CN114101662A

CN114101662A - Copper alloy carbon nanotube composite powder and preparation method and application thereof

Info

Publication number: CN114101662A
Application number: CN202111479354.5A
Authority: CN
Inventors: 赵玉荣; 徐凯; 徐恒; 王珂; 李闪闪
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-12-06
Filing date: 2021-12-06
Publication date: 2022-03-01
Anticipated expiration: 2041-12-06
Also published as: CN114101662B

Abstract

The invention relates to the technical field of copper-based nano composite materials, in particular to copper alloy carbon nano tube composite powder and a preparation method and application thereof. The carbon nano tubes are distributed on the surface of the composite powder, the composite powder is prepared by chemical vapor deposition of copper alloy powder, and the copper alloy powder at least contains at least one of aluminum, chromium, iron, manganese and rhenium; the total content of one or more components of the elements of aluminum, chromium, iron, manganese and rhenium is 0.05 to 1 percent by weight. According to the preparation method of the novel copper alloy carbon nanotube composite powder, the carbon nanotube can be directly synthesized on the copper powder without dispersing Co and Ni catalysts on the copper powder, so that the process is greatly simplified, the cost is reduced, and the industrial batch production is facilitated.

Description

Copper alloy carbon nanotube composite powder and preparation method and application thereof

Technical Field

The invention relates to the technical field of copper-based nano composite materials, in particular to copper alloy carbon nano tube composite powder and a preparation method and application thereof.

Background

Copper and copper alloy are a large amount of wide-range base materials and have extremely wide application in the industries of aerospace, aviation, electronics, electrical appliances and the like. With the development of science and technology, particularly the development of 5G, AR, VR and Yuan universe industries, related hardware electronic products have new requirements on copper materials with high performance or special performance, while the traditional copper and copper alloy materials are difficult to meet the high requirements of the contemporary industry, and the development of copper materials with more excellent comprehensive performance is urgently needed. Proper reinforcing phases such as nano particles and nano fibers are added into the copper matrix, so that the high-performance copper-based composite material with the excellent characteristics of the reinforcing phases and the copper matrix can be prepared.

The traditional copper-based composite material is usually prepared by a mechanical ball milling method, namely, copper powder and reinforcing phase powder are mixed and ground by a ball mill and then sintered to obtain the copper-based composite material. However, the method has the problems of long preparation period, complex process, high energy consumption, high cost, damage to the structure of the reinforcing phase, influence on performance and the like. The other method is an in-situ compounding method, namely, a reinforcing phase is directly generated in situ on the surface of the copper powder through a certain chemical reaction and is sintered, and the method omits the mixing step of a matrix and the reinforcing phase and also avoids the damage of mechanical ball milling to the reinforcing phase.

Carbon Nanotubes (CNTs) are nano materials with unique one-dimensional structures, have excellent mechanical, electrical and thermal properties, and are ideal reinforcing phases capable of improving the comprehensive properties of copper materials. However, a catalyst is needed for in-situ preparation of carbon nanotubes on the surface of copper powder. Although the particles of the transition elements Fe, Ni and Co can be used as the catalyst for preparing the carbon nano tube, the particles are difficult to be uniformly dispersed on the copper powder, and in addition, when the carbon nano tube is prepared at high temperature, the catalyst elements can be dissolved in the copper matrix in a solid way, so that the catalytic activity is reduced and even lost, and the difficulty of preparing the composite material by an in-situ synthesis method is increased.

Therefore, the development of a simple and easy-to-operate method for preparing the copper-based carbon nanotube composite powder, which is easy to realize industrialization, is an important task for preparing the high-performance copper-based composite material.

Disclosure of Invention

In order to solve the defects, the invention provides copper alloy carbon nanotube composite powder and a preparation method and application thereof.

The specific technical scheme of the invention is as follows:

the invention provides copper alloy carbon nanotube composite powder, wherein carbon nanotubes are distributed on the surface of the composite powder, the composite powder is prepared by chemical vapor deposition of copper alloy powder, and the copper alloy powder at least comprises at least one of elements of aluminum, chromium, iron, manganese and rhenium; the total content of one or more components in the elements of aluminum, chromium, iron, manganese and rhenium is 0.05 to 1 percent by weight;

preferably, the carbon nanotubes are multiwalled carbon nanotubes, and the average diameter of the multiwalled carbon nanotubes is 10-35 nm.

The second aspect of the present invention provides a method for preparing the copper alloy carbon nanotube composite powder, including:

step S1, weighing copper alloy powder and cuprous oxide powder according to a certain proportion, mixing uniformly, loading into a sealed container, heating to 300-900 ℃, and keeping the temperature for 30-120 min;

step S2, cooling the sealed container to room temperature when the heat preservation time of the step S1 is up, taking out the mixed powder, putting the mixed powder into a chemical vapor reaction furnace, introducing hydrogen, heating to 200-600 ℃, and preserving the heat for 30-90 min;

step S3, when the heat preservation time of the step S2 is up, keeping introducing hydrogen, adjusting the heating temperature to 700-900 ℃, then introducing a carbon source and keeping for 5-60 min;

and S4, stopping introducing the carbon source, stopping heating, keeping introducing the hydrogen, and cooling the reaction furnace to room temperature to obtain the copper alloy carbon nanotube composite powder.

Preferably, in the step S1, the weight ratio of the copper alloy powder to the cuprous oxide powder is (50-200): 1.

Preferably, the carbon source in step S3 includes at least one of ethylene, acetylene, and methane.

Preferably, the flow ratio of the hydrogen to the carbon source introduced in S3 is (20-80): 1.

