CN110699676A - A kind of high-strength and high-conductivity metallic glass composite material and preparation method thereof - Google Patents

Abstract

The invention provides a high-strength and high-conductivity metallic glass composite material and a preparation method thereof, comprising the following steps: preparing Cu ₅₀ Zr ₄₃ Al ₇ powder particles; pre-plating the obtained Cu ₅₀ Zr ₄₃ Al ₇ powder particles before plating treatment, then electroless plating, cleaning and drying to obtain copper-coated Cu ₅₀ Zr ₄₃ Al ₇ metallic glass powder; the copper-coated Cu ₅₀ Zr ₄₃ Al ₇ metallic glass powder is mixed with copper powder for spark plasma sintering to obtain high strength and high strength The electrical conductivity of the metal glass composite material, the sintering temperature is not more than 503 ℃. By adopting the technical scheme of the present invention, the composite powder is prepared by chemically plating the specific metallic glass powder, so that the crystalline copper is uniformly and firmly combined with the metallic glass powder, and finally mixed with the copper powder for sintering to obtain the composite material. Composite materials have better electrical conductivity while having higher strength.

Description

A kind of high-strength and high-conductivity metallic glass composite material and preparation method thereof

technical field

The invention belongs to the technical field of materials, and in particular relates to a metal glass composite material with high strength and high electrical conductivity and a preparation method thereof.

Background technique

Metallic glasses, also known as amorphous alloys, refer to alloys in which the three-dimensional space of atoms in the solid state is topologically disordered, and this state remains relatively stable within a certain temperature range. Amorphous alloys have unique and excellent physical, chemical and mechanical properties due to their unique long-range disordered and short-range ordered structures without crystallographic defects such as dislocations and grain boundaries. For example, the strength of some cobalt-based amorphous alloys is as high as 6000MPa, which is almost the highest strength of bulk metal materials; in addition, zirconium-based amorphous alloys also have high elastic limit (about 2%), high fracture toughness, supercooled liquid Phase zone superplasticity, high hardness, ultra-high corrosion resistance, wear resistance and fatigue resistance. Since the preparation of bulk amorphous alloys in La-Al-Ni-based alloys by copper mold casting in the late 1980s, after nearly three decades of development, hundreds of types of bulk amorphous alloys have been developed. The alloy system, the specific alloy composition is more. Each alloy family has its own characteristics, both in terms of its glass-forming ability and its physical, chemical and mechanical properties.

On the other hand, in all metals, alloys and composite materials, high strength and high electrical conductivity always have contradictory properties, while high-strength and high-conductivity composite materials refer to excellent electrical and thermal conductivity properties, while the strength is far A class of composite materials higher than pure copper is a class of functional structural materials with excellent comprehensive physical and mechanical properties. It has both high strength and good ductility, as well as good electrical and thermal conduction properties. It is widely used in various modern scientific and technological fields, such as electrical contacts of electrical engineering switches in the electrical communication industry, collector rings, armatures, electrodes, contact wires of electrified railways, high-power asynchronous traction motor rotors in resistance explosion-electrode motors etc.; lead frames of various integrated circuits in the electronics industry; blast furnace tuyere, continuous casting molds, oxygen lance nozzles that need to be in a high electrical and thermal conductivity environment, etc. in the metallurgical industry; and thermonuclear experimental reactor divertor vertical shoe heat dissipation Sheets, high-intensity pulsed magnetic field conductive materials, etc.

However, among many materials currently used in industry, it is difficult to have both high strength and high conductivity. Although pure metals such as Cu and Ag have high conductivity, their strength is extremely low, often less than 200MPa. While increasing its strength, it will inevitably lead to a sharp drop in electrical conductivity. Since the 1980s, with the rapid development of the electronic industry, especially the development of high-strength magnet technology, a new wave of research on a new generation of high-strength and high-conductivity materials has been set off. A large amount of research and development work has been carried out on such materials at home and abroad, which has made such materials develop rapidly. For example, in 2004, Lu Ke et al. published a new way to strengthen metals by using nano-sized growth twins in "Science" to obtain copper with both ultra-high strength and high electrical conductivity. The yield strength can reach 900MPa, and the electrical conductivity It can reach 97% IACS, but its preparation process is extremely complicated, and only thin film samples can be prepared, so it is still far from industrial application. In recent years, the comprehensive index of Cu-Cr(Zr) high-strength and high-conductivity alloy OMLC-1 developed by Mitsubishi Corporation of Japan can reach tensile strength of 621MPa and electrical conductivity of 82.7%IACS. The Cu-Mg alloy developed by Deutsche Bahn (DBAG) was originally used in the catenary of electrified high-speed railways. Compared with other alloying elements, the alloy can obtain higher strength without subsequent heat treatment and maintain a relatively high strength. Good electrical conductivity.

