CN106064241B - A kind of preparation method of internal diameter controllable foam metal - Google Patents

Abstract

The invention discloses a method for preparing foamed metal with controllable inner diameter, which belongs to the field of integrated preparation of new structure and functional materials. The main steps are: (1) pretreatment process: cleaning, roughening and activating the substrate; (2) electroless plating process; (3) preparation of hollow spheres: placing the sample obtained by electroless plating in a strong alkali solution, removing Substrate to obtain hollow metal spheres; cleaning, filtering, and liquid-sealed storage; (4) Sintering process: laying metal nanopowder and hollow metal spheres alternately, drying, vacuuming, passing protective gas, sintering temperature 1200-1600°C, annealing The time is 2-6h; the mass ratio of the hollow metal sphere to the metal nano-powder is 5%-30%. The method obtains substrate particles with different particle diameters by controlling the roughening time, and prepares hollow metal spheres with different inner diameters. This process has the advantages of simple operation, convenience, economy, and controllable inner diameter of the spherical shell, and is especially suitable for preparing foamed metal materials or gradient multifunctional materials with different inner diameters.

Description

A kind of preparation method of metal foam with inner diameter controllable

technical field

The invention belongs to the field of integrated preparation of novel structures and functional materials, and relates to time-controlled roughening of substrates, activation treatment, chemical plating process and removal technology to obtain hollow metal balls with different inner diameters, which are then sintered into blocks by cold pressing , especially related to metal foam or gradient porous functional materials, suitable for various high-tech fields such as heat insulation, electrodes, catalysis, shock absorption, electromagnetic shielding and biomedicine.

Background technique

Metal foam is a widely researched structure-functional integration material with good physical and chemical properties, such as low density, large specific surface area, and good designability and optimizability of the fine structure of the material. Its pores are composed of closed pores in the sphere and gaps between spheres. This unique structure makes it have excellent mechanical, absorption, exchange and compound properties. It is widely used in various high-tech fields such as aerospace, aviation, environmental protection, energy and biomedicine.

At present, the methods for preparing metal foam include casting method, foaming method, sintering method and deposition method. Among them, the metal foams prepared by the first three processes have the disadvantages of uneven pore distribution and size, unremarkable mechanical properties and large discreteness; the electrochemical method in the deposition method is limited to conductive materials due to the substrate and is subject to limiting current. Density is limited, so the deposition rate is slower, the production efficiency is low, and the cost is higher. However, the electroless plating process can not only deposit metal layers on metal substrates (iron, stainless steel, aluminum, copper, etc.) nickel, iron, copper, gold, lead, etc.). There is no need for external power supply, and there is no influence of uneven distribution of electric power lines. The deposited coating is uniform, compact, has few pores, high hardness, and has excellent physical and chemical properties.

The invention combines time-controlled roughening treatment, electroless plating process and substrate removal technology to obtain a metal hollow sphere monomer with controllable inner diameter. Then, the monomeric hollow spheres are mixed with corresponding metal nanoparticles, and cold-pressed and sintered to obtain a foamed metal block. First, by controlling different roughening times, granular substrates with different particle sizes (such as silica gel desiccant, silicon dioxide, silicon) are obtained; secondly, a metal layer is prepared on a non-metallic particle substrate by electroless plating; finally, a strong Alkaline solution removes the substrate to obtain hollow metal spheres. The size of the substrate (that is, the inner diameter of the metal ball) is determined by the roughening time, and the thickness of the spherical shell is determined by the deposition time of the electroless plating. Therefore, this process has the advantages of simple operation, convenience, economy, and controllable inner diameter of the spherical shell, and is especially suitable for preparing foamed metal materials with different inner diameters.

Contents of the invention

The object of the present invention is to provide a process for obtaining a foamed metal block by combining time-controlled roughening treatment, electroless plating, substrate removal technology and cold pressing sintering. And make it used in various high-tech fields.

Technical scheme of the present invention:

A method for preparing metal foam with controllable inner diameter, the steps are as follows:

(1) Pretreatment process

A. Wash the substrate successively with acetone, ethanol and deionized water, filter and dry; the substrate is silica gel desiccant, silicon dioxide or silicon;

B. Heat the substrate and roughening agent to 50°C in a water bath, mix them, keep the temperature at 50°C, and roughen for 1-5 minutes; after the end, wash with deionized water, neutralize with ammonia water, and then wash with deionized water , filtered and dried;

C. Add the activation solution to the roughened substrate obtained in step B, activate for 5-10 minutes, stir until it is uniform, filter and dry to obtain the activated substrate;

(2) Electroless plating process

D. Put the plating solution in a constant temperature water bath and heat it to the required temperature; place the activated substrate obtained in step C in the plating solution for 1-7 minutes, then repeatedly wash with deionized water and ethanol solution, filter and dry at low temperature Dry, the purpose is to prevent the film from falling off due to excessive temperature rise and high temperature;

(3) Preparation of hollow spheres

E. Place the sample obtained in step D in a strong alkali solution, remove the substrate, and obtain a hollow metal sphere; repeatedly wash and filter the hollow metal sphere with deionized water and ethanol solution, and store in a liquid seal;

(4) Sintering process

F. Lay metal nano powder and hollow metal spheres alternately, dry, vacuum, pass protective gas, sintering temperature 1200-1600 ℃, annealing time 2-6h; the mass ratio of hollow metal spheres to metal nano powder is 5%-30% .

