CN119162626A - A two-step electroplating nickel-phosphorus alloy performance improvement process for neodymium iron boron - Google Patents
A two-step electroplating nickel-phosphorus alloy performance improvement process for neodymium iron boron Download PDFInfo
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- CN119162626A CN119162626A CN202411687940.2A CN202411687940A CN119162626A CN 119162626 A CN119162626 A CN 119162626A CN 202411687940 A CN202411687940 A CN 202411687940A CN 119162626 A CN119162626 A CN 119162626A
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/10—Electroplating with more than one layer of the same or of different metals
- C25D5/12—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium
- C25D5/14—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium two or more layers being of nickel or chromium, e.g. duplex or triplex layers
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/38—Electroplating: Baths therefor from solutions of copper
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/56—Electroplating: Baths therefor from solutions of alloys
- C25D3/562—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of iron or nickel or cobalt
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/34—Pretreatment of metallic surfaces to be electroplated
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Abstract
The invention discloses a two-step nickel phosphorus alloy electroplating performance improving process method for neodymium iron boron, which comprises the following steps of S101, pretreating a neodymium iron boron substrate, wherein a copper layer is plated on the surface of the pretreated neodymium iron boron substrate, S102, placing the neodymium iron boron substrate plated with the copper layer in a first nickel phosphorus electroplating solution for nickel phosphorus pre-plating, forming a first nickel phosphorus alloy layer on the outer surface of the copper layer, S103, placing the neodymium iron boron substrate plated with the first nickel phosphorus alloy layer in a second nickel phosphorus electroplating solution for thickening nickel phosphorus, forming a second nickel phosphorus alloy layer on the outer surface of the first nickel phosphorus alloy layer, wherein the concentration of the first nickel phosphorus electroplating solution is lower than that of the second nickel phosphorus electroplating solution, the PH value of the first nickel phosphorus electroplating solution is higher than that of the second nickel phosphorus electroplating solution, the first nickel phosphorus electroplating solution with low concentration and higher PH value can greatly reduce corrosion on the copper layer to form a uniform plating layer, and the second nickel phosphorus electroplating solution with high concentration and lower PH value is fast in plating speed, so that the nickel phosphorus electroplating is thickened.
Description
Technical Field
The invention relates to the technical field of neodymium-iron-boron magnet electroplating, in particular to a two-step method nickel-phosphorus alloy electroplating performance improvement process method for neodymium-iron-boron.
Background
The neodymium-iron-boron base material has extremely high magnetic energy product, and also has excellent magnetic properties such as high coercivity, high coercivity temperature coefficient, high saturation induction intensity and the like, but because the neodymium-iron-boron base material contains rare earth elements with mass fraction of about 35%, the rare earth elements are extremely active and are easy to oxidize and corrode and the like, thereby influencing the service performance and service life of the neodymium-iron-boron base material, the neodymium-iron-boron magnet is required to be formed after protective coating treatment is carried out on the surface of the neodymium-iron-boron base material, and the neodymium-iron-boron magnet has the advantages of high cost performance, good mechanical property and the like.
Electroplating is a common surface treatment mode, in the electroplating process, plating metal or other insoluble materials are used as an anode, a workpiece to be plated is used as a cathode, cations of the plating metal are reduced on the surface of the workpiece to be plated to form a plating layer, the compactness and the protection performance of the plating layer are particularly important for a neodymium iron boron substrate, and the electroplated nickel phosphorus alloy is one of plating species with excellent performance, has the advantages of high deposition speed, high current efficiency, strong corrosion resistance, good wear resistance, small influence on magnetic performance and the like, is often applied to the electroplated neodymium iron boron substrate, in the prior art, in order to exert the best performance of the neodymium iron boron magnet, generally, cyanide-free alkaline copper is electroplated on the neodymium iron boron substrate, then nickel phosphorus alloy is electroplated on the outer surface of a copper layer, generally, a plating solution used for electroplating nickel phosphorus alloy needs to keep low PH to stabilize the phosphorus content of the plating layer, however, when the nickel phosphorus solution with low PH is just contacted with the copper layer, corrosion is generated on the copper layer, the corrosion resistance of the electroplated neodymium iron boron magnet is reduced, and the product performance is greatly reduced.
Disclosure of Invention
The invention aims to provide a two-step method nickel-phosphorus alloy electroplating performance improvement process method for neodymium-iron-boron, which solves the technical problem of improving the corrosion resistance of an electroplated neodymium-iron-boron magnet.
