Chemical plating method for nano composite coating and nano composite coating

Electroless plating method of nano composite coating and technical field of nano composite coating

[0001] The present invention relates to the technical field of electroless plating, in particular to an electroless plating method of a nanocomposite coating and a nanocomposite coating prepared by the electroless plating method.

Background technique

[0002] Photocatalysis technology uses semiconductor materials as photocatalysts and uses the excitation of natural sunlight to generate effective active species on the catalyst surface, and achieve the purpose of degrading harmful organic substances in the environment under multiple transformations and interface effects. The photocatalyst is finally mineralized due to photolysis to form CO2, H2O and other small inorganic molecules without the formation of additional secondary pollution. It is a green and environmentally friendly technology.

[0003] Among many semiconductor materials, titanium dioxide has been extensively studied for its excellent photocatalytic and photoelectric properties. At present, due to the excellent photocatalytic properties of titanium dioxide films, titanium dioxide films can be used as protective coatings on the surface of metal or ceramic substrates. The titanium dioxide film is deposited on the surface of the substrate by chemical plating. However, in the process of practical application of the titanium dioxide film, to ensure the wear resistance of the titanium dioxide film, the supporting technology is the key. Therefore, it is urgent to select a suitable carrier to improve its photocatalytic efficiency and wear resistance.

[0004] The above content is only used to assist in understanding the technical solutions of the present invention, and does not mean that the above content is recognized as prior art.

Summary of the invention

[0005] The main purpose of the present invention is to provide a nano-composite electroless plating method and nano-composite coating, aiming to improve the photocatalytic efficiency and wear resistance of the nano-composite coating.

[0006] In order to achieve the above-mentioned object, the electroless plating method of nanocomposite coating provided by the present invention includes the following steps:

[0007] Titanium dioxide sol was prepared with tetraisopropyl titanate as the titanium source, hydrogen peroxide solution as the oxidant, organic alcohol solvent and water as the solvent, and the titanium dioxide sol was modified with nano-silica to obtain modified titanium dioxide Sol; [0008] The carbon nanotube powder is treated with mixed acid, washed with water to neutrality, filtered and dried to obtain purified carbon nanotube powder;

[0009] The purified carbon nanotube powder is used as a carrier to load the modified titania sol, and after the load is dried, a composite nano-modifier is obtained;

[0010] The composite nano modifier is immersed in a colloidal palladium activation solution and stirred, filtered and washed with water, and then immersed in a dilute hydrochloric acid solution for degumming to obtain a degummed composite nano modifier;

[0011] The debonded composite nano modifier and matrix are placed in an electroless plating solution for electroless plating, and filtered, washed and dried to obtain a nano composite coating.

[0012] Optionally, the volume ratio of the organic alcohol solvent to the water is 3:100 to 5:100; and/or, the particle size of the nano-silica is 25nm-55nm, and the purity is not less than 99.5%, the mass ratio of the nano-silica and the titania sol is 1:1.5 to 1:3.

[0013] Optionally, the aspect ratio of the carbon nanotube powder is 30:1 to 50:1; and/or,

[0014] The "use of mixed acid treatment of carbon nanotube powder, and use water to wash to neutral, filtered and dried, to obtain

The steps of "purified carbon nanotube powder" include:

[0015] The carbon nanotube powder was dispersed in a mixed acid, sonicated for 2h-3h, then washed with deionized water to neutrality, filtered with an acid-resistant microfiltration membrane to obtain a filter residue, and the filter residue was vacuum dried at a temperature of 80°C-110°C 24h, get purified carbon nanotube powder.

[0016] Optionally, the step of "loading the modified titania sol with the purified carbon nanotube powder as a carrier, and drying after loading to obtain a composite nano-modifier" includes:

[0017] The purified carbon nanotube powder and the modified titanium dioxide sol were mixed, and sonicated at 40°C-50°C for 30min-60min, and then heated in a water bath at 60°C-70°C for 1h-2h, and then at 80°C- Drying at a constant temperature of 110°C for 24h-48h to obtain a composite nano-modifier.

[0018] Optionally, the "composite nano modifier is immersed in a colloidal palladium activation solution and stirred, filtered and washed with water, and then immersed in a dilute hydrochloric acid solution for degumming, to obtain the degummed composite nano modifier "The steps include:

[0019] The composite nano-modifier is immersed in a colloidal palladium activation solution at 18°C-30°C, stirred for 3min-10min, filtered to obtain a filter residue, and the filter residue is washed with water and immersed in a 10% dilute hydrochloric acid solution at 40°C-45°C, Stir for 30s-60s to obtain the composite nano-modifier after degumming.

