Patent Description:
Copper is one of metal materials with the longest history of human use. It is well known that, metallic copper itself has high electrical conductivity, thermal conductivity, excellent formability and low price, and is widely used in electric power industry, machinery and vehicle manufacturing industry, chemical industry, construction industry, national defense industry and the like fields. However, metallic copper-containing materials are easily oxidized in air and their surface is easily corroded, which greatly reduces their conductivity, roughens their surface and darkens their colors, thereby limiting their applications.

Copper has a relatively positive potential compared with that of a standard hydrogen electrode, but a relatively negative potential compared with that of a standard oxygen electrode. Therefore, cathodic oxygen absorption corrosion possibly occurs under most conditions, and thus hydrogen cannot be evoluted from an acid. When there is no oxidant in an acid, alkali or air, copper can be corrosion-resistant; and when an oxidant is present, copper will be corroded.

The copper corrosion is divided into chemical corrosion, electrochemical corrosion and physical corrosion according to a basic principle process. The chemical corrosion refers to the damage caused by a direct redox reaction between a copper surface and a surrounding medium. In the process of corrosion, electron transfer is carried out directly between copper and an oxidant. The electrochemical corrosion is a damage caused by an electrochemical reaction between the copper surface and an ion-conducting dielectric. It is also the most general and most common corrosion, and is also a kind of serious corrosion. The corrosion of copper in atmosphere, seawater, soil, and acid, salt and alkali media is mostly the electrochemical corrosion. The electrochemical corrosion can work together with mechanical, dynamical and biological damages to aggravate the loss of the metallic copper. The physical corrosion refers to the damage to copper caused by a simple physical action, and the proportion of such corrosion is small.

At present, the anti-oxidation and anti-corrosion surface treatment methods of copper mainly include:.

Each of the methods (<NUM>) and (<NUM>) has a good anti-oxidation effect, but has a high cost and a complicated process. The copper materials obtained by the methods (<NUM>)-(<NUM>) can play a certain anti-oxidation role, but copper will still be oxidized slowly in a weak oxidizing atmosphere.

In the prior art, corresponding to the method (<NUM>), <CIT> discloses a method for preparing composite copper powder and composite copper conductor slurry for electric conduction, wherein anti-oxidation copper powder is prepared by adopting a silver-coated copper strategy. Due to the high price of silver and the mobility problem of silver, the large-scale application of this method is limited.

Corresponding to the method (<NUM>), <CIT> discloses a high-strength corrosion-resistant six-element brass alloy, wherein the copper alloy prepared from iron, manganese, nickel, zinc and silver has a high strength and can resist acid corrosion; however, the complex preparation process and weak alkali-corrosion resistance limit its large-scale application.

Corresponding to the method (<NUM>), <CIT> discloses a method for conducting surface treatment of conductive copper powder, wherein firstly, the organic matter is removed from the surface by a conventional organic solvent washing method, then the oxide film is removed from copper with an acid, and the product is washed until neutral, and then treated with the coupling agent and a ZB-<NUM> composite treatment agent. The conductive copper powder prepared by this method can be used as a conductive filler in a conductive coating, a conductive ink and a conductive adhesive. However, this method not only requires use of expensive chemical reagents, but also only removes the oxide film from the surface of the copper powder by acid pickling, without inerting an active part on the surface of the copper powder; also, at a later stage of the acid pickling, the pH value of the solution system will increase and the surface of the copper powder will be oxidized again. This layer of oxide film belongs to a low-temperature oxide film, is loose and porous, and thus it is difficult for it to play the role of inhibiting oxidation. Therefore, this method is not suitable for the treatment of the copper powder.

Corresponding to the method (<NUM>), <CIT> discloses a method for modifying a surface of copper powder for a conductive paste, which includes: firstly, removing an organic matter from the surface of the copper powder by using an organic acid mixture; secondly, adding a stabilizer to carry out a recrystallization reaction in an inert gas; and thirdly, adding diethylene diamine and the like to carry out carbon coating. Although this method improves the oxidation resistance of the copper powder, it requires three steps and the process is complicated; and also, it needs to be carried out in an inert atmosphere, and thus the reaction conditions are harsh. This will definitely bring about an increase in the cost.

