Preparation process and system of NiP binary alloy

Abstract

The invention discloses a NiP binary alloy preparation process and system, and particularly relates to the field of NiP binary alloy preparation, the NiP binary alloy preparation process comprises the steps of S1, base material pretreatment, S2, preparation before plating, S3, parameter initialization, adjustment of the plating solution temperature of an electrolytic bath through a temperature control unit, S4, electrified deposition, starting of a high-frequency switching power supply, and output of current in the electrolytic bath in a constant current mode, and S5, post-plating treatment. A servo motor drives a lead screw to drive a moving block to horizontally move along a guide rod, a motor in a balance block is matched to drive a rotating shaft to drive the base material to rotate, the coating thickness of the base material is monitored in real time through an eddy current thickness gauge, when the coating thickness reaches 10-50 microns, electrification is stopped, and the base material in an electrolytic bath is taken out for drying. And each point on the surface of the base material is alternately contacted with a'fresh area 'and a'consumption area' of the plating solution, so that the influence of the plating solution concentration gradient on a plating layer is effectively eliminated.

Description

Technical Field

[0001] This invention relates to the field of NiP binary alloy preparation, and more specifically, to a NiP binary alloy preparation process and system. Background Technology

[0002] In the preparation of Ni-P binary alloys, electroplating is the core process for achieving "precise deposition of Ni-P alloy coatings on the substrate surface".

[0003] Traditional Ni-P alloy electroplating processes often employ fixed cathode mounts, which fix the substrate in a certain position within the electrolytic cell, making it impossible to move or rotate it.

[0004] Furthermore, the fixed mounting fixture keeps the substrate in the "concentration gradient zone" of the plating solution for a long time—the area near the circulation inlet is the "fresh zone," and the area far from the inlet is the "consumption zone." This can easily lead to large deviations in the coating thickness of the substrate during the reaction process. At the same time, during the electrodeposition process, the cathode surface will continuously generate... Bubbles (byproducts of the reaction) cannot be removed by moving the fixed fixture, and they tend to adhere to the substrate surface, forming pinholes and pits, which increases the defect rate. Summary of the Invention

[0005] The present invention provides a NiP binary alloy preparation process and system, the problem of which is: during the electrodeposition process, the cathode surface continuously generates... Bubbles (byproducts of the reaction) cannot be removed by moving the fixed fixture, and they tend to adhere to the substrate surface, forming pinholes and pits, which increases the defect rate.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a preparation process for a NiP binary alloy, comprising the following procedures: S1. Substrate pretreatment: The substrate to be plated is subjected to degreasing, pickling, activation and water washing in sequence. The degreasing is carried out with an alkaline degreasing agent and ultrasonic cleaning. The pickling is carried out with a 10% hydrochloric acid solution. The activation is carried out with a 5% sulfuric acid solution. S2. Pre-plating preparation: Inject plating solution into the electrolytic cell, the plating solution containing Ni 2+ H2PO2 - and complexing agents, of which Ni 2+ Concentration of 40-60 g / L, H2PO2 - The concentration is 80-100 g / L, and the concentration of the complexing agent is 30-50 g / L, wherein the complexing agent is sodium citrate; The pretreated substrate is fixed on a movable rotating cathode fixture in the electrolytic cell. The movable rotating cathode fixture is made of pure titanium. The movable rotating cathode fixture moves along the length of the electrolytic cell. An inert anode is fixed at the preset electrode mounting hole inside the electrolytic cell. Multiple storage tanks for adjusting the concentration and pH value of the plating solution are installed on the side of the movable rotating cathode fixture. pH adjuster and raw materials are added to the multiple storage tanks respectively. S3. Parameter initialization: Adjust the temperature of the electrolytic cell plating solution to 50-60℃ through the temperature control unit, adjust the pH of the plating solution to 4.0-5.0 through the storage tank, and start the plating solution circulation mechanism in the electrolytic cell to filter and circulate the plating solution. S4. Electrodeposition: Start the high-frequency switching power supply and output current in the electrolytic cell in constant current mode. The current density is controlled at 0.5-5A / dm², so that the Ni in the plating solution... 2+ H2PO2 - Driven by an electric field, Ni migrates directionally toward the cathode substrate. 2+ Two electrons are gained on the substrate surface, reducing it to Ni and H2PO2. - Ni gains one electron on the substrate surface, is reduced to P, and generates H2O. Ni and P are co-deposited on the substrate surface to form a Ni-P binary alloy coating. S5. Post-plating treatment: The thickness of the substrate coating is monitored in real time using an eddy current thickness gauge. When the coating thickness reaches 10-50μm, the power is stopped, and the substrate in the electrolytic cell is removed for drying.

