CN112126984A

CN112126984A - Porous copper-based whisker material

Info

Publication number: CN112126984A
Application number: CN202011113774.7A
Authority: CN
Inventors: 左海珍
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-10-17
Filing date: 2020-10-17
Publication date: 2020-12-25

Abstract

The invention provides a high specific surface area copper whisker material, which is prepared by obtaining porous copper with high specific surface area by a chemical-electrochemical corrosion alloy removing method, then obtaining a tungsten sulfide layer on the porous surface by a method of burning tungsten sulfide by pulse laser, and effectively controlling the speed and the size of in-situ growth of copper whiskers on the surface of the porous copper by improving the time and the temperature of a high-temperature reduction process.

Description

Porous copper-based whisker material

Technical Field

The invention relates to the field of preparation of copper whiskers, and particularly relates to a preparation method for preparing copper whiskers on the surface of porous copper.

Technical Field

First, regarding whiskers: a whisker is a naturally occurring or artificially synthesized fiber that grows in the form of a single crystal, with a small diameter, on the order of microns. The whisker has less defects, the strength of the whisker is close to the theoretical value of a complete crystal, and the mechanical strength of the whisker is equal to the force between adjacent atoms. The highly oriented structure of the whisker not only enables the whisker to have high strength, high modulus and high elongation, but also has electric, optical, magnetic, dielectric and super-conductive properties. The strength of the whisker is far higher than that of other chopped fibers, and the whisker is mainly used as a reinforcement of a composite material and used for manufacturing a high-strength composite material.

Whiskers can be classified into two major classes, organic whiskers and inorganic whiskers. The organic whisker mainly comprises several types such as cellulose whisker, poly (butyl acrylate-styrene) whisker, poly (4-hydroxybenzene methyl ester) whisker (PHB whisker) and the like, and is widely applied to polymers. The inorganic whiskers mainly include ceramic whiskers (SiC, potassium titanate, aluminum borate, etc.), inorganic salt whiskers (calcium sulfate, calcium carbonate, etc.), metal whiskers (copper, iron, nickel, tin, aluminum oxide, zinc oxide, etc.), and the like. The ceramic-based whiskers and the inorganic salt whiskers can be applied to a plurality of fields such as ceramic composite materials, polymer composite materials and the like. The metal whisker is mainly applied to improving the metal strength or metal matrix composite materials.

The preparation method of the copper whisker is less, and the method is mainly a chemical solution method which is reported at present, needs to use a large amount of chemical reagents, and has slower whisker growth.

Refer to patent literature: the Shanghai microsystems and information technology research institute of CN201810468715A Chinese academy of sciences provides a preparation method of copper whiskers, which comprises the following steps: 1) providing a copper substrate, and placing the copper substrate in a sulfur source solution for a sulfurization reaction to form a copper sulfide on the surface of the copper substrate; 2) cleaning and drying the copper base material with the copper sulfide on the surface; 3) and placing the copper substrate with the copper sulfide on the surface in a reducing atmosphere to perform a reduction reaction so as to grow and form copper whiskers on the surface of the copper substrate. The invention relates to a hydrocarbon electrode prepared by electrochemical reduction of carbon dioxide and preparation and application thereof, and belongs to the institute of chemical and physical research of the university of the Chinese academy of sciences CN201410310490, wherein the electrode consists of a substrate layer, a thin film layer consisting of porous copper nanoparticles and an ordered layer; a thin film layer composed of porous nano particles is attached to the outer surface of the flaky substrate layer, and a copper whisker layer is attached to the surface of the thin film layer composed of the porous copper nano particles; the thickness of the substrate layer is 100-500 μm; the thickness of the porous nano film layer is 100-200 mu m; the thickness of the copper whisker layer is about 100 nm-500 mu m. The electrode with the structure effectively increases the reaction active area, improves the mass transfer of reactants, and is beneficial to reducing the reaction polarization resistance and the mass transfer polarization resistance, thereby improving the conversion efficiency of CO 2; the selectivity of the ERC reaction product can be improved by regulating and controlling active substances with different morphologies; this structure can improve the stability of the Cu metal, thereby improving the lifetime of the ERC reaction catalyst. From the above, it can be seen that the existence of copper whiskers can broaden the performance of the metal substrate to a certain extent, for example, in the CN201810468715A patent, the growth of whiskers on copper wires, copper plates, copper powders, etc. can be realized by using different copper substrates, and the performance of the substrate is enhanced or expanded, specifically, in the CN201410310490 patent, the reaction active area is effectively increased, the mass transfer of reactants is improved, and the reduction of reaction polarization resistance and mass transfer polarization resistance is facilitated, that is, the whiskers can improve the contact sites of copper base.

