CN102925779B - Method for preparing cobalt-nickel-aluminum (Co-Ni-Al) alloy based on electroplating and thermal diffusion - Google Patents

Abstract

The invention discloses a method for preparing Co-Ni-Al alloy based on electroplating thermal diffusion. In the invention, aluminum foil is used as a base material for composite electroplating Co-Ni alloy layer, and Co-Ni-Al magnetic control shape memory alloy is formed by heat treatment and diffusion. The Co-Ni-Al alloy preparation method provided by the present invention has simple process and good performance stability, and can better solve the existing bottleneck technologies of the current Co-Ni-Al magnetron memory alloy such as large driving magnetic field and small magnetic strain, Promote the practical application of magnetic control memory alloys in high-power underwater sonar, micro-displacement, vibration and noise control, linear motors, microwave devices, robots and other fields.

Description

A method for preparing Co-Ni-Al alloy based on electroplating thermal diffusion

technical field

The invention relates to the preparation technology of magnetically controlled shape memory metal functional materials, in particular to a method for preparing Co-Ni-Al alloys based on electroplating thermal diffusion.

Background technique

Magnetic shape memory alloy (Magnetic Shape Memory Alloy, MSMA) not only has the thermoelastic shape memory effect controlled by the temperature field of the traditional shape memory alloy, but also has the magnetic shape memory effect controlled by the magnetic field. Therefore, the alloy has the comprehensive characteristics of large recovery strain, large output stress, high response frequency and precise control, making it possible to be used in high-power underwater sonar, micro-displacement, vibration and noise control, linear motors, microwave devices, There are important applications in robotics and other fields, and it is expected to become a new generation of driving and sensing materials after piezoelectric ceramics and magnetostrictive materials. At present, the magnetic shape memory alloys that have been discovered mainly include: Ni-based alloys Ni-Mn-Ga, Ni-Al-Mn, Ni-Co-Al, Ni-Fe-Ga-Co, etc.; Co-based alloys Co-Mn, Co -Ni, Co-Ni-Ga, etc.; Fe-based alloys Fe-Pd, Fe-Mn-Si, Fe-Ni-Co-Ti, Fe-Pt, etc. Among them, Ni-Mn-Ga alloy is the earliest discovered MSMA , Its research is relatively mature, and there have been reports on linear drives, linear motors, etc., but the stability and repeatability of the alloy properties are not ideal.

Co-based ferromagnetic shape memory alloys include Co-Ni-Ga and Co-Ni-Al alloys, which have the advantages of large magnetocrystalline anisotropy and excellent thermal processing performance. Co-Ni-Al is the only MSMA that is solidified in a eutectic manner, and there is a two-phase coexistence region with a wide crystallization range, and exhibits rich multi-phase coexistence behavior within the range of functional components. The preparation method is relatively simple and the price is low. It is cheap and has great application prospects.

Researchers at home and abroad have prepared Co-Ni-Al alloys under conventional solidification, deep supercooled solidification, directional solidification, rapid solidification, and powder metallurgy methods, which have good strain-induced shape memory effects, but have not yet solved the problem of CoNiAl alloys. The technical bottleneck of large driving magnetic field and small magnetic strain.

The invention utilizes the composite electroplating of Co-Ni alloy on the aluminum foil, and finally prepares the Co-Ni-Al alloy with excellent comprehensive performance by adjusting the heat treatment process parameters.

Contents of the invention

A method for preparing Co-Ni-Al alloy based on electroplating thermal diffusion provided by the present invention has the following steps:

1) Co-Ni alloy coating is electroplated on the surface of pure aluminum substrate, and the mass ratio of nickel in the above Co-Ni alloy coating is 10-90%; 

2) Put the electroplated Co-Ni/Al into the heater, keep it at a temperature of 250°C-600°C for 60-240 hours, diffuse to form a uniform Co-Ni-Al alloy, and take it out after cooling to room temperature with the furnace.

The thickness of the pure aluminum substrate in the above step 1) is 0.01mm-0.3mm.

The electroplating process in the above step 1) is as follows: at room temperature, the surface of the pure aluminum substrate is cleaned and degreased with distilled water. In the acid etching solution composed of hydrofluoric acid and the remaining amount of deionized water, the etching time at room temperature is 40 hours; then use deionized water to wash; at room temperature, put the sample into a mixture of 15 g/L nickel sulfate and 112 g/L sodium citrate mixed in a solution with a pH value of 13 for activation, and then placed in the electroplating solution for electroplating; stop electroplating and wash and dry the samples.

