀镍溶液配方采用了高浓度氯化镍替代了现有技术中常用的硫酸镍,增大了阴极极化度,使用氯化镍的镀液分散能力和导电性均优于硫酸镍；采用高浓度氯化钾/硫酸钠导电盐,极大提高了镀液的电导率；去除传统配方工艺采用的络合物,可减少药液更换,水处理难度。(The invention discloses a formula of an electronickelling solution for improving the uniform distribution of a neodymium iron boron magnet coating and a method thereof, wherein the formula comprises the following components in percentage by weight: 70-150 g/L of nickel chloride, 80-300 g/L of potassium chloride or sodium sulfate conductive salt, 35-55 g/L of boric acid, 0.1-0.9 mg/L of o-sulfonylbenzene imide and 4.0-4.8 of PH. The formula of the nickel electroplating solution adopts high-concentration nickel chloride to replace the commonly used nickel sulfate in the prior art, so that the cathode polarization degree is increased, and the dispersion capacity and the conductivity of the plating solution using the nickel chloride are superior to those of the nickel sulfate; the conductivity of the plating solution is greatly improved by adopting high-concentration potassium chloride/sodium sulfate conductive salt; complex compound adopted by the traditional formula process is removed, and the liquid medicine replacement and water treatment difficulty can be reduced.)

1. The formula of the nickel electroplating solution for improving the uniformity of the coating of the neodymium-iron-boron magnet is characterized by comprising the following components in parts by weight: comprises the following components in percentage by weight: 70-150 g/L of nickel chloride, 80-300 g/L of potassium chloride or sodium sulfate conductive salt, 35-55 g/L of boric acid, 0.1-0.9 mg/L of o-sulfonylbenzene imide and pH value of 4.0-4.8.

2. A nickel electroplating method for improving the uniformity of a coating of a neodymium iron boron magnet is characterized by comprising the following steps: the method comprises the following steps:

1) pretreating the neodymium iron boron magnet;

2) pre-nickel plating: putting the pretreated neodymium iron boron magnet into a first nickel electroplating solution for nickel preplating treatment for 3600-8800 seconds, wherein the first nickel electroplating solution comprises nickel chloride, boric acid, sodium sulfate or potassium chloride conductive salt, o-sulfonylbenzimide and water, the mass volume concentration of the nickel chloride is 70-150 g/L, the mass volume concentration of the boric acid is 35-55 g/L, the mass volume concentration of the sodium sulfate or potassium chloride is 80-300 g/L, the mass volume concentration of the o-sulfonylbenzimide is 0.1-0.9 mg/L, a high-frequency direct current power supply is adopted in the nickel preplating treatment process, the current density is 0.1-0.5 ampere/square decimeter, the temperature of the nickel preplating solution is 45-55 ℃, and the pH value is 4.0-4.8.

3) Washing with water: after the nickel preplating, washing the neodymium iron boron magnet subjected to the nickel preplating treatment for multiple times by using deionized water;

interlayer activation: placing the washed neodymium-iron-boron magnet into an interlayer activation tank for treatment, wherein an activation solution consists of oxalic acid and water, the mass volume concentration of the oxalic acid is 1-3 g/L, and the temperature of the activation solution is 25-35 ℃;

washing with water: and (2) washing the interlayer activated neodymium-iron-boron magnet for multiple times by using deionized water, washing the residual activating liquid on the surface, and cleaning by using ultrasonic waves with the ultrasonic power of 1200W and the frequency of 40 KHz.

4) Plating semi-gloss nickel: putting the cleaned neodymium iron boron magnet into a second nickel electroplating solution for half-gloss nickel plating treatment, wherein the time is 5800 plus 7500 seconds, the second nickel electroplating solution is composed of nickel chloride, boric acid, sodium sulfate or potassium chloride conductive salt and water, the mass volume concentration of the nickel chloride is 70-150 g/L, the mass volume concentration of the boric acid is 35-55 g/L, the mass volume concentration of the sodium sulfate or potassium chloride is 80-300 g/L, a high-frequency direct current power supply is adopted in the half-gloss nickel plating treatment process, the current density is 0.1-0.5 ampere/square decimeter, the temperature of the half-gloss nickel plating solution is 45-55 ℃, and the pH value is 4.0-4.8.

5) Washing with water: after the semi-gloss nickel is plated, deionized water is adopted to clean the neodymium iron boron magnet which is plated with the semi-gloss nickel for multiple times;

interlayer activation: placing the washed neodymium-iron-boron magnet into an interlayer activation tank for treatment, wherein an activation solution consists of oxalic acid and water, the mass volume concentration of the oxalic acid is 3 g/L, and the temperature of the activation solution is 30 ℃;

washing with water: and (2) washing the interlayer activated neodymium-iron-boron magnet for multiple times by using deionized water, washing the residual activating liquid on the surface, and cleaning by using ultrasonic waves with the ultrasonic power of 1200W and the frequency of 40 KHz.

6) And performing bright nickel treatment on the cleaned neodymium iron boron magnet.