In order to achieve the aim, the technical scheme of the invention is that the two-step method nickel-phosphorus alloy electroplating performance improvement process method for neodymium iron boron comprises the following steps of;
s101, carrying out pretreatment on a neodymium iron boron substrate, wherein a copper layer is plated on the surface of the pretreated neodymium iron boron substrate;
s102, placing a neodymium iron boron substrate plated with a copper layer in a first nickel phosphorus electroplating solution for nickel phosphorus pre-plating, and forming a first nickel phosphorus alloy layer on the outer surface of the copper layer;
S103, placing the neodymium iron boron substrate plated with the first nickel phosphorus alloy layer into a second electroplating nickel phosphorus solution to thicken nickel phosphorus, and forming a second nickel phosphorus alloy layer on the outer surface of the first nickel phosphorus alloy layer;
The chemical components in the first nickel phosphorus electroplating solution are the same as the chemical components in the second nickel phosphorus electroplating solution, the concentration of each chemical component in the first nickel phosphorus electroplating solution is respectively lower than that of each corresponding chemical component in the second nickel phosphorus electroplating solution, so that the concentration of the first nickel phosphorus electroplating solution is lower than that of the second nickel phosphorus electroplating solution, and the PH value of the first nickel phosphorus electroplating solution is higher than that of the second nickel phosphorus electroplating solution.
Further, the first nickel phosphorus plating solution is composed of nickel sulfate, sodium citrate, sodium hypophosphite, orthophosphoric acid radical and water, wherein water is a solvent, and the second nickel phosphorus plating solution is composed of nickel sulfate, sodium citrate, sodium hypophosphite, orthophosphoric acid radical and water, wherein water is a solvent.
Further, in the step S102, the mass concentration of each chemical component in the first nickel phosphorus electroplating solution is as follows:
200-240g/L nickel sulfate;
45-65g/L sodium citrate;
sodium hypophosphite 20-30g/L;
orthophosphoric acid radical 15-25g/L;
The temperature of the nickel-phosphorus pre-plating is 60-70 ℃, the pH is 3.1-3.3, the anode is an electrolytic nickel block anode, if the barrel plating is adopted, the current density is 0.5-2.0A/dm 2, if the rack plating is adopted, the current density is 0.5-4.0A/dm 2;
The thickness d NIP1 = 0.5-2.5 microns of the first nickel-phosphorus alloy layer.
Further, in step S103, the mass concentration of each chemical component in the second nickel phosphorus electroplating solution is as follows:
360-440g/L of nickel sulfate;
70-100g/L of sodium citrate;
sodium hypophosphite 40-50g/L;
35-45g/L orthophosphate radical;
The temperature of thickened nickel phosphorus is 60-70 ℃, the pH is 2.7-2.9, the anode is an electrolytic nickel block anode, if barrel plating is adopted, the current density is 0.5-2.0A/dm 2, if rack plating is adopted, the current density is 0.5-4.0A/dm 2;
The thickness d NIP2 of the second nickel-phosphorus alloy layer=1 to 10 micrometers.
Further, the neodymium-iron-boron base material after the nickel-phosphorus pre-plating treatment in the step S102 is placed into an activating solution for activation, the activating solution adopts sulfuric acid with the concentration of 0.5-2% as the activating solution, and the activating time is 5-50 seconds at room temperature.
Further, the pretreatment process of S101 includes the following steps:
S601, placing a neodymium iron boron substrate into an activating solution for activation, wherein 0.5-2% hydrofluoric acid is adopted as the activating solution, and the activating time is 5-50 seconds at room temperature;
S602, placing the neodymium-iron-boron base material subjected to the activation treatment in a first electrolytic copper plating solution for preplating copper, and forming a first copper layer on the outer surface of the neodymium-iron-boron base material;
s603, placing the neodymium iron boron base material subjected to copper preplating in ultrapure water for water washing, wherein the water washing time is 5-15 seconds at room temperature;
S604, placing the washed neodymium iron boron substrate in a second electrolytic copper plating solution for thickening copper plating, and forming a second copper layer on the outer surface of the first copper layer;
S605, placing the thickened copper-plated neodymium-iron-boron substrate into an activating solution for activation, wherein the activating solution adopts 0.5-2% sulfuric acid as the activating solution, and the activating time is 5-50 seconds at room temperature.
Further, in step S602, the mass concentration of each chemical component in the first electrolytic copper plating solution is as follows:
Copper ions 1.5-2.5g/L;
HEDP:80-150g/L;
20-80g/L of potassium carbonate;
Potassium hydroxide 20-100g/L;
0.001-10g/L of organic amine compound;
The temperature of the preplating copper is 10-25 ℃, the pH value is 9-12, the anode is a phosphor copper anode or an oxygen-free copper anode, if the barrel plating is adopted, the current density is 0.1-0.3A/dm 2, if the hanging plating is adopted, the current density is 0.2-1.0A/dm 2;
The thickness d cu1 =0.5 to 2.5 μm of the first copper layer.