At present, copper beryllium alloys are mostly used in the electrical contact switch industry, with a tensile strength of ≥1000 MPa and a conductivity of only ≥18% IACS. Although it has a relatively good combination of strength, hardness, electrical conductivity, thermal conductivity and high temperature stability, due to the extremely high toxicity of beryllium element and its compounds, only one milligram of beryllium dust per cubic meter of air will Cause people to contract acute pneumonia - beryllium lung disease. Considering the damage caused to the environment and human body during the preparation process, the industry in various countries has been looking for green, environmentally friendly, low-cost, and excellent performance materials to replace copper beryllium alloys.

SUMMARY OF THE INVENTION

In view of the above technical problems, the present invention discloses a high-strength and high-conductivity metal-glass composite material and a preparation method thereof, which take both high strength and high electrical conductivity into consideration.

To this, the technical scheme adopted in the present invention is:

A preparation method of a high-strength and high-conductivity metallic glass composite material, comprising the following steps:

Step S1, preparing Cu ₅₀ Zr ₄₃ Al ₇ powder particles;

In step S2, the Cu ₅₀ Zr ₄₃ Al ₇ powder particles obtained in step S1 are subjected to pre-plating pretreatment, and then chemical plating is performed, and after cleaning and drying, copper-coated Cu ₅₀ Zr ₄₃ Al ₇ metallic glass powder is obtained;

In step S3, the copper-coated Cu ₅₀ Zr ₄₃ Al ₇ metallic glass powder is mixed with the copper powder for spark plasma sintering to obtain a metallic glass composite material with high strength and high conductivity, and the sintering temperature is not greater than 503°C.

This technical solution adopts the method of selecting specific metallic glass powder and combining chemical copper plating to prepare composite powder, so that the crystalline copper can be uniformly and firmly combined with the amorphous metallic glass powder, so that the obtained metallic glass composite material has both With high strength and high conductivity. Among them, sintering is performed below the crystallization temperature of the amorphous alloy to avoid crystallization. Compared with other sintering methods, spark plasma sintering has the advantages of short sintering time, low sintering temperature and uniform heating inside the sample.

In order to develop materials with both high strength and high electrical conductivity, in order to obtain materials that meet the performance requirements of the new generation of electrical devices, researchers at home and abroad have carried out a lot of exploration, but the research so far has focused on the use of high-conductivity materials. (Copper alloy) as a starting material is expected to obtain a new type of high-strength and high-conductivity material through strengthening means, but it is still difficult to meet the requirements due to various reasons. In the present invention, we conversely consider using a metallic glass alloy with ultra-high strength as a starting material, by improving its electrical conductivity, to expect to obtain a new material that meets the requirements of high strength and high electrical conductivity at the same time. The success of the technical solution of the present invention is expected to open up an effective way to prepare a new composite material with both high strength and high electrical conductivity, and has great practical significance for promoting the practical process of metallic glass as a high-performance structural functional material.

As a further improvement of the present invention, step S1 includes: firstly preparing a Cu ₅₀ Zr ₄₃ Al ₇ master alloy ingot by suspension smelting, and then using an argon atomization method to obtain a Cu ₅₀ Zr ₄₃ Al ₇ master alloy ingot powder particles.

Further, the Cu ₅₀ Zr ₄₃ Al ₇ master alloy ingot is prepared by a suspension smelting method.

Further, in the argon atomization method, the melting temperature of the alloy is about 1280°C, and the injection pressure is set to 3.2MPa.

As a further improvement of the present invention, in step S2, the pre-plating pretreatment includes cleaning, sensitization and activation steps.

As a further improvement of the present invention, the pretreatment before plating includes:

First, the Cu ₅₀ Zr ₄₃ Al ₇ powder particles were ultrasonically cleaned with absolute ethanol, then the filtered powder was placed in a mixed solution of stannous chloride and hydrochloric acid for sensitization, and finally the powder was immersed in a solution containing palladium chloride and hydrochloric acid. The activation treatment is carried out in an aqueous solution, and the powder is washed with deionized water after each treatment step.