The third aspect of the present invention provides another method for preparing the copper alloy carbon nanotube composite powder, including:

step S1, filling the copper alloy powder into a chemical vapor reaction furnace, introducing protective gas nitrogen or argon, heating to 300-900 ℃, and then introducing a certain amount of oxygen and preserving heat for 30-120 min;

step S2, stopping introducing oxygen and protective gas when the heat preservation time of the step S1 is up, converting to introducing hydrogen, heating to 200-600 ℃, and preserving heat for 30-90 min;

Preferably, the flow ratio of the protective gas and the oxygen introduced in S1 is (100-3000): 1.

Preferably, the carbon source in step S3 includes at least one of ethylene, acetylene, and methane. .

The fourth aspect of the invention provides an application of copper alloy carbon nanotube composite powder, which is prepared into a copper alloy carbon nanotube composite material by adopting a powder metallurgy method.

Advantageous effects

Compared with the prior art, the technical scheme provided by the invention has the following beneficial effects:

(1) the novel copper alloy carbon nanotube composite powder can be used for directly synthesizing the carbon nanotubes on copper powder without dispersing Co and Ni catalysts on the copper powder, and can be directly prepared only by treating the copper alloy powder at least containing at least one of aluminum, chromium, iron, manganese and rhenium elements, so that the process is simplified, the cost is reduced, and the industrial batch production is facilitated.

(2) The carbon nano tube on the prepared copper alloy carbon nano tube composite powder is not simply covered on the surface of the powder, but one end of the carbon nano tube is connected with the copper alloy powder, so that the agglomeration of the carbon nano tube is avoided, the carbon nano tube is favorable for the composition of the carbon nano tube and a copper matrix during the sintering preparation of the composite material, and the comprehensive performance is improved.

(3) And preparing the copper alloy carbon nanotube composite material from the copper alloy carbon nanotube composite powder by adopting a powder metallurgy method, wherein the obtained composite material carbon nanotubes are uniformly distributed and are tightly combined with a copper matrix.

Drawings

Fig. 1 is a scanning electron microscope photograph of copper alloy powder according to an embodiment of the present invention.

Fig. 2 is a scanning electron microscope photograph of the copper alloy carbon nanotube composite powder prepared in one embodiment of the present invention.

Fig. 3 is a transmission electron microscope photograph of carbon nanotubes on the copper alloy carbon nanotube composite powder prepared in one embodiment of the present invention.

Fig. 4 is an energy spectrometer element analysis diagram of the catalyst on the carbon nanotube on the copper alloy carbon nanotube composite powder prepared in the embodiment of the present invention.

Fig. 5 is a scanning electron microscope photograph of the copper alloy carbon nanotube composite powder pre-pressed block after being electroplated with copper in an embodiment of the invention.

Fig. 6 is a scanning electron microscope photograph of the internal morphology of the copper alloy carbon nanotube composite material prepared by using the copper alloy carbon nanotube composite powder through the powder metallurgy method in the embodiment of the present invention.

Detailed Description

In order to facilitate an understanding of the invention, the invention will now be described more fully hereinafter with reference to the accompanying drawings, in which several embodiments of the invention are shown, but which may be embodied in many different forms and are not limited to the embodiments described herein, but rather are provided for the purpose of providing a more thorough disclosure of the invention.

In order to solve the defects, the invention provides copper alloy carbon nanotube composite powder and a preparation method and application thereof, and the specific technical scheme of the invention is as follows:

the first aspect of the invention provides copper alloy carbon nanotube composite powder, wherein the carbon nanotubes are distributed on the surface of the composite powder, and the composite powder is prepared by copper alloy powder Chemical Vapor Deposition (CVD).

The preparation of carbon nanotube by chemical vapor deposition is carried out by cracking methane, acetylene, ethane, ethylene, benzene and other gases under certain temperature, atmosphere and catalysis conditions, and re-nucleating and growing the carbon atoms formed by cracking to obtain the carbon nanotube. The preparation process is simple and controllable, the yield of the carbon nano tube is high, and the method can be used for large-scale production and becomes the most common and mature method for preparing the carbon nano tube.

However, the catalyst is needed for preparing the carbon nano tube by the chemical vapor deposition method, the catalyst for preparing the carbon nano tube by the chemical vapor deposition method at present mainly comprises transition metal elements, wherein Co and Ni are the most commonly used catalyst for preparing the carbon nano tube at present due to high catalytic activity, but the Co and Ni catalysts are difficult to disperse on copper powder, and in addition, when the carbon nano tube grows by high-temperature CVD, the Co and Ni elements can be dissolved in a copper matrix in a solid manner, so that the catalytic activity is reduced and even lost, and the difficulty of preparing the copper-carbon nano tube composite powder by the CVD method is increased.

The inventors of the present application have found through a large number of studies and experiments that when a certain amount of a specific element is contained in copper alloy powder, carbon nanotubes can be produced on the surface of the copper alloy powder by a CVD method even without introducing a catalyst such as Co or Ni on the surface of the copper powder. The copper alloy powder contains at least one of elements including aluminum, chromium, iron, manganese and rhenium. The experimental analysis shows that the elements of aluminum, chromium, iron, manganese and rhenium can respectively react on the surface of the copper alloy powder to generate CuAl under certain conditions₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄And CuAl₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄The copper alloy powder can be decomposed under certain conditions, copper atoms can be formed in the decomposition process, the decomposed copper atoms form nano copper particles on the surface of the copper alloy powder, and the nano copper particles have catalytic activity, so that the formation of carbon nano tubes on the surface of the copper alloy powder can be catalyzed.