The beneficial effects of the present invention: substrate particles with different particle sizes can be obtained by controlling the roughening time, and then hollow metal spheres with different inner diameters can be prepared without purchasing particle substrates with different particle sizes. This process has the advantages of simple operation, convenience, economy, and controllable inner diameter of the spherical shell, and is especially suitable for preparing foamed metal materials or gradient multifunctional materials with different inner diameters.

detailed description

The specific implementation manners of the present invention will be further described below in conjunction with the technical solutions.

Example 1:

(1) Pretreatment process

A. Clean the silica gel desiccant with acetone, ethanol and deionized water in sequence, filter and dry;

B. Heat the silica gel desiccant and roughening agent to 50°C in a water bath, mix them, keep the temperature at 50°C, and roughen for 3 minutes; after the end, wash with deionized water, neutralize with ammonia water, and then wash with deionized water , filtered and dried;

C. Add the activation solution to the roughened substrate obtained in step B, activate for 5 minutes, stir until uniform, filter and dry to obtain the activated substrate;

(2) Electroless plating process

D. Put the nickel plating solution into a constant temperature water bath and heat it to 88-92°C; place the activated substrate obtained in step C in the nickel plating solution for 3 minutes, then wash it repeatedly with deionized water and ethanol solution, filter and cool Drying, the purpose is to prevent the film from falling off due to excessive temperature rise and high temperature;

(3) Preparation of hollow spheres

E. Place the sample obtained in step D in a strong alkali solution, remove the substrate, and obtain a hollow nickel ball; repeatedly wash and filter the hollow nickel ball with deionized water and ethanol solution, and store it in a liquid seal;

(4) Sintering process

F. Lay nano nickel powder and hollow nickel spheres alternately, dry, vacuum, nitrogen, sintering temperature 1300°C, annealing time 5h; mass ratio of hollow nickel spheres to nano nickel powder is 15%.

Example 2:

(1) Pretreatment process

A. Wash the silicon dioxide with acetone, ethanol and deionized water successively, filter and dry;

B. Heat the silica and roughening agent to 50°C in a water bath, mix them, keep the temperature at 50°C, and roughen for 4 minutes; after the end, wash with deionized water, neutralize with ammonia water, and then wash with deionized water , filtered and dried;

C. Add the activation solution to the roughened substrate obtained in step B, activate for 8 minutes, stir until uniform, filter and dry to obtain the activated substrate;

(2) Electroless plating process

D. Put the iron plating solution into a constant temperature water bath and heat it to 48-52°C; place the activated substrate obtained in step C in the iron plating solution for 5 minutes, then wash it repeatedly with deionized water and ethanol solution, filter and cool Drying, the purpose is to prevent the film from falling off due to excessive temperature rise and high temperature;

(3) Preparation of hollow spheres

E. Place the sample obtained in step D in a strong alkali solution, remove the substrate, and obtain a hollow iron ball; repeatedly wash and filter with deionized water and ethanol solution, and store in a liquid seal;

(4) Sintering process

F. Lay nano-iron powder and hollow iron balls alternately, dry, vacuumize, pass argon, sintering temperature 1400°C, annealing time 6h; the mass ratio of hollow iron balls to nano-iron powder is 20%.

Claims (2)

1. a kind of preparation method of internal diameter controllable foam metal, it is characterised in that step is as follows：

(1) pretreating process

A. substrate is cleaned with acetone, ethanol and deionized water successively, filters and dry；

B. substrate distinguishes heating water bath to 50 DEG C with roughening agent, mixing, 50 DEG C of keeping temperature, coarsening time 1-5min；After end, Cleaned with deionized water, ammoniacal liquor neutralize, cleaned again with deionized water, filter and dry；

C. in roughening substrate activating solution addition step B obtained, soak time 5-10min, stir to it uniformly, filter and dry It is dry, obtain activating substrate；

(2) chemical plating process

D. plating solution is put into thermostat water bath, is heated to required temperature；The activation substrate that step C is obtained is placed in 1- in plating solution 7min, then cleaned repeatedly with ethanol solution with deionized water, filter simultaneously low temperature drying；

(3) hollow metal sphere is prepared

E. the obtained samples of step D are placed in strong base solution, remove substrate, obtain hollow metal sphere；Hollow metal sphere is used Deionized water is cleaned, filtered repeatedly with ethanol solution, and fluid-tight preserves；

(4) sintering process

F. metal nano powder is replaced into laying with hollow metal sphere, dries, vacuumize, lead to protective gas, sintering temperature 1200- 1600 DEG C, annealing time 2-6h；Wherein, hollow metal sphere and metal nano powder mass ratio are 5%-30%.

2. preparation method according to claim 1, it is characterised in that described substrate is silica-gel desiccant, silica Or silicon.