Next, with respect to the porous metal: the porous metal is a porous material with a large number of directional or random holes dispersed therein, and the diameter of the holes is between about 2um and 25 mm. The porous metal material not only retains the conductivity, ductility, weldability and the like of the metal material, but also has the excellent characteristics of small specific gravity, large specific surface area, high specific strength, energy absorption, shock absorption, noise reduction, electromagnetic shielding, low heat conductivity and the like, and the conventional hierarchical porous material mainly comprises a micropore-mesopore material, a micropore-macropore material, a macropore-mesopore material, a micropore-mesopore-macropore material and a mesopore-mesopore material containing two or more different pore diameters. The main preparation methods comprise a template method, a hydrothermal method, a foaming method, a sol-gel method, a molten salt method and the like, and because the method usually relates to a chemical synthesis method in the synthesis process, the preparation steps are multiple, and the process is complex, the synthesis cost of the existing hierarchical pore material is high, the pore structure control difficulty is large, the process stability is poor, and the large-scale production is difficult. The dealloying method utilizes the potential difference of electrodes of different metal elements in the multi-element alloy to carry out free corrosion in electrolyte solutions such as acid and alkali or promote corrosion to remove relatively active components in the electrolyte solutions by applying voltage, and relatively inert components are reserved to form a bicontinuous open porous structure. The method is simple, convenient and feasible, is easy to repeat, is suitable for preparing the nano porous material on a large scale, and can realize the control of the pore diameter/pore wall size distribution of the porous material by controlling the processes of corrosion, subsequent heat treatment and the like.

Such as the patent: the method comprises the steps of mixing and tabletting nickel-aluminum powder in a certain proportion, smelting the mixture into a porous alloy membrane in a sintering mode, and chemically corroding the porous alloy membrane to form a microporous shape inside the porous alloy membrane, wherein the nickel-aluminum alloy is corroded by sodium hydroxide to form a nanopore structure with high specific surface area and high catalytic activity, so that the membrane separation and electrocatalysis function integration are realized without adding a supported catalyst, the treatment capacity of the alloy membrane on dye wastewater is greatly improved, the decolorization rate of the alloy membrane under the maximum flux is increased from 55% to more than 95%, the pore diameter of the prepared porous alloy membrane is distributed between 5 and 20 micrometers, and the specific surface area is 10-40 m 2/g. The specific surface area of the patent is to be improved, and the inventor describes a porous nickel-supported perovskite catalyst in the same series on the same day, wherein the pore diameter of the porous nickel is distributed between 5 and 30 mu m, and the specific surface area is 30 to 60m²The main reason why/g, porosity 50-70%, CN201810567439 is inferior to porous nickel prepared by dealloying of the present inventors is that the dealloying method is different, and furthermore, the specific surface area obtained by preliminary and deep dealloying is 30-60m²G, although sufficiently high, the specific surface area decreases significantly after loading the catalytically active component, e.g. 20 to 50m after loading the perovskite²There is a significant reduction in/g, and therefore there is a need for further improvements in the specific surface area of porous copper-based materials.

Disclosure of Invention

In view of the defects of the prior art, the invention provides a copper whisker material with high specific surface area aiming at the defects of the specific surface area of a de-alloying material. The material has popularization significance for preparing a porous metal catalyst carrier with high specific surface area, and the specific contents are as follows:

the specific surface area of the porous copper-based whisker material is 50-80m²The porous copper-based whisker material consists of a porous copper base and copper whiskers, wherein the copper whiskers grow on the pore walls of the porous copper in situ, the porous copper is obtained by dealloying treatment, the pore size distribution of the porous copper is 5-30 mu m, and the specific surface area is 30-60m²The porosity is 50-70%, wherein the copper whisker is obtained by pulse laser burning and high-temperature treatment.

Further, the dealloyed raw material is a Ni-Al alloy body, and the preparation process of the Ni-Al alloy body is as follows: (a) uniformly mixing 30-40wt.% of 1-5 mu m nickel powder and 60-70wt.% of 5-10 mu m aluminum powder, pressing and forming at 300-400Mpa, and sintering at 1300-1400 deg.C in inert atmosphere or reducing atmosphere^oC, high-temperature lasting for 1-3h, naturally cooling, and keeping the pressure for the compression molding for 5-10 min; the inert atmosphere is N₂The reducing atmosphere is H₂(ii) a Temperature programming rate of the high temperature sintering 10^oC/min。

Further, the dealloying treatment comprises chemical alkaline corrosion preliminary dealloying and electrochemical acid corrosion deep dealloying.

Further, the corrosive liquid used for the preliminary dealloying in the chemical alkaline corrosion is 1-2M NaOH aqueous solution, the corrosion time is 12-24h, and the temperature is 30-35^oAnd C, removing bubbles by ultrasonic assistance in the corrosion process, and washing with deionized water for multiple times after corrosion.

Further, the electrochemical acid liquor corrosion deep dealloying process is as follows: the copper material which is primarily de-alloyed by the corrosion of chemical alkali liquor is taken as an anode, and a Pt sheetAs cathode, 0.6-0.7M HNO₃The corrosion voltage is 0.3-0.5V, the corrosion time is 2-3h, and the electrochemical corrosion temperature is normal temperature.

Further, the dealloying treatment is followed by drying and reduction treatment, wherein the drying process is repeated washing with ethanol-deionized water alternately to remove the corrosive liquid, and vacuum drying is performed, wherein the reduction process is performed at 5vol.% of H₂/N₂Then, reduction treatment is carried out in a tube furnace for 60-90 min.