Further, the concentration of described stannous chloride is 5-10g/L, the concentration of hydrochloric acid is 30-50mL/L, and the sensitization time is 5-10min; In the aqueous solution of palladium chloride and hydrochloric acid, the concentration of palladium chloride is It is 0.3-0.5g/L, and the concentration of hydrochloric acid is 5-10mL/L.

Further preferably, in the mixed solution of stannous chloride and hydrochloric acid, the concentration of described stannous chloride is 10g/L, the concentration of hydrochloric acid is 40mL/L, and the sensitization time is 10min; , the concentration of palladium chloride is 0.5g/L, and the concentration of hydrochloric acid is 10mL/L.

As a further improvement of the present invention, in the chemical plating process, the reducing agent used is formaldehyde.

Further preferably, the reducing agent used is 37wt% formaldehyde solution, the concentration of the formaldehyde in the plating solution is 30-50 mL/L, and further, the concentration of the formaldehyde in the plating solution is 0.4-0.7mol/L L.

As a further improvement of the present invention, in the electroless plating process, the pH value of the plating solution is 12.0-12.7.

As a further improvement of the present invention, during the electroless plating process, the temperature of the plating solution is 50-60°C, and the pH value of the solution is checked regularly. When the pH value is too low, 1 mol/L NaOH solution is added dropwise to the solution to keep The pH value stabilized until the end of the reaction.

As a further improvement of the present invention, the plating solution is prepared by the following steps:

Step S201, firstly adding potassium sodium tartrate to deionized water, stirring until completely dissolved, then adding disodium EDTA, stirring until dissolved to form a double complexing agent solution, and heating the solution to 35-45 ° C; further , heat the solution to 40°C;

Step S202, dissolving copper sulfate in ionized water and heating with constant stirring;

Step S203, adding the heated copper sulfate solution to the complexing agent solution to obtain a copper ion complex solution;

Step S204, adding potassium ferrocyanide and 2,2'-bipyridine into the copper ion complex solution to form a dual stabilizer system, and stirring the solution;

Step S205 , adding the pre-treated powder particles into the plating solution, heating to 50-60° C., stirring and mixing evenly, and adding formaldehyde solution as a reducing agent; and adjusting the pH value of the solution.

As a further improvement of the present invention, in step S3, the copper-coated Cu ₅₀ Zr ₄₃ Al ₇ metallic glass powder and the copper powder are in a mixture, and the mass percentage of the copper powder is 20-50%.

The invention also discloses a high-strength and high-conductivity metal-glass composite material, which is prepared by the method for preparing a high-strength and high-conductivity metal-glass composite material as described in any one of the above.

Compared with the prior art, the beneficial effects of the present invention are:

By adopting the technical scheme of the present invention, the composite powder is prepared by chemically plating the specific metallic glass powder, so that the crystalline copper is uniformly and firmly combined with the metallic glass powder, and finally mixed with the copper powder for sintering to obtain the composite material. Composite materials have better electrical conductivity while having higher strength.

Description of drawings

FIG. 1 is a SEM image of the surface morphology of Cu ₅₀ Zr ₄₃ Al ₇ powder prepared by gas atomization according to an embodiment of the present invention.

FIG. 2 is the DSC curve of the Cu ₅₀ Zr ₄₃ Al ₇ powder prepared by gas atomization according to the embodiment of the present invention.

3 is a SEM image of the surface morphology of the copper-coated Cu ₅₀ Zr ₄₃ Al ₇ powder according to the embodiment of the present invention, wherein (a) is the SEM image of the surface morphology of the copper-coated Cu ₅₀ Zr ₄₃ Al ₇ powder, ( b) is a partially enlarged SEM image of the frame part in (a).

4 is a cross-sectional SEM image of the electroless copper plating powder embedded with epoxy resin according to an embodiment of the present invention.

FIG. 5 is a graph showing the thickness of the copper cladding layer of the electroless copper plating powder according to the embodiment of the present invention.

6 is a XRD comparison diagram of bulk metallic glass composite (BMGC) samples with different copper additions and Cu ₅₀ Zr ₄₃ Al ₇ bulk metallic glass (BMG) samples according to the embodiment of the present invention.