Corresponding to the method (<NUM>), <CIT> discloses a method of imparting oxidation resistance to nano copper powder, which includes: preparing an organic acid aqueous solution with a mass concentration of <NUM> %-<NUM>%, with the pH of the solution being controlled at <NUM>-<NUM>; adding copper powder into the organic acid aqueous solution, continuously stirring, allowing the mixture to stand, and filtering out the supernatant; preparing a copper powder corrosion-inhibiting solution with a mass concentration of <NUM> %-<NUM>%; adding the copper powder slurry into the copper powder corrosion-inhibiting solution, fully stirring, allowing the mixture to stand, and filtering out the supernatant to obtain a copper powder slurry; replacing the copper powder slurry with an organic solvent for <NUM>-<NUM> times, and then conducting fractionation; weighing a alcohol-soluble organic matter at <NUM>%-<NUM>% of the weight of the copper powder contained in the copper powder slurry, dissolving it in an alcohol solvent to prepare a copper powder corrosion-inhibiting solution with a concentration of <NUM>%-<NUM>%, adding the obtained copper powder slurry into the aforementioned copper powder corrosion-inhibiting solution, and stirring for <NUM>-<NUM>. The method can cover a layer of protective film on the surface of the nano copper powder to effectively isolate oxygen, thereby achieving the purpose of oxidation resistance of the copper powder, but the operation process is complicated and the cost is inevitably increased.

Therefore, it is currently a technical problem to develop a simple and efficient oxidation-resistant and corrosion-resistant surface treatment method for metallic copper-containing materials, in order to solve the use of copper in the fields of electric power industry, machinery and vehicle manufacturing industry, chemical industry, construction industry, national defense industry, etc..

<CIT> relates to surface modification of copper powder for conductive paste; <CIT> relates to surface treating composition for copper or a copper alloy; and <CIT> relates to manufacturing an ink base containing carbon-nonbonding metal nanoparticle.

After in-depth research, the inventor of the present invention has discovered that modifying the surfaces of metallic copper-containing materials with a formate can significantly enhance the oxidation resistance and stability of the metallic copper-containing materials while not reducing their conductivity, and the corrosion resistance of the obtained metallic copper-containing materials, especially the saline-alkali corrosion resistance, can be significantly improved. The present invention is completed based on this.

Particularly, the present invention provides a method for anti-corrosion treatment of copper nanowires according to independent claim <NUM>. Further improvement is recited in the dependent claims.

A method for anti-corrosion treatment includes mixing the metallic copper-containing materials with the polar solvent, adding the stabilizer and the additive, then conducting the sealing and pressurizing reaction, and then performing liquid-solid separation, washing, and drying.

The stabilizer include lithium formate, sodium formate, cesium formate, magnesium formate, aluminium triformate, potassium formate, ammonium formate, calcium formate, zinc formate, iron formate, strontium formate, barium formate, beryllium formate, nickel formate, cobalt formate, and manganese formate. Furthermore, the mass ratio of the stabilizer to the metallic copper-containing materials is <NUM>:<NUM>-<NUM>:<NUM>.

The present invention has no specific limitation on the type of the polar solvent, and the polar solvent may be water and/or various existing polar organic solvents, and is preferably at least one selected from water, an amide solvent, an alcohol solvent, an ester solvent, and an ether solvent. Specific examples of the amide solvent include, but are not limited to, at least one of formamide, dimethylformamide, diethylformamide, dimethylacetamide, diethylacetamide, and dimethylpropionamide. Specific examples of the alcohol solvent include, but are not limited to, at least one of monohydric alcohol, dihydric alcohol and polyhydric alcohol. Specific examples of the ester solvent include, but are not limited to, at least one of ethyl acetate, methyl acetate, n-butyl acetate, n-pentyl acetate, ethyl valerate, ethyl propionate, ethyl butyrate, ethyl lactate, ethyl nonanoate, triethyl phosphate, ethyl caproate, ethyl formate, ethyl cyclohexanecarboxylate, ethyl heptanoate, and ethyl cinnamate. Specific examples of the ether solvent include, but are not limited to, at least one of methyl ether, diethyl ether, diphenyl ether, ethylene oxide, and tetrahydrofuran.

The additive is preferably an organic amine; and more preferably oleylamine, and/or an alkylamine with a molecular formula conforming to CnH2n+3N, wherein <NUM> ≤ n ≤ <NUM>. The mass ratio of the organic amine to the metallic copper-containing materials is preferably <NUM>:<NUM>-<NUM>:<NUM> when addition of the organic amine is needed.