Through a great deal of experiments by the inventor of the application, the total content of one or more of the aluminum, chromium, iron, manganese and rhenium elements in the copper alloy powder is preferably 0.05 to 1 percent of the total weight of the copper alloy powder in percentage by weight; if the total content of one or more of the above elements is less than 0.05 percent by mass, CuAl is respectively generated on the surface of the copper alloy powder by reaction₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄The amount of the catalyst is too small, so that the content of the nano copper particle catalyst formed on the surface of the copper alloy powder after decomposition is too small, and the formation amount of the carbon nano tubes on the surface of the copper alloy powder is influenced. If higher than 1%, on the one hand CuAl₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄Too many copper atoms that decompose to aggregate together to form copper particles larger than nanometer scale, which are not active to catalyze carbon nanotube formation; CuAl, on the other hand₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄Respectively has Al after decomposition₂O₃、Cr₂O₃、MnO、La₂O₃、Fe₃O₄Formation of, if the content is too high, Al₂O₃、Cr₂O₃、MnO、La₂O₃、Fe₃O₄The copper alloy powder is covered and wrapped, so that the preparation of the carbon nano tube cannot be catalyzed.

Through a large number of experiments, the carbon nanotubes on the surface of the copper alloy carbon nanotube composite powder are multiwalled carbon nanotubes, and the average diameter of the multiwalled carbon nanotubes is 10-35 nm.

and step S1, weighing the copper alloy powder and the cuprous oxide powder according to a certain proportion, mixing uniformly, then loading into a sealed container, heating to 300-900 ℃, and preserving heat for 30-120 min.

In this process, cuprous oxide decomposes to generate oxygen atoms, and the oxygen atoms diffuse to the surface of the copper alloy powder and into the interior thereof due to the difference in oxygen concentration. Since the copper alloy powder contains at least one of aluminum, chromium, iron, manganese and rhenium elements, and the reducibility of the aluminum, chromium, iron, manganese and rhenium elements is higher than that of the copper element, oxygen atoms are firstly combined with the aluminum, chromium, iron, manganese and rhenium elements to generate CuAl₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄Then as the cuprous oxide is consumed, the reaction proceeds further, CuAl₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄Further decomposing to generate Al with more stable structure₂O₃、Cr₂O₃、MnO、La₂O₃、Fe₃O₄(ii) a And the copper atoms are generated in the decomposition process, and finally the copper atoms form a nano copper particle catalyst capable of catalyzing the generation of the carbon nano tubes on the surface of the copper alloy powder. Through a large number of experiments, the inventors of the present application found that if the temperature is lower than 300 ℃ or higher than 900 ℃, the generation of carbon nanotubes on the surface of the final copper alloy powder is not favorable, and the reason is presumed that the temperature is lower than 300 ℃ and is not favorable for CuAl₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄Further decomposition, and above 900 ℃, the copper alloy powder is easily deformed and stuck into blocks. The heat preservation is best carried out for 30-120 min at the temperature of 300-900 ℃, if the time is too short, the reaction process is not thorough, and thus the copper is treatedThe copper nano-particle catalyst formed on the surface of the alloy powder is insufficient; if the heat preservation time is too long, the waste of efficiency and energy is caused, and the cost is increased. Preferably, in the step S1, the temperature is raised to 400-700 ℃ and the temperature is maintained for 30-100 min, and more preferably, the temperature is raised to 500-600 ℃ and the temperature is maintained for 40-60 min.

And S2, cooling the sealed container to room temperature when the heat preservation time of the step S1 is up, taking out the mixed powder, putting the mixed powder into a chemical vapor reaction furnace, introducing hydrogen, heating to 200-600 ℃, and preserving the heat for 30-90 min.

After the reaction of step S1, there may be some remaining amount of cuprous oxide or cupric oxide, which can avoid the oxidation of the cuprous oxide or cupric oxide on the subsequent carbon nanotube preparation process and the oxidation of the prepared carbon nanotube to destroy the integrity of the carbon nanotube structure. In addition, this step also promotes CuAl that is not completely decomposed in step S1₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄Further decomposition, and in addition, excess cuprous oxide or cupric oxide is reduced to copper by introducing hydrogen. Preferably, in the step S2, the temperature is increased to 300-500 ℃ and is kept for 40-80 min; preferably, the temperature is increased to 400-500 ℃ and the temperature is kept for 40-60 min.

And step S3, when the heat preservation time of the step S2 is up, keeping introducing hydrogen, adjusting the heating temperature to 700-900 ℃, then introducing a carbon source and keeping for 5-60 min.

In the process, the carbon source is cracked into carbon atoms and the atoms are recombined to form the carbon nano tube under the catalytic action of the nano copper particles on the surface of the copper alloy powder. Through a large number of experiments by the inventors of the present application, it was found that if the temperature is lower than 700 ℃, the number of carbon nanotubes generated on the surface of the copper alloy powder is small and the length of the carbon nanotubes is short, which is probably because the catalytic activity of the nano copper particles is low at a temperature lower than 700 ℃, so that the cracking ability of the carbon source and the recombination ability of the carbon atoms are reduced, and thus the number of carbon nanotubes is small and the length of the carbon nanotubes is short. If the temperature is higher than 900 ℃, the cracking speed of the carbon source is accelerated, a large amount of carbon atoms generated by cracking are deposited on the nano copper catalyst and are not dissolved and recombined, the catalyst particles are coated, so that the carbon atoms are recombined to form carbon nano tubes to be blocked, and in addition, the copper alloy powder is solidified into blocks. In the process, the carbon source is introduced and kept for 5-60 min, and unnecessary waste is caused by too little time, insufficient carbon source and too long time. In the step S3, preferably, the heating temperature is adjusted to 800-900 ℃, and then a carbon source is introduced and kept for 20-50 min; preferably, the heating temperature is adjusted to 830-880 ℃, and then the carbon source is introduced and kept for 30-40 min.