Further, in step S604, the mass concentration of each chemical component in the second electrolytic copper plating solution is as follows:
copper ions of 6-12g/L;
HEDP:80-200g/L;
20-80g/L of potassium carbonate;
Potassium hydroxide 20-100g/L;
5-15 ml/L of brightening agent;
5-15 ml/L of auxiliary agent;
The temperature of thickened copper plating is 40-60 o ℃, the pH is 8-10, the anode is a phosphor copper anode or an oxygen-free copper anode, if barrel plating is adopted, the current density is 0.5-2.0A/dm 2, if hanging plating is adopted, the current density is 0.5-4.0A/dm 2;
The thickness d cu2 =1.5 to 2.5 μm of the second copper layer.
Further, the copper ions are obtained by dissolving copper-containing inorganic salts selected from at least one of copper sulfate, copper acetate and copper carbonate during liquid preparation.
After the scheme is adopted, the first nickel phosphorus alloy layer is formed by electroplating the first nickel phosphorus electroplating solution, the second nickel phosphorus alloy layer is formed by electroplating the second nickel phosphorus electroplating solution, the types of chemical components in the first nickel phosphorus electroplating solution are the same as those in the second nickel phosphorus electroplating solution, water is used as a solvent, the concentration of the first nickel phosphorus electroplating solution is lower than that of the second nickel phosphorus electroplating solution, the PH value of the first nickel phosphorus electroplating solution is higher than that of the second nickel phosphorus electroplating solution, and the first nickel phosphorus electroplating solution with the low concentration and the higher PH value is used for electroplating, so that corrosion to the copper layer can be greatly reduced, the thickness difference between the edge and the middle of a neodymium iron boron substrate on which the first nickel phosphorus alloy layer is formed is small, the thickness of each part is more balanced, the plating speed is slower, the plating speed is more compact and more uniform, the second nickel phosphorus electroplating solution with the high concentration and the lower PH value is used for electroplating, the plating speed and the plating thickness is increased, so that the whole plating quality of the product can be improved.
Drawings
Fig. 1 is a flow chart of a prior art electroplating process.
FIG. 2 is a flow chart of the electroplating process of the present invention.
FIG. 3 is a schematic diagram of sampling points of S1 and S5 in the present invention.
FIG. 4 is a comparative view showing the appearance of the product after plating of the first example and the comparative example.
FIG. 5 is a graph showing the comparison of the example one with the comparative example after the neutral salt spray test for 72 hours after the completion of the plating.
FIG. 6 is a comparative table of technical experimental parameters of the first and comparative examples.
Detailed Description
The invention will be described in detail with reference to the accompanying drawings and specific embodiments.
The invention provides a two-step method nickel-phosphorus alloy electroplating performance improvement process method for neodymium iron boron, which comprises the following steps of;
s101, carrying out pretreatment on a neodymium iron boron substrate, wherein a copper layer is plated on the surface of the pretreated neodymium iron boron substrate;
s102, placing a neodymium iron boron substrate plated with a copper layer in a first nickel phosphorus electroplating solution for nickel phosphorus pre-plating, and forming a first nickel phosphorus alloy layer on the outer surface of the copper layer;
S103, placing the neodymium iron boron substrate plated with the first nickel phosphorus alloy layer into a second electroplating nickel phosphorus solution to thicken nickel phosphorus, and forming a second nickel phosphorus alloy layer on the outer surface of the first nickel phosphorus alloy layer;
The first nickel phosphorus plating solution consists of nickel sulfate, sodium citrate, sodium hypophosphite, orthophosphoric acid radical and water, the second nickel phosphorus plating solution consists of nickel sulfate, sodium citrate, sodium hypophosphite, orthophosphoric acid radical and water, each chemical component in the first nickel phosphorus plating solution is the same as each chemical component in the second nickel phosphorus plating solution, namely, the raw materials in the first nickel phosphorus plating solution and the second nickel phosphorus plating solution are the same, wherein the water is used as a solvent, the nickel sulfate is used as a main salt, the sodium hypophosphite and the orthophosphoric acid radical are used as additives, the PH value of the first nickel phosphorus plating solution is higher than the PH value of the second nickel phosphorus plating solution, the main salt concentration of the first nickel phosphorus plating solution is low, the PH value is higher, the corrosion to a copper layer can be greatly reduced, so that a first nickel phosphorus alloy layer with uniform thickness and balanced thickness can be formed, the PH value is lower, the nickel phosphorus plating speed is fast, the thickness of the plating layer can be increased on the basis of the first nickel phosphorus alloy layer, the copper layer cannot be influenced, and other chemical components in the first nickel phosphorus plating solution and the second nickel phosphorus plating solution can not consist of other chemical components.
The method comprises the steps of firstly carrying out activation, water washing and other treatments on the neodymium-iron-boron substrate, then carrying out preplating on the neodymium-iron-boron substrate in a first copper electroplating solution to form a first copper layer, then carrying out thickening copper plating on the neodymium-iron-boron substrate with the first copper layer, forming a second copper layer on the outer surface of the first copper layer, and finally forming the copper layer, wherein the first copper electroplating solution consists of copper ions, HEDP, potassium carbonate, potassium hydroxide, organic amine compounds and water, and the second copper electroplating solution consists of copper ions, HEDP, potassium carbonate, potassium hydroxide, a brightening agent, an auxiliary agent and water.