Further, the process of the pulse laser cauterization is as follows: and placing the porous copper obtained through drying and reduction treatment as a substrate in a vacuum chamber, focusing a laser beam on the tungsten sulfide target material by using Nd-YAG laser after passing through a total reflection mirror and a focusing lens to generate a photoablation reaction, melting and evaporating a target material plume, and depositing the plume on the surface of the porous copper material.

Further, the parameters of the pulse laser cauterizing the tungsten sulfide are as follows: YAG laser with laser beam wavelength of 525nm, maximum output single pulse energy of 50mj, repetition frequency of 100Hz, light spot of 1mm, and vacuum degree less than x 10^-6Torr at a temperature of 200-^oC, preferably 250^oC, the pulse laser burning time is 30-50 min; the distance between the tungsten sulfide target and the substrate is 2cm, and the tungsten sulfide WS₂The purity of (A) is more than 99.9%.

Further, the high-temperature treatment parameters are as follows: the temperature programmed at 10/min is increased to 500-^oC, keeping the temperature for 1-5H, naturally cooling to room temperature, and keeping the high-temperature atmosphere at 0.5vol.% H₂Mixed gas of/He.

Furthermore, the porous copper-based whisker material is blocky and non-powder.

The specific process for preparing the copper whisker material with high specific surface area is further explained as follows:

(1) preparing a Cu-Al alloy block;

(a) uniformly and physically mixing 30-40wt.% of 1-5 mu m copper powder and 60-70wt.% of 5-10 mu m aluminum powder;

(b)300-400 Mpa;

(c) sintering at high temperature under inert atmosphere or reducing atmosphere, wherein the sintering temperature is 800-950^oC, high temperature lasting for 1-3h, natural cooling,

the pressure maintaining time for press forming is 5-10 min; the inert atmosphere is N₂The reducing atmosphere is H₂(ii) a Temperature programming rate of the high temperature sintering 10^oC/min。

This step should be noted:

the proportion and the size of copper and aluminum powder directly influence the pore size distribution, the specific surface area and the porosity of porous copper obtained subsequently, and the invention has the following limited range: 30-40wt.%1-5 μm copper powder, 60-70wt.%5-10 μm aluminium powder, preferably 33-38wt.% 2-3 μm copper powder, 62-68wt.%,7-8 μm aluminium powder, most preferably 35wt.% 2-3 μm copper powder, 65wt.%,7-8 μm aluminium powder.

The three-dimensional porous catalyst has certain compressibility and deformability, the volume and the size of the three-dimensional porous catalyst are larger than or equal to the size of the reactor, the exceeding range is not higher than 10 percent and cannot be lower than the size or the volume of the reactor, otherwise, the reactor has poor tightness, and reaction gas cannot effectively contact the catalyst.

Thirdly, the impurity degree and the stability of the alloy are determined by the sintering atmosphere, if oxygen is mixed, the state of the Cu-Al alloy is obviously influenced, and the influence of oxides on the state of the alloy is also obviously influenced.

And fourthly, the sintering temperature mainly influences the specific form of the alloy.

(2) Preliminary dealloying by chemical lye corrosion: the corrosive liquid used for preliminary dealloying by chemical alkaline corrosion is 1-2M NaOH aqueous solution, the corrosion time is 12-24h, and the temperature is 30-35^oAnd C, removing bubbles by ultrasonic assistance in the corrosion process, and washing with deionized water for multiple times after corrosion.

The primary de-alloying is mainly based on electroless corrosion, mainly based on the following considerations:

firstly, preliminary dealloying is electroless corrosion, namely, the electroless corrosion is completely eliminated, the electroless corrosion is mainly used for taking the electrified corrosion as an anode, and the Ni-Al alloy is used in the invention, wherein Al does not have corrosion reaction, but forms alumina due to anodic oxidation, or forms an oxide film on the Ni-Al alloy, thus not only a corrosion pore channel can not be formed, but also a protective film can be formed.

Secondly, the corrosive liquid of the electroless corrosion for preliminary alloy removal is sodium hydroxide, Al is known to be an amphoteric compound, both acid and alkali can carry out corrosion reaction, and the problem of selective corrosion is considered by only selecting the sodium hydroxide, so that only the Al in the sodium hydroxide is corroded, but not the Cu is corroded, and the corrosion is very important for the formation of the uniformity of the three-dimensional pore channel.

And thirdly, in the corrosion process, the reaction of aluminum and sodium hydroxide can generate hydrogen which can not be captured by naked eyes, and the ultrasonic wave of the hydrogen can obstruct the contact of the sodium hydroxide and the aluminum, so that the ultrasonic assistance must be added in the electroless corrosion process, and the diffusion and the separation of small bubbles are facilitated.

Fourthly, the concentration, the time and the temperature in the electroless corrosion process are obtained through orthogonal experiments, and the porous nickel aluminum material carrier is preliminarily obtained for optimizing the range.

