Treatment method for uniformly dispersing niobium carbide in chemical composite plating solution

Abstract

The invention discloses a treatment method for uniformly dispersing niobium carbide in a chemical composite plating solution, which comprises the following steps: dispersing 0.5-1.5 parts of NbC powder in 100 parts of absolute ethyl alcohol solvent, stirring, and pouring the solution into a ball milling tank filled with nitrogen; and then draining the mixture, and drying the mixture in a vacuum drying oven. And drying and screening to obtain NbC powder with uniform granularity. Adding water into the NbC powder, uniformly stirring, adding an HF solution into the suspension, and standing for more than 24 hours; carrying out centrifugal separation on the suspension liquid; adding NbC obtained by centrifugation into deionized water, and ultrasonically stirring to obtain a uniform suspension; niobium carbide is added into the chemical composite plating solution, so that the surface of a plated part and metal gold are combined with particles, the hardness and wear resistance of a base material are improved, the effect on a 60-80-micron nickel-phosphorus plating layer in the industry is achieved through an ultrathin chemical composite plating layer (8-10 microns), and the adhesive force of the plating layer and the base material is enhanced through introduction of NBC nanoparticles.

Description

Technical Field

[0001] The present invention relates to the technical field of material surface engineering, and particularly relates to a method for uniformly dispersing niobium carbide in a chemical composite plating solution. Background Art

[0002] Niobium carbide (NbC), a black cubic crystal or purple-gray powder, belongs to the sodium chloride-type cubic crystal system. It is insoluble in hydrochloric acid, sulfuric acid, and nitric acid, and is only soluble in a mixed solution of hot hydrofluoric acid and nitric acid. It is easily melted in compounds such as titanium carbide, zirconium carbide, and tungsten carbide to form an isomorphous solid solution. Therefore, it can be used to manufacture cermets, heat-resistant alloys, and hard alloys. As an additive for hard alloys, NbC can significantly improve the hot hardness, thermal shock resistance, hot pressing resistance, and oxidation resistance of hard alloys. Cutting tools made of hard alloys strengthened with NbC also have good hot hardness, thermal shock resistance, and thermal oxidation resistance. At the same time, the composite materials prepared from it have also been widely used in fusion reactors, machining, metallurgy, and aerospace and other fields.

[0003] Electroless plating, also known as autocatalytic plating, is an excellent surface treatment technology. It is a new surface treatment process that deposits alloys on the surface of a substrate using the autocatalytic principle. Different from traditional electroplating that requires an external power source, electroless plating does not require an external current and solely relies on the spontaneous oxidation-reduction reaction of the plating solution to form a coating film. The most commonly used electroless plating technology is electroless Ni-P alloy technology. At the same time, the thickness of the nickel-phosphorus coating is independent of the shape of the part. The coating has the advantages of high hardness, wear resistance, natural lubricity, and excellent corrosion resistance, and there are also many properties that can change with the phosphorus content, such as magnetism, weldability, and polishability. Based on electroless plating, electroless composite plating technology has gradually developed. It refers to adding insoluble second-phase inorganic nanoparticles or fibers to the plating solution so that the surface of the workpiece combines with the metal matrix and the particles, thereby obtaining a composite coating of the material. Depending on the properties of the added particles, different types and functions of coatings can be obtained, and its application prospects are very broad.

[0004] Patent Application Number: CN201910755136.6 discloses a preparation method for the corrosion-resistant structure of petroleum stainless steel pipelines. This method proposes a method for preparing a coating with hydrophobicity and corrosion resistance. Through technical means such as pre-treating the stainless steel surface, performing micro-nano double roughness structure and low surface energy modification, the quality and durability of the coating can be improved. It uses electroless nickel plating and forms a corrosion-resistant coating layer with a certain thickness on the substrate surface through multiple electroless nickel platings. The formed coating layer has poor wear resistance and fatigue strength. Usually, in order to improve its surface wear resistance, the method of increasing the number of electroplating times and thickening the coating thickness is adopted to form a thicker coating layer to improve the wear resistance. This makes the manufacturing process flow longer, and the coating on the surface of the produced coating products is thicker; the coating uniformity is not good. As the coating thickness increases, it becomes more difficult to maintain the coating uniformity, and uneven thickness may occur in some areas; in addition, the subsequent coating may become relatively brittle and hard, reducing the fatigue strength and toughness of the material; and due to the increase in coating thickness, the overall weight of the material also increases significantly. For some weight-sensitive application fields, such as aerospace components, the thicker coating increases the overall weight and affects the design requirements.