FIG. 7 is a comparison diagram of the electrical conductivity of the copper-coated metallic glass powder and the uncoated metallic glass powder obtained in the embodiment of the present invention and the composite material samples obtained after SPS sintering of the copper powder, respectively.

Fig. 8 is the composite material samples obtained after the copper-coated metallic glass powder and the uncoated metallic glass powder obtained in the embodiment of the present invention are respectively sintered with copper powder SPS at a constant strain rate of 5×10 ^-4 s ^-1 Compression curve comparison chart.

9 is the fracture morphology of the copper-coated metallic glass powder obtained in the embodiment of the present invention and the sintered sample of the copper powder and the compression fracture surface of the BMGC sample prepared by mixing the original CuZrAl metallic glass powder and 40wt.% copper powder in the comparative example SEM micrographs, in which (a) is the SEM micrograph of the compressive fracture surface of the BMGC sample prepared by mixing the original CuZrAl metallic glass powder and 40 wt.% copper powder; (b) is the copper-coated metallic glass powder and copper powder. Fracture morphologies of samples prepared from powder.

Fig. 10 is the morphology comparison diagram of the copper-coated metallic glass powder under different formaldehyde concentrations according to the embodiment of the present invention, wherein, a) formaldehyde concentration 20mL/L, b) formaldehyde concentration 30mL/L, c) formaldehyde concentration 40mL/L L.

11 is a comparison diagram of the morphology of the copper-coated metallic glass powder under different pH values of the plating solution according to the embodiment of the present invention, wherein a) the pH value of the plating solution is 11.5, b) the pH value of the plating solution is 12.0, and c) The pH of the plating solution was 12.7, and d) the pH of the plating solution was 13.3.

Detailed ways

The preferred embodiments of the present invention will be further described in detail below.

A high-strength and high-conductivity metallic glass composite material is prepared by adopting the following steps:

Step S1, preparing Cu ₅₀ Zr ₄₃ Al ₇ powder particles;

Cu ₅₀ Zr ₄₃ Al ₇ (atomic ratio) is prepared into a master alloy ingot by the method of suspension smelting according to the nominal ratio, and the prepared alloy is prepared into spherical particle powder by the argon atomization method, wherein the alloy melting temperature is 1280 ℃, and the injection air pressure was set to 3.2 MPa.

In step S2, the Cu ₅₀ Zr ₄₃ Al ₇ powder particles obtained in step S1 are subjected to pre-plating pretreatment, and then chemical plating is performed, and after cleaning and drying, copper-coated Cu ₅₀ Zr ₄₃ Al ₇ metallic glass powder is obtained.

In order to uniformly and firmly combine the crystalline copper with the metallic glass powder, the composite powder is prepared by the method of electroless copper plating of the metallic glass powder. Before starting electroless copper plating, the original powder needs to be pretreated before plating, which can be divided into three steps: cleaning, sensitization and activation. At room temperature, the powder was ultrasonically cleaned with absolute ethanol for half an hour, and then the filtered powder was placed in a mixed solution composed of 10 g/L stannous chloride (SnCl ₂ ) and 40 mL/L hydrochloric acid for 10 min. Then, the amorphous powder was finally immersed in an aqueous solution containing 0.5 g/L palladium chloride (PdCl ₂ ) and 10 mL/L hydrochloric acid for activation treatment. After each treatment step, the powder is washed with deionized water to eliminate the influence of impurity ions. After the above pretreatment, the amorphous powder is introduced into the electroless plating solution for electroless copper plating.

The chemical plating solution preparation process is as follows.

(1) First add the weighed potassium sodium tartrate to a certain amount of deionized water, stir until it is completely dissolved, then add disodium EDTA, and also stir until dissolved to form a double complexing agent solution. Put it in a constant temperature water bath furnace and heat the solution to 40°C;

(2) Dissolve the weighed copper sulfate with deionized water, place it in a constant temperature water bath for heating, and the heating temperature is 40°C;

(3) adding the heated copper sulfate solution into the complexing agent solution, adding slowly, and stirring slowly while adding to ensure that the copper ions fully form the copper ion complex;

(4) adding the weighed potassium ferrocyanide and 2,2'-bipyridine into the solution to form a dual stabilizer system, and then slowly stirring the solution for 5min;