Preferably, the weight ratio of the copper alloy powder to the cuprous oxide powder in step S1 is (50-200): 1, and if the amount of cuprous oxide is too small, the amount of oxygen atoms supplied is insufficient, so that CuAl generated in step 1 is reduced₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄The amount of the catalyst is insufficient, and the nano-copper particle catalyst obtained after decomposition is also insufficient, so that the generation of the carbon nano-tube in the step 3 is influenced. The excessive amount of cuprous oxide causes unnecessary waste on one hand, and on the other hand, the hydrogen reduction time in the step 2 is prolonged, the hydrogen consumption is increased, the waste of hydrogen and energy is caused, and the cost is increased. More preferably, the weight ratio of the copper alloy powder to the cuprous oxide powder is (80-150): 1, and still more preferably, the flow ratio of hydrogen to the carbon source is (100-130): 1.

Preferably, the carbon source in step S3 includes at least one of ethylene, acetylene, and methane, and more preferably, the carbon source in step S3 is ethylene.

Preferably, the flow ratio of the hydrogen to the carbon source introduced in S3 is (20-80): 1, and a large number of experiments by the inventors of the present invention show that when the flow ratio of the hydrogen to the carbon source is (20-80): 1, the obtained carbon nanotubes have higher quality and fewer defects. This is probably because the ratio of the flow rates reflects the concentration of the carbon source in the process. When the concentration of the carbon source is insufficient, the number of the cracked carbon atoms is insufficient to enable the carbon nanotube to grow normally, so that the defects of the carbon nanotube are numerous. When the concentration of the carbon source is too high, the cracked carbon atoms are increased, more amorphous carbon begins to be attached to the carbon nanotubes, so that the recombination of the subsequent carbon atoms is influenced, and the carbon nanotubes generate more defects. More preferably, the flow ratio of the hydrogen to the carbon source is (30-60): 1, and still more preferably, the flow ratio of the hydrogen to the carbon source is (40-50): 1.

and step S1, filling the copper alloy powder into a chemical vapor reaction furnace, introducing protective gas nitrogen or argon, heating to 300-900 ℃, and then introducing a certain amount of oxygen and preserving heat for 30-120 min.

In this process, oxygen diffuses toward the surface of the copper alloy powder and into the interior thereof. Since the copper alloy powder contains at least one of aluminum, chromium, iron, manganese and rhenium elements, and the reducibility of the aluminum, chromium, iron, manganese and rhenium elements is higher than that of the copper element, oxygen is firstly combined with the aluminum, chromium, iron, manganese and rhenium elements to generate CuAl₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄. Preferably, in the step S1, the temperature is raised to 400-700 ℃, then a certain amount of oxygen is introduced and the temperature is maintained for 30-100 min, and further preferably, the temperature is raised to 500-600 ℃ and the temperature is maintained for 40-60 min.

Step S2, stopping introducing oxygen and protective gas when the heat preservation time of the step S1 is up, converting to introducing hydrogen, heating to 200-600 ℃, and preserving heat for 30-90 min; this process, CuAl₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄Further decomposing to generate Al with more stable structure₂O₃、Cr₂O₃、MnO、La₂O₃、Fe₃O₄Thereby promoting the formation of the nano-copper particle catalyst; in addition, oxygen may oxidize a portion of copper in step S1 to remove copperAnd copper oxide or cuprous oxide is produced, which can be reduced by this step. Preferably, in the step S2, the temperature is increased to 300-500 ℃ and is kept for 40-80 min; preferably, the temperature is increased to 400-500 ℃ and the temperature is kept for 40-60 min.

Step S3, when the heat preservation time of the step S2 is up, keeping introducing hydrogen, adjusting the heating temperature to 700-900 ℃, then introducing a carbon source and keeping for 5-60 min; preferably, the heating temperature is adjusted to 800-900 ℃, and then a carbon source is introduced and kept for 20-50 min; preferably, the heating temperature is adjusted to 830-880 ℃, and then the carbon source is introduced and kept for 30-40 min.

Preferably, the flow ratio of the protective gas to the oxygen gas introduced in S1 is (100-3000): 1, the flow ratio of the protective gas to the oxygen gas in the process reacts with the concentration of the oxygen gas in the process, if the concentration of the oxygen gas is too high, the oxygen partial pressure is too high, not only the aluminum, chromium, iron, manganese and rhenium elements are oxidized, but also the copper is oxidized, so that the surface of the copper alloy powder is excessively oxidized, and the CuAl is not easily generated₂O₄、CuCrO₂、CuMn₂O₄、CuLa₂O₄、CuFe₂O₄. If the concentration of oxygen is too low, the partial pressure of oxygen is too low to oxidize the aluminum, chromium, iron, manganese, rhenium elements. More preferably, the flow ratio of the shielding gas to the oxygen gas is (500-2000): 1, and still more preferably, the flow ratio of the shielding gas to the oxygen gas is (1000-2000): 1.

Preferably, the flow ratio of the hydrogen to the carbon source introduced in S3 is (20-80): 1, more preferably (30-60): 1, and still more preferably (40-50): 1.

The fourth aspect of the invention provides a copper alloy carbon nanotube composite material and a preparation method thereof, wherein the copper alloy carbon nanotube composite material is prepared by sintering the copper alloy carbon nanotube composite powder. In some preferred embodiments, the method for preparing the copper alloy carbon nanotube composite material comprises:

and (3) placing the copper alloy carbon nanotube composite powder into a mold, and sintering at the temperature of 750-1000 ℃. The sintering mode can be any one of hot-pressing sintering, microwave sintering, spark plasma sintering and the like.

The following description will be made by taking discharge plasma sintering as an example: placing the electroplated prepressing block into a mold, and sintering at a heating rate of 60-120 ℃/min, wherein the sintering temperature is preferably 700-900 ℃, and the sintering pressure is preferably 30-50 Mpa; the holding time is preferably 5-30 min. And cooling to room temperature after heat preservation is finished, thus obtaining the copper alloy carbon nanotube composite material. Further preferably, the temperature rise speed is 70-110 ℃/min; the sintering temperature is 750-850 ℃; the heat preservation time is preferably 8-20 min; the sintering pressure is preferably 35-45 MPa.