[0007] In a preferred embodiment, lifting slots for raising and lowering movable rotating cathode hangers are provided on both sides of the top of the electrolytic cell. Both lifting slots are equipped with vertically arranged electric push rods. The top of each electric push rod is fixedly connected to a support plate. The top of each support plate is fixedly connected to a vertical frame. A lead screw is rotatably connected between the two vertical frames. The movable rotating cathode fixture includes a movable block with a threaded hole, a lead screw threaded into the threaded hole, a balance block fixedly connected to the bottom end of the movable block, a rotating shaft rotatably connected to the bottom end of the balance block, a base plate fixedly connected to the bottom of the balance block, and multiple electric grippers fixed to the bottom end of the base plate for clamping and fixing the substrate. A motor is fixed inside the balance block, and the drive shaft and the top of the rotation shaft of the motor are fixedly connected.

[0008] In a preferred embodiment, the electrolytic cell is provided with a circulating liquid inlet and a filter box; The bottom of the electrolytic cell is provided with an inclined slope for the plating solution to flow to the circulation port. The plating solution circulation mechanism includes a corrosion-resistant circulation pump, which is located above the filter box and fixed to one side of the electrolytic cell. The circulating liquid inlet, the filter box, and the electrolytic cell are connected in sequence through connecting pipes, and the inclined slope is set downward at the end facing the circulating liquid inlet.

[0009] In a preferred embodiment, a guide rod is provided below the lead screw, the guide rod is fixed between two uprights, and a sliding hole is provided on the balance block, through which the guide rod passes.

[0010] In a preferred embodiment, multiple storage tanks are fixed to the outside of the movable block, and the bottom of the storage tanks is connected to a drain pipe, with a solenoid valve installed at the connection between the drain pipe and the storage tank.

[0011] In a preferred embodiment, a drying port is provided at the top of each opposite side inside the electrolytic cell, and a fan is fixed on both sides outside the electrolytic cell, with the air outlets of the two fans connected to the corresponding drying ports.

[0012] In a preferred embodiment, baffles are provided above both drying ports, and the two baffles are fixed to the top sides of the electrolytic cell, respectively.

[0013] In a preferred embodiment, a primary filter cotton and a secondary filter element are sequentially arranged inside the filter housing, and the connecting pipe connected to the corrosion-resistant circulating pump is located on the side of the secondary filter element away from the primary filter cotton.

[0014] In a preferred embodiment, an interlayer is provided on the electrolytic cell between the outer wall and the inner wall, and the temperature control unit is disposed inside the interlayer. The electrolytic cell is fixed with support legs at both ends of the bottom, and the filter box is fixed with an auxiliary bracket at the bottom. Both the support legs and the auxiliary bracket are located on the ground.

[0015] The present invention also discloses a NiP binary alloy preparation system, which includes a central control unit, a temperature control unit, and a monitoring unit. The output terminals of the monitoring unit are all connected to the input terminals of the central control unit, and the input terminal of the temperature control unit is connected to the output terminal of the central control unit. The temperature control unit includes an electric heating element, which is disposed inside the interlayer. The monitoring unit includes a pH electrode, a temperature sensor, and an ICP-OES spectrometer. The detection ends of the pH electrode and the temperature sensor extend into the plating solution. A sampling port is provided at the connection between the corrosion-resistant circulating pump and the filter box. The Ni2+ concentration of the plating solution removed by the sampling port is detected using the ICP-OES spectrometer.

[0016] The beneficial effects of this invention are as follows: 1. This invention uses a servo motor to drive a lead screw to move a moving block horizontally along a guide rod, and a motor inside a balance block drives a rotating shaft to rotate the substrate. This allows the substrate surface to alternately contact the "fresh zone" and "consumed zone" of the plating solution, effectively eliminating the influence of the plating solution concentration gradient on the coating.

[0017] 2. This invention generates centrifugal force through the rotation of a movable rotating cathode holder, which, combined with the horizontal fluid disturbance, accelerates the detachment of bubbles from the substrate surface, thereby reducing the coating defect rate. At the same time, a high-definition camera added to the bottom of the base plate can monitor the amount of bubbles in real time. When the bubble concentration exceeds the standard, the central control unit automatically increases the rotation and movement speed to further enhance the bubble detachment effect, forming a closed-loop control of "monitoring-adjustment-optimization".

