A nanocrystalline twinned copper material with a (110) orientation and a preparation method thereof

Abstract

The present invention discloses a nano-twinned copper material with a (110) orientation and a preparation method thereof. The nano-twinned copper material includes an equiaxed crystal structure and a strip structure. The equiaxed crystal structure is at the bottom of the nano-twinned copper material, and its average grain size is between 300 and 900 nm. As the thickness of the nano-twinned copper material increases, the strip structure appears. The aspect ratio of the monomers in the strip structure is above 1:100. The strip structure contains twin lamellae. The twin plane of the twin lamellae is perpendicular to the growth plane, has a (110) orientation, and the average thickness of the twin lamellae is below 150 nm. By using the direct current electrolytic deposition technique, the present invention prepares a nano-twinned copper material with a high density of twins and a twin plane perpendicular to the growth plane. The nano-twinned copper material has a (110) orientation and can obtain greater strength and toughness while having high thermal stability and conductivity at the twin boundary.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic copper material preparation, and in particular to a nano-twinned copper material with a (110) orientation and a preparation method thereof. Background Art

[0002] Electrolytic copper materials are indispensable materials in current fields such as electronic circuits and lithium-ion batteries. In the field of electronic circuits, electrical interconnection is an important part of very large scale integrated circuits and nanoelectromechanical devices, and they require highly conductive, strong and stable wires. The emerging three-dimensional integrated circuit technology also requires signal transmission, power supply and heat dissipation through the through-silicon via wiring system between vertically stacked integrated circuit chips, and these wires must be deposited with a high aspect ratio through a structure surrounded by a dielectric. In lithium-ion batteries, copper foil is widely used as the current collector of the anode of lithium-ion batteries. During charge and discharge, when graphite is used as the anode, it expands by about 13%, and when silicon is used as the anode, the volume can increase significantly to 300%, which may cause ordinary electrolytic copper foil to fail. Therefore, to solve the above problems, it is necessary to improve the mechanical properties of copper foil while obtaining the high thermal conductivity and electrical conductivity of copper.

[0003] Generally, copper foil can be strengthened by solid solution / precipitation hardening, strain hardening and grain refinement. However, due to the distorted lattice and grain boundary-induced electron scattering, these strengthening methods inevitably reduce the electrical conductivity. Nano-sintered copper foil can improve the mechanical strength of the material and maintain good ductility and electrical conductivity of the material. However, it does not meet the requirements in terms of ultimate tensile strength and thermal stability. Nano-twin strengthening is widely regarded as the fifth strengthening mechanism of metals. Research shows that the dense nano-scale ∑3 coherent twin boundaries in nano-twinned copper foil can improve the thermal stability, anti-electromigration property and corrosion / oxidation resistance of copper metal, etc. In addition, while the strength / toughness of nano-twinned copper is improved, it can maintain the excellent electrical conductivity of copper. The above outstanding properties of nano-twinned copper make it have broad application prospects in fields such as advanced electronic industry, new energy, 5G telecommunications equipment and flexible wearable devices.

[0004] Considering the convenience and low cost of large-scale preparation, at present, nano-twinned copper materials are mainly prepared by electroplating. The prepared copper materials have a columnar crystal structure, a strong (111) texture, and a nano-twinned structure with twin planes parallel to the deposition surface. Patent CN 113621998 A, a nano-twinned copper foil and its preparation method, CN 110724981 A, a preparation method of a copper thin film material with a fully nano-twinned structure, CN 109136987 A, a gradient nano-twinned copper bulk material and its temperature-controlled preparation method, and CN 112941586 A, nano-twinned copper components, all obtained columnar crystal, (111) textured copper foils by direct current electroplating, and comprehensively utilized the high strength, toughness, high thermal conductivity and electrical conductivity of such nano-twinned copper materials for application development.