[0020] Optionally, when the "composite nano-modifier and the matrix after debonding are put into an electroless plating solution for electroless plating", the pH of the electroless plating solution is 4.5-4.7, and the stirring speed It is 120r/min-240r/min, the electroless plating temperature is 94 °C -98 °C, and the electroless plating time is 10min-15min.

[0021] Optionally, the electroless plating solution includes nickel salt, hypophosphite, complexing agent, stabilizer and wetting agent, the content of the nickel salt is 30g/L-80g/L, the hypophosphorous acid The content of salt is 60g/L-140g/L, the content of described complexing agent is 36g/L43g/L, the content of described stabilizer is 16.5mg/L-23mg/L, and the content of described wetting agent is 5mg/L-10mg/L.

[0022] Optionally, the complexing agent is selected from at least one of succinic acid, lactic acid, malic acid, and glycine; and/or, the stabilizer is selected from thiourea, potassium iodate, and butane At least one of enedioic acid; and/or, the wetting agent is selected from polyethylene glycol.

[0023] Optionally, the substrate is a metal or ceramic block, part, or powder.

[0024] The present invention also provides a nano-composite coating, the nano-composite coating is prepared by the electroless plating method of the above-mentioned nano-composite coating.

[0025] In the technical scheme of the present invention, the modified titania sol is loaded by using carbon nanotubes as a carrier, and the surface is activated by palladium after loading. After the treatment, the substrate is placed in an electroless plating solution for electroless plating, and plating After filtering, washing and drying, the nano composite coating can be obtained. Among them, titanium dioxide can reduce the scattering intensity of long-wave ultraviolet rays, absorb short-wave ultraviolet rays, and has good photocatalytic performance; and, using carbon nanotubes as a carrier can improve its photocatalytic efficiency. At the same time, carbon nanotubes can also improve nanocomposite The wear resistance, hardness and impermeability of the coating.

Detailed ways

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0027] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on what can be achieved by a person of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that this technical solution is The combination does not exist, nor does it fall within the scope of protection claimed by the present invention.

[0028] The present invention provides an electroless plating method for nanocomposite coatings. The electroless plating method includes the following steps:

[0029] Titanium dioxide sol was prepared with tetraisopropyl titanate as the titanium source, hydrogen peroxide solution as the oxidant, organic alcohol solvent and water as the solvent, and the titanium dioxide sol was modified with nano-silica to obtain modified titanium dioxide Sol; [0030] The carbon nanotube powder is treated with mixed acid, washed with water to neutrality, filtered and dried to obtain purified carbon nanotube powder;

[0031] The purified carbon nanotube powder is used as a carrier to load the modified titania sol, and after the load is dried, a composite nano-modifier is obtained;

[0032] The composite nano modifier is immersed in a colloidal palladium activation solution and stirred, filtered and washed with water and then immersed in a dilute hydrochloric acid solution for degumming to obtain a composite nano modifier after degumming;

[0033] Put the debonded composite nano modifier and the matrix into an electroless plating solution for electroless plating, and filter, wash and dry to obtain a nano composite coating.

[0034] The electroless plating method of the nanocomposite coating of the present invention specifically includes the following steps: (1) Preparation of modified titanium dioxide sol: the titanium source is selected from tetraisopropyl titanate, the oxidant is selected from hydrogen peroxide, and the solvent is selected from organic alcohols Solvents and water, organic alcohols can be isopropanol, butanediol, glycerol, etc., and deionized water is used for water. When these substances react, they need to be heated to a temperature of 60°C-75°C. Generally, water bath heating is used. Heating will make the temperature more uniform. By this method, a titania sol can be prepared, and then modified with nano-silica, the role of which is to load the titania sol to improve the dispersibility of the titania sol. (2) Purification of carbon nanotubes: The carbon nanotubes are treated with mixed acid to dissolve the impurities on the surface of the carbon nanotubes, so as to achieve the surface purification of the carbon nanotubes, and then use deionized water to wash the carbon nanotubes to the middle And filter out the acid liquid, and then dry the filtered filter residue to obtain purified carbon nanotubes. Composite nano-modifier loading: the purified carbon nanotube powder is used as a carrier to load the modified titania sol. After loading, the composite nano-modifier can be obtained by drying. The composite nano-modifier is in powder form. (4) Surface colloidal palladium activation treatment: immerse the composite nano-modifier in colloidal palladium solution, stir, filter and wash, and then immerse in dilute hydrochloric acid for degumming. Here, dilute hydrochloric acid is selected as the degumming agent, and the colloid is in strong acid. Under the action, it can dissolve and dissolve. Chemical plating treatment: will solve After the glue, the composite nano-modifier and the matrix are put into the electroless plating solution for electroless plating. After the plating is completed, it is filtered, washed, and dried to obtain the nano-composite coating. The nano-composite coating is a carbon nanotube-loaded TiO2 coating. Ni-P metal coating. Here, the substrate may be a metal substrate sheet, a ceramic substrate sheet, or a powdered substrate.