[0018] 3. In this invention, the movable rotating cathode hanger drives the substrate to rotate, and at the same time, the air force generated by the fan can evenly cover the surface of the substrate during subsequent drying.

[0019] 4. The storage tank moves synchronously with the mounting fixture. Raw materials and pH adjusters are added "following" the substrate's movement path through the drain pipe. The addition point is always close to the substrate. Combined with the stirring effect of the substrate's rotation, the raw materials can be evenly dispersed into the plating solution, avoiding plating quality problems caused by local concentration abnormalities. The follow-up addition allows the pH adjuster to act directly on the pH fluctuation area, without the need for excessive addition to offset diffusion loss. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the preparation process of the NiP binary alloy of the present invention; Figure 2 This is a schematic diagram of the overall structure of the electrolytic cell of the present invention; Figure 3 For the present invention Figure 2 Enlarged view of point A in the middle; Figure 4 For the present invention Figure 2 Enlarged view of point B in the middle; Figure 5 This is a schematic diagram of the inclined slope and the support frame of the present invention; Figure 6 This is a schematic diagram of the movable rotating cathode mounting structure of the present invention; Figure 7 This is a schematic diagram of the structure of the electric heating tube of the present invention; Figure 8 This is a schematic diagram of the internal structure of the filter housing of the present invention; The attached diagram is labeled as follows: 1. Electrolytic cell; 2. Movable rotating cathode hanger; 3. Support leg; 4. Auxiliary bracket; 5. Filter box; 6. Circulation liquid port; 7. Connecting pipe; 8. Corrosion-resistant circulation pump; 9. Drying port; 10. Baffle; 11. Fan; 12. Cover plate; 13. Lifting tank; 14. Electric push rod; 15. Support plate; 16. Inert anode; 17. Inclined slope; 18. Stand; 19. Servo motor; 20. Lead screw; 21. Guide rod; 22. Moving block; 23. Balance block; 24. Storage tank; 25. Drain pipe; 26. Base plate; 27. Electric gripper; 28. Rotating shaft; 29. ​​Interlayer; 30. Electric heating tube; 31. Primary filter cotton; 32. Secondary filter element. Detailed Implementation

[0021] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0022] Refer to the instruction manual appendix Figures 1-8 The structure shown illustrates a preparation process for a NiP binary alloy, comprising the following steps: S1. Substrate pretreatment: The substrate to be plated is subjected to degreasing, pickling, activation and water washing in sequence. Degreasing is performed with an alkaline degreasing agent and ultrasonic cleaning. Pickling is performed with a 10% hydrochloric acid solution and activation is performed with a 5% sulfuric acid solution. Specifically, the degreasing treatment involves using an alkaline degreasing agent (composition: sodium hydroxide 50g / L, sodium carbonate 30g / L, sodium phosphate 20g / L, temperature 50-60℃) on the substrate, combined with ultrasonic cleaning (power 300-500W, frequency 40kHz), for 15-20 minutes, to ensure that the removal rate of oil stains (such as cutting oil and rust-preventive oil) on the substrate surface is ≥98%. After degreasing, the substrate is immediately transferred to a deionized water washing tank (water temperature 40-50℃) for 5-8 minutes to avoid uneven pickling caused by degreasing agent residue.

[0023] Pickling treatment: Use a 10% hydrochloric acid solution (temperature 25-30℃) on the substrate for 8-12 minutes. Adjust the time according to different substrates (e.g., 10-12 minutes for steel substrates, 8-10 minutes for copper alloy substrates) to ensure complete removal of oxide scale (can be verified by the "water film test": the water film on the surface of the substrate is uniform and continuous without any breaks after pickling); after pickling, transfer to the second deionized water washing tank for 5 minutes to neutralize the residual hydrochloric acid.

[0024] Activation treatment: The substrate is treated with a 5% sulfuric acid solution (temperature 30-35℃) for 3-5 minutes. This process slightly corrodes the substrate surface to form a micro-rough surface (surface roughness Ra 0.2-0.4μm), improving the adhesion between the coating and the substrate. After activation, the substrate is immediately transferred to the third deionized water rinsing tank (water temperature 25-30℃) for 5 minutes. Then, compressed air (pressure 0.3-0.5MPa) is used to dry the surface moisture of the substrate to prevent secondary oxidation (the substrate must enter the pre-plating preparation stage within 30 minutes after activation).