(3) Deep dealloying by electrochemical acid corrosion: the obtained copper material is used as an anode, a Pt sheet is used as a cathode, and 0.6-0.7M HNO is used₃The corrosion voltage is 0.3-0.5V, the corrosion time is 2-3h, and the electrochemical corrosion temperature is normal temperature.

Attention is paid to:

the electrochemical corrosion is positioned after the electroless corrosion, and the steps can not be randomly reversed.

The electrochemical corrosion liquid is acid liquid, which can be sulfuric acid, nitric acid, phosphoric acid and oxalic acid, and the nitric acid is preferably selected in consideration of corrosion effect and corrosion rate, in addition, the acid liquid is adopted for corrosion in the electrochemical corrosion process, so that the preparation steps of the catalyst carrier can be reduced, namely, the preliminary corrosion and the deep corrosion directly do not need any cleaning and drying treatment, and certainly, if the steps of water cleaning and air drying can be carried out on the preliminary corrosion copper and aluminum materials, and repeated for multiple times, the porous structure obtained by the subsequent deep corrosion is the best, but for convenience of operation, the acid liquid can be selected to directly neutralize the alkali corrosion liquid to remove the adhesive film on the surface of the nickel-aluminum alloy.

And thirdly, the electrochemical corrosion is preferred because the aluminum can be removed by the electroless corrosion but can not be completely removed, at least within 12-24h of the invention, the aluminum can not be effectively removed by the electroless corrosion, and the existence of the aluminum can obviously reduce the porosity of a three-dimensional pore channel structure, so that the residual aluminum can be effectively removed by the subsequent electrochemical corrosion, and further, mesopores are effectively formed, the generation of the mesopores is favorable for improving the specific surface area of the porous nickel, and the pore size distribution of the obtained porous nickel is 5-30 μm, the specific surface area is 30-60m2/g, and the porosity is 50-70%.

The concentration and the voltage of the corrosive acid liquid are lower, the time is shorter, and the consideration of preventing the anodic oxidation of the aluminum is based on the premise of effective corrosion.

(4) Drying and reducing: the drying process comprises the steps of removing the corrosive liquid by using ethanol-deionized water for multiple times of alternate washing, and drying in vacuum, wherein the reduction process is that H accounts for 5vol.% in₂/N₂Then, reduction treatment is carried out in a tube furnace for 60-90 min.

The obtained porous material is a porous copper material, and due to the fact that numerous tiny mesopores are formed through electrochemical dealloying, acid liquor in the mesopores cannot be effectively discharged, and if the acid liquor cannot be effectively discharged, the subsequent copper whisker in-situ growth is directly influenced by N elements in nitric acid; therefore, the etching solution, especially the acid solution in the mesopores, is removed by multiple alternate washing with ethanol and deionized water, the number of cyclic washing is 2-5 and preferably 4, and the cyclic washing is accompanied by vacuum drying, and common air furnace drying is not available to prevent the oxidation of the porous copper, and then the reduction is carried out by using a tubular furnace for removing the copper oxygen synovium caused by improper operation in the previous step.

(5) And using the porous copper as a substrate, and burning tungsten sulfide by using pulse laser;

the pulse laser cauterization PLD is characterized in that pulse laser is guided into a vacuum cavity through a synthetic quartz window to irradiate a film-forming target, the target absorbs high-density energy after irradiation to form a plume-shaped plasma state, then the plume-shaped plasma state is accumulated on a substrate arranged on the opposite side, the plasma state obtained through high energy can be uniformly distributed on the surface of a porous copper material, an excellent foundation is laid for in-situ growth of copper whiskers, and a pulse laser deposition system (PLD) is specifically configured with an ultrahigh vacuum cavity, a molecular pump, a laser scanning system, a substrate heating platinum sheet, a substrate heating structure design and a substrate heating power supply.

As for the laser source, Nd: YAG laser or Pr: YAG laser can be selected without any significant limitation, and the selected wavelength should be 525nm, which is determined by absorption spectrum, and 1046nm wavelength cannot be used, and the maximum single pulse energy output is 50mj and the spot is 1mm at a repetition frequency of 100Hz, and the vacuum degree is less than x 10^-6Under Torr conditions, WS2 ablation can produce a plasma plume evenly distributed over the surface of the porous substrate. .

With respect to temperature, the selection range is 200-300^oC, the PLD temperature range is the first key factor for the growth of subsequent whiskers, such as 200^oThe number of whiskers under C is less than 300^oThe number of whiskers under C, in contrast, was determined using room temperature PLD and 300^oThe effect of the CPLD is most obvious, and meanwhile, within a certain range, the higher the temperature is, the higher the obtained whisker value is, the more the PLD temperature is optimally 250^oC, PLD has a significant effect on the subsequent whisker growth, possibly related to the distribution of WS2 in porous copper.

(6) And (4) carrying out high-temperature treatment to obtain the porous copper-based whisker material.

High-temperature treatment parameters: the temperature programmed at 10/min is increased to 500-^oC, keeping the temperature for 1-5H, naturally cooling to room temperature, and keeping the high-temperature atmosphere at 0.5vol.% H₂Mixed gas of/He.

