CN116329562A - High-uniformity nano dispersion strengthening copper and preparation method thereof - Google Patents

Abstract

The invention relates to a high-uniformity nano-dispersion-strengthened copper and a preparation method thereof. The preparation method comprises screening a metal more active than copper as a dispersion-strengthening phase, and preparing the metal salt through a liquid phase reduction process to obtain a stock solution of nano-metal particles; Add a copper salt solution to it, and through a replacement reduction reaction, copper is evenly coated on the surface of the nano metal particles, and then washed to neutrality and dried in turn to obtain a copper-coated nano-particle composite powder; then add an appropriate amount of pure copper powder, After pressing, reducing and sintering, a high-uniform nano-dispersion strengthened copper composite material is obtained. The preparation method of the invention avoids the addition of dispersion strengthening phase particles during powder metallurgy pressing, thereby overcoming the defects of uneven distribution and easy agglomeration of the dispersion strengthening phase, and the distance between the dispersion strengthening phases is controllable and highly dispersible. The prepared dispersion-strengthened copper has excellent mechanical and electrical comprehensive properties, and the process flow is simple and controllable, the cost is low, and it is easy for large-scale production.

Description

A kind of high homogeneity nano-dispersion strengthened copper and preparation method thereof

technical field

The invention relates to the technical field of metal matrix composite materials, in particular to a high-uniformity nano-dispersion strengthened copper and a preparation method thereof.

Background technique

Copper and copper alloys are the key basic materials supporting the development of the national economy and people's livelihood, national defense and military industry. As a typical structural-functional integration material, copper alloy needs comprehensive service performance of high strength, high plasticity and high conductivity. Dispersion-strengthened copper is a kind of high-strength and high-conductivity copper-based material with excellent comprehensive properties, which uses second-phase nanoparticles uniformly distributed in the copper matrix to hinder dislocation movement and grain boundary merging through pinning dislocations and bypass mechanisms. , are widely used in electrical, rail transit, electronic communications and other fields.

The preparation methods of dispersion strengthened copper alloy include internal oxidation method, powder metallurgy method, mechanical alloying method, spray deposition method and chemical precipitation method, among which internal oxidation method and powder metallurgy method are more mature and widely used. However, the internal oxidation method has problems such as complicated process, long production cycle and high cost, and the product quality cannot be precisely controlled. Powder metallurgy is a low-cost method for preparing high-performance metal composites. However, due to the large differences between the dispersion-strengthened particles and the copper matrix in terms of size, shape, and physical properties, it is difficult to uniformly disperse the dispersion-strengthened particles. It causes segregation, which leads to poor bonding of the dispersion strengthening phase/copper matrix interface, and the performance improvement is restricted.

In-situ generation of dispersion strengthening phase or preparation of strengthening phase particles and copper into composite powder is a feasible solution to solve the dispersibility. Patent document CN114921673A discloses a preparation method of nano-oxide particle dispersion strengthened copper, using induction melting and melt atomization technology to prepare Zr-4Cu-2O oxide powder with good wettability and close specific gravity to the matrix alloy melt , followed by melting and casting together with the matrix copper metal as a raw material to prepare kilogram-scale ODS-Cu materials. Patent document CN103981381A discloses a method for preparing nano-alumina dispersion-strengthened copper-based composite materials by a sol method, using soluble salts of copper and aluminum or adding carbon nanotubes as raw materials to prepare a composite of nano-alumina/carbon nanotubes and copper powder, the composite powder is isostatically pressed and sintered in a hydrogen atmosphere to obtain a dispersion-strengthened copper-based composite material with 0.1-3wt.% of nano-alumina.

The currently disclosed methods mostly use physical methods, which cannot effectively avoid the segregation caused by the difference in physical properties between the dispersion-strengthened phase and the copper matrix, and have not effectively improved the powder raw materials, resulting in long production process, long cycle, and high cost. A series of high-level problems are difficult to solve completely, which limits the further development and application of dispersion-strengthened copper alloys.