The present invention has no specific limitation on the conditions of the sealing and pressurizing reaction, as long as the formate provided by the stabilizer can be attached to the surfaces of the metallic copper-containing materials. For example, for the sealing and pressurizing reaction, the temperature can be <NUM>-<NUM>, and preferably <NUM>-<NUM>; and the time can be <NUM>-<NUM>, and preferably <NUM>-<NUM>.

According to the present invention the copper-containing materials are copper nanowires.

According to a specific embodiment of the present invention, the method for anti-corrosion treatment includes the following steps:.

The diameter of the copper nanowire is preferably <NUM>-<NUM>.

The dispersant is preferably at least one selected from polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, sodium dodecyl sulfate, polyoxyethylene-<NUM>-octylphenyl ether, and cetyl trimethyl ammonium bromide. Furthermore, the mass ratio of the dispersant to the copper nanowire is preferably <NUM>:<NUM>-<NUM>:<NUM>.

In an embodiment not being covered by the present claims, when the metallic copper-containing materials are the copper wires, the method for anti-corrosion treatment includes the following steps:.

During the anti-corrosion treatment of the copper wire, in the step <NUM>), the specific steps of the surface cleaning are:.

In part (<NUM>) of the step <NUM>), the copper wire is a pure copper wire or a copper alloy wire.

In part (<NUM>) of the step <NUM>), ethanol is adopted to remove the organic matter from the copper wire; and the time for removing the organic matters from the copper wire is <NUM>-<NUM>.

In part (<NUM>) of the step <NUM>), the solvent used for the acid pickling is sulfuric acid, the molar concentration of the sulfuric acid is <NUM>-<NUM> mol/L, and the time for the acid pickling time is <NUM>-<NUM>.

In part (<NUM>) of the step <NUM>), the rinsing is conducted with a solvent of ethanol and/or water for a time of <NUM>-<NUM>.

In an embodiment not being covered by the present claims, when the metallic copper-containing materials are the copper alloys, the method for anti-corrosion treatment includes the following steps:.

During the anti-corrosion treatment of the copper alloy, in the step <NUM>), the specific steps of the surface cleaning of the copper alloy are:.

In part (<NUM>) of the Step <NUM>), the copper alloy is selected from one of copper-nickel alloy, copper-zinc alloy, and copper-tin alloy.

In part (<NUM>) of the Step <NUM>), ethanol is adopted to remove the organic matter from the copper alloy; and the time for removing the organic matter from the copper alloy is <NUM>-<NUM>.

In part (<NUM>) of the Step <NUM>), acetone is adopted to remove the oxide film from the copper alloy, and the time for removing the oxide film from the copper alloy is <NUM>-<NUM>.

In part (<NUM>) of the Step <NUM>), the copper alloy is rinsed with a solvent of ethanol and/or water for a time of <NUM>-<NUM>.

In the step <NUM>), the solvent is water and/or ethanol.

The beneficial effects of the present invention are as follows:.

The above and other objectives, features and advantages of the present invention will become more apparent by describing exemplary embodiments of the present invention in conjunction with the accompanying drawings in more detail.

Hereinafter, embodiments of the present invention will be described in detail, and examples of the embodiments are intended to explain the present invention and should not be construed as limiting the present invention. If no specific technology or condition is indicated in the examples, it shall be carried out according to the technology or condition described in the literature in the art or according to product instructions. All of the used agents or instruments which are not specified with the manufacturer are conventional commercially available products.

A copper foil with a mass of <NUM> and a thickness of <NUM> was weighed with an electronic balance, ultrasonically washed with ethanol for <NUM> to remove an organic matter from the surface, then rinsed with deionized water to remove the ethanol from the surface, soaked in <NUM> diluted hydrochloric acid and subjected to ultrasonic treatment for <NUM> to remove the oxide layer from the surface, then ultrasonically washed with water for <NUM>, and dried. The cleaned copper foil was placed in a solution containing <NUM> of sodium formate, <NUM> of deionized water and <NUM> of a N,N-dimethylformamide (DMF) solution for ultrasonic treatment for <NUM>, transferred into a reaction kettle, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, and washed with water and ethanol for many times, so as to obtain the formate-modified antioxidative copper foil. The resistance change of the copper foil before and after modification was measured by a multimeter (with an electrode spacing of <NUM>). The resistance of the unmodified copper foil was increased from <NUM>Ω to <NUM>Ω after being placed in air atmosphere at <NUM> for <NUM>; and the resistance of the formate-modified copper foil remained almost unchanged (at <NUM>Ω) after being placed at <NUM> for <NUM>.