The temperature range is the second key factor of whisker growth, and only the temperature reaches 800+ under the condition of not introducing reducing gas^oThe crystal whisker can be obtained by C, but the requirement on equipment is high, such as the currently common equipment is not higher than 1000^oC, while introducing a very small amount of reducing gas, can significantly lower the temperature point of whisker formation, introducing 0.5vol.% H₂The mixed gas of the/He can effectively reduce the forming temperature of the crystal whisker at 500+^oThe whiskers can be obtained by C.

The time range is a third key factor, the shorter the time is, the smaller the length and width of the whisker is, the longer the time is, the larger the length-width ratio of the whisker is, and the number of the whiskers is obviously increased and decreased along with the increase of the time.

By controlling the PLD temperature and the temperature and time during the high-temperature treatment as described above, the number and aspect ratio of whiskers can be obtained, the whisker heterochronologically grows the contact area of the porous copper significantly increased, the specific surface area of the material is significantly increased, and the whisker is advantageous for the application as a catalyst carrier in industry, thereby providing infinite possibilities for the expanded application of the porous copper.

In addition, with respect to the selection of copper as a base material, through a plurality of attempts, it is found that only copper material is easy to control the growth of whiskers, and other metals, such as nickel, can not obtain the expected whisker growth and specific surface area increase.

The scheme of the invention has the following beneficial effects:

(1) the invention obtains three-dimensional porous copper material by electroless preliminary dealloying and charged deep dealloying treatment, the obtained macropores and mesopores provide sufficient places for subsequent active site loading and catalytic reaction, the pore diameter of the porous copper is distributed between 5 and 30 mu m, and the specific surface area is 30 to 60m²G, porosity 50-70%.

(2) Through the subsequent laser pulse laser burning tungsten sulfide treatment process, tungsten sulfide can be fully and uniformly distributed on the surface of the porous copper material, and a favorable place is provided for uniform growth of copper whiskers.

(3) The in-situ growth of the whiskers effectively increases the contact area of the porous copper and fully enlarges the specific surface area of the material, and when the copper whiskers are added in situ in the porous copper, the specific surface area of the catalyst carrier is increased to 50-80m²/g。

(4) The porous copper-based whisker material can be used as a carrier of a catalyst, the metal characteristics of the porous copper-based whisker material determine that the thermal conductivity of the catalyst carrier is high, the metal characteristics of the porous copper-based whisker material determine that the catalyst carrier can effectively avoid the hot spot problem of a catalyst bed layer, avoid inactivation, be beneficial to the stability of the catalyst, and the metal carrier has high mechanical strength and meets the basic requirements of a massive catalyst carrier.

(5) Through alloying treatment, when the material is used as a block material, the material has adjustable shape and structure, strong applicability, high mechanical property of the carrier and high compressive strength of the catalyst.

Drawings

Fig. 1 an optical macroscopic view of porous copper material obtained after preliminary dealloying-deep dealloying.

Figure 2 SEM image of in situ grown copper whisker catalyst support in porous copper.

FIG. 3 PLD200^oC. High temperature processing 500^oC, SEM image of the porous copper whisker material obtained after treatment time of 15 m.

FIG. 4 PLD250^oC. High temperature processing 600^oAnd C, SEM image of the porous copper whisker material obtained after treatment for 3 h.

FIG. 5 PLD300^oC. High temperature processing 700^oAnd C, SEM image of the porous copper whisker material obtained after treatment for 5 h.

Detailed Description

Example 1

A high specific surface area copper whisker material is characterized by comprising the following processing steps:

(1) preparing a Cu-Al alloy block: (a) uniformly and physically mixing 30wt.% of 2-3 mu m copper powder and 60wt.% of 7-8 mu m aluminum powder, (b) pressing and forming under 300Mpa, (c) sintering at high temperature of 800 ℃ under inert atmosphere or reducing atmosphere^oC, keeping the temperature for 1h, and naturally cooling, wherein the pressure maintaining time of the compression molding is 5 min; the inert atmosphere is N₂The reducing atmosphere is H₂(ii) a Temperature programming rate of the high temperature sintering 10^oC/min。

(2) Preliminary dealloying by chemical lye corrosion: the used corrosive liquid is 1M NaOH aqueous solution, the corrosion time is 12h, and the temperature is 30^oAnd C, removing bubbles by ultrasonic assistance in the corrosion process, and washing with deionized water for multiple times after corrosion.

(3) Deep dealloying by electrochemical acid corrosion: taking the copper material obtained in the step (2) as an anode, taking a Pt sheet as a cathode and taking 0.6M HNO₃The corrosion voltage is 0.3V, the corrosion time is 2h, and the electrochemical corrosion temperature is normal temperature.

(4) Drying and reducing: the drying process comprises alternately washing with ethanol-deionized water for several times to remove corrosive liquid, and vacuum dryingDrying; the reduction process was at 5vol.% H₂/N₂Then, reduction treatment was carried out in a tube furnace for 60 min.