[0005] The excellent properties of nano-twinned copper materials mainly come from nano-scale Σ3 coherent twin boundaries. For example, high strength and toughness are achieved through the complex interaction between dislocations and twin boundaries in the crystal. And because the orientation of nano-twins affects dislocation slip, and a significant dependence of material strength on the nano-twin orientation and loading direction has been experimentally observed [D.C Jang, X.Y.Li, H.J.Gao, J.R.Greer. Nature Nanotechnology, 2012; Z.You, X.Li, L.Gui, Q.Lu, T.Zhu, H.Gao, L.Lu. Acta Materialia, 2013]. When the angle (θ) between the loading direction and the twin plane is 90 degrees, the nano-twins in the copper material can exert the maximum strengthening effect; when θ is 0 degrees, the strengthening effect is the second best; when θ is 45 degrees, the strengthening effect is the worst. For the currently widely prepared nano-twinned copper materials with twin planes parallel to the deposition plane and a (111) texture, the strengthening effect obtained in its length direction (θ is 0 degrees) does not reach the best. Summary of the Invention

[0006] In view of this, the present invention aims to provide a nano-twinned copper material with a (110) orientation and its preparation method to prepare a nano-twinned copper material with a high density of twins and twin planes perpendicular to the growth plane, so as to obtain greater strength and toughness while having the high thermal stability and electrical conductivity of twin boundaries.

[0007] According to one aspect of the present invention, there is provided a nano-twinned copper material with a (110) orientation, including an equiaxed crystal structure and a strip structure, wherein:

[0008] At the bottom of the nano-twinned copper material is the equiaxed crystal structure, and its average grain size is between 300 - 900 nm;

[0009] As the thickness of the nanotwinned copper material increases, the strip-shaped structure appears;

[0010] In the strip-shaped structure, the aspect ratio of the monomer is more than 1:100. The strip-shaped structure contains twin lamellae. The twin plane of the twin lamellae is perpendicular to the growth plane, has a (110) orientation, and the average thickness of the twin lamellae is 150 nm or less.

[0011] In the above solution, the volume ratios of the equiaxed crystal structure and the strip-shaped structure in the nanotwinned copper material are adjustable, and the volume ratio of the strip-shaped structure is between 10% and 90%.

[0012] In the above solution, the average grain size of the equiaxed crystal structure is between 400 and 700 nm, the aspect ratio of the monomer in the strip-shaped structure is 1:150 to 1:200, and the average thickness of the twin lamellae is 50 to 100 nm.

[0013] In the above solution, the orientation of the nanotwinned copper material changes from a random orientation to a strong (110) texture from bottom to top, that is, a (110) orientation.

[0014] In the above solution, the thickness of the nanotwinned copper material is 50 - 350 μm. Optionally, the thickness of the nanotwinned copper material is 150 - 300 μm.

[0015] According to another aspect of the present invention, a method for preparing a nanotwinned copper material with a (110) orientation is also provided. This method uses a direct current electrolytic deposition technique, uses a copper plate as the anode material, uses a Ti plate as the cathode, the area ratio of the anode to the cathode is greater than 10:1, and the distance between the anode and the cathode is 10 - 20 cm;

[0016] In the direct current electrolytic deposition technique, the composition and content of the electrolyte used are: divalent copper ions Cu 2+ , 20 - 100 g / L; hydrogen ions H + , 0.07 - 2 mol / L; chloride ions Cl - , 40 - 80 mg / L; additive, 5 - 20 mg / L; the balance is deionized water;

[0017] In the direct current electrolytic deposition technique, a constant current mode is adopted, the current density is 20 - 80 mA / cm 2 , the electrolyte temperature is 5 - 30 °C, and the deposition time is 30 min to 16 h.

[0018] In the above solution, the copper plate uses a high-purity copper plate with a copper content greater than 99.99%, the Ti plate uses a pure Ti plate, the area ratio of the anode to the cathode is 12:1 - 20:1, and the distance between the anode and the cathode is 12 - 15 cm.

[0019] In the above solution, in the electrolyte, the content of divalent copper ions (Cu 2+ ) is 40 - 80 g / L; the content of hydrogen ions (H + ) is 1 - 1.5 mol / L; the content of chloride ions (Cl - ) is 50 - 60 mg / L; the content of the additive is 6 - 12 mg / L.

[0020] In the above solution, in the electrolyte, Cu 2+ is derived from copper sulfate, copper sulfate hydrate, or a mixture of copper sulfate and copper chloride; H + is derived from hydrochloric acid or sulfuric acid; Cl - is derived from hydrochloric acid or sodium chloride.

[0021] In the above solution, in the electrolyte, the additive includes gelatin and sodium polydithiopropanesulfonate SPS, and the weight ratio of gelatin to sodium polydithiopropanesulfonate SPS is 2∶1 to 1∶3. Optionally, the weight ratio of gelatin to sodium polydithiopropanesulfonate SPS is 1∶1 to 1∶2.