[0035] Therefore, it can be understood that the technical solution of the present invention is to support the modified titania sol by using carbon nanotubes as a carrier, and after loading, the surface palladium activation treatment is performed, and after the treatment, the substrate is put into an electroless plating solution for chemical treatment. After plating, filtering, washing, and drying after plating is completed, a nano-composite plating layer can be obtained. Among them, titanium dioxide can reduce the scattering intensity of long-wave ultraviolet rays, absorb short-wave ultraviolet rays, and has good photocatalytic performance; and, using carbon nanotubes as a carrier can improve its photocatalytic efficiency. At the same time, carbon nanotubes can also improve nanocomposite The wear resistance, hardness and impermeability of the coating.

[0036] It should be noted that the colloidal palladium activation solution used in step (4) can be prepared by the following steps: 70g of SnCl2·2H2O is added to 100mL of concentrated hydrochloric acid, and the mixture is continuously stirred until it is completely dissolved. After adding 7g of Na2SnO3·7H2O, stir evenly. , Get UB solution. Add 1g of PdCl2 into 200mL of 37% concentrated hydrochloric acid and stir until completely dissolved, and then add 2.54g of SnCl2 · 2H2O under constant stirring at 30±5°C to obtain liquid A. Start timing from the addition of SnCl2 · 2H2O, stir A solution for 12 minutes, then slowly pour solution B into solution A, stir the prepared colloidal palladium solution in a water bath at 45±5°C for 3 hours, and then add it Ionized water to 1L, the colloidal palladium activation solution is obtained. Of course, the colloidal palladium solution can also be selected from other formulations that play the same role. [0037] Optionally, the volume ratio of the organic alcohol solvent and water is 3:100 to 5:100. In the preparation of titanium dioxide sol, organic

The ratio of alcohol solvent and water should be selected appropriately so that the final titanium dioxide obtained has a higher purity and better quality. For example, an organic alcohol solvent and a water solvent with a volume ratio of 3:100, or 4:100, or 5:100 are used.

[0038] Optionally, the particle size of the nano-silica can be 25nm-55nm, the purity is not less than 99.5%, and the mass ratio of the nano-silica and the titania sol is 1:1.5 to 1:3. When nano-silica is used to modify the titania sol, the particle size of the nano-silica should be selected appropriately, and the amount of silica should also be selected appropriately, so that the modified titania sol has better dispersion performance. For example, nano-silica and titania sol with a mass ratio of 1:1.5, or 1:2, or 1:3 are used. And, the purity of nano-silica is not less than 99.5%.

[0039] Further, the step of "processing the carbon nanotube powder with mixed acid, washing to neutrality with water, filtering and drying, and obtaining purified carbon nanotube powder" includes:

[0040] Disperse the carbon nanotube powder in a mixed acid, sonicate for 2h-3h, then wash with deionized water to neutrality, filter with an acid-resistant microfiltration membrane to obtain a filter residue, and dry the filter residue in a vacuum at a temperature of 80°C to 110°C 24h, get purified carbon nanotube powder. The carbon nanotube powder should also be selected appropriately. Generally, carbon nano powders with an aspect ratio of 30:1 to 50:1 are used, for example, carbon nano powders with an aspect ratio of 30:1, or 40:1, or 50:1 are used. powder. The mixed acid is a super strong acid, and the mixed acid of nitric acid and hydrochloric acid can be selected. The mixed acid can adsorb and dissolve the impurities on the surface of the carbon nanotube powder to realize the purification treatment of the carbon nanotube powder.

[0041] The step of "loading the modified titania sol with purified carbon nanotube powder as a carrier, and drying after loading to obtain a composite nano-modifier" includes:

[0042] The purified carbon nanotube powder and the modified titanium dioxide sol were mixed, and ultrasonically vibrated at 40°C-50°C for 30min-60min, and then heated in a water bath at 60°C-70°C for 1h-2h, and then at 80°C- Drying at a constant temperature of 110°C for 24h-48h, a composite nano-modifier was obtained. Specifically, the purified carbon nanotube powder and the modified titanium dioxide sol were mixed in a beaker, and placed in an ultrasonic cleaner at 40°C for ultrasonic vibration for 30 minutes, and then placed in a magnetic stirrer and heated in a 70°C water bath for 1 hour, after which Then put the beaker into a vacuum drying oven at 110°C for 24 hours and dry it to a constant weight to obtain the composite nano-modifier.