(5) Add the powder particles that have been treated before plating into the plating solution, heat to 50-60 ° C, and add formaldehyde solution as a reducing agent after fully stirring and mixing, and the concentration is 40ml/L;

(6) adding the weighed sodium hydroxide into the solution, and adjusting the pH to be 12.0～12.7;

During the electroless plating process, ensure that the temperature of the solution is 50-60 °C; at the same time, measure the pH value of the solution with a pH tester every 3 minutes. When the pH value is too low, add 1 mol/L NaOH solution dropwise to the solution. Keep the pH stable until the end of the reaction. During the whole copper plating process, use a magnetic stirrer to stir continuously. When the solution no longer bubbles for 5 minutes, the electroless copper plating ends. The plated powder is filtered, washed with deionized water, and finally dried under vacuum to obtain copper-coated metallic glass powder.

In step S3, the copper-coated Cu ₅₀ Zr ₄₃ Al ₇ metallic glass powder is mixed with the copper powder for spark plasma sintering to obtain a metallic glass composite material with high strength and high electrical conductivity.

Compared with other sintering methods, SPS has the advantages of short sintering time, low sintering temperature and uniform heating inside the sample. First, place the weighed powder in a tungsten carbide mold and load it with a certain pressure for pre-compacting. Then sintered at a loading pressure of 300 MPa using SPS. In order to avoid crystallization, sintering needs to be carried out below the crystallization temperature (T _X ) of the amorphous alloy. The temperature set in this embodiment is 420° C., and the temperature is kept for 10 minutes. The furnace was cooled to room temperature to obtain sintered samples. The shape of the sample is a cylinder with a diameter of 15mm and a thickness of about 5mm, and the mass is about 6g.

In this embodiment, different copper contents are selected to be mixed and sintered with the obtained copper-coated metallic glass powder, wherein the mass percentages of copper are respectively 20wt.%, 30wt.%, 40wt.%, and 50wt.%. The effects of the different copper content of the composites on the electrical conductivity and mechanical properties were analyzed, as shown in Table 1.

Table 1 Comparison of properties of composites with different copper contents

From the performance comparison in Table 1, it can be seen that by adding different contents of copper, a metallic glass composite material with both electrical conductivity, high strength and high plasticity is prepared. During the preparation process, the crystallization of metallic glass did not occur, and with the increase of copper content, the plasticity and electrical conductivity of the composite material increased continuously. The final test results show that the mass percentage of copper is 30-50%, which not only has better electrical conductivity, but also has good Young's modulus and compressive plastic strain properties. When the copper content is 50wt.%, the metallic glass composite has the best comprehensive properties.

In step S1, the surface morphology copper-clad metallic glass powder of the Cu ₅₀ Zr ₄₃ Al ₇ powder prepared by gas atomization is subjected to surface morphology analysis and DSC analysis. The results are shown in Figures 1 and 2, from Figure 2. Differential scanning calorimetry analysis results showed that the glass transition temperature (T _g ) of the powder was 442°C, and the crystallization temperature (T _X ) was 503°C. In step S3, the temperature of plasma sintering is determined according to the crystallization temperature of the powder obtained in step S1, as long as it is lower than the crystallization temperature of the powder.

In step S2, the surface morphology of the copper-coated Cu ₅₀ Zr ₄₃ Al ₇ powder was analyzed by electron microscopy, and the results are shown in Figure 3. It can be seen that the copper-plated layer is uniformly and densely distributed on the surface of the amorphous substrate, and no Leakage phenomenon. It can be observed from the partial enlarged picture that the copper particles produced by electroless plating are about several hundred nanometers to one micron. Since the copper particles are gradually generated with the reaction during the electroless plating process, they are adhered to the non-ferrous metal layer by layer. The surface of the crystalline powder has the position of catalytically active sites, so it can be seen that the powder surface has a grainy texture.

In addition, the copper-clad Cu ₅₀ Zr ₄₃ Al ₇ powder was embedded with epoxy resin, and the electron microscope analysis of the cross-section was carried out after brittle fracture, and the thickness of the copper cladding layer was characterized. The results are shown in Figure 4 and Figure 5 , it can be seen that the surface of the Cu ₅₀ Zr ₄₃ Al ₇ powder is uniformly coated with a dense copper plated layer, and the thickness of the copper cladding layer is characterized as about 1 micron.