(5) And (3) taking the porous copper obtained in the step (4) as a substrate, and performing pulse laser burning on tungsten sulfide: YAG laser is used to focus laser beam on the tungsten sulfide target material after passing through a holophote and a focusing lens, a photoablation reaction occurs, a target material plume is evaporated by melting and deposited on the surface of the porous copper material, and the parameters of tungsten sulfide are burned by pulse laser: YAG laser with wavelength of 525nm, maximum output single pulse energy of 50mj, repetition frequency of 100Hz and light spot of 1mm; vacuum degree less than x 10^-6Torr, temperature 200^oC, the pulse laser burning time is 30 min; the distance between the tungsten sulfide target and the substrate is 2 cm.

(6) And (3) obtaining the porous copper-based whisker material by high-temperature treatment: the temperature programmed at high temperature is increased to 500 ℃ from 10/min^oC, keeping the temperature for 1H, naturally cooling to room temperature, and keeping the high-temperature atmosphere at 0.5vol.% H₂Mixed gas of/He.

Finally, the porous copper-based whisker material is in a block shape and is not powder, and the tungsten sulfide WS is₂The purity of (A) is more than 99.9%.

Example 2

(1) preparing a Cu-Al alloy block: (a) the preparation method comprises the following steps of (a) physically and uniformly mixing 35wt.% of 2-3 mu m copper powder and 65wt.% of 7-8 mu m aluminum powder, (b) press forming under 350Mpa, (c) high-temperature sintering under inert atmosphere or reducing atmosphere, wherein the sintering temperature is 900 DEG C^oC, the high temperature lasts for 2h, and the product is naturally cooled, wherein the pressure maintaining time of the compression molding is 8 min; the inert atmosphere is N₂The reducing atmosphere is H₂(ii) a Temperature programming rate of the high temperature sintering 10^oC/min。

(2) Preliminary dealloying by chemical lye corrosion: the used corrosion solution is 1.5M NaOH aqueous solution, the corrosion time is 18h, and the temperature is 33^oAnd C, removing bubbles by ultrasonic assistance in the corrosion process, and washing with deionized water for multiple times after corrosion.

(3) Deep dealloying by electrochemical acid corrosion: taking the copper material obtained in the step (2) as an anode, taking a Pt sheet as a cathode and taking 0.65M HNO₃The corrosion voltage is 0.4V, the corrosion time is 2.5h, and the electrochemical corrosion temperature is normal temperature.

(4) Drying and reducing: the drying process comprises alternately washing with ethanol-deionized water for several times to remove corrosive liquid, and vacuum drying; the reduction process was at 5vol.% H₂/N₂Then, the mixture was reduced in a tube furnace for 75 min.

(5) And (3) taking the porous copper obtained in the step (4) as a substrate, and performing pulse laser burning on tungsten sulfide: YAG laser is used to focus laser beam on the tungsten sulfide target material after passing through a holophote and a focusing lens, a photoablation reaction occurs, a target material plume is evaporated by melting and deposited on the surface of the porous copper material, and the parameters of tungsten sulfide are burned by pulse laser: YAG laser with wavelength of 525nm, maximum output single pulse energy of 50mj, repetition frequency of 100Hz and light spot of 1mm; vacuum degree less than x 10^-6Torr, temperature 250^oC, the pulse laser burning time is 40 min; the distance between the tungsten sulfide target and the substrate is 2 cm.

(6) And (3) obtaining the porous copper-based whisker material by high-temperature treatment: the temperature programmed at high temperature is increased to 600 ℃ from 10/min^oC, keeping the temperature for 3 hours, naturally cooling to room temperature, and keeping the high-temperature atmosphere at 0.5vol.% H₂Mixed gas of/He.

Is named as S.

Example 3

(1) preparing a Cu-Al alloy block: (a) uniformly mixing 30-40wt.% of 2-3 mu m copper powder and 60-70wt.% of 7-8 mu m aluminum powder, pressing and molding under 400Mpa, and sintering at high temperature of 950 ℃ in inert atmosphere or reducing atmosphere^oC, high temperature lasting for 3 hours, natural cooling,wherein the dwell time for the press forming is 10 min; the inert atmosphere is N₂The reducing atmosphere is H₂(ii) a Temperature programming rate of the high temperature sintering 10^oC/min。

(2) Preliminary dealloying by chemical lye corrosion: the used corrosive liquid is 2M NaOH aqueous solution, the corrosion time is 24h, and the temperature is 35^oAnd C, removing bubbles by ultrasonic assistance in the corrosion process, and washing with deionized water for multiple times after corrosion.

(3) Deep dealloying by electrochemical acid corrosion: taking the copper material obtained in the step (2) as an anode, taking a Pt sheet as a cathode and taking 0.7M HNO₃The corrosion voltage is 0.5V, the corrosion time is 3h, and the electrochemical corrosion temperature is normal temperature.

(4) Drying and reducing: the drying process comprises alternately washing with ethanol-deionized water for several times to remove corrosive liquid, and vacuum drying; the reduction process was at 5vol.% H₂/N₂Then, reduction treatment was carried out in a tube furnace for 90 min.

