A method for electroless nickel plating on the surface of basalt fiber
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- UNIV OF ELECTRONICS SCI & TECH OF CHINA
- Filing Date
- 2026-03-12
- Publication Date
- 2026-05-29
AI Technical Summary
Existing technologies for electroless nickel plating on basalt fiber surfaces suffer from high costs, complex processes, and severe environmental pollution, making it difficult to achieve green and continuous production.
By in-situ oxidation-polymerization on the surface of basalt fibers under weakly alkaline oxidation conditions to form a polydopamine (PDA) chelate ion exchange layer, a multidentate coordination site is provided to induce or assist the formation of nanocatalytic nuclei, thereby achieving efficient electroless nickel plating.
A continuous and dense nickel plating layer with a thickness of 1-3 μm and a volume resistivity of ≤1×10-3 Ω·cm was prepared. The coating exhibited high bonding strength, and the process was environmentally friendly and simple, making it suitable for industrial production.
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Figure CN122105381A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of chemical plating technology, specifically relating to a method for nickel plating on the surface of basalt fibers. Background Technology
[0002] Basalt fiber, due to its excellent high-temperature resistance, chemical corrosion resistance, mechanical property stability, and good insulation properties, is widely used in aerospace, electronics, electrical engineering, special protection, flexible composite materials, and high-temperature filtration. With the development of flexible electronics, smart fabrics, electromagnetic shielding, and antistatic materials, the demand for metallized fiber materials with conductive, thermally conductive, or electromagnetically shielding functions based on basalt fiber is increasing. Compared to directly weaving metal wires or using conductive coatings, constructing a continuous and dense metal layer on the surface of basalt fiber has advantages such as lower cost, excellent conductivity, strong processability, and ease of achieving lightweight and flexible designs, thus becoming a current focus of research and industrialization.
[0003] To expand the application boundaries of basalt fibers, surface metallization has become a research hotspot. Electroless nickel plating is a technique that deposits a layer of metallic nickel-phosphorus or nickel-boron alloy on the material surface through an autocatalytic reaction without the need for an external current. It has advantages such as uniform and dense coating, ability to cover complex structures, and good adhesion, making it particularly suitable for metallizing non-conductive substrates. However, electroless nickel plating requires the substrate surface to possess catalytically active sites. Basalt fibers themselves lack catalytic activity and cannot directly initiate the electroless plating reaction. Therefore, pretreatment is necessary to introduce catalytic centers.
[0004] In existing technologies, a two-step "sensitization-activation" method is often used to introduce noble metal catalysts such as palladium (e.g., Pd) onto the surface of ceramics or glass fibers. 2+ The process involves electroless nickel plating on basalt fibers, followed by chemical plating. However, this method suffers from high costs (dependent on precious metals), complex processes, wastewater containing heavy metals, and severe environmental pollution, making it difficult to achieve green and continuous production. Therefore, developing a low-cost, environmentally friendly, efficient, and industrially applicable pretreatment technology for electroless nickel plating on basalt fibers has become a pressing technical challenge in this field. Summary of the Invention
[0005] To address the problems existing in the background technology, the present invention aims to provide a method for nickel plating on the surface of basalt fibers. This method involves in-situ oxidation and polymerization of dopamine monomers on the fiber surface under weakly alkaline oxidation conditions to form a thin film containing multifunctional sites such as catechol, quinone, and amine. This constructs a polydopamine (PDA) chelate ion exchange layer, providing multidentate coordination sites to induce or assist in in-situ nucleation within the layer / at the interface, forming dispersed nanocatalytic nuclei, thereby achieving efficient and high-quality surface nickel plating.
[0006] To achieve the above objectives, the technical solution of the present invention is as follows:
[0007] A method for nickel plating on the surface of basalt fibers includes the following steps:
[0008] Step 1. Roughen the basalt fibers by alkaline etching:
[0009] Basalt fibers are immersed in an alkaline solution with a concentration of 5-15 wt% and treated at a temperature of 60-90°C for 30-90 minutes.
[0010] After treatment, the basalt fibers were repeatedly rinsed with deionized water until neutral, resulting in activated basalt fibers with significantly improved surface roughness and negative charge.