In step S3, a comparative XRD analysis was performed on the bulk metallic glass composite (BMGC) samples prepared with different copper additions and the Cu ₅₀ Zr ₄₃ Al ₇ bulk metallic glass (BMG) samples, as shown in FIG. 6 , It can be seen that the sintered CuZrAl bulk amorphous (CuZrAl BMG, Cu = 0) shows a typical amorphous state, and no other peaks (corresponding to the sharp diffraction peaks of the crystalline copper phase) are found except for the broad diffuse scattering peak, indicating that No crystal phase precipitation occurred during SPS sintering. In the copper-containing composite material, with the increase of copper content, the diffraction peaks of copper crystals became stronger, and no other crystal phases such as Cu ₂ O were found, indicating that no oxidation reaction precipitation occurred during the sintering process.

The electrical conductivity of the composite material samples obtained by sintering the copper-coated Cu ₅₀ Zr ₄₃ Al ₇ metallic glass powder obtained in this example and copper SPS with different contents was tested, and at the same time, the uncoated Cu ₅₀ Zr ₄₃ Al ₇ The composite material samples obtained by sintering metallic glass powder and copper SPS with different contents are used as a comparative example. The results are shown in Figure 7 (refer to standard annealed pure copper. Generally, the conductivity of standard annealed pure copper is defined as 100% IACS, which is 5.80E +7(1/Ω·m), the comparison of the compression curves at a constant strain rate of 5×10 ^-4 s ^-1 is shown in Fig. 8. It can be seen from Fig. 7 that the Cu ₅₀ Zr ₄₃ Al ₇ metallic glass clad with copper is used The powder has better electrical conductivity, and the electrical conductivity increases with the increase of the added copper content, meanwhile, as can be seen in Fig. 8, the sintered CuZrAl bulk amorphous exhibits a strength of about 1600 MPa, and before the compressive fracture occurs No plastic deformation. When the addition amount of Cu is less than 30 wt.%, the compression process of the bulk amorphous composite does not show obvious plastic deformation, and the bulk amorphous composite samples prepared with Cu-coated amorphous powder The compressive fracture strength is similar to that of the uncoated powder. The uncoated bulk amorphous composite sample with a copper mass fraction of 40% exhibits a fracture strength of about 700 MPa and a plastic strain of about 5.8%. While the same mass fraction of The bulk amorphous composite samples prepared by electroless copper-plated amorphous powders had 7.4% higher compressive plasticity without affecting the strength.

In addition, the compressive fracture surface morphology of BMGC samples prepared by mixing pristine CuZrAl metallic glass powder and 40 wt.% copper powder was compared with the fracture morphology of samples prepared by copper-coated metallic glass powder and copper powder, as shown in Figure 9(a ), the untreated amorphous and copper obviously show weak interface bonding, which makes the cracks propagate along the interface, causing the cracking phenomenon at the interface, and the smooth surface of the amorphous is exposed, which is the result of compression The main reason for the decrease in fracture strength. Figure 9(b) shows that after treating the original amorphous powder by electroless copper plating, due to the tight bonding between the interface and copper on the fracture surface of the bulk amorphous composite sample, almost no exposed surface is found, which is a higher conductivity sex and higher plasticity. In addition, the observed large area creep deformation also indicates ductile fracture.

The electrical properties and mechanical properties of the amorphous alloy composite material with a copper content of 40-50% obtained in this example were compared with other conventional composite materials. The results are shown in Table 2.

Table 2 Comparison of electrical and mechanical properties of amorphous alloy composites with beryllium bronze and copper matrix composites

It can be seen from Table 2 that the amorphous alloy composite material of this example has higher strength, hardness and density under the condition of higher electrical conductivity. The copper beryllium alloy currently used in Table 2 also has beryllium element that is harmful to human body, and its comprehensive performance is not the best, and its comprehensive performance needs to be improved by subsequent aging treatment. However, the ceramic particle reinforced composite materials under study have two biggest problems. One is that it is difficult to improve the sintered density due to their irregular morphology, and the other is that it is difficult to improve the strength. Carbon nanotubes or graphene-enhanced composites have even greater gaps in usage requirements. However, the present invention uses the self-prepared amorphous alloy of specific composition, which can make the composite material completely dense and greatly improve the strength on the basis of ensuring good electrical conductivity. Excellent overall performance.