[0022] In the above solution, in the direct current electrolytic deposition technology, the current density matches the weight ratio of gelatin to sodium polydithiopropanesulfonate SPS in the additive. As the gelatin / SPS increases, the current density decreases, and the relationship between the gelatin / SPS and the current density satisfies 1∶30 - 1∶100. Optionally, the relationship between the gelatin / SPS and the current density satisfies 1∶50 - 1∶90.

[0023] In the above solution, the current density is 30 - 55 mA / cm 2 , the temperature of the electrolyte is 15 - 25 °C, and the deposition time is 4 h to 16 h.

[0024] In the above solution, in the direct current electrolytic deposition technology, magnetic stirring is used to keep the components in the electrolyte always uniform.

[0025] From the above technical solutions, it can be seen that the present invention has the following beneficial effects:

[0026] 1. The nanoscale twinned copper material with (110) orientation and its preparation method provided by the present invention prepare a nanoscale twinned copper material with high-density twins and twin planes perpendicular to the growth plane by adopting the direct current electrolytic deposition technology. This nanoscale twinned copper material has (110) orientation and can obtain greater strength and toughness while having high thermal stability and conductivity of twin boundaries.

[0027] 2. The provided nanoscale twinned copper material with a (110) orientation and its preparation method. Since the twin planes in the nanoscale twinned copper material are perpendicular to the growth plane, the nanoscale twinned copper material can utilize the strengthening mechanism where the twin planes are at a 90° angle to the stress direction, obtaining higher strength and plasticity, and further expanding the application scope of the nanoscale twinned copper material.

[0028] 3. The provided nanoscale twinned copper material with a (110) orientation and its preparation method. By adjusting the electrolyte composition and electrodeposition process parameters, nanoscale twinned copper materials with different microstructures can be obtained, enabling controllable adjustment of material properties and expanding the application scenarios of the materials.

[0029] 4. The provided nanoscale twinned copper material with a (110) orientation and its preparation method. By adjusting the current density and electrolyte temperature to control the reduction rate of copper ions at the cathode, the thickness of the nanoscale twinned copper material and the sizes of the equiaxed grains and twins can be regulated.

[0030] 5. The provided nanoscale twinned copper material with a (110) orientation and its preparation method. By regulating the weight ratio of gelatin to sodium polydithiopropane sulfonate (SPS), a nanoscale twinned copper material with a (110) orientation containing different proportions of strip-like structures and equiaxed grains can be prepared, and the twin planes contained therein are perpendicular to the growth plane. Description of the Drawings

[0031] The present invention will be further described below in conjunction with the drawings and embodiments.

[0032] Figure 1a is a backscattered electron mode (BSE) picture of the cross-section of the nanoscale twinned copper material with a (110) orientation provided by the present invention. The white arrow indicates the growth direction of the copper material during the electroplating process;

[0033] Figure 1b is Figure 1a an enlarged backscattered electron mode (BSE) picture of the strip-like structure in

[0034] Figure 1c is the X-ray diffraction pattern of the nanoscale twinned copper material with a (110) orientation provided by the present invention, indicating that the out-of-plane texture is (110), i.e., having a (110) orientation;

[0035] Figure 1d is the morphology of the growth surface of the electroplated copper material provided by the present invention under an optical microscope.

[0036] Figure 2 is a backscattered electron mode (BSE) picture of the cross-section of the nanoscale twinned copper material with a (110) orientation according to Example 1 of the present invention. The white arrow indicates the growth direction of the copper material during the electroplating process.

[0037] Figure 3 It is a backscattered electron mode (BSE) picture of the cross-section of a nano-twinned copper material with a (110) orientation according to Embodiment 2 of the present invention. The white arrow indicates the growth direction of the copper material during the electroplating process.

[0038] Figure 4 It is a backscattered electron mode (BSE) picture of the cross-section of a nano-twinned copper material with a (110) orientation according to Embodiment 3 of the present invention. The white arrow indicates the growth direction of the copper material during the electroplating process.

[0039] Figure 5 It is the engineering stress-strain curve of a nano-twinned copper material with a (110) orientation according to Embodiments 1-3 of the present invention. Detailed implementation manners

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings.

[0041] Aiming at the defect that the strengthening effect obtained in the length direction (θ is 0 degree) of the currently widely prepared nano-twinned copper material with twin planes parallel to the deposition plane and having a (111) texture does not reach the best, the present invention provides a nano-twinned copper material with a (110) orientation and a preparation method thereof. By using a direct current electro-deposition technique, a nano-twinned copper material with a high density of twins and twin planes perpendicular to the growth plane is prepared. This nano-twinned copper material has a (110) orientation and can obtain greater strength and toughness while having both the high thermal stability and conductivity of twin boundaries.