The pretreatment process in the step S101 comprises the following steps:
S601, placing a neodymium iron boron substrate into an activating solution for activation, wherein 0.5-2% hydrofluoric acid is adopted as the activating solution, and the activating time is 5-50 seconds at room temperature;
S602, placing the neodymium-iron-boron base material subjected to the activation treatment in a first electrolytic copper plating solution for preplating copper, and forming a first copper layer on the outer surface of the neodymium-iron-boron base material;
s603, placing the neodymium iron boron base material subjected to copper preplating in ultrapure water for water washing, wherein the water washing time is 5-15 seconds at room temperature;
S604, placing the washed neodymium iron boron substrate in a second electrolytic copper plating solution for thickening copper plating, and forming a second copper layer on the outer surface of the first copper layer;
S605, placing the thickened copper-plated neodymium-iron-boron substrate into an activating solution for activation, wherein the activating solution adopts 0.5-2% sulfuric acid as the activating solution, and the activating time is 5-50 seconds at room temperature.
Preferably, in the step S102, the mass concentration of each chemical component in the first nickel phosphorus electroplating solution is as follows:
200-240g/L nickel sulfate;
45-65g/L sodium citrate;
sodium hypophosphite 20-30g/L;
orthophosphoric acid radical 15-25g/L;
The temperature of the nickel-phosphorus pre-plating is 60-70 ℃, the pH is 3.1-3.3, the anode is an electrolytic nickel block anode, if the barrel plating is adopted, the current density is 0.5-2.0A/dm 2, if the rack plating is adopted, the current density is 0.5-4.0A/dm 2;
The thickness d NIP1 = 0.5-2.5 microns of the first nickel-phosphorus alloy layer.
Preferably, in the step S103, the mass concentration of each chemical component in the second nickel phosphorus electroplating solution is as follows:
360-440 g/L of nickel sulfate;
70-100g/L of sodium citrate;
sodium hypophosphite 40-50g/L;
35-45g/L orthophosphate radical;
The temperature of thickened nickel phosphorus is 60-70 ℃, the pH is 2.7-2.9, the anode is an electrolytic nickel block anode, if barrel plating is adopted, the current density is 0.5-2.0A/dm 2, if rack plating is adopted, the current density is 0.5-4.0A/dm 2;
The thickness d NIP2 of the second nickel-phosphorus alloy layer=1 to 10 micrometers.
Preferably, in the step S602, the mass concentration of each chemical component in the first electrolytic copper plating solution is as follows:
Copper ions 1.5-2.5g/L;
HEDP:80-150g/L;
20-80g/L of potassium carbonate;
potassium hydroxide 20-100g/L;
0.001-10g/L of organic amine compound;
The temperature of the preplating copper is 10-25 ℃, the pH value is 9-12, the anode is a phosphor copper anode or an oxygen-free copper anode, if barrel plating is adopted, the current density is 0.1-0.3A/dm 2, if hanging plating is adopted, the current density is 0.2-1.0A/dm 2, wherein the organic amine compound is triethylenediamine and diethylenetriamine, after the organic amine compound is added, the appearance uniformity of an electroplating product is good, HEDP is used as a complexing agent, and a stable complex can be generated with metal ions, and the full name is hydroxyethylidene diphosphonic acid;
The thickness d cu1 =0.5 to 2.5 μm of the first copper layer.
Preferably, in the step S604, the mass concentration of each chemical component in the second electrolytic copper plating solution is as follows:
copper ions of 6-12g/L;
HEDP:80-200g/L;
20-80g/L of potassium carbonate;
Potassium hydroxide 20-100g/L;
5-15 ml/L of brightening agent;
5-15 ml/L of auxiliary agent;
The temperature of thickened copper plating is 40-60 o ℃, the pH is 8-10, the anode is a phosphor copper anode or an oxygen-free copper anode, if barrel plating is adopted, the current density is 0.5-2.0A/dm 2, if hanging plating is adopted, the current density is 0.5-4.0A/dm 2, wherein the brightening agent adopts tin dioxide, the capability of reflecting light on the surface of the product is improved, and the auxiliary agent adopts butynediol;
The thickness d cu2 =1.5 to 2.5 μm of the second copper layer.
And in the step S102, the neodymium-iron-boron substrate plated with the first nickel-phosphorus alloy layer is activated to improve the binding force of the plating layer on the surface, so that the surface layer of the neodymium-iron-boron substrate is more uniform, the subsequent thickening nickel-phosphorus process is convenient to implement, the neodymium-iron-boron substrate after the nickel-phosphorus pre-plating treatment in the step S102 is placed into an activating solution to be activated, the activating solution adopts 0.5-2% sulfuric acid as the activating solution, and the activating time is 5-50 seconds at room temperature.