<NUM> of copper foam was weighed, ultrasonically washed with ethanol for <NUM> to remove an organic matter from the surface, then rinsed with deionized water to remove the ethanol from the surface, and dried. The cleaned copper foam was placed in a high temperature and high pressure vessel containing <NUM> of formic acid and <NUM> of a formamide solution for ultrasonic treatment for <NUM>, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, and washed with water and ethanol for many times, so as to obtain an formate-modified antioxidative copper foam. The resistance change of the copper foam before and after modification was measured by a multimeter (with an electrode spacing of <NUM>). The resistance of the unmodified copper foam was increased from <NUM>Ω to <NUM>Ω after being placed in air atmosphere at <NUM> for <NUM>; and the resistance of the formate-modified copper foil remained almost unchanged (at <NUM>Ω) after being placed at <NUM> for <NUM>.

<NUM> of copper powder (<NUM> mesh) was weighed, ultrasonically washed with ethanol for <NUM> to remove an organic matter from the surface, then rinsed with deionized water to remove ethanol from the surface, soaked in <NUM> diluted sulfuric acid and subjected to ultrasonic treatment for <NUM> to remove the oxide layer from the surface, then ultrasonically washed with water for <NUM>, and dried for later use. The copper powder was placed in a high temperature and high pressure vessel containing <NUM> of potassium formate and <NUM> of a benzyl alcohol solution for ultrasonic treatment for <NUM>, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, washed with water and ethanol for many times, so as to obtain formate-modified antioxidative copper powder. <FIG> was an SEM image of unmodified copper powder (<NUM> mesh) after being placed in air atmosphere at <NUM> for <NUM>, showing that the unmodified copper powder has a rough surface and many copper oxide particles after being oxidized at <NUM>. <FIG> was an XRD pattern of the copper powder (<NUM> mesh) without formate modification after being heated in an air atmosphere at <NUM> for different times, which showed that the peak of the (<NUM>) crystal plane of cuprous oxide became more and more obvious over time as the unmodified copper powder was heated at <NUM>, and the copper powder slowly turned black and the oxidation degree became higher and higher.

<NUM> of copper powder (<NUM> mesh) was weighed, ultrasonically washed with acetone for <NUM> to remove an organic matter from the surface, then rinsed with deionized water to remove acetone from the surface, soaked in <NUM> diluted sulfuric acid and subjected to ultrasonic treatment for <NUM> to remove the oxide layer from the surface, then ultrasonically washed with water for <NUM>, and dried for later use. The cleaned copper powder was placed in a high temperature and high pressure vessel containing <NUM> of sodium formate and <NUM> of a deionized water solution for ultrasonic treatment for <NUM>, added with <NUM> of dodecylamine, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, and washed with water and ethanol for many times, so as to obtain an formate-modified antioxidative copper powder. <FIG> was an SEM image of the formate-modified copper powder (<NUM> mesh) after being placed in an air atmosphere at <NUM> for <NUM>, showing that the surface of the formate-modified copper powder was smooth and flat. <FIG> was an XRD pattern of the formate-modified copper powder (<NUM> mesh) after being heated in an air atmosphere at <NUM> for different times, which showed that the formate-modified copper powder was heated at <NUM>, with the increase of time, there was almost no peak of a copper oxide, and the copper powder remained brownish red, illustrating that it had strong oxidation resistance.

<NUM> of spherical copper micro powder was weighed, ultrasonically washed with ethanol for <NUM> to remove an organic matter from the surface, then rinsed with deionized water to remove ethanol from the surface, soaked in <NUM> diluted hydrochloric acid and subjected to ultrasonic treatment for <NUM> to remove the oxide layer from the surface, then ultrasonically washed with water for <NUM>, and dried for later use. The cleaned copper powder was placed in a high-temperature and high-pressure vessel containing <NUM> of potassium formate and <NUM> of a dimethylpropionamide solution for ultrasonic treatment for <NUM>, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, washed with water and ethanol for many times, so as to obtain formate-modified spherical antioxidative copper powder. <FIG> was an SEM image of the formate-modified spherical copper powder after being placed in an air atmosphere at <NUM> for <NUM>, illustrating that the surface of the formate-modified spherical copper powder was smooth and flat.