(5) And (3) taking the porous copper obtained in the step (4) as a substrate, and performing pulse laser burning on tungsten sulfide: YAG laser is used to focus laser beam on the tungsten sulfide target material after passing through a holophote and a focusing lens, a photoablation reaction occurs, a target material plume is evaporated by melting and deposited on the surface of the porous copper material, and the parameters of tungsten sulfide are burned by pulse laser: YAG laser with wavelength of 525nm, maximum output single pulse energy of 50mj, repetition frequency of 100Hz and light spot of 1mm; vacuum degree less than x 10^-6Torr, temperature 300^oC, the pulse laser burning time is 50 min; the distance between the tungsten sulfide target and the substrate is 2 cm.

(6) And (3) obtaining the porous copper-based whisker material by high-temperature treatment: the temperature programmed at high temperature is increased to 700 from 10/min^oC, keeping the temperature for 1-5H, naturally cooling to room temperature, and keeping the high-temperature atmosphere at 0.5vol.% H₂Mixed gas of/He.

Comparative example 1

(2) Deep dealloying by electrochemical acid corrosion: the obtained copper material is used as an anode, a Pt sheet is used as a cathode, and 0.65M HNO is used₃The corrosion voltage is 0.4V, the corrosion time is 2.5h, and the electrochemical corrosion temperature is normal temperature.

(3) Preliminary dealloying by chemical lye corrosion: the used corrosion solution is 1.5M NaOH aqueous solution, the corrosion time is 18h, and the temperature is 33^oAnd C, removing bubbles by ultrasonic assistance in the corrosion process, and washing with deionized water for multiple times after corrosion.

(6) Height ofAnd (3) performing warm treatment to obtain a porous copper-based whisker material: the temperature programmed at high temperature is increased to 600 ℃ from 10/min^oC, keeping the temperature for 3 hours, naturally cooling to room temperature, and keeping the high-temperature atmosphere at 0.5vol.% H₂Mixed gas of/He.

Is named D-1.

Comparative example 2

(1) carrying out oil removal pretreatment by taking commercial foam copper as a base material;

(2) using foamed copper as a substrate, and performing pulse laser burning on tungsten sulfide: YAG laser is used to focus laser beam on the tungsten sulfide target material after passing through a holophote and a focusing lens, a photoablation reaction occurs, a target material plume is evaporated by melting and deposited on the surface of the porous copper material, and the parameters of tungsten sulfide are burned by pulse laser: YAG laser with wavelength of 525nm, maximum output single pulse energy of 50mj, repetition frequency of 100Hz and light spot of 1mm; vacuum degree less than x 10^-6Torr, temperature 250^oC, the pulse laser burning time is 40 min; the distance between the tungsten sulfide target and the substrate is 2 cm.

Is named D-2.

Comparative example 3

(1) preparing a Cu-Al alloy block: (a) the preparation method comprises the following steps of (a) physically and uniformly mixing 35wt.% of 2-3 mu m copper powder and 65wt.% of 7-8 mu m aluminum powder, (b) press forming under 350Mpa, (c) high-temperature sintering under inert atmosphere or reducing atmosphere, wherein the sintering temperature is 900 DEG C^oC, high temperature lasting for 2 hours, natural cooling, wherein the pressure maintaining of the compression moldingThe time is 8 min; the inert atmosphere is N₂The reducing atmosphere is H₂(ii) a Temperature programming rate of the high temperature sintering 10^oC/min。

(5) And (3) taking the porous copper obtained in the step (4) as a substrate, and performing pulse laser burning on tungsten sulfide: YAG laser is used to focus laser beam on the tungsten sulfide target material after passing through a holophote and a focusing lens, a photoablation reaction occurs, a target material plume is evaporated by melting and deposited on the surface of the porous copper material, and the parameters of tungsten sulfide are burned by pulse laser: YAG laser with wavelength of 525nm, maximum output single pulse energy of 50mj, repetition frequency of 100Hz and light spot of 1mm; vacuum degree less than x 10^-6Torr, temperature is normal temperature^oC, the pulse laser burning time is 40 min; the distance between the tungsten sulfide target and the substrate is 2 cm.

Designated as D-3.

TABLE 1 summary of specific surface area of samples

As shown in Table 1, after the S sample is subjected to preliminary and deep dealloying, the specific surface area of the obtained porous copper is 52g/g, and after the in-situ whisker treatment, the specific surface area of the S sample is increased to 76m²The preliminary and deep dealloying steps in the D-1 sample were replaced, so that the fine electrochemical step of generating mesopores did not work, and the specific surface area of the obtained porous copper was 19 m²G, the specific surface area of the D-1 sample increased to 32m through in-situ whisker growth²And/g, benefit from the mesopores generated by the staggered growth of the whiskers. D-2 sample, copper foam, having a specific surface area of only 5m²The specific surface area of the D-2 sample is increased to 9m through in-situ whisker growth²(ii)/g; compared with the PLD of D-3, the temperature is normal temperature, the whisker growth is smaller, the distribution is sparser, the obtained mesopores are less, and compared with porous copper, the specific surface area is 52m2/g, the specific surface area is only 57 m2/g, the change is not obvious.