The method further comprises the steps of post-processing the neodymium iron boron base material with the second nickel phosphorus alloy layer formed after the step S103, placing the neodymium iron boron base material plated with the second nickel phosphorus alloy layer into ultrapure water, washing for 5-15 seconds at room temperature, wherein the ultrapure water is water containing water molecules and almost no impurities except water, packaging the neodymium iron boron base material by using a PVC box with meshes, drying the neodymium iron boron base material in a drying box downwards, and finally inspecting and delivering the neodymium iron boron base material.
The copper ions used in step S602 and S604 are obtained by dissolving a copper-containing inorganic salt selected from at least one of copper sulfate, copper acetate, and copper carbonate at the time of liquid preparation.
Embodiment one:
A two-step method for improving the performance of electroplated nickel-phosphorus alloy of neodymium iron boron is disclosed, wherein the substrate workpiece is a neodymium iron boron sheet, the size is 4mm multiplied by 6mm multiplied by 0.3mm, wherein 0.3mm is the thickness of the product, the neodymium iron boron substrate to be electroplated is placed in an electroplating bath for electroplating, steel balls and a co-plating sheet are adopted for co-plating, and the key combination is shown in fig. 2, and the method comprises the following steps:
(1) Activating the neodymium iron boron substrate in an activating solution, wherein the activating solution adopts 0.5-2% hydrofluoric acid, and the activating time is 5-50 seconds at room temperature;
(2) Placing the neodymium iron boron substrate subjected to the activation treatment into a first electrolytic copper plating solution for preplating copper, and forming a first copper layer on the outer surface of the neodymium iron boron substrate, wherein the mass concentration of each chemical component in the first electrolytic copper plating solution is as follows:
copper ions 2g/L;
HEDP:135g/L;
50g/L of potassium carbonate;
Potassium hydroxide 60g/L;
5g/L of organic amine compound,
The temperature of the preplating copper is 19 ℃ and the pH value is 10.4, an anode oxygen-free copper anode is subjected to barrel plating, the current density is 0.2A/dm 2, wherein the thickness d cu1 =1.5 micrometers of a first electroplated copper layer is mainly shown in fig. 6, the impact current of 300S is firstly applied during preplating copper, the current density of the impact current is about 0.25A/dm 2, a neodymium iron boron substrate is firstly rapidly plated with a copper layer so as to avoid substrate corrosion, then the current with the current density of 0.2A/dm 2 is applied for electroplating, the electroplating time is 5700S, and the thickness d cu1 =1.5 micrometers of the formed first electroplated copper layer is formed;
(3) Placing the pre-plated neodymium iron boron substrate into ultrapure water for water washing, wherein the water washing time is 5-15 seconds at room temperature;
(4) And (3) placing the washed neodymium iron boron substrate in a second electrolytic copper plating solution for thickening copper plating, and forming a second copper layer on the outer surface of the neodymium iron boron substrate, wherein the mass concentration of each chemical component in the second electrolytic copper plating solution is as follows:
copper ion 9.5g/L;
HEDP:150g/L;
55g/L of potassium carbonate;
potassium hydroxide 35g/L;
8ml/L of brightening agent;
auxiliary agent 7ml/L;
The temperature of the thickened copper plating was 50 ℃, the pH was 8.8, the current density was 0.3A/dm 2 by barrel plating, the plating time was 6600S, and the thickness d cu2 = 2.5 microns of the second electroplated copper layer formed.
(5) Activating the thickened copper-plated neodymium-iron-boron base material, and adopting 0.5-2% sulfuric acid as an activating solution, wherein the activating time is 5-50 seconds at room temperature.
(6) Placing the activated neodymium iron boron substrate in a first nickel phosphorus electroplating solution to carry out nickel phosphorus pre-plating, and forming a first nickel phosphorus alloy layer on the outer surface of the second copper electroplating layer, wherein the mass concentration of each chemical component in the first nickel phosphorus electroplating solution is as follows:
220g/L nickel sulfate;
55g/L sodium citrate;
Sodium hypophosphite 25g/L;
orthophosphoric acid radical 20g/L;
The temperature of the nickel-phosphorus pre-plating is 65 ℃, the pH value is 3.2, the anode is an electrolytic nickel block anode, the current density is 0.3A/dm 2, the electroplating time is 2400S, and the thickness d NIP1 =1.2 microns of the formed first nickel-phosphorus alloy layer is adopted.
(7) The neodymium iron boron substrate plated with the first nickel phosphorus alloy layer is placed in a second nickel phosphorus electroplating solution to thicken nickel phosphorus, and a second nickel phosphorus alloy layer is formed on the outer surface of the first nickel phosphorus alloy layer, wherein the mass concentration of each chemical component in the second nickel phosphorus electroplating solution is as follows:
440g/L nickel sulfate;
sodium citrate 100g/L;
45g/L of sodium hypophosphite;
orthophosphoric acid radical 40g/L;
The temperature of thickened nickel phosphorus is 65 ℃, the pH value is 2.9, the anode is an electrolytic nickel block anode, barrel plating is adopted, the current density is 0.3A/dm 2, the electroplating time is 4200S, and the thickness d NIP2 =1.8 microns of the second nickel phosphorus alloy layer.