[0011] Step 2. The activated basalt fibers are completely immersed in a Tris buffer solution containing dopamine and placed in the dark at room temperature for 4-12 hours to allow the basalt fiber surface to self-assemble and form a polydopamine (PDA) chelate-ion exchange layer. After deposition, the fibers are rinsed with deionized water and dried.
[0012] Step 3. Loading catalytic metal nanoparticles onto basalt fibers:
[0013] The basalt fibers obtained in step 2 were immersed in a transition metal salt solution with a concentration of 0.05~0.2 mol / L and stirred for 60~120 minutes at a temperature of 40~60°C and a pH of 6.5~8.0 to achieve ion exchange and complexation adsorption between transition metal cations and the chelation layer on the surface of basalt fibers. After treatment, the fibers were removed, washed with deionized water, and dried at 60~80°C.
[0014] The loaded metal ions are reduced in the reducing solution to form metal nanoparticles with a size of 10~100nm, which are uniformly distributed on the fiber surface and serve as catalytic active centers for electroless nickel plating.
[0015] Step 4. Electroless nickel plating:
[0016] Basalt fibers loaded with catalytic metal are immersed in an electroless nickel plating solution to carry out an electroless nickel plating reaction at a temperature of 50-70°C for 30-60 minutes. After the reaction is completed, the fibers are cleaned and dried to obtain a nickel plating layer on the surface of the basalt fibers.
[0017] Furthermore, the alkaline solution in step 1 is a NaOH or KOH solution.
[0018] Furthermore, the specific process of step 2 is as follows:
[0019] Step 2.1. Prepare Tris (tris(hydroxymethyl)aminomethane) buffer solution:
[0020] Tris was added to deionized water at a concentration of 0.01-0.05 mol / L, and then acid solution was added to adjust the pH of the solution to 8.0-9.0 to obtain a Tris buffer solution.
[0021] Step 2.2. Add dopamine hydrochloride to the Tris buffer solution and stir until completely dissolved to obtain a dopamine solution. The concentration of dopamine hydrochloride in the Tris buffer solution is 1.0-5.0 g·L⁻¹. -1 ;
[0022] Step 2.3. Completely immerse the basalt fibers treated in Step 1 in dopamine solution and place them in the dark at room temperature for 4-12 hours. The longer the deposition time, the thicker the film.
[0023] Step 2.4. After deposition, the basalt fibers are removed and gently rinsed with deionized water to remove unpolymerized dopamine and soluble polymers. Then, they are rinsed with a mixture of deionized water and ethanol to improve drying uniformity. Subsequently, they are air-dried at room temperature or dried at 40-50°C for 1-2 hours.
[0024] Furthermore, the transition metal salt solution is one or more of silver salts, copper salts, nickel salts, and cobalt salts.
[0025] Further, in step 3, the transition metal salt solution is one or more of AgNO3, CuCl2, CuSO4, NiCl2, NiSO4, CoCl2·6H2O, and CoSO4·H2O.
[0026] Further, the reducing agent is at least one of NaHB4, N2H4·H2O, and NaH2PO2·H2O, with a concentration of 0.1-0.3 mol / L.
[0027] Furthermore, in step 4, the formula for the electroless nickel plating solution is as follows:
[0028] Nickel sulfate (NiSO4·6H2O) at 25~35 g / L, sodium hypophosphite (NaH2PO2·H2O) at 20~30 g / L, sodium citrate (C6H5Na3O7·2H2O) at 10~20 g / L (complexing agent), and sodium acetate (CH3COONa) at 10~15 g / L (buffer).
[0029] Stabilizers (such as thiourea or potassium iodate) at 0.1–1 mg / L, and surfactants (such as sodium dodecyl sulfate) at 0.05–0.2 g / L.
[0030] The pH of the plating solution is adjusted to 8.5-9.5 using dilute ammonia.
[0031] Furthermore, electroless nickel plating can be followed by heat treatment at a temperature of 200-300°C for 1-3 hours to improve the density and bonding strength of the plating layer.