[0042] The technical principle adopted by the present invention is as follows: Sodium polydithiopropane sulfonate (SPS) accelerates grain nucleation through a depolarization effect during electro-deposition to refine grains, which is opposite to the function of gelatin. Usually, in the presence of a single additive gelatin, copper is deposited through two-dimensional nucleation and finally forms a columnar grain microstructure (FT type, (111) texture). When SPS is added, the two additives in the electrolyte competitively adsorb, and then continuously changing local deposition conditions are formed on the surface. When SPS replaces the pre-adsorbed gelatin on the deposition surface, new particles nucleate on top of the existing particles. This dynamic situation can lead to the formation of equiaxed grains (UD type), in which the deposited material grows through three-dimensional nucleation. According to the Winand diagram, after the formation of UD type equiaxed grains, an FT type (111) texture nano-twin structure will be formed. However, from an energy perspective, the reason for the appearance of the (111) texture is that it has the lowest surface energy, while the (110) texture can minimize the accumulated strain energy in the material. The appearance of twin boundaries is also the result of coordinating lattice distortion to reduce strain energy. In addition, the exchange current density of the copper (110) plane during electro-deposition is five times that of the (111) plane, which promotes the rapid growth of the (110) texture and forms a structure with a high aspect ratio. Therefore, as the thickness of the deposited copper increases, the strain energy becomes larger, promoting the formation of vertical twins with a high aspect ratio and a (110) texture.

[0043] Considering the above mechanism, the present invention designs and prepares a nano-twin copper material with a (110) texture by regulating the ratio of SPS and gelatin, and the twin boundaries contained therein are perpendicular to the deposition plane, as Figures 1a to 1d shown, Figure 1a is a backscattered electron mode (BSE) picture of the cross-section of the nano-twin copper material with a (110) orientation provided by the present invention. The white arrow indicates the growth direction of the copper material during electroplating, Figure 1b is Figure 1a an enlarged backscattered electron mode (BSE) picture of the strip-shaped structure in Figure 1c is the X-ray diffraction pattern of the nano-twin copper material with a (110) orientation provided by the present invention, indicating that the out-of-plane texture is (110), that is, it has a (110) orientation, Figure 1d is the morphology of the growth surface of the electroplated copper material provided by the present invention under an optical microscope.

[0044] Figures 1a to 1d The preparation process of the nano-twin copper material with a (110) texture shown in Figure 1dAs shown in the figure. Subsequently, by finely adjusting the weight ratio of SPS and gelatin and the matching current density, nano-twinned copper materials with different proportions of strip-like structures and equiaxed grains can be prepared. Further, by adjusting the current density and the electrolyte temperature and controlling the reduction rate of copper ions at the cathode, the thickness of the nano-twinned copper material and the sizes of the equiaxed grains and twins can be regulated.

[0045] According to an embodiment of the present invention, there is provided a nano-twinned copper material having a (110) orientation, including an equiaxed grain structure and a strip-like structure. Among them, at the bottom of the nano-twinned copper material is the equiaxed grain structure, and its average grain size is between 300 and 900 nm; as the thickness of the nano-twinned copper material increases, the strip-like structure appears; the aspect ratio of the monomers in the strip-like structure is above 1:100, the strip-like structure contains twin lamellae, the twin plane of the twin lamellae is perpendicular to the growth plane, has a (110) orientation, and the average thickness of the twin lamellae is below 150 nm.

[0046] In an embodiment of the present invention, the volume ratios of the equiaxed grain structure and the strip-like structure in the nano-twinned copper material are adjustable, and the volume ratio of the strip-like structure is between 10% and 90%. Optionally, the volume ratio of the strip-like structure is 10%, 20%, 23.6%, 30%, 40%, 50%, 56.1%, 60%, 70%, 80%, 81.3% or 90%.

[0047] In an embodiment of the present invention, the average grain size of the equiaxed grain structure is between 400 and 700 nm. Optionally, the average grain size of the equiaxed grain structure can be 400 nm, 500 nm, 600 nm or 700 nm.

[0048] In an embodiment of the present invention, the aspect ratio of the monomers in the strip-like structure is 1:150 to 1:200. Optionally, the aspect ratio of the monomers in the strip-like structure can be 1:150, 1:160, 1:170, 1:180, 1:190 or 1:200.