[0005] In view of the above, it is necessary to propose a treatment method for the uniform dispersion of niobium carbide in the chemical composite plating solution to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects existing in the prior art and provide a treatment method for the uniform dispersion of niobium carbide in the chemical composite plating solution. Insoluble second-phase inorganic nanoparticles - niobium carbide are introduced into the plating solution. The introduction of the nanoparticles can not only fill the pores growing in the electroless nickel plating layer to improve its corrosion resistance and denseness, but also change the crystal structure of the coating, thereby reducing the coating thickness and making up for the limitations in the development of the electroless NiP layer.

[0007] To achieve the above purpose, the technical solution of the present invention is as follows: A treatment method for the uniform dispersion of niobium carbide in the chemical composite plating solution, including a substrate material, a pre-coating layer, and a composite coating layer. The composite coating layer adheres to the surface of the pre-coating layer, and the pre-coating layer adheres to the surface of the substrate material; the substrate material can be metal or non-metal. Metals include but are not limited to Q235B carbon steel, copper alloy, aluminum alloy, nickel material, stainless steel; non-metal materials include but are not limited to plastics, ceramics, glass, neodymium iron boron; the pre-coating layer is a nickel layer, and the thickness of the composite coating layer is 8 - 10 μm, as Figure 4 shown.

[0008] The preparation of the pre-plating layer is based on a nickel layer as the substrate, which can enable the subsequent plating layer to adhere better and improve the adhesion of the plating layer. The nickel layer itself also has good corrosion resistance, equivalent to a double-layer corrosion-resistant layer. The composition of the pre-plating nickel solution includes: nickel chloride hexahydrate (NiCl2•6H2O) 40 - 50 g / L, nickel sulfate hexahydrate (NiSO4•6H2O) 240 - 260 g / L, boric acid (H3BO3) 25 - 35 g / L, sodium dodecyl sulfate 0.20 - 0.30 g / L, sodium hydroxymethylsulfonate (PN) 35 - 45 mg / L, and propynol propoxy ether (PAP) 25 - 35 mg / L; The process conditions for the pre-plating layer are as follows: the anode is a nickel plate, and the cathode takes Q235B as the substrate material as an example. The temperature is 20 - 30 °C, the pH is 3 - 4, the plating time is 1 - 2 min, and the current density during plating is 2 - 3 A / dm 2 .

[0009] Nickel ions mainly come from nickel sulfate hexahydrate, and partially from nickel chloride. Nickel chloride has two main functions: one is to greatly improve the conductivity of the solution and reduce the required voltage; the other is very important for the satisfactory dissolution of the nickel anode. Boric acid is a buffer, and its main function is to control the pH value of the solution. Sodium dodecyl sulfate is a plating solution additive that reduces the surface tension of the solution and promotes the release of bubbles, improves the uniformity and smoothness of the plating layer, and reduces the phenomenon of uneven deposition. Sodium hydroxymethylsulfonate (PN) and propynol propoxy ether (PAP) are used as the "carrier" and "brightener" of bright pre-electroplating respectively, which can significantly change the appearance and properties, making the plating layer brighter and flatter.

[0010] A composite plating layer can be formed on the surface of the pre-plating layer using an electroless plating solution or an electroless composite plating solution, as Figure 1 shown.