The preparation of the copper alloy carbon nanotube composite powder is different from that of a conventional copper or copper alloy material, because the existence of the carbon nanotubes on the surface of the copper alloy carbon nanotube composite powder can influence the metallurgical bonding between the composite powders in the sintering process, the final performance of the material is influenced by the problems of insufficient densification degree, excessive internal defects and the like of the composite material obtained after sintering.

In order to overcome the above problems, a fifth aspect of the present invention provides a method for preparing a copper alloy carbon nanotube composite material, comprising:

s1, prepressing: filling the copper alloy carbon nanotube composite powder into a mold, then placing the mold under a press machine, pressurizing to the pressure of 200-400 Mpa, maintaining the pressure for 2-6 minutes, pressing into a pre-pressed block and taking out;

through a large number of experiments by the inventors of the present application, it is found that if the pressure in the step S1 is too low, due to the existence of the carbon nanotubes on the surface of the copper alloy carbon nanotube composite powder, the formation of the pre-pressed block is hindered or the formed pre-pressed block is too loose to affect the subsequent electroplating and sintering, and if the pressure is too high, the number of gaps of the pre-pressed block is reduced and the communication between the gaps is reduced, thereby affecting the subsequent electroplating process.

S2, electroplating: placing the prepressing block in an electro-coppering solution to carry out electro-coppering on the prepressing block, so that an electro-coppering layer is formed on the surface of the composite powder in the prepressing block, and taking out the prepressing block to be dried after the electro-coppering is finished; the copper electroplating bath and the copper electroplating process are prior art and will not be described in detail in this application.

Through a large number of experiments, the inventor verifies that in the electroplating process, copper ions in the electroplating solution can enter the pre-pressing blocks through gaps among the pre-pressing blocks, an electroplating copper layer is gradually formed on the surface of each copper alloy carbon nanotube composite powder, the formed electroplating copper layer covers and wraps a large number of carbon nanotubes, and then the obstruction of the carbon nanotubes to metallurgical bonding among the composite powders in the subsequent sintering process is reduced or avoided, so that the densification of the composite material obtained after sintering is facilitated, the internal defects are reduced, and the comprehensive performance of the composite material is improved.

S3, sintering: and (3) placing the electroplated prepressing block into a mould, and sintering at the temperature of 750-1000 ℃.

The sintering mode can be any one of hot-pressing sintering, microwave sintering, spark plasma sintering and the like. The following description will be made by taking discharge plasma sintering as an example: placing the electroplated prepressing block into a mold, and sintering at a heating rate of 60-120 ℃/min, wherein the sintering temperature is preferably 700-900 ℃, and the sintering pressure is preferably 30-50 Mpa; the holding time is preferably 5-30 min. And cooling to room temperature after heat preservation is finished, thus obtaining the copper alloy carbon nanotube composite material.

Through a large number of experiments, the inventor finds that if the temperature rising rate is too slow, the grain refinement of the composite material is not facilitated, and if the temperature rising rate is too fast, residual gas in the composite powder cannot be discharged in time, so that the defects are increased; further preferably, the temperature rise rate is 70-110 ℃/min. If the sintering temperature is too low or the heat preservation time is too short, copper atoms do not have enough energy to diffuse and fill gaps formed by the carbon nanotubes in the metallurgical bonding process of the composite powder, so that the defects of the composite material are increased, the densification is insufficient, and the comprehensive performance is influenced; the sintering temperature is too high, the difference between the thermal expansion coefficients of the copper substrate and the carbon nano tube is large, so that the residual stress at the joint between the copper substrate and the carbon nano tube is large, gaps or cracks are easy to appear, and even the composite material is melted to interrupt the sintering process; if the heat preservation time is too long, crystal grains are easy to grow, and further optimization is carried out, wherein the sintering temperature is 750-850 ℃; the heat preservation time is preferably 8-20 min. If the sintering pressure is too low, the density of the composite material is insufficient, and if the sintering pressure is too high, the mold can be damaged, and the service life of the mold is shortened; more preferably, the sintering pressure is preferably 35-45 Mpa.

The sixth aspect of the present invention provides a method for preparing another copper alloy carbon nanotube composite material, comprising:

s1, premixing: uniformly mixing the copper alloy carbon nanotube composite powder with a certain proportion of copper powder and/or copper alloy powder;

through the premixing of S1, the copper alloy carbon nanotube composite powder is diluted by copper powder and/or copper alloy powder, so that the periphery of each copper alloy carbon nanotube composite powder is not completely the copper alloy carbon nanotube composite powder, and in the sintering process, the number and the density of carbon nanotubes between adjacent powder are reduced, thereby reducing the obstruction of the carbon nanotubes on the metallurgical bonding between the adjacent powder in the sintering process, enabling the components to be more easily metallurgically bonded, reducing the defects and improving the density, and further improving the density of the composite material.

S2, sintering: and putting the uniformly mixed powder into a die, and sintering at the temperature of 750-1000 ℃.

The sintering mode can be any one of hot-pressing sintering, microwave sintering, spark plasma sintering and the like. The following description will be made by taking discharge plasma sintering as an example: placing the mixed powder into a mold, and sintering at a heating rate of 60-120 ℃/min, wherein the sintering temperature is preferably 700-900 ℃, and the sintering pressure is preferably 30-50 Mpa; the holding time is preferably 5-30 min. And after the heat preservation is finished, the temperature is returned to the room temperature, and the copper alloy carbon nanotube composite material is obtained.

Further preferably, the temperature rise speed is 70-110 ℃/min; the sintering temperature is 750-850 ℃; the heat preservation time is preferably 8-20 min; the sintering pressure is preferably 35-45 MPa.