[0049] In an embodiment of the present invention, the average thickness of the twin lamellae is 50 - 100 nm. Optionally, the average thickness of the twin lamellae can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm.

[0050] In an embodiment of the present invention, the orientation of the nano-twinned copper material changes from a random orientation to a strong (110) texture from bottom to top, that is, a (110) orientation.

[0051] In the embodiment of the present invention, the thickness of the nanotwinned copper material is 50 - 350 μm. Optionally, the thickness of the nanotwinned copper material can be 150 - 300 μm. For example, the thickness of the nanotwinned copper material is 145 μm, 150 μm, 187 μm, 200 μm, 250 μm or 300 μm.

[0052] In the embodiment of the present invention, the prepared nanotwinned copper material with a (110) orientation has the following properties: the purity is greater than 99.99%, and the tensile strength and uniform elongation at room temperature can be regulated by the proportion of the strip structure. The achievable tensile strength is 300 - 500 MPa, and the uniform elongation is 7% - 30%.

[0053] According to the embodiment of the present invention, a method for preparing a nanotwinned copper material with a (110) orientation is also provided. This method uses a direct current electrolytic deposition technique, with a copper plate as the anode material and a Ti plate as the cathode. The area ratio of the anode to the cathode is greater than 10:1, and the distance between the anode and the cathode is 10 - 20 cm; in the direct current electrolytic deposition technique, the composition and content of the electrolyte used are as follows: divalent copper ions Cu 2+ , 20 - 100 g / L; hydrogen ions H + , 0.07 - 2 mol / L; chloride ions Cl - , 40 - 80 mg / L; additive, 5 - 20 mg / L; the balance is deionized water; in the direct current electrolytic deposition technique, a constant current mode is adopted, the current density is 20 - 80 mA / cm 2 , the electrolyte temperature is 5 - 30 °C, and the deposition time is 30 min to 16 h.

[0054] In the embodiment of the present invention, the copper plate uses a high-purity copper plate with a copper content greater than 99.99%, the Ti plate uses a pure Ti plate, the area ratio of the anode to the cathode is 12:1 - 20:1. Optionally, the area ratio of the anode to the cathode can be 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1 or 20:1; the distance between the anode and the cathode is 12 - 15 cm. Optionally, the distance between the anode and the cathode can be 12 cm, 13 cm, 14 cm or 15 cm.

[0055] In the electrolyte of the embodiment of the present invention, the content of divalent copper ions (Cu 2+ ) is 40 - 80 g / L. Optionally, the content of divalent copper ions (Cu 2+ ) can be 40 g / L, 50 g / L, 60 g / L, 70 g / L or 80 g / L.

[0056] In the electrolyte of the embodiment of the present invention, the hydrogen ions (H +) has a content of 1 - 1.5 mol / L. Optionally, the content of hydrogen ions (H + ) can be 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L or 1.5 mol / L.

[0057] In the electrolyte of the embodiment of the present invention, the content of chloride ions (Cl - ) is 50 - 60 mg / L. Optionally, the content of chloride ions (Cl - ) can be 50 mg / L, 52 mg / L, 54 mg / L, 56 mg / L, 58 mg / L or 60 mg / L.

[0058] In the electrolyte of the embodiment of the present invention, the content of the additive is 6 - 12 mg / L. Optionally, the content of the additive can be 6 mg / L, 8 mg / L, 10 mg / L or 12 mg / L.

[0059] In the electrolyte of the embodiment of the present invention, Cu 2+ is derived from copper sulfate, copper sulfate hydrate, or a mixture of copper sulfate and copper chloride; H + is derived from hydrochloric acid or sulfuric acid; Cl - is derived from hydrochloric acid or sodium chloride.

[0060] In the electrolyte of the embodiment of the present invention, the additive includes gelatin and sodium polydisulfide propane sulfonate SPS, and the weight ratio of gelatin to sodium polydisulfide propane sulfonate SPS (i.e., gelatin / SPS) is 2:1 to 1:3. Optionally, the gelatin / SPS is 1:1 to 1:2. For example, the gelatin / SPS can be 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.7 or 1:2.