[0011] As an implementation manner, the first coating is a pre - coating, and the second coating is a chemical coating. The composition of the electroless plating solution used for the chemical coating includes: main salt NiCl2•6H2O 225 - 35 g / L, reducing agent sodium hypophosphite (NaH2PO2•H2O) 15 - 25 g / L, main complexing agent sodium citrate (Na3C6H5O7•2H2O) 8 - 12 g / L, secondary complexing agent glycine [CH2(NH2)COOH] 4 - 6 g / L, buffer sodium acetate (CH3COONa) 8 - 12 g / L, surfactant sodium dodecylbenzenesulfonate 0.25 - 0.35 g / L, stabilizer zinc molybdate 75 - 85 mg / L; the temperature is 80 - 85 °C, the pH is 5 - 6, and the plating time is 0.5 - 1.5 h; using sodium citrate as the main complexing agent, it has strong complexing ability, and the plating solution is very stable, but the plating rate is low. In this patent, a second complexing agent is used. The complexing ability of glycine is relatively weak and it is generally not used alone as a complexing agent, but mainly added to the plating solution as an auxiliary complexing agent. Its function is that by adding a small amount of glycine, the deposition rate can be significantly increased and the surface quality of the deposited layer can be improved.

[0012] As another implementation manner, also with electroless nickel plating as the first coating, the second coating is prepared by electroless composite plating. In this embodiment, insoluble particles are added to the electroless composite plating solution. When the coating is formed, the insoluble particles are co - deposited on the nickel - phosphorus alloy. The co - deposition of alloy second - phase particles and different substances in the coating produces a new generation of electroless composite coating to produce coatings with different physical and chemical properties; specifically, it includes the following steps: Pretreatment of niobium carbide NbC powder: The purchased raw material of niobium carbide NbC powder has a purity of 99.9% and the NbC powder with a Fisher average particle size of less than 3 μm.

[0013] The NbC powder is wet - milled and mixed evenly and then dried by the rolling ball - milling method to obtain nano - niobium carbide powder. In the present invention, by pretreating the NbC powder, ultrafine NbC powder with an average particle size of 100 nm is obtained. The finer the niobium carbide is refined to the nano - scale and the more uniform its distribution in the crystal grains, the more beneficial it is to improve the strength of the coating. The present invention uses wet - milling so that the ultrafine NbC powder can be more fully and evenly mixed, solving the problem that it is difficult to uniformly mix the nearly ultrafine NbC powder, improving the uniformity of the distribution of the second - phase NbC powder in the crystal grains, and further improving the strengthening effect of NbC.

[0014] The NbC powder raw material is subjected to high - energy wet - milling ball - milling in a ball mill under the condition that the rotation speed is above 1000 r / min. Using the above - mentioned high - energy ball - milling further refines the particle size of the NbC powder and promotes the uniform mixing of the NbC powder in the subsequent electroless composite plating solution.

[0015] Specifically, the NbC powder raw material is dispersed in anhydrous ethanol and stirred, and then the solution is poured into a ball milling tank filled with nitrogen. To ensure the ball milling efficiency, grinding balls with a mass ratio of 10:1 to the material are weighed into the ball milling tank. The tank is placed in a ball mill and ball milled for 48 hours, and then the mixture is drained and dried in a vacuum drying oven. After drying and screening, NbC powder with uniform particle size is obtained, and the average particle size of the NbC powder is 100 nm. After the NbC powder is stirred evenly with water, an HF solution is added to the suspension. Using hydrofluoric acid, firstly, the strong corrosiveness of HF is utilized to clean the NbC powder and remove pollutants that are difficult to remove by other means. Secondly, it can be used as a surfactant or dispersant, which helps to improve the interaction force between NbC powder particles, thereby enhancing the dispersibility and stability of the powder in the solvent. This is mainly achieved by changing the surface properties of the particles. Then it is left standing for more than 24 h; next, the suspension is centrifuged; the NbC obtained by centrifugation is added to deionized water, and ultrasonic stirring is used to obtain a uniform suspension for subsequent use.

[0016] The method for preparing the chemical composite plating solution includes the following steps: Step 1: Based on the aforementioned electroless plating solution, an appropriate amount of the electroless plating solution is measured. Step 2: Measure the niobium carbide suspension, and add a surfactant (cetyltrimethylammonium bromide (CTAB)) and a 5% Nafion (0.5 mL) solution thereto, and stir evenly. Step 3: Ultrasonically stir the niobium carbide suspension in Step 2 for 10 min to fully wet the particles. Step 4: Mix the niobium carbide suspension processed in Step 3 with the electroless plating solution in Step 1, then stir evenly, then dilute and make up the volume, and adjust the pH to 5.8 to form a chemical composite plating solution. Step 5: Ultrasonically stir the chemical composite plating solution for 30 min.