[0025] S2. Pre-plating preparation: Inject plating solution into electrolytic cell 1. The plating solution contains Ni. 2+ H2PO2 - and complexing agents, of which Ni 2+ Concentration of 40-60 g / L, H2PO2 - The concentration of the complexing agent is 30-50 g / L, and the concentration of the complexing agent is 80-100 g / L. The complexing agent is sodium citrate. The plating solution should be prepared in the following order: first dissolve the complexing agent, then dissolve the Ni salt, and finally dissolve the reducing agent. First, add sodium citrate (30-50 g / L) to deionized water and stir until completely dissolved (using a stirrer plate, with a speed of 150-200 rpm and a temperature of 40-45℃). Then add nickel sulfate (calculated based on a Ni²⁺ concentration of 40-60 g / L, with a nickel sulfate purity ≥99.5%) and continue stirring for 15-20 minutes. Finally, add sodium hypophosphite (purity ≥99%, calculated based on H₂PO₂). - (Calculated at a concentration of 80-100 g / L). After stirring for 10 min, pre-adjust the pH to 4.0-5.0 with 10% sulfuric acid or 5% sodium hydroxide solution. After standing for 24 h, filter (using a 5 μm PTFE filter element) to remove undissolved impurities and then inject into electrolytic cell 1.

[0026] The pretreated substrate is fixed on the movable rotating cathode hanger 2 in the electrolytic cell 1. Lifting slots 13 are provided on both sides of the top of the electrolytic cell 1 for raising and lowering the movable rotating cathode hanger 2. Vertically arranged electric push rods 14 are fixed inside each of the two lifting slots 13. Support plates 15 are fixedly connected to the top of each electric push rod 14. Stands 18 are fixedly connected to the tops of both support plates 15. A lead screw 20 is rotatably connected between the two stands 18. The movable rotating cathode hanger 2 includes a moving block 22 with threaded holes. The lead screw 20 is threaded into these threaded holes. A balance block 23 is fixedly connected to the bottom of the moving block 22. A rotating shaft 28 is rotatably connected to the bottom of the balance block 23. A base plate 26 is fixedly connected to the bottom of the balance block 23. Multiple electric grippers 27 are fixed to the bottom of the base plate 26. The electric grippers 27 hold and fix the substrate. A motor is fixed inside the balance block 23. The drive shaft of the motor is fixedly connected to the top of the rotating shaft 28. The electric gripper 27 is connected to the power supply. The gripper head is made of polytetrafluoroethylene to avoid scratching the substrate. The electric gripper 27 is used to control the substrate to be clamped and fixed.

[0027] One of the uprights 18 is fixedly connected to one side of a servo motor 19. The drive shaft of the servo motor 19 is fixedly connected to one end of the lead screw 20. By starting the servo motor 19, the lead screw 20 can be driven to rotate, thereby moving the moving block 22.

[0028] The movable rotating cathode mount 2 is made of pure titanium. It moves along the length of the electrolytic cell 1 and fixes the inert anode 16 at a pre-set electrode mounting hole inside the electrolytic cell 1. Multiple storage tanks 24 for adjusting the plating solution concentration and pH value are installed on the side of the movable rotating cathode mount 2. pH adjuster and supplementary raw materials are added to the storage tanks 24 respectively. The pH adjuster is a 10% sulfuric acid solution and a 5% sodium hydroxide solution. The supplementary raw material is Ni salt (nickel sulfate solution, concentration 200 g / L). Concentration error ±2g / L), reducing agent (sodium hypophosphite solution, concentration 300g / L), Concentration error ±5g / L), complexing agent (sodium citrate solution, concentration 150g / L, error ±3g / L).

[0029] S3. Parameter Initialization: The temperature of the plating solution in electrolytic cell 1 is adjusted to 50-60℃ via the temperature control unit, and the pH of the plating solution is adjusted to 4.0-5.0 via the storage tank 24. The plating solution circulation mechanism in electrolytic cell 1 is started to filter and circulate the plating solution. An interlayer 29 is provided between the outer wall and the inner wall of electrolytic cell 1, and the temperature control unit is located inside the interlayer 29. Support legs 3 are fixed at both ends of electrolytic cell 1, and an auxiliary bracket 4 is fixed at the bottom of the filter box 5. The temperature control unit includes an electric heating tube 30. The heating element 30 is located inside the interlayer 29. The electric heating element 30 (power 2-5kW, material titanium alloy) inside the interlayer 29 adopts a PID temperature control algorithm. When the temperature sensor (the detection end extends 10-15mm into the plating solution) detects that the temperature of the plating solution is lower than 50℃, it will transmit the signal to the central control unit. The central control unit controls the electric heating element 30 to start at full power, with a heating rate of 5-8℃ / min. When the temperature reaches 55℃, it switches to half power for heat preservation. When the temperature exceeds 60℃, heating stops.