[0032] The mechanism of this invention is as follows:
[0033] This invention first performs alkaline etching on basalt fibers, a process that has a dual effect: alkaline treatment can roughen the surface and improve mechanical interlocking force, and also increase the hydroxyl density and hydrophilicity of the basalt fiber surface, providing a driving force for PDA deposition and adsorption. Then, it provides a method for constructing a polydopamine (PDA) chelate ion exchange layer on the surface of basalt fibers. This method involves in-situ oxidation and polymerization of dopamine monomers on the surface of basalt fibers under weakly alkaline oxidation conditions to form a thin film containing multifunctional sites such as catechol, quinone, and amine. The PDA film achieves high-strength adhesion to the basalt fiber surface through: 1) coordination and chemical reaction between catechol / amine and the exposed hydroxyl groups (−Si−OH, −M−OH) on the basalt fiber surface and the surface metal sites; 2) mechanical embedding of the film with the micro-roughness of the substrate; and 3) a triple synergistic effect of multiple non-covalent interactions (hydrogen bonds, π–π, van der Waals forces), forming a uniformly covered film on the basalt fiber, improving the initial contact and wettability of the substrate with subsequent coatings or plating. PDA readily ionizes into a negatively charged state in solution. The negatively charged PDA surface attracts positively charged catalytic metal ions (e.g., selected from Ag) through electrostatic attraction. + Cu 2+ Ni 2+ Co 2+The PDA layer attracts and immobilizes metal ions (in solutions of various concentrations) through ion exchange / complexation. It provides multidentate coordination sites, enabling the metal ions to be firmly immobilized via a "ion exchange + coordination chelation" mechanism. For metal ions that can be reduced by PDA, PDA can also induce or assist in their in-situ nucleation within the layer / at the interface, forming dispersed nanocatalytic nuclei. Fibers treated in this way possess autocatalytic activity, shortening the induction period, improving plating uniformity, and significantly enhancing the bonding strength and leaching resistance of the coating to the substrate during electroless nickel plating.
[0034] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:
[0035] 1. The nickel plating layer prepared on the surface of basalt fibers by this invention is continuous and dense, with a thickness of 1-3 μm and a volume resistivity ≤1×10⁻⁶. -3 Ω·cm.
[0036] 2. Ion-exchange supported catalytic metal: Ni 2+ Cu 2+ Co 2+ Under weakly acidic to neutral conditions, they can be effectively exchanged and adsorbed onto negatively charged surfaces. Furthermore, Ni, Co, and Cu are co-deposition elements in electroless nickel plating and have self-catalytic capabilities, eliminating the need for Pd.
[0037] 3. The method of this invention has strong process compatibility. All steps are aqueous treatments, which is green and environmentally friendly. The equipment is simple and the method is convenient, providing a path for large-scale basalt fiber metallization. Attached Figure Description
[0038] Figure 1 The images shown are SEM images of basalt fibers before and after electroless nickel plating in Example 1 of this invention.
[0039] Figure 2 The images show the cross-sectional SEM and EDS images of nickel content of basalt fibers after nickel plating in Example 1 of this invention.
[0040] Figure 3 This is a SEM image of basalt fiber after chemical nickel plating in Example 2 of the present invention.
[0041] Figure 4 This is a SEM image of basalt fiber electroless nickel plating in Comparative Example 1 of this invention. Detailed Implementation
[0042] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings.
[0043] Example 1
[0044] A method for nickel plating on the surface of basalt fibers includes the following steps:
[0045] Step 1. Roughen the basalt fibers by alkaline etching:
[0046] Basalt fibers were immersed in a 10 wt% alkaline solution and treated at 70°C for 60 minutes.
[0047] After treatment, the basalt fibers were repeatedly rinsed with deionized water until neutral, resulting in activated basalt fibers with significantly improved surface roughness and negative charge.
[0048] Step 2. The activated basalt fibers were completely immersed in a Tris buffer solution containing dopamine and deposited in the dark at room temperature for 4 hours to allow the basalt fiber surface to self-assemble and form a polydopamine (PDA) chelate-ion exchange layer. After deposition, the fibers were rinsed with deionized water and dried. The specific process is as follows:
[0049] Step 2.1. Prepare Tris buffer solution:
[0050] Tris was added to deionized water at a concentration of 10 mM, and then hydrochloric acid solution was added to adjust the pH of the solution to 8.5 to obtain a Tris buffer solution.