[0017] Cetyltrimethylammonium bromide is added to the niobium carbide (NbC) suspension. CTAB is a cationic surfactant, which can improve the stability and dispersibility of the niobium carbide suspension. CTAB can adsorb on the surface of niobium carbide particles, forming a protective film on the surface. The agglomeration phenomenon between particles is reduced through electrostatic repulsion or steric hindrance effects, thereby increasing the dispersion degree of the particles in the solvent. To prevent the agglomeration of NbC particles, CTAB can change the surface charge properties of the particles, which helps to prevent the particles from settling due to gravity, making the suspension more stable. Thus, the stability of the suspension is improved. CTAB can change the surface properties of the substrate, making it more receptive to the deposition of metal ions, thereby improving the quality of the coating.

[0018] Nafion is a perfluorosulfonic acid / perfluorocarboxylic acid copolymer, which has excellent proton conduction performance, chemical stability and mechanical strength; adding 5% Nafion solution to niobium carbide (NbC) suspension can improve the dispersibility. As a dispersant, it helps metal ions to be more evenly distributed in the solution, thus contributing to obtaining a more uniform and dense coating. The addition of CTAB in step 2 has already helped to improve the dispersibility of niobium carbide particles, but the introduction of Nafion can further help to maintain a stable suspension state, especially under long-term storage or specific processing conditions. It can also adjust the hydrophilic-hydrophobic balance: Nafion itself has a certain hydrophilicity, which will affect the wetting characteristics of the final material surface, and is beneficial for application scenarios where the liquid contact angle needs to be controlled on the surface of chemical composite plating products. In addition, Nafion can be used to adjust the pH value. Nafion has a certain acidity, which can help to adjust the pH value of the electroless plating solution and maintain suitable reaction conditions.

[0019] The combined use of Nafion, CTAB and niobium carbide can produce a synergistic effect, making the coating not only have good electrical conductivity and mechanical properties, but also have excellent corrosion resistance and adhesion. By precisely controlling the proportions of each component and the processing conditions, the characteristics such as the thickness, density, and porosity of the coating can be customized and adjusted to meet the requirements of different applications. Good dispersibility and uniformity can improve the efficiency of the electroless plating process, reduce defects, and improve product quality.

[0020] The key technologies for adding nanoparticle NbC to form a smooth and flat coating in the composite electroless plating solution mainly include the following aspects: 1. Uniform dispersion of nanoparticles: Due to the high surface energy, nano NbC particles are extremely easy to agglomerate in the plating solution, affecting the uniformity and flatness of the coating. Therefore, ensuring the uniform dispersion of nanoparticles in the plating solution is the key. In this invention, physical methods such as mechanical stirring and ultrasonic dispersion, as well as adding surfactants, are used to achieve the uniform dispersion of nanoparticles.

[0021] 2. Use of surfactants: The type and concentration of surfactants have an important impact on the adsorption amount and distribution uniformity of nanoparticles. Ionic surfactants and non-ionic surfactants can prevent the agglomeration of nanoparticles by forming an electric double layer or hydration, improving the stability of the plating solution.

[0022] 3. Plating solution composition and ratio: Select appropriate coating materials and precisely control the ratio of the materials to obtain the desired nano-coating performance and characteristics. The concentration of nanoparticles in the plating solution and other chemical components of the plating solution need to be precisely proportioned to ensure the uniformity and flatness of the coating.

[0023] After preparing the composite electroless plating solution and pre-treating and pre-plating nickel on the specimen, the plating process is as follows: 1) Put the prepared plating solution into a thermostatic heating magnetic stirrer and heat it to 82 °C.

[0024] 2) Put the specimen after pre-nickel plating into the chemical composite plating solution, adjust the rotation speed to 300 r / min, and carry out plating.

[0025] 3) After plating for 60 min, take out the specimen, rinse it with deionized water, put it into absolute ethanol, and ultrasonically clean it in an ultrasonic cleaner for 10 min. 4) Take it out after cleaning and dry it in a blast drying oven.