[0030] A pH electrode (using an acid-resistant glass electrode, measurement range 0-14) is used to collect the pH value of the plating solution in real time. When pH > 5.0, the central control unit opens the acid tank solenoid valve and adds sulfuric acid solution dropwise at a rate of 0.1-0.5 mL / s, pausing for 5 seconds every 10 seconds of addition to allow the pH to mix evenly before measuring again, until the pH drops to 4.5-5.0. When pH < 4.0, the alkali tank solenoid valve is opened and sodium hydroxide solution is added dropwise at the same rate to avoid a sudden increase in pH. hydrolysis.

[0031] An inclined slope 17 is provided at the bottom of the electrolytic cell 1. A circulation port 6 is connected to the bottom of one side of the electrolytic cell 1. A filter box 5 is fixed on the other side of the electrolytic cell 1. A corrosion-resistant circulation pump 8 is provided above the filter box 5. The corrosion-resistant circulation pump 8 is fixed to one side of the electrolytic cell 1. The circulation port 6, the filter box 5 and the electrolytic cell 1 are connected in sequence through a connecting pipe 7. The inclined slope 17 is inclined downward at the end facing the circulation port 6.

[0032] Inside the filter housing 5, a primary filter cotton 31 and a secondary filter element 32 are arranged in sequence. The connecting pipe 7 of the corrosion-resistant circulating pump 8 is located on the side of the secondary filter element 32 away from the primary filter cotton 31. A test port is opened at the top of the filter housing 5, and a cover plate 12 is snapped into the test port. By removing the cover plate 12, it is easy to replace the primary filter cotton 31 and the secondary filter element 32 inside.

[0033] During preparation, the corrosion-resistant circulating pump 8 is started. The plating solution flows out from the circulating liquid port 6 (inner diameter 50mm, with filter screen, pore size 5mm to prevent large particles of impurities from entering) at the bottom of the electrolytic cell 1, and enters the filter box 5 through the connecting pipe 7 (material PPR, inner diameter 40mm). It first passes through the primary filter cotton 31 (precision 10μm, material polypropylene, to intercept large particles of impurities), and then through the secondary filter element 32 (precision 1μm, material PTFE pleated filter element, to intercept tiny Ni-P particles). After filtration, the plating solution is transported back to the electrolytic cell 1 by the corrosion-resistant circulating pump 8, circulating 3-5 times per hour. The turbidity of the plating solution after filtration is ≤5NTU (monitored online by a turbidity meter).

[0034] S4. Electrodeposition: The inert anode 16 is connected to the positive output terminal of the high-frequency switching power supply via a wire, and the movable rotating cathode mount 2 is connected to the negative output terminal of the high-frequency switching power supply. The high-frequency switching power supply is started, and current is output in the electrolytic cell 1 in constant current mode, with the current density controlled at 0.5-5 A / dm², so that the Ni in the plating solution... 2+ H2PO2 - Driven by an electric field, Ni migrates directionally toward the cathode substrate. 2+ Two electrons are gained on the substrate surface, reducing it to Ni and H2PO2. - Ni gains one electron on the substrate surface, is reduced to P, and generates H2O. Ni and P are co-deposited on the substrate surface to form a Ni-P binary alloy coating. During the electrodeposition process, the central control unit is connected to the electric push rod 14 and the servo motor 19 to actively control the rotation speed of the lead screw 20 and the extension and retraction of the electric push rod 14. This ensures that the substrate is always in the plating solution during the electrodeposition process and drives the substrate to move or rotate uniformly in the plating solution, thereby increasing the contact efficiency.

[0035] It should be noted that a high-definition camera can be added to the bottom of the base plate 26 to monitor the amount of bubbles on the substrate surface in real time. When the bubble concentration exceeds ≥5 per cm², the central control unit automatically increases the substrate rotation speed (by 5-10 rpm) and the moving speed (by 5-10 mm / s), and simultaneously opens the solenoid valve of the raw material storage tank 24 to replenish 5%-10% sodium hypophosphite solution to suppress bubbles. Excessive reduction reduces bubble formation.

[0036] S5. Post-plating treatment: The thickness of the substrate coating is monitored in real time by an eddy current thickness gauge. When the coating thickness reaches 10-50μm, the power is stopped and the substrate in electrolytic cell 1 is taken out for drying.