<NUM> of spherical copper micro powder was weighed, ultrasonically washed with acetone for <NUM> to remove an organic matter from the surface, then rinsed with water for <NUM>, and dried for later use. The cleaned copper powder was placed in a high temperature and high pressure vessel containing <NUM> of calcium formate and <NUM> of a DMF solution for ultrasonic treatment for <NUM>, added with <NUM> of oleylamine, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, and washed with water and ethanol for many times, so as to obtain an formate-modified spherical antioxidative copper powder.

<NUM> of flake copper micro powder was weighed, ultrasonically washed with ethanol for <NUM> to remove an organic matter from the surface, then rinsed with deionized water to remove ethanol from the surface, soaked in <NUM> diluted hydrochloric acid and subjected to ultrasonic treatment for <NUM> to remove the oxide layer from the surface, then ultrasonically washed with water for <NUM>, and dried for later use. The cleaned copper powder was placed in a high-temperature and high-pressure vessel containing <NUM> of sodium formate and <NUM> of a DMF solution for ultrasonic treatment for <NUM>, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, washed with water and ethanol for many times, so as to obtain formate-modified flake antioxidative copper powder. <FIG> was an SEM image of the formate-modified flake copper powder after being placed at <NUM> for <NUM>, illustrating that the surface of the formate-modified flake copper powder was smooth and flat.

<NUM> of flake copper micro powder was weighed, ultrasonically washed with acetone for <NUM> to remove an organic matter from the surface, then rinsed with deionized water to remove acetone from the surface, soaked in <NUM> diluted hydrochloric acid and subjected to ultrasonic treatment for <NUM> to remove the oxide layer from the surface, then ultrasonically washed with water for <NUM>, and dried for later use. The cleaned copper powder was placed in a high-temperature and high-pressure vessel containing <NUM> of ammonium formate and <NUM> of a DMF solution for ultrasonic treatment for <NUM>, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, washed with water and ethanol for many times, so as to obtain formate-modified flake antioxidative copper powder.

<NUM> of a copper nanowire was weighed, ultrasonically washed with ethanol for <NUM> for multiple times to remove an organic matter from the surface, then rinsed with deionized water to remove ethanol from the surface, dispersed in <NUM> diluted hydrochloric acid and subjected to ultrasonic treatment for <NUM> to remove the oxide layer from the surface, then ultrasonically washed with water for <NUM>, and dried for later use. The cleaned copper nanowire was placed in a high-temperature and high-pressure vessel containing <NUM> of sodium formate and <NUM> of a DMF solution for ultrasonic treatment for <NUM>, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, washed with water for many times, so as to obtain formate-modified antioxidative copper nanowire.

<NUM> of a copper nanowire was weighed, ultrasonically washed with hot ethanol for <NUM> for multiple times to remove an organic matter from the surface, then rinsed with deionized water to remove the ethanol from the surface, and dried. The cleaned copper nanowire was placed in a high temperature and high pressure vessel containing <NUM> of potassium formate and <NUM> of a DMF solution for ultrasonic treatment for <NUM>, added with <NUM> of cetylamine, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, and washed with water and ethanol for many times, so as to obtain an formate-modified antioxidative copper nanowire. <FIG> was an SEM image of the unmodified copper nanowire after being placed at room temperature for <NUM>, illustrating that the unmodified copper nanowire was easily oxidized, and thus the surface became rough; and <FIG> was an SEM image of the formate-modified copper nanowire after being placed at room temperature for <NUM>, showing that the surface of the formate-modified copper nanowire was smooth and flat, and the oxidation resistance was significantly enhanced.

A copper wire with a diameter of <NUM> and a length of <NUM> was taken, ultrasonically washed with ethanol for <NUM> to remove an organic matter from the surface, then rinsed with deionized water to remove ethanol from the surface, dispersed in <NUM> diluted sulfuric acid and subjected to ultrasonic treatment for <NUM> to remove the oxide layer from the surface, then ultrasonically washed with water and ethanol for <NUM>, and dried. The cleaned copper wire was placed in a high temperature and high pressure vessel containing <NUM> of sodium formate and <NUM> of a DMF solution for ultrasonic treatment for <NUM>, added with <NUM> of oleylamine, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, and washed with water and ethanol for many times, so as to obtain an formate-modified copper wire. The copper wires before and after formate modification were placed in a <NUM> sodium hydroxide solution and treated at <NUM> for <NUM> to investigate alkali resistance of them. <FIG> showed the alkali resistance investigation of copper wires before and after formate modification, showing that the unmodified copper wire itself was not alkali resistant and had strong alkali resistance after the formate modification.