[0061] In the DC electrolytic deposition technology of the embodiment of the present invention, the current density is matched with the weight ratio of gelatin to sodium polydisulfide propane sulfonate SPS in the additive. As the gelatin / SPS increases, the current density decreases, and the relationship between the gelatin / SPS and the current density satisfies 1:30 - 1:100. Optionally, the relationship between the gelatin / SPS and the current density satisfies 1:50 - 1:90. For example, 1:50, 1:60, 1:70, 1:80 or 1:90.

[0062] In the embodiment of the present invention, the current density is 30 - 55 mA / cm 2 , optionally, the current density can be 30 mA / cm 2 , 35 mA / cm 2 , 40 mA / cm 2 , 45 mA / cm 2 , 50 mA / cm2 、55 mA / cm 2 。

[0063] In the embodiment of the present invention, the temperature of the electrolyte is 15 - 25 °C. Optionally, the temperature of the electrolyte can be 15 °C, 20 °C or 25 °C.

[0064] In the embodiment of the present invention, the deposition time is 4 h to 16 h. Optionally, the deposition time can be 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h or 16 h.

[0065] In the direct current electrolytic deposition technology of the embodiment of the present invention, magnetic stirring is used to keep the components in the electrolyte always uniform. The rotation speed of the magnetic stirring is: 300 - 1000 r / min. Optionally, the rotation speed of the magnetic stirring can be 350 r / min, 500 r / min or 800 r / min.

[0066] According to the nano-twinned copper material with (110) orientation and its preparation method provided by the embodiment of the present invention, by adopting the direct current electrolytic deposition technology, a nano-twinned copper material with high-density twins and twin planes perpendicular to the growth plane is prepared. This nano-twinned copper material has (110) orientation and can obtain greater strength and toughness while having high thermal stability and conductivity of twin boundaries. Since the twin planes in the nano-twinned copper material are perpendicular to the growth plane, the nano-twinned copper material can utilize the strengthening mechanism in which the twins are at 90° to the stress direction to obtain higher strength and plasticity, further expanding the application range of the nano-twinned copper material. By adjusting the composition of the electrolyte and the electro-deposition process parameters, nano-twinned copper materials with different microstructures can be obtained, realizing controllable adjustment of material properties and expanding the application scenarios of the materials. By adjusting the current density and the temperature of the electrolyte to control the reduction rate of copper ions at the cathode, the thickness of the nano-twinned copper material and the size of equiaxed grains and twins can be regulated. By regulating the weight ratio of gelatin to sodium polydithiopropane sulfonate (SPS), a nano-twinned copper material with (110) orientation containing different proportions of strip-like structures and equiaxed grains can be prepared, and the twin planes contained therein are perpendicular to the growth plane.

[0067] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0068] Example 1: Preparation and tensile test of nano-twinned copper material with (110) orientation

[0069] In this example, a stable current is provided by the constant current mode of the electrochemical workstation, and the current density is 30 mA / cm 2 . The area of the anode plate is 150 cm 2 , and the area of the cathode Ti plate is 12 cm 2, and the facing distance between the two is 10 cm. The electrolyte composition includes: 60 g / L of Cu 2+ , 0.1 mol / L of H + , 60 mg / L of Cl - ; 10 mg / L of additives, where the weight ratio of gelatin to SPS is 1:3. During the electroplating process, magnetic stirring (500 r / min) is used to keep the components in the electrolyte uniform all the time, and the electrolyte temperature is 15 °C. The direct current deposition time is 8 h.

[0070] The prepared nano-twinned copper material has an area of 12 cm 2 , and its average thickness measured by a micrometer is 187 μm. Specifically, as Figure 2 shown, Figure 2 is a backscattered electron mode (BSE) picture of the cross-section of the nano-twinned copper material with a (110) orientation according to Example 1 of the present invention. The white arrow indicates the growth direction of the copper material during the electroplating process. The equiaxed crystal structure is near the titanium plate substrate side under the nano-twinned copper material, and its grain size is small; as the thickness increases, strip-like structures appear, and the proportion is about 23.6%. The twin thickness in the strip-like structures is below 100 nm. This copper material has good toughness, can be directly removed from the titanium plate substrate, and has no defects such as pinholes and pockmarks.

[0071] In the example, the room temperature tensile results of the nano-twinned copper material are as Figure 5 shown by the curve 1 of the example in. The test conditions are as follows: the tensile test sample is cut by wire cutting, and its tensile section length, width and thickness are 10 mm × 3 mm × 0.181 mm respectively. The tensile properties are tested by a tensile tester SEMTester100-MTI, and the tensile rate is 3 mm / min. The mechanical properties of the nano-twinned copper material: the tensile strength is 340 MPa, and the uniform elongation rate is 25.8%.