The seventh aspect of the present invention provides another method for preparing a copper alloy carbon nanotube composite material, comprising:

s2, prepressing: putting the uniformly mixed powder into a mold, then placing the mold under a press machine, pressurizing to the pressure of 200-400 Mpa, maintaining the pressure for 2-6 minutes, pressing into a pre-pressed block, and taking out;

s3, electroplating: placing the prepressing block in an electro-coppering solution to carry out electro-coppering on the prepressing block, so that an electro-coppering layer is formed on the surface of the composite powder in the prepressing block, and taking out the prepressing block to be dried after the electro-coppering is finished; the copper electroplating bath and the copper electroplating process are prior art and will not be described in detail in this application.

S4, sintering: and putting the uniformly mixed powder into a die, and sintering at the temperature of 750-1000 ℃.

The present invention will be described in further detail with reference to examples.

Example 1

Embodiment 1 provides a method for preparing the copper alloy carbon nanotube composite powder, including:

step S1, weighing copper alloy powder and cuprous oxide powder according to a weight ratio of 120:1, wherein the copper alloy powder is copper-aluminum alloy powder, the mass fraction of aluminum element is 0.8%, and fig. 1 is a scanning electron microscope photograph of the copper-aluminum alloy powder in this embodiment.

Uniformly mixing copper alloy powder and cuprous oxide powder, putting the mixture into a sealed container, putting the sealed container into a heating device, heating the mixture to 800 ℃ at the heating rate of 10 ℃/min, and keeping the temperature for 60 min;

step S2, stopping heating when the heat preservation time of the step S1 is up, cooling the sealed container to room temperature, taking out the mixed powder, packaging the mixed powder in a chemical vapor reaction furnace, introducing hydrogen at the speed of 500-2000 mL/min, heating to 400 ℃, and preserving heat for 60 min;

step S3, when the heat preservation time of the step S2 is up, keeping introducing hydrogen, adjusting the heating temperature to 800 ℃, then introducing ethylene and keeping for 30 min; the flow ratio of ethylene to hydrogen is 50: 1;

and S4, stopping introducing carbon source ethylene, stopping heating, keeping introducing hydrogen continuously, and cooling the reaction furnace to room temperature to obtain the copper alloy carbon nanotube composite powder. Fig. 2 is a scanning electron microscope photograph of the copper alloy carbon nanotube composite powder prepared in this example. Fig. 3 is a transmission electron microscope photograph of the carbon nanotubes on the copper alloy carbon nanotube composite powder prepared, and at the same time, the existence of the catalyst at the top of the carbon nanotubes can be seen, and fig. 4 is an energy spectrometer element analysis diagram of the catalyst, and the analysis shows that the catalyst is nano copper particles.

Example 2

Embodiment 2 provides a method for preparing copper alloy carbon nanotube composite powder, including:

step S1, loading the copper-aluminum alloy powder obtained in the embodiment 1 into a chemical vapor reaction furnace for packaging, introducing protective gas nitrogen at the speed of 1000mL/min, heating to 800 ℃, and then introducing a certain amount of oxygen for heat preservation for 60 min; the flow ratio of nitrogen to oxygen was 500: 1.

Step S2, stopping introducing oxygen and protective gas when the heat preservation time of the step S1 is up, switching to introducing hydrogen, and heating for 60min at the temperature of 400 ℃; the introduction speed of the hydrogen is 500-2000 mL/min.

Step S3, when the heating time of the step S2 is up, keeping introducing hydrogen, adjusting the heating temperature to 800 ℃, then introducing a carbon source ethylene and keeping for 30min, wherein the flow ratio of the ethylene to the hydrogen is 50: 1;

and S4, stopping introducing carbon source ethylene, stopping heating, keeping introducing hydrogen, and stopping introducing hydrogen when the reaction furnace is cooled to room temperature to obtain the copper alloy carbon nanotube composite powder.

Example 3

Similar to example 1, but the mass fraction of the aluminum element in the copper-aluminum alloy is 0.05%.

Example 4

Similar to example 1, but the mass fraction of the aluminum element in the copper-aluminum alloy is 1%.

Example 5

Similar to example 1, but in step S1, the copper alloy powder and the cuprous oxide powder were mixed uniformly, placed in a sealed container, placed in a heating device, heated to 700 ℃ at a heating rate of 5 ℃/min, and then held for 90 min.

Example 6

Similar to example 1, but in the step S1, the copper alloy powder and the cuprous oxide powder were uniformly mixed, and then the mixture was placed in a sealed container and placed in a heating device, heated to 900 ℃ at a heating rate of 10 ℃/min, and then kept warm for 20 min.

Example 7

Similar to example 1, but in the step S2, hydrogen is introduced at a speed of 500-2000 mL/min, and the temperature is raised to 200 ℃ and kept for 90 min.

Example 8

Similar to example 1, but in the step S2, hydrogen is introduced at a speed of 500-2000 mL/min, and the temperature is raised to 600 ℃ and maintained for 30 min.

Example 9

Similar to example 1, but in the step S3, the heating temperature was adjusted to 700 ℃, and then ethylene was introduced again and maintained for 60 min.

Example 10

Similar to example 1, but in the step S3, the heating temperature was adjusted to 900 ℃, and then ethylene was introduced again and maintained for 5 min.

Example 11

Similarly to example 1, but in the step S1, the copper alloy powder and the cuprous oxide powder were weighed in a weight ratio of 50:1, respectively.

Example 12

Similar to example 1, but in the step S1, the copper alloy powder and the cuprous oxide powder were weighed in a weight ratio of 200:1, respectively.

Example 13

Similar to example 1, but in step S3, the ethylene to hydrogen flow ratio was 20: 1.

Example 14

Similar to example 1, but in step S3, the ethylene to hydrogen flow ratio was 80: 1.

Example 15

Similar to example 1, but the carbon source was acetylene.

Example 16

Similar to example 1, but the carbon source was methane.