A cupronickel faucet was taken, ultrasonically washed with ethanol for <NUM> to remove an organic matter from the surface, then rinsed with deionized water to remove the ethanol from the surface, and dried. The cleaned cupronickel faucet was placed in a high-temperature and high-pressure vessel containing <NUM> of sodium formate and <NUM> of a DMF solution for ultrasonic treatment for <NUM>, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, washed with water for many times, so as to obtain formate-modified cupronickel faucet. The cupronickel faucets before and after the formate modification were placed in a <NUM> sodium hydroxide solution and treated at <NUM> for <NUM> to investigate their alkali resistance. It was found that the surface of the formate-modified cupronickel faucet was not blackened after alkali treatment, and was still silvery white, while the surface of the cupronickel faucet without formate modification was blackened.

The brass foil was placed in a high-temperature and high-pressure vessel containing <NUM> of sodium formate and <NUM> of a DMF solution for, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, washed with water for many times, so as to obtain formate-modified brass foil. The brass foils before and after formate modification were placed in a <NUM> sodium hydroxide solution and treated in an air atmosphere at <NUM> for <NUM> to investigate alkali resistance of them. As shown in <FIG>, the surface of the untreated brass foil was blackened after being soaked in an alkali solution. As shown in <FIG>, it was found that the surface of the formate-modified brass foil was not blackened after alkali treatment, and still remained yellow, while the surface of the brass foil without formate modification was blackened.

A brass casting was taken and placed in a high-temperature and high-pressure vessel containing <NUM> of sodium formate and <NUM> of a DMF solution, heated from room temperature to <NUM> for <NUM>, then kept at <NUM> for <NUM>, naturally cooled, washed with water for many times, so as to obtain a formate-modified brass casting. The brass castings before and after formate modification were placed in a <NUM> sodium hydroxide solution and treated in air atmosphere at <NUM> for <NUM> to investigate their alkali resistance. As shown in <FIG>, it was found that the surface of the formate-modified brass casting was not blackened after the alkali treatment, and still had metallic luster, while the surface of the brass casting without formate modification was blackened.

Preparation of a copper nanowire with a diameter of <NUM>-<NUM>: firstly, <NUM> of CuCl2·2H2O (<NUM> mmol) and <NUM> of glucose (<NUM> mmol) were weighed, dissolved in <NUM> of deionized water and mixed uniformly under stirring; then, a mixed solution consisting of <NUM> of oleylamine, <NUM> of oleic acid and <NUM> of ethanol was slowly added into the mixed aqueous solution of CuCl<NUM>·<NUM><NUM>O and glucose, and then diluted to <NUM>. The aforementioned mixed solution was pre-reacted in an oil bath of <NUM> for <NUM>, then transferred into a hydrothermal reaction kettle after the reaction was completed, and reacted at <NUM> for <NUM>. Finally, a red precipitate appeared at the bottom of the reaction kettle, which was the copper nanowire. The copper nanowire was dissolved in an ethanol solution containing polyvinylpyrrolidone (<NUM> wt%) for ultrasonic dispersion until uniform dispersion, and centrifuged at <NUM>,<NUM> r/min for <NUM>. The precipitate was collected, ultrasonically dispersed in anhydrous ethanol, and then centrifuged twice to remove excess polyvinylpyrrolidone. Finally, the copper nanowire was dispersed in ethanol, and subjected to suction filtering, and the filter cake was baked in a drying oven for later use. <FIG> was an SEM image of a freshly prepared copper nanowire. It could be seen that the prepared copper nanowire had a diameter of <NUM>-<NUM>, had a smooth surface, and had no sign of oxidation.