Contents of the invention

The purpose of the present invention is to provide a high-uniformity nano-dispersion strengthened copper and its preparation method. The dispersion-strengthened copper is based on copper-coated nano-metal particle composite powder. The dispersion-strengthened copper prepared by the method provided by the present invention has high density and high dispersion The strengthening phase has a highly uniform dispersion, the distance between the dispersion strengthening phases is controllable, and there is a strong interface bonding strength with the copper matrix, the phase is single and there is no other impurity pollution. This method avoids the problem of insufficient performance caused by the process from the raw material, and the mechanical and electrical comprehensive properties of the prepared dispersion-strengthened copper are better than the traditional method, and the process is simple.

For this reason, the invention provides a kind of preparation method of nano-dispersion strengthened copper composite material, it comprises the following steps:

S1, adding a reducing agent and a surfactant to the metal salt solution to react to obtain a stock solution of nano metal powder particles;

S2. Mix the nano metal powder particle stock solution with the copper salt solution, and obtain a copper-coated nanoparticle composite powder stock solution through a displacement reduction reaction;

S3. Washing the stock solution of the copper-coated nanoparticle composite powder in sequence to neutrality and drying to obtain a copper-coated nanoparticle composite powder;

S4. Mix the copper-coated nanoparticle composite powder with pure copper powder, and sequentially undergo pressing and reduction sintering to prepare a nano-dispersion strengthened copper composite material.

Further, in step S1, the activity of the metal element of the metal salt is higher than that of copper element.

Further, the metal salt includes one or a combination of two or more selected from the following group: molybdenum (Mo), iron (Fe), chromium (Cr), manganese (Mn) chloride, sulfate, nitrate or Other water soluble salts.

Further, in step S1, in the metal salt solution, the concentration of the metal salt is 0.1-5 mol/L; for example, 0.1 mol/L, 0.2 mol/L, 0.45 mol/L, 0.5 mol/L, 0.6 mol/L L, 1mol/L, 2mol/L, 3mol/L, 4mol/L, 5mol/L, etc.

Further, in step S1, the metal salt solution is prepared by dissolving the metal salt in deionized water.

Further, in step S1, the reducing agent includes one or a combination of two or more selected from the following group: KBH ₄ , NaBH ₄ , N ₂ H ₄ ·H ₂ O, C ₆ H ₈ O ₆ .

Further, in step S1, the concentration of the reducing agent is in excess relative to the metal salt. In some embodiments, after adding the reducing agent in step S1, the concentration is 0.5-20 mol/L; for example, 0.5 mol/L, 1 mol/L, 5 mol/L, 10 mol/L, 15 mol/L, 20 mol/L wait.

Further, in step S1, the surfactant includes one or a combination of two or more selected from the following group: polyvinylpyrrolidone (PVP), benzotriazole (BTA), octylphenol polyoxyethylene ether OP -10. Cetyltrimethylammonium bromide (CTAB), disodium ethylenediaminetetraacetic acid (EDTA-2Na), sodium dodecyl sulfate (SDS), sodium dodecylbenzenesulfonate (SDBS) ),Sodium citrate.

Further, after adding the surfactant in step S1, the concentration is 0.05-10 mol/L; for example, 0.05 mol/L, 0.1 mol/L, 0.2 mol/L, 0.3 mol/L, 0.45 mol/L, 0.5 mol /L, 1mol/L, 5mol/L, 10mol/L, etc.

Further, in step S1, the reaction is carried out under stirring conditions, and the stirring speed is 600-2000 rpm; for example, 600 rpm, 1000 rpm, 13000 rpm, 1600 rpm, 2000 rpm, etc.

Further, in step S1, the reaction is carried out at a pH value of 5-15, for example, a pH value of 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15; in some implementations In the method, HCl, NaOH, NH ₃ ·H ₂ O, etc. are used to adjust the pH value.

Further, in step S1, the temperature of the reaction is 20°C to 100°C; for example, it can be 20°C, 25°C, 30°C, 35°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C etc.

Further, in step S1, the median diameter of the nano-metal powder particles is 50-900nm; for example, 50nm, 100nm, 150nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, etc.

Further, in step S2, the copper salt includes one or a combination of two or more selected from the following group: CuSO ₄ ·5H ₂ O, CuCl ₂ ·2H ₂ O, Cu(NO ₃ ) ₂ .