Further, this example explores the influence of the formaldehyde concentration of the reducing agent and the pH value of the plating solution on the stability of the plating solution during the electroless plating process, and the concentration of the reducing agent is 20mL/L, 30mL/L, and 40mL/L; 11.5, 12.0, 12.7, 13.3. And compared the coating effect of powder under different conditions.

Figure 10 shows the powder surface morphologies of electroless copper plating after adding different concentrations of formaldehyde. It can be seen from Figure 10 that with the increase of formaldehyde concentration, the copper plating layer and the amorphous powder are combined better and better, and the copper layer is more dense. When the formaldehyde concentration was 20mL/L, some coatings showed the phenomenon of "shelling", and some powder surfaces were not completely plated; as the formaldehyde concentration increased to 30mL/L, no obvious shelling phenomenon was found, but the It was found that part of the powder surface was not completely coated, and part of the coating layer was relatively rough; when its concentration was 40mL/L, it could be seen that the coating layer on the powder surface was significantly denser and smoother, and the powder surface was rarely damaged. cladding phenomenon. In general, when the formaldehyde concentration is above 20mL/L, the electroless copper plating effect is obviously improved with the increase of formaldehyde concentration. This is because the higher formaldehyde concentration accelerates the reaction rate and accelerates the speed of copper deposition. The reacted copper particles are covered by the copper generated by the subsequent reaction before they can be oxidized, and the higher the formaldehyde content, the faster the reaction proceeds. The more thorough the coating, the higher the copper content, which makes the surface of the amorphous powder coated with a denser and brighter copper layer when the concentration is 40mL/L.

Since this experiment uses an alkaline plating solution, pH value is a very important factor in the process of electroless copper plating, and the redox reaction can only start after the pH value is greater than 11. If the pH value is too low, the reaction speed is too slow, resulting in a slow deposition rate of the copper plating layer, which may cause copper deposition on the inner wall or bottom of the reaction vessel, reducing the amount of copper deposition on the surface of the particles. Contamination of the sample caused by the plating solution. However, if the pH value is too high, the reaction is too violent, resulting in the deposition of copper near the surface of the particles, and a large amount of copper element will be attached to the inside of the plating solution, which will reduce the plating effect.

As shown in FIG. 11 , SEM pictures of the composite powder obtained by carrying out the reaction at four different pHs are shown. When the pH value is 11.5, due to the low concentration of OH ^- contained in the solution, the total reaction is incomplete, so only a small amount of copper is generated, resulting in a large number of powders that are not coated with copper; when the pH value is 13.3, a large amount of copper was found. Free copper scraps are generated and cannot be coated on the amorphous powder matrix, which may be due to the unstable reaction caused by the too fast reaction rate, and the generated copper scraps are loose and rough. Relatively speaking, when the pH value is 12.0 or 12.7, the copper cladding layer produced by the reaction is more dense and the cladding effect is better.

For different pH values of plating solutions and different reaction times, corresponding experiments were carried out on the copper plating content of the obtained copper-coated metallic glass powder, and the results are shown in Table 3.

Table 3 Copper plating content of copper-coated metallic glass powder at different pH

As can be seen from Table 3, the higher the pH value, the shorter the reaction time, and the degree of shortening is obvious. With the increase of pH, the copper content of the composite powder after electroless plating became higher and higher. Comparing with Fig. 11, in Fig. 11d) it can be seen that although the copper content is very high, most of the copper particles and clusters are not formed into a coating layer.

The high-strength and high-conductivity composite materials in the prior art all use high-conductivity materials as starting materials, and various strengthening means are used to obtain better comprehensive properties. In the present invention, considering the starting material, high-strength metallic glass is used as the starting material to obtain a new composite material with both high strength and high electrical conductivity by improving its electrical conductivity. The interface between the metallic glass and the copper is improved by the method of electroless plating, the interface resistance is reduced, the electrical conductivity is improved, and the purpose of improving the strength is achieved at the same time. The method of spark plasma sintering SPS can achieve rapid sintering at low temperature, avoid amorphization, and ensure the high strength of the reinforcing phase particles. Therefore, in the composite material with a copper content of 40wt.%, the conductivity can reach 22.06%IACS, At the same time, the compressive strength is close to 700MPa.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be considered that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field of the present invention, without departing from the concept of the present invention, some simple deductions or substitutions can be made, which should be regarded as belonging to the protection scope of the present invention.