[0026] The surface layer formed by chemical composite plating using the method of the present invention is compared with the surface layer formed by the method without chemical composite plating as Figure 3 shown.

[0027] Chemical composite electroless nickel plating is a process in which insoluble particles are added to an electroless nickel plating solution and co-deposited on a nickel-phosphorus alloy to produce different coatings with different physical and chemical properties. The co-deposition of alloy second-phase particles and different substances in the coating produces a new generation of chemical composite coatings. Previous studies have shown that some composite coatings have excellent wear resistance and corrosion resistance. On the one hand, the electroless nickel-phosphorus coating has unprecedented properties, unique corrosion resistance and wear resistance. On the other hand, with the continuous in-depth research of nanomaterials and nanotechnology, niobium carbide, a nanoscale insoluble particle, is introduced into the composite coating in the present invention. The chemical composite coating is prepared by chemically depositing nanometer particles and attaching them to the surface of the substrate to form nanomaterials, endowing the substrate with special properties. The chemical composite coating technology with added nanoparticles in the present invention has the advantages of simple equipment, convenient operation, low cost, easy operation, etc., and can improve the corrosion resistance, wear resistance and oxidation resistance of the metal surface, and endow the material with special properties such as a decorative appearance.

[0028] Improving wear resistance: In the chemical composite coating Ni-P / NbC of this patent, the addition of hard particles (niobium carbide nanoparticles) can be dispersed in the coating matrix (Ni-P alloy). These hard particles can effectively refine the matrix metal, thereby improving the hardness of the matrix metal. This dispersion strengthening mechanism can significantly improve the wear resistance of the coating. During the wear process, the niobium carbide hard phase particles play a supporting role and become the first sliding surface due to their high hardness, excellent wear resistance, large yield limit and compressive ability. The matrix metal Ni-P alloy is coated around the hard particles to form the second sliding surface. Based on the double protection, therefore, the hard particle chemical composite coating has excellent wear resistance. In addition, as Figure 4 shown, compared with the Ni-P coating and the carbon steel substrate, the connection between the Ni-P / NbC coating of the composite coating and the carbon steel is tight, without obvious gaps, indicating stronger adhesion.

[0029] Improve hardness: The hardness of the chemical composite coating Ni-P / NbC is significantly enhanced. This is mainly due to the introduction of hard nano-particles NbC. The presence of these particles increases the hardness of the coating, thereby enhancing its wear resistance.

[0030] The Vickers hardness (HV) value of Q235B steel is about 130 - 150, the Vickers hardness value of the electroless Ni-P alloy coating is about 740 - 760, and the Vickers hardness value of the chemical composite coating Ni-P / NbC is about 980 - 1000.

[0031] Improve corrosion resistance: Compared with the Ni-P alloy coating, the corrosion resistance of the chemical composite coating Ni-P / NbC is enhanced, far higher than that of the substrate carbon steel. This is because the nano-particles added in the composite coating can form a denser structure, reducing the penetration of corrosive media, thereby improving the corrosion resistance. The improvement of corrosion resistance can be reflected by the improvement of electrochemical performance. In the electrochemical test, the chemical composite coating Ni-P / NbC shows more excellent corrosion resistance than the Ni-P alloy coating. The reason for this phenomenon is the presence of nano-particles in the composite coating, which improves the electrochemical performance, reduces the corrosion current, and increases the self-corrosion potential, thereby enhancing its corrosion resistance.

[0032] For application scenarios with high requirements for conductivity, the addition of niobium carbide also improves the conductivity of the coating: 1. Concentration of nickel chloride: The concentration of nickel chloride has a significant impact on the deposition rate, deposition amount, and conductivity of the amorphous coating. With the increase in the concentration of nickel salt, the deposition rate and deposition amount gradually increase, while the sheet resistance of the coating gradually decreases and the conductivity increases. In the plating solution of this patent, when the concentration of nickel sulfate is 30 g / L, it has good conductivity.