Further, in step S2, in the copper salt solution, the concentration of the copper salt is 0.5-20 mol/L; for example, 0.5 mol/L, 1 mol/L, 2 mol/L, 4 mol/L, 5 mol/L, 10 mol/L, 15mol/L, 20mol/L, etc.

Further, in step S2, the copper salt solution is prepared by dissolving the copper salt in deionized water.

Further, in step S2, the copper salt is in excess relative to the nano metal powder particles. In some embodiments, the volume ratio of the nano-metal powder stock solution to the copper salt solution is 5-8:1.

Further, in step S2, the displacement reduction reaction is carried out under stirring conditions, and the stirring speed is 800-2000 rpm; for example, 800 rpm, 1000 rpm, 13000 rpm, 1600 rpm, 2000 rpm, etc.

Further, in step S2, the temperature of the displacement reduction reaction is 20-100°C; for example, it can be 20°C, 25°C, 30°C, 35°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C ℃, 100℃, etc.

Further, in the copper-coated nanoparticle composite powder, the thickness of the copper coating is 0.5-10 μm; for example, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm.

Further, in step S3, the drying process is drying; the drying temperature is 40-80°C; for example, 40°C, 50°C, 60°C, 70°C, 80°C, etc.

Further, in step S3, the drying is carried out under vacuum conditions.

Further, in step S4, the pressing is mold pressing or cold isostatic pressing; the pressure of the pressing is 100-800 MPa.

Further, in step S4, the reduction sintering is carried out under a mixed atmosphere of N ₂ and H ₂ , wherein the ratio of N ₂ to H ₂ is 1-5:1-5.

Further, in step S4, the reduction and sintering temperature is 700-1350°C, such as 700°C, 800°C, 1000°C, 1200°C, 1300°C, 1350°C, etc.; the reduction and sintering time is 1-8h, for example 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, etc.

The second aspect of the present invention provides a nano-dispersion strengthened copper composite material, which is prepared according to the preparation method described in the first aspect of the present invention.

Compared with prior art, the beneficial effect of the present invention is:

In the preparation process of the dispersion-strengthened copper alloy, the invention avoids the addition of dispersion-strengthened phase particles during powder metallurgy pressing, thereby avoiding the segregation in the mixing process caused by the difference in physical properties between the dispersion-strengthened phase and the copper matrix, and effectively solving the problem of dispersion strengthening The problems of uneven distribution and easy agglomeration of the phases in the copper matrix, and the controllable distance between the phases of the dispersion strengthening, have better wettability and bonding strength with the copper matrix.

The present invention utilizes the property that copper is less reactive than the core metal, and replaces and reduces copper ions to copper atoms to coat the surface of the core metal nanoparticles. The dispersion-strengthened phase of nanoparticles in the dispersion-strengthened copper alloy can still ensure uniform distribution. The particle size of the nanoscale dispersion strengthening phase of the invention is controllable and uniform, and the macro performance of the material is better than that of the traditional preparation method. In addition, the entire technological process of the present invention is simple and controllable, has low cost, and is easy to realize large-scale production.

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below. It should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

Example 1 Fe-Cu dispersion strengthened copper

S1: Weigh FeCl·4HO and dissolve it in 5L deionized water and stir to dissolve it completely to prepare an aqueous FeCl solution with a concentration of 0.45mol/L; add SDS and dissolve it in the aqueous FeCl solution so that the concentration of SDS is 0.45mol/L, Mix and stir for 20min, slowly dropwise add NaOH aqueous solution (concentration is 2.0mol/L) therein to adjust pH _to 9; After completion, the temperature was raised to 40°C, and after 30 minutes of reaction, the iron nanoparticles were precipitated, and the stock solution of nano metal powder particles was prepared;

S2: Weigh CuSO ₄ 5H ₂ O and dissolve it in 1L of deionized water to prepare a CuSO ₄ aqueous solution with a concentration _of 4.1mol/L; The reaction was continued for 30 minutes under temperature conditions, and the copper-coated nanoparticle composite powder stock solution was prepared;

S3: Take the stock solution of copper-coated nanoparticle composite powder, and carry out centrifugation and washing 5 times, each time at 10,000 rpm for 5 minutes, until the washing is neutral, and then the precipitate obtained by washing is vacuum-dried in a vacuum drying oven at 50°C for 5 hours to prepare Copper-coated nanoparticle composite powder;