And (3) carrying out post-treatment on the neodymium iron boron substrate on which the second nickel phosphorus alloy layer is formed, namely placing the neodymium iron boron substrate with thickened nickel phosphorus into ultrapure water, washing for 5-15 seconds at room temperature, packaging the neodymium iron boron substrate with a PVC box with meshes, and then placing the neodymium iron boron substrate into a drying box for drying downwards.
Comparative example
The difference from the first embodiment is that the nickel-phosphorus pre-plating process is absent, as shown in fig. 1, and is simply referred to as a single-layer nickel-phosphorus plating process, and as can be seen with emphasis on fig. 6, the plating time of the thickened nickel-phosphorus in the comparative example is 5400S, and the plating time of the thickened nickel-phosphorus in the first embodiment is 4200S, so that the nickel-phosphorus layers with the same thickness are formed.
And in combination with the illustration of fig. 3, S1 is the thickness of the edge sampling point of the neodymium iron boron product, S5 is the thickness of the middle sampling point of the neodymium iron boron product, the ratio in the edge is denoted as S1/S5, the smaller the ratio in the edge is, the closer the edge thickness and the middle thickness of the neodymium iron boron product are, the better the product quality and the better the performance are, if the ratio in the edge is bigger, the larger the difference between the edge thickness and the middle thickness of the neodymium iron boron product is, the copper layer is corroded by different layers, and the product quality is lower.
The results of example one and comparative example are shown in table 1 and table 2:
table 1. In the first embodiment, 5 samples were randomly selected for measurement to obtain a table of specific data in each sample edge:
table 2. In the comparative example, 5 samples were randomly selected for measurement to obtain a table of specific data for each sample edge:
The data comparison of tables 1 and 2 shows that the edge ratio fluctuation range of the neodymium iron boron product after being processed by the single-layer nickel phosphorus electroplating process in the comparison example is 1.33-1.51 under the premise of consistent electroplating conditions, the edge ratio fluctuation range of the neodymium iron boron product after being processed by the two-step nickel phosphorus alloy electroplating process in the first embodiment is 1.25-1.31, and compared with the two, the edge ratio fluctuation range of each sample block in the comparison example is large, the numerical value is high, the difference between the thickness of the edge part and the thickness of the middle part of the product is large, the thickness of the coating is unbalanced, the corrosion of different layers is generated on the copper layer everywhere, the thickness of the formed nickel phosphorus coating is unbalanced, the fluctuation range is large, and the edge ratio of each sample block is small, the difference between the thickness of the middle part and the edge part of the sample block is small, and the product performance is better after being processed by the two-step nickel phosphorus alloy electroplating process.
Meanwhile, the important point is that the product in the first embodiment has more uniform appearance, small difference and better appearance quality, and the product in the comparative example has large appearance difference and uneven color as shown in the figure 4.
With the key point shown in fig. 5, 32 neodymium iron boron products in the first embodiment and the comparative embodiment are randomly selected, and 72-hour neutral salt spray test experiments are respectively carried out, wherein 5% sodium chloride saline solution is adopted in the experiments, the pH value of the solution is adjusted to a neutral range (6-7), the test temperature is constant at 35 ℃ plus or minus 2 ℃, the relative humidity is 95% -98%, the sedimentation rate of salt spray is 1-2 ml/80cm & lt2 & gt h, and it can be seen that the 32 neodymium iron boron products in the first embodiment are uniform in appearance, all pass through the 72-hour neutral salt spray test experiments, the apparent color difference in the 32 neodymium iron boron products in the comparative embodiment is obvious, and 3 neodymium iron boron products do not pass through the 72-hour neutral salt spray test experiments.
In the second embodiment, compared with the first embodiment, the performance improvement process method for the two-step nickel-phosphorus electroplating alloy for neodymium iron boron is different in technological parameters of the first nickel-phosphorus electroplating solution in the nickel-phosphorus pre-plating process, and specifically comprises the following steps:
Placing the activated neodymium iron boron substrate in a first nickel phosphorus electroplating solution to carry out nickel phosphorus pre-plating, and forming a first nickel phosphorus alloy layer on the outer surface of the second copper electroplating layer, wherein the mass concentration of each chemical component in the first nickel phosphorus electroplating solution is as follows:
240g/L nickel sulfate;
60g/L sodium citrate;
30g/L of sodium hypophosphite;
orthophosphoric acid radical 25g/L;
The current density of barrel plating adopted in the treatment process of the first nickel-phosphorus alloy layer is 0.3A/dm 2, the anode is an electrolytic nickel block anode, the temperature of the first nickel-phosphorus electroplating solution is 65 ℃, the pH value is 3.2, the electroplating time is 2400S, and the thickness d NIP1 =1.2 microns of the formed first nickel-phosphorus alloy layer.