3. The method of electroplating nickel for improving the uniformity of a coating on a neodymium iron boron magnet according to claim 2, wherein the method comprises the following steps:

before pre-plating nickel, the neodymium iron boron magnet needs to be pre-treated;

1) acid washing: pickling the neodymium iron boron magnet by using a dilute nitric acid solution as a pickling solution;

2) washing with water: washing the neodymium iron boron magnet after the acid washing by using deionized water for multiple times, washing the pickling solution remained on the surface, and carrying out ultrasonic cleaning in the washing process, wherein the ultrasonic power is 2000W, and the frequency is 28 KHz;

3) electrolysis: putting the washed neodymium-iron-boron magnet into an electrolytic bath for electrolytic treatment, wherein the electrolytic treatment time is 320-450 seconds, the electrolyte consists of sodium hydroxide, sodium carbonate and water, the mass volume concentration of the sodium hydroxide is 20-60 g/L, the mass volume concentration of the sodium carbonate is 10-40 g/L, the current density in the electrolytic treatment process is 0.2-0.7 ampere/square decimeter, and the temperature of the electrolyte is 45-55 ℃;

4) washing with water: the electrolyzed neodymium-iron-boron magnet is cleaned for multiple times by deionized water, electrolyte remained on the surface is cleaned, ultrasonic cleaning is arranged in the cleaning process, the ultrasonic power is 2000W, and the frequency is 28 KHz;

5) and (3) activation: placing the washed neodymium-iron-boron magnet into an activation tank for treatment, wherein an activation liquid consists of ammonium bifluoride and water, the mass volume concentration of the ammonium bifluoride is 3-5 g/L, and the temperature of the activation liquid is 25-35 ℃;

6) washing with water: and (3) washing the activated neodymium-iron-boron magnet for multiple times by using deionized water, cleaning the residual activating liquid on the surface, and cleaning by using ultrasonic waves with the ultrasonic power of 2000W and the frequency of 28 KHz.

Technical Field

The invention relates to the field of neodymium iron boron magnet coatings, in particular to a formula of an electronickelling solution for improving the uniform distribution of neodymium iron boron magnet coatings and a method thereof.

Background

The electroplating process can effectively play a role in protecting and decorating the magnet, and is widely applied to the surface protection treatment of the neodymium iron boron magnet at present. There are many kinds of plating processes, such as nickel plating, copper plating, and tin plating. The nickel electroplating layer formed on the surface of the neodymium iron boron magnet by the nickel electroplating process has fine crystals and high stability in air, and is a more electroplating process currently used. The existing nickel electroplating process for the neodymium iron boron magnet mainly comprises pretreatment, nickel preplating, semigloss nickel, bright nickel and post-treatment. The most widely applied nickel electroplating process in the prior art is a watt nickel and neutral nickel formula, and the nickel electroplating process is characterized by mainly comprising the following steps of: the watt nickel plating solution has high main salt concentration, high deposition speed and good plating performance; the disadvantages are as follows: the nickel salt content is high, the allowable current density is high, the cathode polarization degree is reduced, the dispersion capability is poor, and the carrying-out loss of the plating solution is large. Neutral nickel plating solution is neutral, and the pH value is as follows: 5.6-7.0, the corrosivity is small, and the dispersing ability of the plating solution is improved by adopting a complexing agent; the disadvantages are as follows: the plating solution has short service cycle, high solution replacement cost and difficult treatment.

For example, in the prior art, a patent with publication number CN104120469B and named as a neodymium iron boron magnet nickel electroplating method discloses a neodymium iron boron magnet nickel electroplating method, which specifically comprises a pretreatment process, a nickel pre-plating process, a water washing process, a semigloss nickel electroplating process, a water washing process, a bright nickel electroplating process and a water washing process for a neodymium iron boron magnet, wherein a first nickel electroplating solution composed of nickel sulfate, boric acid, sodium succinate, sodium carboxyethyl sulfonate and water is adopted in the nickel pre-plating process, and a second nickel electroplating solution composed of nickel sulfate, diammonium hydrogen citrate, boric acid, ammonia water and water is adopted in the semigloss nickel electroplating process.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a formula of an electronickelling solution for improving the uniform distribution of a coating of a neodymium iron boron magnet, which obviously optimizes the uniform distribution of the coating of a product, greatly reduces the bone effect, and can save the cost of liquid replacement and water treatment.

The technical purpose of the invention is realized by the following technical scheme: a formula of an electronickelling solution for improving the uniformity of a coating of a neodymium iron boron magnet comprises the following components in percentage by weight: 70-150 g/L of nickel chloride, 80-300 g/L of potassium chloride or sodium sulfate conductive salt, 35-55 g/L of boric acid, 0.1-0.9 mg/L of o-sulfonylbenzene imide and pH value of 4.0-4.8.