[0043] Further, the step of "soaking the composite nano modifier in the colloidal palladium activation solution and stirring, and immersing it in a dilute hydrochloric acid solution after filtering and washing with water for degumming to obtain the composite nano modifier after degumming" includes :

[0044] The composite nano modifier is immersed in a colloidal palladium activation solution at 18°C-30°C, stirred for 3min-10min, filtered to obtain a filter residue, and the filter residue is washed with water and immersed in a 10% dilute hydrochloric acid solution at 40°C-45°C, Stir for 30s-60s to obtain the composite nano-modifier after degumming. Here, 10% dilute hydrochloric acid is used as the gel dissolving agent, which can make the dissolution operation more fully.

[0045] Further, when the composite nano-modifier and the matrix after dissolution are put into the electroless plating solution for electroless plating, the pH of the electroless plating solution is 4.5-4.7, and the stirring speed is 120r/min-240r/ min, the electroless plating temperature is 94 °C-98 °C, and the electroless plating time is 10min-15min. In the process of electroless plating, strict control of various operating conditions can make the electroless plating operation more fully performed, so that the final electroless plating nanocomposite coating is more uniform and has better performance. For example, the pH of the electroless plating solution is 4.5, or 4.6, or 4.7, the stirring speed is 1201, or 2001, or 240r/min, and the electroless plating temperature is 94°C, or 96°C, or 98°C. , The electroless plating time is 10min, or 12min, or 15min.

[0046] Optionally, the electroless plating solution includes silver salt, hypophosphite, complexing agent, stabilizer and wetting agent, the content of nickel salt is 0.114mol/L-0.304mol/L, and the content of hypophosphite is 0.484mol/L-1.130mol/L, the content of complexing agent is 36g/L-43g/L, the content of stabilizer is 16.5mg/L-23mg/L, the content of wetting agent is 5mg/L-10mg/ L. Here, the nickel salt can be nickel sulfate hexahydrate, and the hypophosphite can be sodium hypophosphite monohydrate. Nickel salt is the source of nickel, and sodium hypophosphite is the reducing agent,

The complexing agent plays the role of controlling the plating rate and stabilizing the plating solution, the stabilizer plays the role of stabilizing the plating solution, and the wetting agent plays the role of improving the bonding strength of the plating layer.

[0047] Optionally, the complexing agent is selected from at least one of succinic acid, lactic acid, malic acid, and glycine; the stabilizer is selected from at least one of thiourea, potassium iodate, and maleic acid ; The wetting agent is selected from polyethylene glycol.

[0048] In the process of electroless plating, the selected substrate can be a metal or ceramic block, a part, or a powder. When diamond powder is selected as the matrix, the diamond powder must first be treated with surface colloidal palladium activation solution and treated with 10% dilute hydrochloric acid.

[0049] The present invention also provides a nano-composite coating, the nano-composite coating is prepared by the above-mentioned electroless plating method of the nano-composite coating. The nano composite plating layer includes a substrate and a carbon nanotube loaded TiO2 modified Ni-P metal composite plating layer plated on the surface of the substrate.

[0050] Hereinafter, the electroless plating method and nano-composite coating of the nano-composite coating of the present invention will be described in detail through specific examples.

Example 1

[0052] The electroless plating method of nano composite coating mainly includes the following steps:

[0053] (1) Add 75 mL of isopropanol to 2000 mL of deionized water while stirring, and then slowly add 75 mL of tetraisopropyl titanate dropwise. After the addition is complete, stir for 2 hours, and then add a little hydrogen peroxide solution until the solution becomes clarify. Then transfer to a constant temperature oil tank, and return to the oil bath for 48 hours to obtain titanium dioxide sol. After the sol is prepared, 50 g of nano SiO2 is added and stirred to prepare a modified TiO2 sol.

[0054] Weigh 500g of carbon nanotube powder in a beaker, disperse it in a mixed acid, sonicate for 2h, then wash with deionized water to neutrality, filter with a microporous membrane, and put it in a vacuum drying oven , Dried at 110 °C for 24h, then take it out for later use.

[0055] The modified TiO2 sol is loaded with carbon nanotubes as a carrier, the carbon nanotubes and the modified TiO2 sol are mixed in a beaker, and the beaker is placed in an ultrasonic cleaner at 40°C under ultrasonic vibration for 30 minutes, and then released. Heated in a 70°C water bath in a magnetic stirrer for 1h, then put the beaker in a vacuum drying oven at 110°C for 24h at a constant temperature, and dried to constant weight to obtain the composite nano-modifier.