Table 3. In the second embodiment, 5 samples were randomly selected for measurement to obtain a table of specific data in each sample edge:
The method has the advantages that the specific fluctuation range in the edges of each sample block is 1.24-1.29, the specific value in the edges of each sample block is balanced, the fluctuation range is small, the difference between the middle part and the edge part of each sample block is small, the corrosion to a copper layer can be effectively reduced after the two-step process treatment of nickel phosphorus pre-plating and nickel phosphorus thickening is adopted, the corrosion to the copper layer can be greatly reduced by adopting the first nickel phosphorus plating solution with low main salt content and high PH value during nickel phosphorus pre-plating, the plating speed is slower, the plating layer is more compact, the plating layer is more uniform, the specific value in the edges is more uniform, on the basis, the second nickel phosphorus plating solution with high main salt content and lower PH value is adopted during nickel phosphorus thickening, the plating speed and the plating layer thickness are improved, the whole plating layer quality of a product can be improved, and the nickel phosphorus alloy layer is more uniform.
The above embodiments are only preferred embodiments of the present invention, and are not limited to the present invention, and all equivalent changes made according to the design key of the present invention fall within the protection scope of the present invention.
Claims (9)
1. A two-step method for improving the performance of electroplated nickel-phosphorus alloy of NdFeB is characterized by comprising the following steps of;
s101, carrying out pretreatment on a neodymium iron boron substrate, wherein a copper layer is plated on the surface of the pretreated neodymium iron boron substrate;
s102, placing a neodymium iron boron substrate plated with a copper layer in a first nickel phosphorus electroplating solution for nickel phosphorus pre-plating, and forming a first nickel phosphorus alloy layer on the outer surface of the copper layer;
S103, placing the neodymium iron boron substrate plated with the first nickel phosphorus alloy layer into a second electroplating nickel phosphorus solution to thicken nickel phosphorus, and forming a second nickel phosphorus alloy layer on the outer surface of the first nickel phosphorus alloy layer;
The chemical components in the first nickel phosphorus electroplating solution are the same as the chemical components in the second nickel phosphorus electroplating solution, the concentration of each chemical component in the first nickel phosphorus electroplating solution is respectively lower than that of each corresponding chemical component in the second nickel phosphorus electroplating solution, so that the concentration of the first nickel phosphorus electroplating solution is lower than that of the second nickel phosphorus electroplating solution, and the PH value of the first nickel phosphorus electroplating solution is higher than that of the second nickel phosphorus electroplating solution.
2. The process for improving performance of a two-step electroplated nickel-phosphorus alloy of neodymium iron boron according to claim 1, wherein the first electroplated nickel-phosphorus solution is composed of nickel sulfate, sodium citrate, sodium hypophosphite, orthophosphate and water, wherein water is a solvent, and the second electroplated nickel-phosphorus solution is composed of nickel sulfate, sodium citrate, sodium hypophosphite, orthophosphate and water, wherein water is a solvent.
3. The process for improving the performance of the nickel-phosphorus alloy electroplated by the two-step method for neodymium iron boron according to claim 2, wherein in the step S102, the mass concentration of each chemical component in the first nickel-phosphorus electroplating solution is as follows:
200-240g/L nickel sulfate;
45-65g/L sodium citrate;
sodium hypophosphite 20-30g/L;
orthophosphoric acid radical 15-25g/L;
The temperature of the nickel-phosphorus pre-plating is 60-70 ℃, the pH is 3.1-3.3, the anode is an electrolytic nickel block anode, if the barrel plating is adopted, the current density is 0.5-2.0A/dm 2, if the rack plating is adopted, the current density is 0.5-4.0A/dm 2;
The thickness d NIP1 = 0.5-2.5 microns of the first nickel-phosphorus alloy layer.
4. The process for improving the performance of the nickel-phosphorus alloy electroplated by the two-step method for neodymium iron boron according to claim 2, wherein in the step S103, the mass concentration of each chemical component in the second nickel-phosphorus electroplating solution is as follows:
360-440g/L of nickel sulfate;
70-100g/L of sodium citrate;
sodium hypophosphite 40-50g/L;
35-45g/L orthophosphate radical;
The temperature of thickened nickel phosphorus is 60-70 ℃, the pH is 2.7-2.9, the anode is an electrolytic nickel block anode, if barrel plating is adopted, the current density is 0.5-2.0A/dm 2, if rack plating is adopted, the current density is 0.5-4.0A/dm 2;
The thickness d NIP2 of the second nickel-phosphorus alloy layer=1 to 10 micrometers.