[0037] Therefore, drying ports 9 are provided at the top of opposite sides inside the electrolytic cell 1. Fans 11 are fixed on both sides of the outside of the electrolytic cell 1. The air outlets of the two fans 11 are connected to the corresponding drying ports 9. Baffles 10 are provided above the two drying ports 9, and the two baffles 10 are fixed on both sides of the top of the electrolytic cell 1. The baffles 10 are used to shield the liquid splashed during drying.

[0038] Specifically, after electroplating is completed, the high-frequency switching power supply stops outputting, the electric push rod 14 starts, driving the support plate 15, the stand 18, and the movable rotating cathode hanger 2 to rise, so that the substrate is removed from the plating solution; when the substrate rises to the height of the drying port 9, the electric push rod 14 stops, the fan 11 starts, and room temperature compressed air is introduced into the drying port 9, while the substrate continues to rotate to ensure that the surface moisture evaporates evenly. The drying time is 10-15 minutes (adjusted according to the coating thickness, extended to 20 minutes for thick coatings); after drying, the surface temperature of the substrate is detected by an infrared thermometer to ensure that the temperature is ≤40℃ (to avoid high temperature causing coating oxidation), and then the electric gripper 27 releases and removes the substrate.

[0039] The dried substrate needs to undergo three tests: ① Adhesion test: using the cross-cut test (1mm spacing, depth to the substrate surface), the coating is adhered and then peeled off with 3M tape. No peeling is acceptable; ② Hardness test: using a microhardness tester (100g load, 10s holding time), 5 points are tested on the substrate surface. The average hardness ≥ HV500 is acceptable; ③ Appearance inspection: visually inspected (or with a magnifying glass, 10x magnification), the coating surface is free of pinholes, pits, and peeling, and the color is uniform (silver gray).

[0040] A guide rod 21 is provided below the lead screw 20. The guide rod 21 is fixed between the two uprights 18. A sliding hole is provided on the balance block 23. The guide rod 21 passes through the sliding hole, which can increase the stability of movement.

[0041] Multiple storage tanks 24 are fixed to the outside of the movable block 22, and the bottom of the storage tanks 24 are connected to a drain pipe 25. A solenoid valve is provided at the connection between the drain pipe 25 and the storage tanks 24.

[0042] Working principle: First, through the electrode mounting holes reserved on the side wall of electrolytic cell 1, the inert anode (DSA-coated titanium anode) is fixed and the substrate is clamped by the movable rotating cathode hanger 2, forming a closed loop of "anode-plating solution-cathode". The inclined slope 17 at the bottom of the tank is designed with a 15° inclination angle to avoid plating solution residue and sediment accumulation, providing favorable conditions for subsequent circulation filtration. Then, the temperature of the plating solution inside electrolytic cell 1 is controlled at 50-60℃. The DSA-coated titanium anode (IrO2-Ta2O5 coating) acts as the oxidation end in the electric field, mainly undergoing the water oxidation reaction: 2H2O-4e - →O2+4H + The generated H+ It can replenish the hydrogen ions consumed by the cathode reaction and maintain the pH stability of the plating solution. The plating solution is driven by the corrosion-resistant circulating pump 8, circulating along the path from the electrolytic cell 1 to the filter box 4 and finally back to the electrolytic cell 1. It circulates 3-5 times per hour, intercepting the tiny Ni-P particles and impurities generated in the plating solution and preventing defects such as pinholes and pits from appearing in the plating layer.

[0043] The movable rotating cathode holder 2 can move the clamped substrate along the length of the electrolytic cell 1, and the motor can drive the base plate 26 and the clamped substrate to rotate in the plating solution. This facilitates full contact between the substrate and the plating solution, and also allows for thorough mixing with the plating solution when adding raw materials or pH adjusters, thereby accelerating the detection efficiency and efficiency.

[0044] The movable rotating cathode holder 2 can change the depth of its insertion into the plating solution according to the extension and descent of the electric push rod 14. When it rises, it is convenient for personnel to remove the substrate. When the movable rotating cathode holder 2 moves to the position of the drying port 9, the electric push rod 14 rises, causing the substrate to be removed from the plating solution, making it easy to drain the substrate. At the same time, the fan 11 starts, and the generated wind can quickly blow away the liquid on the substrate.

[0045] The present invention also discloses a NiP binary alloy preparation system, including a central control unit, a temperature control unit, and a monitoring unit. The output end of the monitoring unit is connected to the input end of the central control unit, and the input end of the temperature control unit is connected to the output end of the central control unit.