S4: crush and sieve the copper-coated nanoparticle composite powder, mix it with pure copper powder with a particle size of 60 μm at a mass ratio of 2:3, then weigh 100 g of the powder and press it under a pressure of 300 MPa, and then press the powder The block is put into the sintering furnace and sintered at 1000°C for 3 hours, the heating rate is 5°C/min, and the volume ratio of N ₂ to H ₂ in the reducing atmosphere is 2:1. After sintering is completed, it is taken out with furnace cooling to obtain dispersion-strengthened copper.

Example 2Cr-Cu dispersion strengthened copper

S1: Weigh Cr(NO ₃ ) ₃ 9H ₂ O and dissolve it in 5L deionized water and stir to dissolve it completely to prepare a Cr(NO 3 ) ₃ aqueous solution with a concentration of 0.2mol/L; add EDTA-2Na to dissolve Cr(NO ₃ ) 3 In (NO ₃ ) ₃ aqueous solution, make the concentration of EDTA-2Na 0.2mol/L, mix and stir for 20min, add dropwise NaOH aqueous solution (concentration is 2.0mol/L) to adjust the pH to 11; under the action of mechanical stirring at 900rpm Slowly add 2L of NaBH ₄ aqueous solution with a concentration of 1.0mol/L dropwise. After the dropwise addition is completed, the temperature is raised to 60°C for reaction. After 30 minutes of reaction, chromium nanoparticles are precipitated, and the stock solution of nano metal powder particles is prepared;

S2: Weigh CuSO ₄ 5H ₂ O and dissolve it in _{1L of deionized water to prepare a CuSO 4 aqueous} solution with a concentration of 2.0mol/L. The reaction was continued for 60 minutes under temperature conditions to prepare a copper-coated nanoparticle composite powder stock solution;

S3: Take the original solution of copper-coated nanoparticle composite powder, and carry out centrifugation and washing 6 times, each time at 10,000 rpm for 5 minutes, until the washing is neutral, and then the precipitate obtained by washing is vacuum-dried in a vacuum drying oven at 50°C for 5 hours to prepare Copper-coated nanoparticle composite powder;

S4: crush and sieve the copper-coated nanoparticle composite powder, mix it with pure copper powder with a particle size of 65 μm at a mass ratio of 1:4, then weigh 100 g of the powder and press it under a pressure of 350 MPa, and then press the powder The block is put into the sintering furnace and sintered at 1025°C for 3 hours, the heating rate is 5°C/min, and the volume ratio of N ₂ to H ₂ in the reducing atmosphere is 1:1. After sintering is completed, it is taken out with furnace cooling to obtain dispersion-strengthened copper.

Example 3Mn-Cu dispersion strengthened copper

S1: Weigh MnC ₄ H ₆ O ₄ 4H ₂ O and dissolve it in 3L of deionized water and stir to dissolve it completely to prepare an aqueous solution of MnC ₄ H ₆ O ₄ with a concentration of 0.6mol/L; add CTAB to dissolve MnC ₄ H In ₆ O ₄ aqueous solution, make the concentration of CTAB be 0.3mol/L, mix and stir for 20min, slowly dropwise add HCl aqueous solution (concentration is 1.0mol/L) thereinto adjust pH to 5; The mixed aqueous solution is mechanically stirred at 900rpm rotating speed, Slowly add 2.5L of _NaBH4 solution with a concentration of 1.25mol/L dropwise. After the dropwise addition, the temperature is raised to 50°C for reaction. After 30 minutes of reaction, manganese nanoparticles are precipitated, and the stock solution of nano metal powder particles is prepared;

S2: Weigh CuSO ₄ 5H ₂ O and dissolve it in 1L of deionized water to prepare a CuSO ₄ aqueous solution with a concentration _of 1.0mol/L; The reaction was continued for 60 minutes under temperature conditions to prepare a copper-coated nanoparticle composite powder stock solution;

S3: Take the original solution of copper-coated nanoparticle composite powder, and perform centrifugation and washing 6 times, each time at 8000 rpm for 5 minutes, until the washing is neutral, and then the precipitate obtained by washing is placed in a vacuum drying oven at 50°C for 5 hours in vacuum to prepare Copper-coated nanoparticle composite powder;