[0056] (4) Colloidal palladium activation treatment on the surface of the powder: 3g of the composite nano-modifier and copper flakes were added to the colloidal palladium activation solution at 30°C, stirred slowly, after 5 minutes, the powder was filtered, washed with water and immersed in 10% of 40°C Stir slowly in the diluted hydrochloric acid solution for 60 seconds to dissolve the gel and filter.

[0057] Put the debonded composite nano-modifier and the copper sheet into an electroless plating solution for electroless plating. The formula of the electroless plating solution is: nickel sulfate hexahydrate 45g/L, sodium hypophosphite monohydrate 80g /L, succinic acid 12g/L, lactic acid 12g/L, malic acid 8g/L, glycine 5g/L, thiourea 0.5mg/L, potassium iodate 10mg/L, maleic acid 5mg/L, Polyethylene glycol 2g/L. During the plating process, the temperature of the plating solution is adjusted to 95°C, the pH value is 4.5 to 4.7, the stirring rate is 180r/min, and the reaction time is 15min. After the plating is completed, it is filtered, washed, and dried to obtain a copper sheet coated with a nano composite coating on the surface, and the nano composite coating is a carbon nanotube loaded TiO2 modified Ni-P metal composite coating.

Example 2

[0059] The electroless plating method of nanocomposite coating mainly includes the following steps:

[0060] (1) Add 37.5 mL of isopropanol to 1000 mL of deionized water while stirring, and then slowly add 37.5 mL of tetraisopropyl titanate dropwise. After the addition is complete, stir for 1 hour, and add a little hydrogen peroxide solution to The solution became clear. Then transfer to a constant temperature oil tank and return to the oil bath for 48 hours to obtain titanium dioxide sol. After the sol is made, add 15g of nano SiO2 and stir to make it

Modified TiO2 sol.

[0061] Weigh 100g of carbon nanotube powder in a beaker, disperse it in a mixed acid, sonicate for 2h, then wash with deionized water to neutrality, filter with a microporous membrane, and put it in a vacuum drying oven , Dried at 110°C for 24h, then take it out for later use.

[0062] The modified TiO2 sol was loaded with carbon nanotubes as a carrier, the carbon nanotubes and the modified TiO2 sol were mixed in a beaker, and the beaker was placed in an ultrasonic cleaner at 40°C under ultrasonic vibration for 30 minutes, and then released. Heat in a 70°C water bath in a magnetic stirrer for 1 hour, then place the beaker in a vacuum drying oven at 110°C for 24 hours at a constant temperature, and dry to constant weight to obtain the composite nano-modifier.

[0063] Colloidal palladium activation treatment on the powder surface: 180g, 240 mesh diamond powder and 5g composite nano-modifier were added to the colloidal palladium activation solution at 30°C, stirred slowly, after 5min, filtered the powder, washed with water and immersed in 40°C Stir slowly in a 10% dilute hydrochloric acid solution for 60 seconds to dissolve the gel and filter.

[0064] The diamond powder and the composite nano-modifier after the glue is placed in an electroless plating solution for electroless plating. The formula of the electroless plating solution is: nickel sulfate hexahydrate 60g/L, sodium hypophosphite monohydrate 120g/ L, succinic acid 15g/L, lactic acid 14g/L, malic acid 8g/L, glycine 6g/L, thiourea 1mg/L, potassium iodate 10mg/L, maleic acid 10mg/L, polyethylene Glycol 3.5g/L. During the plating process, adjust the bath temperature to 95°C, pH value of 4.5, stirring rate of 240r/min, and reaction time of 15min. After the plating is completed, it is filtered, washed, and dried to obtain diamond powder coated with a nano-composite plating layer, and the nano-composite plating layer is a carbon nanotube-loaded TiO2 modified Ni-P metal composite plating layer.

[0065] The performance of the nanocomposite coatings obtained in Example 1 and Example 2 was tested, and the results were as follows: The nanocomposite coatings prepared in Example 1, compared with the unmodified coatings, had a wear life increased by 20% ; The nano composite coating prepared in Example 2, compared with the unmodified coating, can increase the wear resistance of diamond powder by 25%. Therefore, the nano composite coating prepared by the electroless plating method of the nano composite coating of the present invention has better wear resistance.

[0066] The above descriptions are only preferred embodiments of the present invention, and do not limit the scope of the present invention. Any equivalent structural transformation made by using the content of the present invention under the inventive concept of the present invention, or directly/indirectly applied to Other related technical fields are included in the scope of patent protection of the present invention.