[0033] 2. Electroless plating time: The extension of electroless plating time affects the resistance value of the conductive coating. With the increase in electroless plating time, the resistance value of the aromatic coating at the same length gradually decreases, and the decreasing amplitude gradually decreases with the extension of time and finally tends to be stable. When the electroless plating time is 20 minutes, the coating is basically perfect. After that, when the time is extended, the thickness of the coating continues to increase, but the increase in thickness at this time will not cause obvious changes in its conductivity.

[0034] 3. Microstructure: This ultra-fine microstructure on the surface of the chemical composite coating Ni-P / NbC enables the alloy to have the best comprehensive performance of tensile strength and conductivity.

[0035] 4. Pre-plating nickel time: The pre-plating nickel time affects the corrosion resistance and porosity of the electroless Ni-P alloy coating, and thus affects the conductivity. With the extension of the pre-plating Ni time, the porosity of the Ni-P alloy coating shows a trend of first decreasing and then increasing. In this patent, when the pre-plating Ni time is 1 - 2 minutes, the corrosion resistance is the best at this time.

[0036] 5. Doping with a second phase: Introducing NbC particles into the Ni-P alloy can induce redistribution of electron density, optimize the adsorption energy of intermediate products, reduce the energy barrier, and thus improve electrical conductivity.

[0037] The advantages and beneficial effects of the present invention are as follows: 1. The core of the NbC powder pretreatment process is to be evenly dispersed in the plating solution so that the niobium carbide in the coating is evenly distributed and not prone to agglomeration. A treatment method for uniform dispersion of niobium carbide in the chemical composite plating solution according to the present invention can make the niobium carbide powder evenly distributed in the plating solution, effectively improving the quality of the coating.

[0038] 2. By adding the second-phase inorganic nanoparticles of niobium carbide to the chemical composite plating solution in the present invention, the surface of the workpiece and the metal matrix are combined with the particles, and thus a composite coating of the material can be obtained, effectively improving the hardness and wear resistance of the substrate. Moreover, this method can replace multiple coatings in the prior art through one-time chemical composite plating, so that the effect achieved by a 60-80 μm nickel-phosphorus coating in the industry can be achieved through an ultra-thin chemical composite coating (8-10 μm). The introduction of NBC nanoparticles enhances the adhesion between the coating and the substrate, and enhances the corrosion resistance and wear resistance of the product. Description of the Drawings

[0039] Figure 1 is a schematic flow chart of chemical composite plating in the present invention; Figure 2 is an SEM image of NbC nanoparticles in Example 2 of the present invention; Figure 3 is an SEM image of the Ni-P coating (left) and the Ni-P / NbC composite coating (right); Figure 4 is a cross-sectional SEM image of the Ni-P coating (left) and the Ni-P / NbC composite coating (right); Specific Embodiments

[0040] The following combines the drawings and examples to further describe the specific embodiments of the present invention. The following examples are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0041] Example 1: Disperse 0.5 parts of NbC powder raw material in 100 parts of anhydrous ethanol solvent and stir for no less than 20 min. Specifically, take 0.5 g of NbC powder raw material and disperse it in 100 ml of anhydrous ethanol solvent. Then pour the solution into a ball milling tank filled with nitrogen. To ensure the ball milling efficiency, weigh grinding balls with a mass ratio of 10:1 to the material into the ball milling tank, place the tank in a ball mill and ball mill for 48 hours, then drain the mixture and place it in a vacuum drying oven to dry at 120 °C for 16 hours. After drying and sieving, NbC powder with uniform particle size is obtained. After the NbC powder is stirred evenly with water, add HF solution to the suspension, and the concentration of the hydrofluoric acid solution is 0.5%; the dosage is to add 1 mL of hydrofluoric acid solution to every 100 ml of NbC suspension, and let it stand for more than 24 h; next, centrifuge the suspension; the NbC obtained by centrifugation is added to deionized water, and ultrasonic stirring is used to obtain a uniform suspension (preparation of mother liquor concentration: 1 g / L) for experimental measurement.

[0042] The dried NbC powder needs to be sieved to ensure the uniformity of particle size. When preparing the suspension, ultrasonic stirring is used to improve the dispersion of NbC powder in deionized water.