Example 17

Similar to the embodiment 1, the copper alloy powder is copper-chromium alloy powder, and the mass fraction of the aluminum element of the chromium is 0.05-1%.

Example 18

Similar to the embodiment 1, the copper alloy powder is copper-iron alloy powder, and the mass fraction of the iron element of the chromium is 0.05-1%.

Example 19

Similar to the embodiment 1, the copper alloy powder is copper-manganese alloy powder, and the mass fraction of manganese element in the chromium is 0.05-1%.

Example 20

Similar to example 1, but the copper alloy powder is copper-rhenium alloy powder, and the mass fraction of rhenium element in the chromium is 0.05-1%.

Example 21

Similar to example 2, but the mass fraction of the aluminum element in the copper-aluminum alloy is 0.05%.

Example 22

Similar to example 2, but the mass fraction of the aluminum element in the copper-aluminum alloy is 1%.

Example 23

Similar to example 2, but in step S1, a protective gas of nitrogen is introduced at a speed of 1500mL/min, the temperature is heated to 700 ℃, and then a certain amount of oxygen is introduced for heat preservation for 90 min.

Example 24

Similar to example 2, but in step S1, argon gas as protective gas is introduced at the speed of 1200mL/min, the temperature is heated to 900 ℃, and then a certain amount of oxygen is introduced for heat preservation for 20 min.

Example 25

Similar to example 2, but in step S1, the flow ratio of nitrogen to oxygen was 100: 1.

Example 26

Similar to example 2, but in step S1, the flow ratio of nitrogen to oxygen was 3000: 1.

Example 27

Similar to example 2, but in said step S2, heating was carried out at a temperature of 200 ℃ for 90 min.

Example 28

Similar to example 2, but in said step S2, heating was carried out at a temperature of 600 ℃ for 30 min.

Example 29

Similar to example 2, but in the step S3, the heating temperature was adjusted to 700 ℃, and then ethylene was introduced again and maintained for 60 min.

Example 30

Similar to example 2, but in the step S3, the heating temperature was adjusted to 900 ℃, and then ethylene was introduced again and maintained for 5 min.

Example 31

Similar to example 2, but in step S3, the ethylene to hydrogen flow ratio was 20: 1.

Example 32

Similar to example 2, but in step S3, the ethylene to hydrogen flow ratio was 80: 1.

Example 33

Similar to example 2, but the carbon source was acetylene.

Example 34

Similar to example 2, but the carbon source was methane.

Example 35

Similar to the embodiment 2, the copper alloy powder is copper-chromium alloy powder, and the mass fraction of the aluminum element of the chromium is 0.05-1%.

Example 36

Similar to the embodiment 2, the copper alloy powder is copper-iron alloy powder, and the mass fraction of the iron element of the chromium is 0.05-1%.

Example 37

Similar to the embodiment 2, the copper alloy powder is copper-manganese alloy powder, and the mass fraction of manganese element in the chromium is 0.05-1%.

Example 38

Similar to example 2, but the copper alloy powder is copper-rhenium alloy powder, and the mass fraction of rhenium element in the chromium is 0.05-1%.

The scanning electron microscope photos of the copper alloy carbon nanotube composite powder prepared in the above examples 2 to 38 are similar to the scanning electron microscope photo 2 of the copper alloy carbon nanotube composite powder prepared in the example 1, and are not shown in the drawings separately. The transmission electron microscope photographs of the carbon nanotubes and the catalysts thereof on the copper alloy carbon nanotube composite powder prepared in the above examples 2 to 38 are similar to those in fig. 3, and it can be known through analysis that the catalysts are all nano copper particles, and the catalysts are not shown in the drawings one by one.

Example 39

The method for preparing the copper alloy carbon nanotube composite material by adopting the spark plasma sintering method from the copper alloy carbon nanotube composite powder prepared by any one of the embodiments 1 to 38 or any other method without departing from the concept of the invention comprises the following steps:

placing the copper alloy carbon nanotube powder into a mould, and sintering at a heating rate of 100 ℃/min, wherein the sintering temperature is preferably 800 ℃, and the sintering pressure is preferably 40 Mpa; the holding time is preferably 10 min. And cooling to room temperature after heat preservation is finished, thus obtaining the copper alloy carbon nanotube composite material. A scanning electron micrograph of the tensile port of the copper alloy carbon nanotube composite is shown in fig. 6.

Example 40

s1, prepressing: filling the copper alloy carbon nanotube composite powder into a mold, then placing the mold under a press machine, pressurizing to 300Mpa, maintaining the pressure for 4 minutes, pressing into a pre-pressed block body and taking out;

S3, sintering: placing the electroplated prepressing block into a mould, and sintering at a heating rate of 100 ℃/min, wherein the sintering temperature is 800 ℃, and the sintering pressure is 40 Mpa; the holding time is preferably 10 min. And cooling to room temperature after heat preservation is finished, thus obtaining the copper alloy carbon nanotube composite material.

EXAMPLE 41

s1, premixing: uniformly mixing copper alloy carbon nanotube composite powder and copper powder in a weight ratio of 1: 1;

s2, sintering: putting the uniformly mixed powder into a die, and sintering at a heating rate of 100 ℃/min, wherein the sintering temperature is 800 ℃, and the sintering pressure is 40 Mpa; the holding time is 10 min. And after the heat preservation is finished, the temperature is returned to the room temperature, and the copper alloy carbon nanotube composite material is obtained.