[0072] Example 2: Preparation and tensile test of nano-twinned copper material with (110) orientation

[0073] In this example, a stable current is provided by the constant current mode of the electrochemical workstation, and the current density is 40 mA / cm 2 . The anode plate area is 150 cm 2 , the cathode Ti plate area is 12 cm 2 , and the facing distance between the two is 12 cm. The electrolyte composition includes: 70 g / L of Cu 2+ , 0.08 mol / L of H + , 50 mg / L of Cl -; 12 mg / L additives, wherein the weight ratio of gelatin to SPS is 1:2. During the electroplating process, magnetic stirring (500 r / min) was used to keep the components in the electrolyte uniform, and the electrolyte temperature was 15°C. The DC electrodeposition time was 8 h.

[0074] The prepared nano-twinned copper material has an area of 12cm 2 The average thickness measured by the micrometer is 145 μm. Figure 3 As shown, Figure 3 This is a backscattered electron mode (BSE) image of the cross section of the nano-twinned copper material with (110) orientation according to Example 2 of the present invention. The white arrow indicates the growth direction of the copper material during the electroplating process. The nano-twinned copper material has an equiaxed crystal structure near the titanium substrate below, and its grain size is small; as the thickness increases, a strip-like structure appears, accounting for about 56.1%. The thickness of the twins in the strip-like structure is less than 100nm. The copper material has good toughness and can be directly removed from the titanium substrate, and has no defects such as pinholes and pitting.

[0075] In the embodiment, the room temperature tensile test results of the nano twinned copper material are as follows: Figure 5 The test conditions are as follows: the tensile test sample is cut by wire cutting, and the length, width and thickness of the tensile section are 10mm×3mm×0.140mm respectively. The tensile performance is tested by SEMTester100-MTI tensile tester, and the tensile rate is 3mm / min. The mechanical properties of the nano twinned copper material are as follows: the tensile strength is 402MPa, and the uniform elongation is 11.8%.

[0076] Example 3: Preparation and tensile testing of nano-twinned copper materials with (110) orientation

[0077] This example uses the constant current mode of the electrochemical workstation to provide a stable current with a current density of 50 mA / cm 2 . Anode plate area 150cm 2 , cathode Ti plate area 12cm 2 The distance between the two is 15 cm. The electrolyte composition includes: 80g / L Cu 2+ , 0.07 mol / L H + , 45mg / L Cl - ; 15 mg / L additives, wherein the weight ratio of gelatin to SPS is 1:1. During the electroplating process, magnetic stirring (500 r / min) was used to keep the components in the electrolyte uniform, and the electrolyte temperature was 15°C. The DC electrodeposition time was 8 h.

[0078] The prepared nano-twinned copper material has an area of 12cm 2 The average thickness measured by the micrometer is 150μm.Figure 4 As shown Figure 4 This is a backscattered electron mode (BSE) picture of the cross-section of a nano-twinned copper material with a (110) orientation according to Embodiment 3 of the present invention. The white arrow indicates the growth direction of the copper material during the electroplating process. Near the titanium plate substrate side below the nano-twinned copper material is an equiaxed crystal structure with a relatively small grain size; as the thickness increases, strip-like structures appear, accounting for approximately 81.3%. The twin thickness in the strip-like structures is below 100 nm. This copper material has good toughness, can be directly removed from the titanium plate substrate, and has no defects such as pinholes and pitting.

[0079] In the embodiment, the room-temperature tensile results of the nano-twinned copper material are as Figure 5 shown by the curve of Embodiment 3 in it. The test conditions are as follows: The tensile test sample is cut by wire electrical discharge machining. The length, width, and thickness of its tensile section are 10 mm × 3 mm × 0.145 mm respectively. The tensile properties are tested using a tensile tester SEM Tester100-MTI, and the tensile rate is 3 mm / min. The mechanical properties of the nano-twinned copper material: The tensile strength is 465 MPa, and the uniform elongation is 8.1%.