[0043] Example Two: The difference between this example and Example One is: Disperse 1 part of NbC powder raw material in 100 parts of anhydrous ethanol solvent and stir for no less than 20 min. Specifically, take 1 g of NbC powder raw material and disperse it in 100 ml of anhydrous ethanol solvent. The concentration of the HF solution is 2.5%, and the addition amount is to add 5 mL of HF solution to every 100 ml of NbC suspension; the other preparation processes are the same as above. The SEM image of NbC nanoparticles in this example is as Figure 2 shown.

[0044] Example Three: The difference between this example and Example One is: Disperse 1.5 parts of NbC powder raw material in 100 parts of anhydrous ethanol solvent and stir for no less than 20 min. Specifically, take 1.5 g of NbC powder raw material and disperse it in 100 ml of anhydrous ethanol solvent. The concentration of the HF solution is 5%, and the addition amount is to add 10 mL of HF solution to every 100 ml of NbC suspension; the other preparation processes are the same as above.

[0045] Example Four: The difference between this example and Example One is: Disperse 0.75 parts of NbC powder raw material in 100 parts of anhydrous ethanol solvent and stir for no less than 20 min. Specifically, take 0.75 g of NbC powder raw material and disperse it in 100 ml of anhydrous ethanol solvent. The concentration of the HF solution is 1%, and the addition amount is 3 mL of HF solution added to every 100 ml of NbC suspension; the other preparation processes are the same as above.

[0046] Example 5: The difference between this example and Example 1 is that: Disperse 1.25 parts of NbC powder raw material in 100 parts of anhydrous ethanol solvent and stir for no less than 20 min. Specifically, take 1.25 g of NbC powder raw material and disperse it in 100 ml of anhydrous ethanol solvent. The concentration of the HF solution is 3%, and the addition amount is 7 mL of HF solution added to every 100 ml of NbC suspension; the other preparation processes are the same as above.

[0047] Test on the dispersion uniformity of NbC suspension: (1) Particle size distribution analysis: Use a laser particle size analyzer (Malvern Zetasizer) to test the particle size distribution of the ball-milled NbC powder. Record the average particle size, particle size distribution width (D90 - D10), and standard deviation of each example. Example Average particle size (nm) Particle size distribution width (nm) Standard deviation (nm) 1 120 80 35 2 100 60 25 3 110 70 30 4 115 75 32 5 105 65 28 According to the test, the average particle size of Example 2 is the smallest and the particle size distribution is the narrowest, indicating that its dispersion effect is the best. The particle size distributions of Example 1 and Example 3 are wider, probably because the concentration of NbC powder is too low or too high, resulting in uneven dispersion. The particle size distributions of Example 4 and Example 5 are in the middle, but slightly inferior to Example 2.

[0048] (2) Suspension stability test: Evaluate the stability and dispersion of NbC powder in the suspension. Method: Prepare the NbC suspension of each example with a concentration of 1 g / L. Place the suspension in a static state and observe and record whether there is precipitation or stratification phenomenon at regular intervals (2 hours, 4 hours, 8 hours, 24 hours). Use a UV-visible spectrometer to measure the absorbance changes at different time points to quantitatively evaluate the stability of the suspension. According to this test, the change in absorbance of the suspension in Example 2 is the smallest, indicating that its suspension stability is the highest. The absorbance of Example 1 and Example 3 decreases relatively fast, indicating that the NbC powder under these conditions is prone to sedimentation. The suspension stabilities of Example 4 and Example 5 are in the middle and are not as good as Example 2.

[0049] (3) Chemical plating performance test, to evaluate the dispersion effect of NbC powder through the actual plating performance. Chemical plating was carried out using NbC suspensions under different treatment conditions. Mechanical properties such as the hardness and wear resistance of the plating were tested. The distribution of NbC in the plating was analyzed using SEM or X-ray diffraction (XRD). Example Coating hardness (HV) Wear resistance (wear rate, mg / 1000 cycles) NbC distribution uniformity (SEM / XRD) 1 600 0.25 Non-uniform 2 700 0.18 Uniform 3 650 0.22 Relatively uniform 4 680 0.20 Relatively uniform 5 690 0.19 Uniform According to this test, the plating in Example 2 has the highest hardness, the best wear resistance, and the most uniform distribution of NbC. The plating performance of Example 1 is poor and the distribution of NbC is uneven. The plating performances of Examples 3 and 4 are in the middle, but the distribution of NbC is relatively uniform. The plating performance of Example 5 is close to that of Example 2 but slightly inferior.