[0046] The temperature control unit includes an electric heating element 30, which is disposed inside the interlayer 29; The monitoring unit includes a pH electrode and a temperature sensor, an ICP-OES spectrometer, and an eddy current thickness gauge. The detection ends of the pH electrode and temperature sensor extend into the plating solution. A sampling port is located at the connection between the corrosion-resistant circulating pump 8 and the filter housing 4. The plating solution removed through the sampling port is analyzed using the ICP-OES spectrometer. Concentration detection was performed every 2 hours, with sampling as follows: ① Open the shut-off valve to release the first 50 mL of plating solution (to rinse the sampling tube), then collect 10 mL of plating solution sample; ② Dilute the sample 100 times with 5% nitric acid solution (the dilution process was carried out in a clean bench to avoid contamination); ③ Inject the diluted sample into an ICP-OES spectrometer (model: PerkinElmer Optima 8300, detection limit ≤0.01 mg / L) for detection. Concentration; ④ After the detection is completed, the data is automatically imported into the central control unit. If the concentration is lower than 40g / L or higher than 60g / L, the system will immediately start the replenishment procedure.

[0047] The temperature sensor (model: PT100 platinum resistance thermometer, accuracy ±0.5℃) extends into the plating solution through a sealed interface on the side wall of electrolytic cell 1 to a depth of 10-15mm. The interface is sealed with a polytetrafluoroethylene (PTFE) sealing ring (temperature resistance ≤200℃, acid corrosion resistance) to prevent plating solution leakage. The pH electrode (model: Mettler Toledo InPro3250) is fixed by a dedicated electrode holder, with the electrode head 50-80mm away from the bottom of electrolytic cell 1 (avoiding contact with sediment at the bottom of the cell). It is calibrated every 7 days (using standard buffer solutions of pH=4.01 and pH=6.86) to ensure detection accuracy.

[0048] The probe of the eddy current thickness gauge (model: Fischer MPO, measuring range 0-100μm, accuracy ±1μm) is mounted above electrolytic cell 1 via a robotic arm (travel 500-1000mm, positioning accuracy ±0.1mm). During testing, the robotic arm moves the probe directly above the substrate, 5-10mm away from the substrate surface. Five points are collected for each test (one point at the center of the substrate and four points 10mm from the edge). The system automatically calculates the average value as the current coating thickness. If the thickness of a single point deviates from the average value by more than 10%, it is judged as uneven coating, and the moving speed or current density of the fixture is automatically adjusted.

Claims

1. A preparation process for a NiP binary alloy, characterized in that, Includes the following procedures: S1. Substrate pretreatment: The substrate to be plated is subjected to degreasing, pickling, activation and water washing in sequence. The degreasing is carried out with an alkaline degreasing agent and ultrasonic cleaning. The pickling is carried out with a 10% hydrochloric acid solution. The activation is carried out with a 5% sulfuric acid solution. S2, preparation before plating: injecting plating solution into the electrolytic cell (1), the plating solution comprising Ni 2+ , H2PO2 - and complexing agent, wherein the concentration of Ni 2+ is 40-60 g / L, the concentration of H2PO2 - is 80-100 g / L, and the concentration of complexing agent is 30-50 g / L, and the complexing agent is sodium citrate; The pretreated substrate is fixed on the movable rotating cathode fixture (2) in the electrolytic cell (1). The movable rotating cathode fixture (2) is made of pure titanium. The movable rotating cathode fixture (2) moves along the length of the electrolytic cell (1). An inert anode (16) is fixed at the preset electrode mounting hole inside the electrolytic cell (1). Multiple storage tanks (24) for adjusting the concentration and pH value of the plating solution are installed on the side of the movable rotating cathode fixture (2). pH adjuster and raw materials are added to the multiple storage tanks (24) respectively. S3. Parameter initialization: Adjust the temperature of the plating solution in the electrolytic cell (1) to 50-60℃ through the temperature control unit, adjust the pH of the plating solution to 4.0-5.0 through the storage tank (24), and start the plating solution circulation mechanism in the electrolytic cell (1) to filter and circulate the plating solution. S4. Electrodeposition: Start the high-frequency switching power supply and output current in the electrolytic cell (1) in constant current mode. The current density is controlled at 0.5-5A / dm², so that the Ni in the plating solution... 2+ H2PO2 - Driven by an electric field, Ni migrates directionally toward the cathode substrate. 2+ Two electrons are gained on the substrate surface, reducing it to Ni and H2PO2. - Ni gains one electron on the substrate surface, is reduced to P, and generates H2O. Ni and P are co-deposited on the substrate surface to form a Ni-P binary alloy coating. S5. Post-plating treatment: The thickness of the substrate coating is monitored in real time by an eddy current thickness gauge. When the coating thickness reaches 10-50μm, the power is stopped and the substrate in the electrolytic cell (1) is taken out for drying.