[0080] In the specific embodiments described above, the purpose, technical solution, and beneficial effects of the present invention have been further described in detail. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A nanocrystalline twinned copper material with a (110) orientation, including equiaxed crystal grains and strip-shaped grains, characterized in that: At the bottom of the nanocrystalline twinned copper material is the equiaxed crystal grains with an average grain size between 300 - 900 nm; As the thickness of the nanocrystalline twinned copper material increases, the strip-shaped grains appear; In the strip-shaped grains, the aspect ratio of the monomers is above 1:100, the strip-shaped grains contain twin lamellae, the twin plane of the twin lamellae is perpendicular to the growth plane, with a (110) orientation, and the average thickness of the twin lamellae is below 150 nm; Among them, the volume ratios of the equiaxed crystal grains and the strip-shaped grains in the nanocrystalline twinned copper material are adjustable, and the volume ratio of the strip-shaped grains is between 10% - 90%; the orientation of the nanocrystalline twinned copper material changes from a random orientation at the bottom to a strong (110) texture, that is, a (110) orientation.

2. The nanoscale twin copper material with a (110) orientation according to claim 1, characterized in that, The average grain size of the equiaxed crystal grains is between 400 - 700 nm, the aspect ratio of the monomers in the strip-shaped grains is from 1:150 to 1:200, and the average thickness of the twin lamellae is 50 - 100 nm.

3. The nanoscale twinned copper material with a (110) orientation according to claim 1, characterized in that, The thickness of the nanocrystalline twinned copper material is 50 - 350 μm.

4. The nanoscale twinned copper material with a (110) orientation according to claim 3, characterized in that, The thickness of the nanocrystalline twinned copper material is 150 - 300 μm.

5. A method for preparing the nanoscale twinned copper material according to any one of claims 1 to 4, characterized in that, This method uses a direct current electrolytic deposition technique, with a copper plate as the anode material and a Ti plate as the cathode. The area ratio of the anode to the cathode is greater than 10:1, and the distance between the anode and the cathode is 10 - 20 cm; In the direct current electrolytic deposition technology, the composition and content of the electrolyte used are as follows: divalent copper ions Cu 2+ , 20 - 100 g / L; hydrogen ions H + , 0.07 - 2 mol / L; chloride ions Cl - , 40 - 80 mg / L; additive, 5 - 20 mg / L; the balance is deionized water; In the DC electrolytic deposition technology, a constant current mode is adopted, and the current density is 20 - 80 mA / cm 2 , the temperature of the electrolyte is 5 - 30 °C, and the deposition time is 30 min to 16 h; In the electrolyte, the additives include gelatin and sodium polydithiopropane sulfonate (SPS), and the weight ratio of gelatin to sodium polydithiopropane sulfonate (SPS) is from 2:1 to 1:3; In the direct current electrolytic deposition technique, the current density matches the weight ratio of gelatin to sodium polydithiopropane sulfonate (SPS) in the additives. As the gelatin / SPS increases, the current density decreases, and the relationship between the gelatin / SPS and the current density satisfies 1:30 - 1:100; The current density is 30 - 55 mA / cm 2 , the temperature of the electrolyte is 15 - 25 °C, and the deposition time is 4 h to 16 h.

6. The method for preparing the nanotwinned copper material according to claim 5, wherein, The copper plate uses a high-purity copper plate with a copper content greater than 99.99%, the Ti plate uses a pure Ti plate, the area ratio of the anode to the cathode is 12:1 - 20:1, and the distance between the anode and the cathode is 12 - 15 cm.

7. The method for preparing a nanoscale twin copper material according to claim 5, wherein In the electrolyte, the content of divalent copper ions Cu 2+ is 40 - 80 g / L; the content of hydrogen ions H + is 1 - 1.5 mol / L; the content of chloride ions Cl - is 50 - 60 mg / L; the content of the additive is 6 - 12 mg / L.

8. The method for preparing the nanotwinned copper material according to claim 7, wherein, In the electrolyte, Cu 2+ is derived from copper sulfate, copper sulfate hydrate, or a mixture of copper sulfate and copper chloride; H + is derived from hydrochloric acid or sulfuric acid; Cl - is derived from hydrochloric acid or sodium chloride.

9. The method for preparing a nanotwinned copper material according to claim 5, wherein The weight ratio of gelatin to sodium polydithiopropane sulfonate (SPS) is 1:1 to 1:

2.

10. The method for preparing a nanotwinned copper material according to claim 9, wherein The relationship between the gelatin / SPS and the current density satisfies 1:50 - 1:

90.

11. The method for preparing the nano-twinned copper material according to claim 5, wherein In the direct current electrolytic deposition technique, magnetic stirring is used to keep the components in the electrolyte always uniform.

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