Example 42

s2, prepressing: putting the uniformly mixed composite powder into a mold, then placing the mold under a press machine, pressurizing to 300Mpa, maintaining the pressure for 4 minutes, pressing into a pre-pressed block body and taking out;

s3, electroplating: placing the prepressing block in an electro-coppering solution to carry out electro-coppering on the prepressing block, so that an electro-coppering layer is formed on the surface of the composite powder in the prepressing block, and taking out the prepressing block to be dried after the electro-coppering is finished; the copper electroplating bath and the copper electroplating process are prior art and will not be described in detail in this application. Fig. 5 is a scanning electron microscope photograph of the pre-pressed bulk after the copper electroplating, which clearly shows that a large amount of carbon nanotubes are wrapped by the electroplated copper.

S4, sintering: placing the electroplated prepressing block into a mould, and sintering at a heating rate of 100 ℃/min, wherein the sintering temperature is 800 ℃, and the sintering pressure is 40 Mpa; the holding time is 10 min. And cooling to room temperature after heat preservation is finished, thus obtaining the copper alloy carbon nanotube composite material.

Example 43

Similar to example 40, but in step S1, the pressure was increased to 200MPa, and the pressure was maintained for 6 minutes to press a pre-pressed block and taken out.

Example 44

Similar to example 40, but in step S1, the pressure was increased to 400MPa, and the pressure was maintained for 2 minutes to press a pre-pressed block and taken out.

Example 45

Similar to example 40, but in step S3, the electroplated pre-pressed block was placed in a mold and sintered at a temperature rise rate of 60 ℃/min, wherein the sintering temperature was 700 ℃ and the sintering pressure was 50 Mpa; the holding time is preferably 30 min.

Example 46

Similar to example 40, but in step S3, the electroplated pre-pressed block was placed in a mold and sintered at a temperature-increasing rate of 120 ℃/min, wherein the sintering temperature was 900 ℃ and the sintering pressure was 30 Mpa; the incubation time is preferably 5 min.

Example 47

Similar to example 41, but in step S1, the copper alloy carbon nanotube composite powder and the copper silver alloy powder were mixed uniformly at a weight ratio of 1: 2.

Example 48

Similar to example 41, but in step S2, sintering was carried out at a temperature rise rate of 70 ℃/min, wherein the sintering temperature was 700 ℃ and the sintering pressure was 50 MPa; the holding time is preferably 30 min.

Example 49

Similar to example 41, but in step S1, sintering was carried out at a temperature rise rate of 120 ℃/min, wherein the sintering temperature was 900 ℃ and the sintering pressure was 30 MPa; the incubation time is preferably 5 min.

Example 50

Similar to example 42, but in step S1, the copper alloy carbon nanotube composite powder and the copper powder were mixed uniformly at a weight ratio of 2: 1.

Example 51

Similar to example 42, but in step S2, the pressure was increased to 200MPa, and the pressure was maintained for 6 minutes to press a pre-pressed block and taken out.

Example 52

Similar to example 42, but in step S2, the pressure was increased to 400MPa, and the pressure was maintained for 2 minutes to press a pre-pressed block and taken out.

Example 53

Similar to example 42, but in step S4, sintering was carried out at a temperature rise rate of 60 ℃/min, wherein the sintering temperature was 700 ℃ and the sintering pressure was 50 MPa; the holding time is preferably 30 min.

Example 54

Similar to example 42, but in step S4, sintering was carried out at a temperature rise rate of 120 ℃/min, wherein the sintering temperature was 900 ℃ and the sintering pressure was 30 MPa; the incubation time is preferably 5 min.

The above-mentioned embodiments only express a certain implementation mode of the present invention, and the description thereof is specific and detailed, but not construed as limiting the scope of the present invention; it should be noted that, for those skilled in the art, without departing from the concept of the present invention, several variations and modifications can be made, which are within the protection scope of the present invention; therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The copper alloy carbon nanotube composite powder is characterized in that: the carbon nano tubes are distributed on the surface of the composite powder, the composite powder is prepared by chemical vapor deposition of copper alloy powder, and the copper alloy powder at least contains at least one of aluminum, chromium, iron, manganese and rhenium; the total content of one or more components of the elements of aluminum, chromium, iron, manganese and rhenium is 0.05 to 1 percent by weight.

2. The preparation method of the copper alloy carbon nanotube composite powder according to claim 1, wherein the carbon nanotubes are multi-walled carbon nanotubes, and the average diameter of the multi-walled carbon nanotubes is 10 to 35 nm.

3. The method for preparing the copper alloy carbon nanotube composite powder according to claim 1 or 2, comprising:

4. The method for preparing copper alloy carbon nanotube composite powder according to claim 3, characterized in that: in the step S1, the weight ratio of the copper alloy powder to the cuprous oxide powder is (50-200): 1.

5. The method for preparing copper alloy carbon nanotube composite powder according to claim 4, characterized in that: in step S3, the carbon source includes at least one of ethylene, acetylene, and methane.

6. The method for preparing copper alloy carbon nanotube composite powder according to claim 5, characterized in that: the flow ratio of the hydrogen and the carbon source introduced into the S3 is (20-80): 1.

7. The method for preparing the copper alloy carbon nanotube composite powder according to claim 1 or 2, comprising:

step S3, when the heat preservation time of the step S2 is up, keeping introducing hydrogen, adjusting the heating temperature to 700-900 ℃, then introducing a carbon source and keeping for 5-60 min; the carbon source comprises at least one of ethylene, acetylene and methane;

8. The method for preparing copper alloy carbon nanotube composite powder according to claim 7, characterized in that: the flow ratio of the protective gas and the oxygen introduced into the S1 is (100-3000): 1.

9. The method for preparing copper alloy carbon nanotube composite powder according to claim 8, wherein: the flow ratio of the hydrogen and the carbon source introduced into the S3 is (20-80): 1.

10. An application of the copper alloy carbon nanotube composite powder prepared by the preparation method of the copper alloy carbon nanotube composite powder according to any one of claims 3 to 9 is characterized in that: and preparing the copper alloy carbon nanotube composite material from the copper alloy carbon nanotube composite powder by adopting a powder metallurgy method.