[0051] Step 2.2. Add 0.2 g of dopamine hydrochloride to 100 mL of Tris buffer solution and stir until completely dissolved to obtain a dopamine solution;
[0052] Step 2.3. Completely immerse the basalt fiber treated in Step 1 in the dopamine solution and place it in the dark at room temperature for 4 hours. The reason for placing it in the dark is that light will accelerate the generation of free radicals from dissolved oxygen in the solution. If exposed to strong light, dopamine will undergo very rapid self-polymerization in the buffer solution, forming a large number of PDA nanoparticles that are suspended in the solution or precipitated at the bottom of the container. If the reaction is too fast, the constructed PDA layer will become rough and loose.
[0053] The longer the deposition time, the thicker the film. However, if the coating is too thick, the adhesion between the PDA coating and the fiber will weaken. If the deposition time in the solution is too long, dopamine will not only form a film on the fiber surface, but will also self-aggregate into many large nanoparticles in the solution. These large particles physically accumulate on the fiber, making the originally dense and smooth coating very rough and loose.
[0054] Step 2.4. After deposition, the basalt fibers are removed and gently rinsed with deionized water to remove unpolymerized dopamine and soluble polymers. Then, they are rinsed with a mixture of deionized water and ethanol to improve drying uniformity. Subsequently, they are air-dried at room temperature or dried at 50°C for 1 hour.
[0055] Step 3. Loading catalytic metal nanoparticles onto basalt fibers:
[0056] The basalt fibers obtained in step 2 were immersed in a transition metal salt solution with a concentration of 0.1 mol / L and stirred for 60 minutes at a temperature of 40°C and a pH of 8 to achieve ion exchange and complexation adsorption between transition metal cations and the chelation layer on the surface of basalt fibers. After treatment, the fibers were removed, washed with deionized water, and dried at 60°C.
[0057] The loaded metal ions are reduced in a 0.1 mol / L reducing solution to form nanoparticles with a size of 10~100 nm through in-situ reduction or autocatalytic reduction during the electroless plating process. These nanoparticles are uniformly distributed on the fiber surface and serve as catalytic active centers for electroless nickel plating.
[0058] Step 4. Electroless nickel plating:
[0059] Basalt fibers loaded with catalytic metal are immersed in an electroless nickel plating solution to carry out the electroless nickel plating reaction. The electroless nickel plating solution formula is as follows: 30 g / L nickel sulfate (NiSO4·6H2O), 25 g / L sodium hypophosphite (NaH2PO2·H2O), 15 g / L (complexing agent) sodium citrate (C6H5Na3O7·2H2O), 12 g / L (buffer agent) sodium acetate (CH3COONa), 0.5 mg / L stabilizer (such as thiourea or potassium iodate), and 0.1 g / L surfactant (such as sodium dodecyl sulfate). The pH value of the plating solution is adjusted to 9 with dilute ammonia water. The reaction temperature is 55°C and the reaction time is 60 minutes. After the reaction is completed, the fibers are cleaned and dried to obtain a nickel plating layer on the surface of the basalt fibers.
[0060] Example 2
[0061] Chemical nickel plating was performed on the surface of basalt fibers following the steps in Example 1, except that the deposition time in step 2.3 was adjusted to 8 hours, while the rest remained unchanged. The test results are as follows. Figure 3 As shown.
[0062] Comparative Example 1
[0063] Following the steps in Example 1, electroless nickel plating was performed on the surface of basalt fibers, except that step 2 was removed, while the rest remained unchanged. The resulting test results are as follows: Figure 4 As shown.
[0064] Figure 1 The images show SEM images of basalt fibers before and after electroless nickel plating in Example 1 of this invention. The left image is the SEM image of the basalt fiber, and the right image is the SEM image after nickel plating. As can be seen from the images, a nickel layer was successfully deposited on the basalt fiber using the method of this invention. The cross-sectional SEM and EDS images of the fiber after nickel plating are shown below. Figure 2 As shown, the right figure is the EDS diagram of nickel.
[0065] As can be seen from the EDS image, the nickel layer thickness in the annular region is uniform, with a thickness of 1-3 μm.
[0066] Figure 3 This is a SEM image of basalt fiber after electroless nickel plating according to Example 2 of the present invention. The image shows that the nickel layer can also be successfully prepared using the parameters of Example 2.
[0067] Figure 4 This is a SEM image of basalt fiber electroless nickel plating in Comparative Example 1 of this invention. As can be seen from the image, without the construction of a PDA layer, insufficient plating adhesion occurs, resulting in a loose and easily detached nickel layer on the surface.
[0068] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.