The above-mentioned electroplating uses pure aluminum as the anode, and the formula of the electroplating solution is: nickel sulfate 100-250 g/L, sodium chloride 10-20 g/L, boric acid 20-40 g/L, cobalt sulfate 10-120 g/L , saccharin 1g/L; constant current during the electroplating process, the current is 0.15A, and the pH value of the plating solution is 4.6. Co-Ni alloy coatings with different compositions can be obtained on pure aluminum substrates by adjusting the composition of the electroplating solution and the electroplating parameters.

The heater in the above step 2) is a muffle furnace or a vacuum furnace; in order to avoid oxidation of the coating, the muffle furnace adopts nitrogen, argon or hydrogen protective gas, or puts Co-Ni/Al into carbon powder reducing substances medium heat.

The holding time in the above step 2) is determined according to the pure aluminum substrate and the thickness of the coating, and the Co-Ni-Al alloy with uniform composition is obtained by heating until diffusion.

Beneficial effects of the present invention:

1. The Co-Ni alloy is prepared on the aluminum substrate by the method of composite electroplating, and the parameters such as the heat treatment process, the composition of the coating and the thickness of the substrate are controlled to prepare a Co-Ni-Al alloy with excellent comprehensive properties.

2. The equipment cost and technical requirements for preparing the Co-Ni-Al alloy are low, and the Co-Ni-Al alloy can be prepared only by a simple power supply and a heater.

3. The preparation method of the present invention has simple process and good performance stability, and can better solve the existing bottleneck technical difficulties of the current Co-Ni-Al magnetron memory alloy such as large driving magnetic field and small magnetic strain.

Detailed ways

The present invention is described in detail below in conjunction with specific embodiment.

Example 1

1) On the surface of a pure aluminum substrate with a thickness of 0.05mm, wash and degrease the surface of the pure aluminum substrate with distilled water at room temperature. After cleaning and degreasing, place it in nitric acid with a volume ratio of 20% and a volume ratio of 1%. In the acid etching solution composed of hydrofluoric acid and the remaining amount of deionized water, the etching time at room temperature is 40 hours; then use deionized water to wash; at room temperature, put the sample into a mixture of 15 g/L nickel sulfate and 112 g/L sodium citrate mixture solution with a pH value of 13 was activated, and then placed in the electroplating solution for electroplating; the electroplating sample was stopped and washed and dried.

The composition formula of above-mentioned electroplating solution is: nickel sulfate 250g/L, sodium chloride 10 g/L, boric acid 40 g/L, cobalt sulfate 55 g/L, saccharin 1g/L; , the current is 0.15A, and the pH value of the bath is 4.6. Stop electroplating sample washing and drying, obtain Co-54.2%Ni alloy coating, wherein the mass ratio of nickel in the above-mentioned Co-Ni alloy coating is 54.2%;

2) Put the electroplated Co-54.2%Ni /Al sample into the muffle furnace, and keep it at a temperature of 550°C under an argon atmosphere for 60 hours to obtain a Co-45.0%Ni-17%Al alloy.

3) Take it out after cooling to room temperature with the furnace.

Example 2

1) On the surface of a pure aluminum substrate with a thickness of 0.1 mm, wash the surface of the pure aluminum substrate with distilled water to remove oil at room temperature, and place it in nitric acid with a volume ratio of 20% and a volume ratio of 1% after cleaning and degreasing In the acid etching solution composed of hydrofluoric acid and the remaining amount of deionized water, the etching time at room temperature is 40 hours; then use deionized water to wash; at room temperature, put the sample into a mixture of 15 g/L nickel sulfate and 112 g/L sodium citrate mixture solution with a pH value of 13 was activated, and then placed in the electroplating solution for electroplating; the electroplating sample was stopped and washed and dried.

The composition formula of above-mentioned electroplating solution is: nickel sulfate 100g/L, sodium chloride 20 g/L, boric acid 40 g/L, cobalt sulfate 120 g/L, saccharin 1g/L; Electroplating parameter is: constant current during plating process , the current is 0.15A, and the pH value of the bath is 4.6. Stop washing and drying the electroplating sample to obtain a Co-9.9%Ni alloy coating, wherein the mass ratio of nickel in the above-mentioned Co-Ni alloy coating is 9.9%;

2) Put the electroplated Co-9.9%Ni /Al sample into a vacuum hot furnace, and keep it at 300°C for 200 hours to obtain a Co-6.0%Ni-40.0%Al alloy.

3) Take it out after cooling to room temperature with the furnace.

Example 3

1) On the surface of a pure aluminum substrate with a thickness of 0.2mm, wash and degrease the surface of the pure aluminum substrate with distilled water at room temperature. After cleaning and degreasing, place it in nitric acid with a volume ratio of 20% and a volume ratio of 1%. In the acid etching solution composed of hydrofluoric acid and the remaining amount of deionized water, the etching time at room temperature is 40 hours; then use deionized water to wash; at room temperature, put the sample into a mixture of 15 g/L nickel sulfate and 112 g/L sodium citrate mixture solution with a pH value of 13 was activated, and then placed in the electroplating solution for electroplating; the electroplating sample was stopped and washed and dried.