Referring to the attached figure 1, an optical photo of a porous copper material is obtained after preliminary alloy removal and deep alloy removal, wherein the porous copper material is a three-dimensional network porous structure and is an integral block structure.

As shown in the attached figure 2, a plurality of filamentous whiskers grow in situ on the pore wall of the macropore, and the staggered growth of the whiskers obviously improves the specific surface area of the porous copper.

As shown in FIG. 3, PLD200^oC. High temperature processing 500^oC, the treatment time is 15m, and obvious in-situ convex can be found, and the copper whisker is in an initial form for growth.

As shown in FIG. 4, PLD250^oC. High temperature processing 600^oAnd C, treating for 3h to obtain an SEM image of the porous copper whisker material, and forming filament whiskers to a certain extent.

As shown in FIG. 5, PLD300^oC. High temperature processing 700^oC, processing for 5h to obtain porous copper crystalsSEM pictures of whisker material, the whiskers overgrow with time and temperature.

Although the present invention has been described above by way of examples of preferred embodiments, the present invention is not limited to the specific embodiments, and can be modified as appropriate within the scope of the present invention.

Claims

1. A copper whisker material with high specific surface area, which is characterized in that the specific surface area of the porous copper-based whisker material is 50-80m²The porous copper-based whisker material consists of a porous copper base and copper whiskers, wherein the copper whiskers grow on the pore walls of the porous copper in situ, the porous copper is obtained by dealloying treatment, the pore size distribution of the porous copper is 5-30 mu m, and the specific surface area is 30-60m²The porosity is 50-70%, wherein the copper whisker is obtained by pulse laser burning and high-temperature treatment.

2. A high surface area copper whisker material according to claim 1, wherein the dealloyed raw material is a Ni-Al alloy body prepared by the following process: (a) uniformly mixing 30-40wt.% of 1-5 mu m nickel powder and 60-70wt.% of 5-10 mu m aluminum powder, pressing and forming at 300-400Mpa, and sintering at 1300-1400 deg.C in inert atmosphere or reducing atmosphere^oC, high-temperature lasting for 1-3h, naturally cooling, and keeping the pressure for the compression molding for 5-10 min; the inert atmosphere is N₂The reducing atmosphere is H₂(ii) a Temperature programming rate of the high temperature sintering 10^oC/min。

3. The high surface area copper whisker material of claim 1, wherein the dealloying comprises chemical alkaline etching preliminary dealloying and electrochemical acid etching deep dealloying.

4. The copper whisker material with high specific surface area according to claim 3, wherein the etching solution used for the preliminary dealloying by the chemical alkaline etching is an etching solution1-2M NaOH aqueous solution, the corrosion time is 12-24h, and the temperature is 30-35^oAnd C, removing bubbles by ultrasonic assistance in the corrosion process, and washing with deionized water for multiple times after corrosion.

5. The high surface area copper whisker material of claim 4, wherein the electrochemical acid etching deep dealloying process comprises: the copper material which is primarily de-alloyed by the corrosion of chemical alkali liquor is taken as an anode, a Pt sheet is taken as a cathode, and 0.6-0.7M HNO is taken₃The corrosion voltage is 0.3-0.5V, the corrosion time is 2-3h, and the electrochemical corrosion temperature is normal temperature.

6. The high specific surface area copper whisker material of claim 3, wherein the dealloying treatment is followed by drying and reduction treatment, wherein the drying process comprises a plurality of alternate washing with ethanol-deionized water to remove the corrosive liquid, and vacuum drying, wherein the reduction process comprises 5vol.% H₂/N₂Then, reduction treatment is carried out in a tube furnace for 60-90 min.

7. The high specific surface area copper whisker material of claim 1, wherein the pulsed laser firing is carried out by the following process: and placing the porous copper obtained through drying and reduction treatment as a substrate in a vacuum chamber, focusing a laser beam on the tungsten sulfide target material by using Nd-YAG laser after passing through a total reflection mirror and a focusing lens to generate a photoablation reaction, melting and evaporating a target material plume, and depositing the plume on the surface of the porous copper material.

8. The high specific surface area copper whisker material of claim 7, wherein the pulsed laser burns tungsten sulfide with parameters: YAG laser with laser beam wavelength of 525nm, maximum output single pulse energy of 50mj, repetition frequency of 100Hz, light spot of 1mm, and vacuum degree less than x 10^-6Torr at a temperature of 200-^oC, preferably 250^oC, the pulse laser burning time is 30-50 min; the distance between the tungsten sulfide target and the substrate is 2cm, and the tungsten sulfide WS₂The purity of (A) is more than 99.9%.

9. A high surface area copper whisker material according to claim 7, wherein the high temperature processing parameters are: the temperature programmed at 10/min is increased to 500-^oC, keeping the temperature for 1-5H, naturally cooling to room temperature, and keeping the high-temperature atmosphere at 0.5vol.% H₂Mixed gas of/He.

10. A high surface area copper whisker material according to claim 1, wherein the porous copper-based whisker material is in bulk, non-powder form.