Claims
1. A method for nickel plating on the surface of basalt fibers, characterized in that, Includes the following steps: Step 1. Roughen the basalt fibers by alkaline etching: Basalt fibers are immersed in an alkaline solution with a concentration of 5-15 wt% and treated at a temperature of 60-90°C for 30-90 minutes. After treatment, the basalt fibers were repeatedly rinsed with deionized water until neutral to obtain activated basalt fibers. Step 2. The activated basalt fibers are completely immersed in a Tris buffer solution containing dopamine and placed in the dark at room temperature for 4-12 hours to allow the basalt fiber surface to self-assemble and form a polydopamine chelate-ion exchange layer. After deposition, the fibers are rinsed with deionized water and dried. Step 3. Loading catalytic metal nanoparticles onto basalt fibers: The basalt fibers obtained in step 2 were immersed in a transition metal salt solution with a concentration of 0.05~0.2 mol / L and stirred for 60~120 minutes at a temperature of 40~60°C and a pH of 6.5~8.0 to achieve ion exchange and complexation adsorption between transition metal cations and the chelation layer on the surface of basalt fibers. After treatment, the basalt fibers were removed, washed with deionized water, and dried at 60~80°C. The loaded metal ions are reduced in a reducing solution to form metal nanoparticles with a size of 10~100 nm, which are uniformly distributed on the fiber surface and serve as catalytic active centers for electroless nickel plating. Step 4. Electroless nickel plating: Basalt fibers loaded with catalytic metal nanoparticles are immersed in an electroless nickel plating solution to carry out an electroless nickel plating reaction at a temperature of 50-70°C for 30-60 minutes. After the reaction is completed, the fibers are cleaned and dried to obtain a nickel plating layer on the surface of the basalt fibers.
2. The method for nickel plating on the surface of basalt fibers as described in claim 1, characterized in that, In step 1, the alkaline solution is either NaOH or KOH solution.
3. The method for nickel plating on the surface of basalt fibers as described in claim 1, characterized in that, The specific process of step 2 is as follows: Step 2.
1. Prepare Tris buffer solution: Tris was added to deionized water at a concentration of 0.01-0.05 mol / L, and then acid solution was added to adjust the pH of the solution to 8.0-9.0 to obtain a Tris buffer solution. Step 2.
2. Add dopamine hydrochloride to the Tris buffer solution and stir until completely dissolved to obtain a dopamine solution. The concentration of dopamine hydrochloride in the Tris buffer solution is 1.0-5.0 g·L⁻¹. -1 ; Step 2.
3. Completely immerse the basalt fibers treated in Step 1 in a dopamine solution and place them in the dark at room temperature for 4-12 hours; Step 2.
4. After deposition, remove the basalt fibers, gently rinse them with deionized water, then rinse them with a deionized water / ethanol mixture, and then air dry them at room temperature or dry them at 40-50℃ for 1-2 hours.
4. The method for nickel plating on the surface of basalt fibers as described in claim 1, characterized in that, The transition metal salt solution is one or more of the following: silver salt, copper salt, nickel salt, and cobalt salt.
5. The method for nickel plating on the surface of basalt fibers as described in claim 4, characterized in that, In step 3, the transition metal salt solution is one or more of AgNO3, CuCl2, CuSO4·5H2O, NiCl2, NiSO4, CoCl2·6H2O, and CoSO4·H2O.
6. The method for nickel plating on the surface of basalt fibers as described in claim 1, characterized in that, The reducing agent in the reducing solution is at least one of NaHB4, N2H4·H2O, and NaH2PO2·H2O, with a concentration of 0.1-0.3 mol / L.
7. The method for nickel plating on the surface of basalt fibers as described in claim 1, characterized in that, In step 4, the formula for the electroless nickel plating solution is as follows: 25-35 g / L nickel sulfate, 20-30 g / L sodium hypophosphite, 10-20 g / L sodium citrate, 10-15 g / L sodium acetate, 0.1-1 mg / L stabilizer, and 0.05-0.2 g / L surfactant. The pH of the plating solution is adjusted to 8.5-9.5 using dilute ammonia.
8. The method for nickel plating on the surface of basalt fibers as described in claim 1, characterized in that, After electroless nickel plating, heat treatment is performed at a temperature of 200~300°C for 1-3 hours.