The invention has the advantages that: the formula of the nickel electroplating solution adopts high-concentration nickel chloride to replace the commonly used nickel sulfate in the prior art, so that the cathode polarization degree is increased, and the dispersion capacity and the conductivity of the plating solution using the nickel chloride are superior to those of the nickel sulfate; the conductivity of the plating solution is greatly improved by adopting high-concentration potassium chloride/sodium sulfate conductive salt; complex compound adopted by the traditional formula process is removed, and the liquid medicine replacement and water treatment difficulty can be reduced.

Aiming at the defects in the prior art, the invention also aims to provide the nickel electroplating method for improving the uniform distribution of the coating of the neodymium iron boron magnet, which has the advantages that the uniform distribution of the coating of the product is obviously optimized, the bone effect is greatly reduced, and the liquid change cost and the water treatment cost can be saved.

The technical purpose of the invention is realized by the following technical scheme:

a nickel electroplating method for improving the uniformity of a coating of a neodymium iron boron magnet comprises the following steps:

1) pretreating the neodymium iron boron magnet;

2) pre-nickel plating: putting the pretreated neodymium iron boron magnet into a first nickel electroplating solution for nickel preplating treatment for 3600-8800 seconds, wherein the first nickel electroplating solution comprises nickel chloride, boric acid, sodium sulfate or potassium chloride conductive salt, o-sulfonylbenzimide and water, the mass volume concentration of the nickel chloride is 70-150 g/L, the mass volume concentration of the boric acid is 35-55 g/L, the mass volume concentration of the sodium sulfate or potassium chloride is 80-300 g/L, the mass volume concentration of the o-sulfonylbenzimide is 0.1-0.9 mg/L, a high-frequency direct current power supply is adopted in the nickel preplating treatment process, the current density is 0.1-0.5 ampere/square decimeter, the temperature of the nickel preplating solution is 45-55 ℃, and the pH value is 4.0-4.8.

3) Washing with water: after the nickel preplating, washing the neodymium iron boron magnet subjected to the nickel preplating treatment for multiple times by using deionized water;

interlayer activation: placing the washed neodymium-iron-boron magnet into an interlayer activation tank for treatment, wherein an activation solution consists of oxalic acid and water, the mass volume concentration of the oxalic acid is 1-3 g/L, and the temperature of the activation solution is 25-35 ℃;

washing with water: and (2) washing the interlayer activated neodymium-iron-boron magnet for multiple times by using deionized water, washing the residual activating liquid on the surface, and cleaning by using ultrasonic waves with the ultrasonic power of 1200W and the frequency of 40 KHz.

4) Plating semi-gloss nickel: putting the cleaned neodymium iron boron magnet into a second nickel electroplating solution for half-gloss nickel plating treatment, wherein the time is 5800 plus 7500 seconds, the second nickel electroplating solution is composed of nickel chloride, boric acid, sodium sulfate or potassium chloride conductive salt and water, the mass volume concentration of the nickel chloride is 70-150 g/L, the mass volume concentration of the boric acid is 35-55 g/L, the mass volume concentration of the sodium sulfate or potassium chloride is 80-300 g/L, a high-frequency direct current power supply is adopted in the half-gloss nickel plating treatment process, the current density is 0.1-0.5 ampere/square decimeter, the temperature of the half-gloss nickel plating solution is 45-55 ℃, and the pH value is 4.0-4.8.

5) Washing with water: after the semi-gloss nickel is plated, deionized water is adopted to clean the neodymium iron boron magnet which is plated with the semi-gloss nickel for multiple times;

interlayer activation: placing the washed neodymium-iron-boron magnet into an interlayer activation tank for treatment, wherein an activation solution consists of oxalic acid and water, the mass volume concentration of the oxalic acid is 3 g/L, and the temperature of the activation solution is 30 ℃;

washing with water: and (2) washing the interlayer activated neodymium-iron-boron magnet for multiple times by using deionized water, washing the residual activating liquid on the surface, and cleaning by using ultrasonic waves with the ultrasonic power of 1200W and the frequency of 40 KHz.

6) And performing bright nickel treatment on the cleaned neodymium iron boron magnet.

The invention has the advantages that: the nickel pre-plating step in the nickel electroplating method adopts a first nickel electroplating solution consisting of nickel chloride, boric acid, sodium sulfate or potassium chloride conductive salt, o-sulfonylbenzene imide and water, and the semi-gloss nickel plating step adopts a second nickel electroplating solution consisting of nickel chloride, boric acid, sodium sulfate or potassium chloride conductive salt and water, wherein the formulas of the first and second nickel electroplating solutions adopt high-concentration nickel chloride to replace the commonly used nickel sulfate in the prior art, the cathode polarization degree is increased, and the dispersion capacity and the conductivity of the plating solution using nickel chloride are superior to those of nickel sulfate; the conductivity of the plating solution is greatly improved by adopting high-concentration potassium chloride/sodium sulfate conductive salt; complex compound adopted by the traditional formula process is removed, and the liquid medicine replacement and water treatment difficulty can be reduced.

Drawings

Fig. 1 is a schematic structural diagram of a neodymium iron boron thin steel sheet magnet product in an embodiment of the invention.

Detailed Description

The present invention will be described in further detail with reference to examples.