S4: The copper-coated nanoparticle composite powder is crushed and screened, mixed with pure copper powder with a particle size of 65 μm in a mass ratio of 3:7, and then 100 g of the powder is weighed and pressed under a pressure of 300 MPa by cold isostatic pressing. Then put the pressed block into the sintering furnace for sintering at 1050°C for 2 hours, the heating rate is 5°C/min, and the volume ratio of _N2 to _H2 in the reducing atmosphere is 1:2. Reinforced copper.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (10)

1. The preparation method of the nano dispersion strengthening copper composite material is characterized by comprising the following steps of:

s1, adding a reducing agent and a surfactant into a metal salt solution, and reacting to obtain a nano metal powder particle stock solution;

s2, mixing the nano metal powder particle stock solution with copper salt solution, and obtaining copper-coated nano particle composite powder stock solution through a displacement reduction reaction;

s3, washing the copper-coated nanoparticle composite powder stock solution to be neutral and drying to obtain copper-coated nanoparticle composite powder;

and S4, mixing the copper-coated nanoparticle composite powder with pure copper powder, and sequentially performing pressing, reduction and sintering treatment to obtain the nano dispersion strengthening copper composite material.

2. The production method according to claim 1, wherein in step S1, the metal element of the metal salt is more active than the copper element;

preferably, the metal salt comprises one or a combination of two or more selected from the group consisting of: chloride, sulfate, nitrate or other water soluble salts of molybdenum, iron, chromium, manganese;

preferably, in the metal salt solution, the concentration of the metal salt is 0.1-5 mol/L.

3. The method of claim 1, wherein in step S1, the reducing agent comprises one or a combination of two or more selected from the group consisting of: KBH (K-bh) ₄ 、NaBH ₄ 、N ₂ H ₄ ·H ₂ O、C ₆ H ₈ O ₆ ；

Preferably, the concentration of the reducing agent is in excess relative to the metal salt.

4. The method of claim 1, wherein in step S1, the surfactant comprises one or a combination of two or more selected from the group consisting of: polyvinylpyrrolidone, benzotriazole, octylphenol polyoxyethylene ether OP-10, cetyl trimethyl ammonium bromide, disodium ethylenediamine tetraacetate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate and sodium citrate;

preferably, the surfactant is added in the step S1 to have a concentration of 0.05 to 10mol/L.

5. The preparation method according to claim 1, wherein in step S1, the reaction is performed under stirring at 600 to 2000rpm;

preferably, in step S1, the reaction is carried out at a pH of 5 to 15;

preferably, in step S1, the temperature of the reaction is 20 to 100 ℃.

6. The method of claim 1, wherein in step S2, the copper salt comprises one or a combination of two or more selected from the group consisting of: cuSO ₄ ·5H ₂ O、CuCl ₂ ·2H ₂ O、Cu(NO ₃ ) ₂ ；

Preferably, in the copper salt solution, the concentration of the copper salt is 0.5-20 mol/L.

7. The method according to claim 1, wherein in step S2, the substitution reduction reaction is performed under stirring at a rotation speed of 800 to 2000rpm;

preferably, the temperature of the substitution reduction reaction is 20 to 100 ℃.

8. The method according to claim 1, wherein the copper-coated nanoparticle composite powder has a copper-coated thickness of 0.5 to 10 μm.

9. The method according to claim 1, wherein in step S3, the drying treatment is drying; the temperature of the drying is 40-80 ℃;

preferably, in step S4, the pressing is embossing or cold isostatic pressing; the pressing pressure is 100-800 MPa;

preferably, in step S4, the reduction sintering is performed in N ₂ And H ₂ Under a mixed atmosphere, wherein N ₂ And H is ₂ The ratio of (2) is 1-5: 1 to 5;

preferably, in step S4, the temperature of the reduction sintering is 700-1350 ℃, and the time of the reduction sintering is 1-8 hours.

10. A nano-dispersion strengthened copper composite material, characterized in that the nano-dispersion strengthened copper composite material is prepared according to the preparation method of any one of claims 1 to 9.