<NUM> of a copper nanowire was weighed, ultrasonically washed with hot anhydrous ethanol for <NUM> for multiple times to remove an organic matter from the surface, then rinsed with deionized water to remove ethanol from the surface, dispersed in <NUM> diluted hydrochloric acid and subjected to ultrasonic treatment for <NUM> to remove the oxide layer from the surface, then ultrasonically washed with ultrapure water for <NUM>, and dried for later use. The copper nanowire was placed in a high temperature and high pressure vessel containing <NUM> of lithium formate and <NUM> of a DMF solution for ultrasonic treatment for <NUM>, added with <NUM> of dodecylamine, heated from room temperature to <NUM> within <NUM>, then kept at <NUM> for <NUM>, naturally cooled, and centrifugally washed with ultrapure water and anhydrous ethanol for many times, so as to obtain the formate-modified copper nanowire.

<FIG> was an SEM image of the prepared formate-modified copper nanowire. It could be seen that the diameter of the formate-modified copper nanowire was <NUM>-<NUM>, and the structure of the intact nanowire was still maintained. The copper nanowire and the formate-modified copper nanowire were aged in an oven at <NUM> for <NUM> respectively, and the morphologies of the copper nanowires before and after aging were characterized by scanning electron microscopy. Surface XRD was used to measure the crystal structures of the copper nanowires before and after oxidation, and a four-probe tester was used to measure the surface resistance change of the copper nanowire over time before and after modification.

<FIG> was an SEM image of the copper nanowire without formate modification after being aged in an oven at <NUM> for <NUM>. The result was that the nanowire was almost completely destroyed, and obvious nanoparticles could be seen, which might be copper oxide particles. <FIG> was an SEM image of the formate-modified copper nanowire after being aged in an oven at <NUM> for <NUM>, where the entire nanowire structure of the formate-modified copper nanowire was still maintained.

Preparation of a copper nanowire with an average diameter of <NUM>: <NUM> mmol of copper chloride was weighed, ultrasonically dispersed in <NUM> of oleylamine, slowly heated to <NUM> under the protection of nitrogen, added with <NUM> of benzoin under the condition of stirring, heated to <NUM> while stirring in a nitrogen atmosphere, and stabilized at this temperature for <NUM>. The nitrogen was removed, and it was heated to <NUM> in a sealed environment, and kept at this temperature for <NUM>, so as to obtain an ultrafine copper nanowire with an average diameter of <NUM>. The copper nanowire was washed with hot ethanol and n-hexane for several times to remove free organic matters, and finally the filter cake was baked in a drying oven for later use. <FIG> was a TEM image of the prepared copper nanowire with an average diameter of <NUM>, showing that the copper nanowire had good flexibility, a diameter of <NUM>-<NUM> and a length of about <NUM>.

<NUM> of a copper nanowire was weighed, ultrasonically washed with hot anhydrous ethanol for <NUM> for multiple times to remove an organic matter from the surface, and dried for later use. The copper nanowire was placed in a high temperature and high pressure vessel containing <NUM> of calcium formate, <NUM> of deionized water and <NUM> of a benzyl alcohol solution for ultrasonic treatment for <NUM>, heated from room temperature to <NUM> within <NUM>, then kept at <NUM> for <NUM>, naturally cooled, and washed with ultrapure water for many times, so as to obtain a formate-modified antioxidative copper nanowire.

<FIG> was an XRD pattern of the formate-modified copper nanowires before and after the modification, after being heated at <NUM> for different times. <FIG> illustrated that the peak of the (<NUM>) crystal plane of cuprous oxide appeared after the unmodified copper nanowire was heated placed at room <NUM> for <NUM>, and the copper wire slowly turned black, while the formate-modified copper nanowire was still red after being heated at <NUM> for <NUM>, and no peak of copper oxide occurred. <FIG> was a graph showing a curve of the resistance change of the copper nanowire before and after formate modification over time under the aging condition of <NUM>. It could be obviously seen that, the resistance of the formate-modified copper nanowire remained unchanged, while the resistance of the unmodified copper nanowire was increased sharply.

<NUM> of a copper nanowire with a diameter of <NUM>-<NUM> was weighed, ultrasonically washed with hot anhydrous ethanol for <NUM> for many times to remove an organic matter from the surface, then rinsed with deionized water to remove ethanol from the surface, dispersed in <NUM> diluted sulfuric acid and subjected to ultrasonic treatment for <NUM> to remove the oxide layer from the surface, then ultrasonically washed with ultrapure water for <NUM>, and dried for later use. The copper nanowire was placed in a high temperature and high pressure vessel containing <NUM> of magnesium formate and <NUM> of an ethylene glycol solution for ultrasonic treatment for <NUM>, heated from room temperature to <NUM> within <NUM>, then kept at <NUM> for <NUM>, naturally cooled, washed with ultrapure water and anhydrous ethanol for many times, so as to obtain the formate-modified antioxidative copper nanowire.