[0050] In summary, based on the above performance test results, the following conclusions can be drawn: Preferred solution: Example 2 (1 part of NbC powder is dispersed in 100 parts of absolute ethanol, the concentration of HF solution is 2.5%, and 5 mL of HF solution is added to every 100 mL of NbC suspension). This solution performs excellently in terms of particle size distribution, suspension stability, and plating performance, and can ensure the uniform dispersion of NbC powder in the plating solution, improving the plating quality.

[0051] Sub-optimal solution: Example 5 (1.25 parts of NbC powder is dispersed in 100 parts of absolute ethanol, the concentration of HF solution is 3%, and 7 mL of HF solution is added to every 100 mL of NbC suspension). Although it is slightly inferior to Example 2 in some indicators, the overall performance is still good, especially in terms of plating performance.

[0052] In summary, Example 2 is the best choice because it shows excellent performance in all tests, can ensure the uniform dispersion of NbC powder in the plating solution, and thus improve the quality of the plating. It can be understood that those skilled in the art can make fine adjustments based on Example 2 to achieve further optimization effects.

[0053] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A treatment method for the uniform dispersion of niobium carbide in a chemical composite plating solution, characterized in that, This method uses NbC powder with a mass purity greater than 99.9% and a Fisher average particle size less than 3 µm as the raw material. The NbC powder is subjected to high-energy ball milling using a ball mill, and then dried to obtain nano niobium carbide powder; it includes the following steps: Step 1, disperse the NbC powder raw material in a solvent and stir; Step 2, pour the mixed solution prepared in Step 1 into a ball milling tank filled with nitrogen; Step 3, weigh a certain mass of grinding balls and put them into the grinding tank, and carry out ball milling in a ball mill; Step 4, drain the mixture after ball milling, put it into a vacuum drying oven for drying, and after drying and screening, obtain NbC powder with uniform particle size; Step 5, clean the NbC powder with a hydrofluoric acid solution; Step 6, let it stand after being cleaned with hydrofluoric acid, and carry out centrifugal separation on it to obtain NbC powder; Step 7, add the NbC powder in Step 6 to deionized water, and stir with ultrasonic waves to obtain a uniform suspension of NbC powder.

2. The treatment method for uniform dispersion of niobium carbide in a chemical composite plating solution according to claim 1, wherein The average particle size of the NbC particles in the uniform suspension obtained in Step 7 is 100 nm.

3. A method for uniformly dispersing niobium carbide in a chemical composite plating solution according to claim 2, characterized in that, The solvent is anhydrous ethanol.

4. A method for uniformly dispersing niobium carbide in a chemical composite plating solution according to claim 3, characterized in that In Step 1, 0.5 - 1.5 parts of NbC powder raw material are dispersed in 100 parts of anhydrous ethanol solvent and stirred for no less than 20 min.

5. The treatment method for uniform dispersion of niobium carbide in a chemical composite plating solution according to claim 1, characterized in that, In Step 3, grinding balls with a mass ratio of 10:1 to the material are weighed into the ball milling tank, and ball milling is carried out in a ball mill for 48 hours.

6. A processing method for uniformly dispersing niobium carbide in a chemical composite plating solution according to claim 1, characterized in that, In Step 4, the mixture is put into a vacuum drying oven and dried at 120 °C for 16 hours; after drying and screening, NbC powder with uniform particle size is obtained.

7. The treatment method for uniform dispersion of niobium carbide in a chemical composite plating solution according to claim 1, characterized in that, The concentration range of the hydrofluoric acid solution in Step 5 is 0.5% to 5%; the dosage is 1 - 10 mL of hydrofluoric acid solution added to every 100 ml of NbC suspension.

8. A method for uniformly dispersing niobium carbide in a chemical composite plating solution according to claim 1, characterized in that, The concentration of the mother liquor of the NbC uniform suspension prepared by adding the NbC powder in Step 7 to deionized water is 1 g / L.

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