5. The process for improving the performance of the nickel-phosphorus alloy electroplated by the two-step method for neodymium iron boron according to claim 1, wherein the neodymium iron boron base material after the nickel-phosphorus pre-plating treatment in the step S102 is placed into an activating solution for activation, the activating solution adopts sulfuric acid with the concentration of 0.5-2% as the activating solution, and the activating time is 5-50 seconds at room temperature.
6. The two-step electroplated nickel-phosphorus alloy performance improvement process for NdFeB according to claim 1, wherein the pretreatment process of S101 comprises the following steps:
S601, placing a neodymium iron boron substrate into an activating solution for activation, wherein 0.5-2% hydrofluoric acid is adopted as the activating solution, and the activating time is 5-50 seconds at room temperature;
S602, placing the neodymium-iron-boron base material subjected to the activation treatment in a first electrolytic copper plating solution for preplating copper, and forming a first copper layer on the outer surface of the neodymium-iron-boron base material;
s603, placing the neodymium iron boron base material subjected to copper preplating in ultrapure water for water washing, wherein the water washing time is 5-15 seconds at room temperature;
S604, placing the washed neodymium iron boron substrate in a second electrolytic copper plating solution for thickening copper plating, and forming a second copper layer on the outer surface of the first copper layer;
S605, placing the thickened copper-plated neodymium-iron-boron substrate into an activating solution for activation, wherein the activating solution adopts 0.5-2% sulfuric acid as the activating solution, and the activating time is 5-50 seconds at room temperature.
7. The method for improving the performance of a neodymium iron boron two-step electroplated nickel-phosphorus alloy according to claim 6, wherein in the step S602, the mass concentration of each chemical component in the first electroplated copper solution is as follows:
Copper ions 1.5-2.5g/L;
HEDP:80-150g/L;
20-80g/L of potassium carbonate;
Potassium hydroxide 20-100g/L;
0.001-10g/L of organic amine compound;
The temperature of the preplating copper is 10-25 ℃, the pH value is 9-12, the anode is a phosphor copper anode or an oxygen-free copper anode, if the barrel plating is adopted, the current density is 0.1-0.3A/dm 2, if the hanging plating is adopted, the current density is 0.2-1.0A/dm 2;
The thickness d cu1 =0.5 to 2.5 μm of the first copper layer.
8. The method for improving the performance of a neodymium iron boron two-step electroplated nickel-phosphorus alloy according to claim 6, wherein in the step S604, the mass concentration of each chemical component in the second electroplated copper solution is as follows:
copper ions of 6-12g/L;
HEDP:80-200g/L;
20-80g/L of potassium carbonate;
Potassium hydroxide 20-100g/L;
5-15 ml/L of brightening agent;
5-15 ml/L of auxiliary agent;
The temperature of thickened copper plating is 40-60 o ℃, the pH is 8-10, the anode is a phosphor copper anode or an oxygen-free copper anode, if barrel plating is adopted, the current density is 0.5-2.0A/dm 2, if hanging plating is adopted, the current density is 0.5-4.0A/dm 2;
The thickness d cu2 =1.5 to 2.5 μm of the second copper layer.
9. The process for improving the performance of the nickel-phosphorus alloy electroplated by the two-step method for neodymium iron boron according to claim 7 or 8, wherein the copper ions are obtained by dissolving copper-containing inorganic salts in a liquid preparation process, and the copper-containing inorganic salts are at least one selected from copper sulfate, copper acetate and copper carbonate.
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| US20190156974A1 (en) * | 2017-11-17 | 2019-05-23 | Yantai Shougang Magnetic Materials, Inc. | Nd-fe-b magnet including a composite coating disposed thereon and a method of depositing a composite coating on the nd-fe-b magnet |
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| CN115198272A (en) * | 2022-06-20 | 2022-10-18 | 包头市英思特稀磁新材料股份有限公司 | Method for forming composite coating by directly electroplating copper on surface of neodymium iron boron |
| CN117802544A (en) * | 2023-12-29 | 2024-04-02 | 包头市英思特稀磁新材料股份有限公司 | Pretreatment process for improving interfacial binding force of nickel-phosphorus alloy plating layer on surface of neodymium iron boron |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US20190156974A1 (en) * | 2017-11-17 | 2019-05-23 | Yantai Shougang Magnetic Materials, Inc. | Nd-fe-b magnet including a composite coating disposed thereon and a method of depositing a composite coating on the nd-fe-b magnet |
| CN112899684A (en) * | 2020-08-21 | 2021-06-04 | 天津京磁电子元件制造有限公司 | Neodymium iron boron magnet copper nickel electroplating process |
| CN115198272A (en) * | 2022-06-20 | 2022-10-18 | 包头市英思特稀磁新材料股份有限公司 | Method for forming composite coating by directly electroplating copper on surface of neodymium iron boron |
| CN117802544A (en) * | 2023-12-29 | 2024-04-02 | 包头市英思特稀磁新材料股份有限公司 | Pretreatment process for improving interfacial binding force of nickel-phosphorus alloy plating layer on surface of neodymium iron boron |
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