<NUM> of a copper nanowire with a diameter of <NUM> was weighed, ultrasonically washed with hot anhydrous ethanol and acetone for <NUM> for multiple times to remove an organic matter from the surface, then rinsed with deionized water to remove ethanol from the surface, dispersed in <NUM> diluted hydrochloric acid and subjected to ultrasonic treatment for <NUM> to remove the oxide layer from the surface, then ultrasonically washed with <NUM>% ethanol for <NUM>, and dried for later use. The copper nanowire was placed in a high temperature and high pressure vessel containing <NUM> of sodium formate and <NUM> of a DMF solution for ultrasonic treatment for <NUM>, added with <NUM> of oleylamine, heated from room temperature to <NUM> within <NUM>, then kept at <NUM> for <NUM>, naturally cooled, and washed with ultrapure water and anhydrous ethanol for many times, so as to obtain an formate-modified antioxidative copper nanowire.

An untreated copper wire was put into a <NUM> NaOH solution for alkali resistance test at <NUM> for <NUM>. The photograph of the result was shown in <FIG>.

The copper wire obtained by treating in Example <NUM>-<NUM> was put into a <NUM> NaOH solution for alkali resistance test at a temperature of <NUM> for a period of <NUM>. The photograph of the obtained result was shown in <FIG>.

It could be seen from the comparison between <FIG> that, the untreated copper wire was blackened and had poor alkali resistance, while the copper wire treated in Example <NUM>-<NUM> had a smooth and glossy surface and had alkali resistance.

The copper wire in <FIG> was observed for surface morphology on a scanning electron microscope. <FIG> was an SEM photograph of the copper wire of <FIG>. As could be seen from the figure, the surface was rough and had been oxidized, indicating that it did not have alkali resistance.

The copper wire in <FIG> was observed for surface morphology on a scanning electron microscope. <FIG> was an SEM photograph of the copper wire of <FIG>. As could be seen from the figure, the surface was smooth and seamless, had not been oxidized, and had alkali resistance.

A copper wire with a diameter of <NUM> and a length of <NUM> was taken, wound into a spring shape as a copper winding, and subjected to no treatment to obtain <FIG>.

The copper winding obtained after the treatment in Example <NUM>-<NUM> was shown in <FIG>.

As could be seen from the comparison between <FIG>, the surface of the untreated copper winding was dim and dark, while the surface of the formate-modified copper winding was glossy and shiny.

An untreated brass foil was put into a <NUM> NaOH solution for alkali resistance test at <NUM> for <NUM>. The photograph of the obtained result was shown in <FIG>.

The brass foil obtained after treatment in Example <NUM>-<NUM> was put into a <NUM> NaOH solution for an alkali resistance test at <NUM> for <NUM>. The photograph of the obtained result was shown in <FIG>.

It could be seen from the comparison between <FIG> that, the untreated brass foil was blackened and had poor alkali resistance, while the brass foil treated in Example <NUM>-<NUM> had a smooth and glossy surface and had alkali resistance.

The brass foil in <FIG> was observed for surface morphology on a scanning electron microscope. <FIG> was an SEM photograph of the brass foil in <FIG>. As could be seen from the figure, the surface was rough and had been oxidized, indicating that it did not have alkali resistance.

Claim 1:
A method for anti-corrosion treatment of copper nanowires, comprising subjecting the copper nanowires and a stabilizer to a reaction in a sealed and pressurized reactor in the presence of a polar solvent and an additive, wherein the stabilizer is a compound capable of providing a formate, so that the formate is adsorbed on the surfaces of the copper nanowires, wherein the mass ratio of the stabilizer to the copper nanowires is <NUM>:<NUM> to <NUM>:<NUM>, wherein the stabilizer is a formate salt, and wherein the formate salt is at least one selected from lithium formate, sodium formate, cesium formate, magnesium formate, aluminium triformate, potassium formate, ammonium formate, calcium formate, zinc formate, iron formate, strontium formate, barium formate, beryllium formate, nickel formate, cobalt formate, and manganese formate.