2. The preparation process of a NiP binary alloy according to claim 1, characterized in that: The electrolytic cell (1) has lifting slots (13) on both sides of the top of the cell for raising and lowering the movable rotating cathode hanger (2). Both lifting slots (13) are fixed with vertically arranged electric push rods (14), and the top of the electric push rods (14) is fixedly connected with support plates (15). The top of the two support plates (15) is fixedly connected with uprights (18), and the two uprights (18) are rotatably connected with screws (20). The movable rotating cathode fixture (2) includes a movable block (22), which has a threaded hole. The lead screw (20) is threaded into the threaded hole. A balance block (23) is fixedly connected to the bottom end of the movable block (22). A rotating shaft (28) is rotatably connected to the bottom end of the balance block (23). A base plate (26) is fixedly connected to the bottom of the balance block (23). Multiple electric grippers (27) are fixed to the bottom end of the base plate (26). The electric grippers (27) are used to clamp and fix the substrate. The balance block (23) has a motor fixed inside, and the drive shaft and the top of the rotating shaft (28) of the motor are fixedly connected.

3. The preparation process of a NiP binary alloy according to claim 1, characterized in that: The electrolytic cell (1) is provided with a circulation liquid port (6) and a filter box (5); The electrolytic cell (1) has an inclined slope (17) at the bottom inside for the plating solution to flow to the circulation port (6). The plating solution circulation mechanism includes a corrosion-resistant circulation pump (8), which is located above the filter box (5) and fixed to one side of the electrolytic cell (1). The circulating liquid port (6), the filter box (5) and the electrolytic cell (1) are connected in sequence through the connecting pipe (7), and the inclined slope (17) is inclined downward towards the end of the circulating liquid port (6).

4. The preparation process of a NiP binary alloy according to claim 1, characterized in that: A guide rod (21) is provided below the lead screw (20). The guide rod (21) is fixed between two uprights (18). A sliding hole is provided on the balance block (23), and the guide rod (21) passes through the sliding hole.

5. The preparation process of a NiP binary alloy according to claim 1, characterized in that: Multiple storage tanks (24) are fixed to the outside of the moving block (22), and the bottom of the storage tanks (24) is connected to a drain pipe (25). A solenoid valve is provided at the connection between the drain pipe (25) and the storage tanks (24).

6. The preparation process of a NiP binary alloy according to claim 1, characterized in that: Drying ports (9) are provided at the top of opposite sides inside the electrolytic cell (1). Fans (11) are fixed on both sides outside the electrolytic cell (1). The air outlets of the two fans (11) are connected to the corresponding drying ports (9).

7. The preparation process of a NiP binary alloy according to claim 6, characterized in that: Two baffles (10) are installed above the two drying ports (9), and the two baffles (10) are fixed on the top two sides of the electrolytic cell (1).

8. The preparation process of a NiP binary alloy according to claim 3, characterized in that: The filter box (5) is provided with a primary filter cotton (31) and a secondary filter element (32) in sequence. The connecting pipe (7) connected to the corrosion-resistant circulating pump (8) is located on the side of the secondary filter element (32) away from the primary filter cotton (31).

9. The preparation process of a NiP binary alloy according to claim 3, characterized in that: An interlayer (29) is provided on the electrolytic cell (1) between the outer wall and the inner wall, and the temperature control unit is located inside the interlayer (29); The electrolytic cell (1) has support legs (3) fixed at both ends of the bottom, and the filter box (5) has an auxiliary bracket (4) fixed at the bottom. The support legs (3) and the auxiliary bracket (4) are both located on the ground.

10. A system for preparing a NiP binary alloy, characterized in that, The NiP binary alloy preparation process described in any one of claims 9 is provided, wherein the NiP binary alloy preparation system includes a central control unit, a temperature control unit, and a monitoring unit, wherein the output terminals of the monitoring units are all connected to the input terminals of the central control unit, and the input terminals of the temperature control units are connected to the output terminals of the central control unit. The temperature control unit includes an electric heating tube (30), which is disposed inside the interlayer (29); The monitoring unit includes a pH electrode, a temperature sensor, and an ICP-OES spectrometer. The detection ends of the pH electrode and the temperature sensor extend into the plating solution. A sampling port is provided at the connection between the corrosion-resistant circulating pump (8) and the filter box (4). The plating solution removed through the sampling port is subjected to Ni testing using the ICP-OES spectrometer. 2+ Concentration detection.

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