Claims (10)

1. A preparation method of a metal glass composite material with high strength and high conductivity is characterized by comprising the following steps: the method comprises the following steps:

step S1, preparing Cu₅₀Zr₄₃Al₇Powder particles;

step S2, for the Cu obtained in step S1₅₀Zr₄₃Al₇Pretreating the powder particles before plating, then carrying out chemical plating, cleaning and drying to obtain the Cu coated with copper₅₀Zr₄₃Al₇A metallic glass powder;

step S3, coating Cu on the copper₅₀Zr₄₃Al₇And mixing the metal glass powder and the copper powder to perform discharge plasma sintering to obtain the high-strength high-conductivity metal glass composite material, wherein the sintering temperature is not more than 503 ℃.

2. The method for preparing a high-strength high-conductivity metal glass composite material according to claim 1, wherein the step S1 includes: firstly, preparing Cu by adopting a suspension smelting method₅₀Zr₄₃Al₇A mother alloy ingot, and then obtaining Cu by using the prepared mother alloy ingot through an argon atomization method₅₀Zr₄₃Al₇Powder particles.

3. The method for preparing a high-strength high-conductivity metal glass composite material according to claim 1, wherein in step S2, the pre-plating pretreatment comprises the steps of cleaning, sensitizing and activating.

4. The method of claim 3, wherein the pre-plating pretreatment comprises:

firstly adopting absolute ethyl alcohol to Cu₅₀Zr₄₃Al₇Ultrasonically cleaning powder particles, sensitizing the filtered powder in a mixed solution of stannous chloride and hydrochloric acid, and finally soaking the powder into an aqueous solution containing palladium chloride and hydrochloric acid for activation treatment, wherein the powder is cleaned by deionized water after each step of treatment; in the mixed solution of stannous chloride and hydrochloric acid, the concentration of the stannous chloride is 5-10g/L, the concentration of the hydrochloric acid is 30-50mL/L, and the sensitization time is 5-10 min; in the aqueous solution of palladium chloride and hydrochloric acid, the concentration of the palladium chloride is 0.3-0.5g/L, and the concentration of the hydrochloric acid is 5-10 mL/L.

5. The method of preparing a high strength high conductivity metallic glass composite as claimed in claim 1, wherein: in the chemical plating process, the adopted reducing agent is formaldehyde, and the concentration of the formaldehyde in the plating solution is 0.4-0.7 mol/L.

6. The method for preparing a high-strength high-conductivity metal glass composite material according to claim 5, wherein the pH value of the plating solution is 12.0 ~ 12.7.7 during the electroless plating process.

7. The method of preparing a high strength high conductivity metallic glass composite as claimed in claim 6, wherein: in the chemical plating process, the temperature of the plating solution is 50-60 ℃, the pH value of the solution is periodically detected, when the pH value is too low, 1mol/L NaOH solution is dripped into the solution, and the pH value is kept stable until the reaction is finished.

8. The method of preparing a high strength high conductivity metallic glass composite as claimed in claim 7, wherein: the plating solution is prepared by the following steps:

step S201, adding sodium potassium tartrate into deionized water, stirring until the sodium potassium tartrate is completely dissolved, adding disodium ethylene diamine tetraacetate, stirring until the disodium ethylene diamine tetraacetate is dissolved to form a double-complexing agent solution, and heating the solution to 35-45 ℃;

step S202, dissolving copper sulfate in deionized water and stirring;

step S203, adding the heated copper sulfate solution into a complexing agent solution to obtain a copper ion complex solution;

step S204, adding potassium ferrocyanide and 2,2' -bipyridine into the copper ion complex solution to form a bi-stabilizer system, and stirring the solution;

step S205, adding the pretreated powder particles into a plating solution, heating to 50-60 ℃, uniformly stirring and mixing, and adding a formaldehyde solution as a reducing agent; and adjusting the pH of the solution.

9. The method of claim 1 ~ 7, wherein in step S3, the Cu is coated with copper₅₀Zr₄₃Al₇The metal glass powder and the copper powder are mixed, and the mass percent of the copper powder is 20 ~ 50%.

10. The high-strength high-conductivity metal glass composite material is characterized by being prepared by the preparation method of the high-strength high-conductivity metal glass composite material as claimed in any one of claims 1 ~ 9.

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