The composition formula of above-mentioned electroplating solution is: nickel sulfate 175g/L, sodium chloride 20 g/L, boric acid 20 g/L, cobalt sulfate 10 g/L, saccharin 1g/L; , the current is 0.15A, and the pH value of the bath is 4.6. Stop washing and drying the electroplating sample to obtain a Co-41.5%Ni alloy coating, wherein the mass ratio of nickel in the above-mentioned Co-Ni alloy coating is 41.5%;

2) Put the electroplated Co-41.5%Ni /Al sample into a muffle furnace, and keep it at a temperature of 400°C in a nitrogen atmosphere for 180 hours to obtain a Co-35.0%Ni-14.5%Al alloy.

3) Take it out after cooling to room temperature with the furnace.

Example 4

1) On the surface of a pure aluminum substrate with a thickness of 0.15mm, wash and degrease the surface of the pure aluminum substrate with distilled water at room temperature. After cleaning and degreasing, place it in nitric acid with a volume ratio of 20% and a volume ratio of 1%. In the acid etching solution composed of hydrofluoric acid and the remaining amount of deionized water, the etching time at room temperature is 40 hours; then use deionized water to wash; at room temperature, put the sample into a mixture of 15 g/L nickel sulfate and 112 g/L sodium citrate mixture solution with a pH value of 13 was activated, and then placed in the electroplating solution for electroplating; the electroplating sample was stopped and washed and dried. the

The composition formula of above-mentioned electroplating solution is: nickel sulfate 250g/L, sodium chloride 20 g/L, boric acid 30 g/L, cobalt sulfate 10 g/L, saccharin 1g/L; , the current is 0.15A, and the pH value of the bath is 4.6. Stop electroplating sample washing and drying, obtain Co-88.3%Ni alloy coating, wherein the mass ratio of nickel in the above-mentioned Co-Ni alloy coating is 88.3%;

2) Put the electroplated Co-88.3%Ni /Al sample into a muffle furnace, and keep it at 600°C for 80 hours under carbon powder coating to obtain a Co-80%Ni-9.4%Al alloy .

3) Take it out after cooling to room temperature with the furnace.

Example 5

1) On the surface of a pure aluminum substrate with a thickness of 0.3mm, wash and degrease the surface of the pure aluminum substrate with distilled water at room temperature. After cleaning and degreasing, place it in nitric acid with a volume ratio of 20% and a volume ratio of 1%. In the acid etching solution composed of hydrofluoric acid and the remaining amount of deionized water, the etching time at room temperature is 40 hours; then use deionized water to wash; at room temperature, put the sample into a mixture of 15 g/L nickel sulfate and 112 g/L sodium citrate mixture solution with a pH value of 13 was activated, and then placed in the electroplating solution for electroplating; the electroplating sample was stopped and washed and dried.

The composition formula of above-mentioned electroplating solution is: nickel sulfate 220g/L, sodium chloride 15 g/L, boric acid 40 g/L, cobalt sulfate 50 g/L, saccharin 1g/L; , the current is 0.15A, and the pH value of the bath is 4.6. Stop electroplating sample washing and drying, obtain Co-49.9%Ni alloy coating, wherein the mass ratio of nickel in the above-mentioned Co-Ni alloy coating is 49.9%;

2) Put the electroplated Co-49.9%Ni /Al sample into a muffle furnace, and keep it in a vacuum heat furnace for 240 hours at a temperature of 450°C to obtain a Co-14.9%Ni-70.2%Al alloy .

3) Take it out after cooling to room temperature with the furnace.

Claims (4)

1. A method for preparing Co-Ni-Al alloy based on electroplating thermal diffusion, is characterized in that the method has the following steps: 1) Co-Ni alloy coating is electroplated on the surface of pure aluminum substrate, the mass ratio of nickel in the above Co-Ni alloy coating is 10-90%; the above electroplating process is: use distilled water on the surface of pure aluminum substrate at room temperature After cleaning and degreasing, place it in an acid etching solution consisting of 20% nitric acid by volume, 1% hydrofluoric acid by volume and the rest of deionized water. Etch time at room temperature for 40 hours; then wash with deionized water; at room temperature, put the sample into a solution with a pH value of 13 consisting of 15 g/L nickel sulfate and 112 g/L sodium citrate for activation, and then place it in Electroplating in the electroplating solution; stop washing and drying the electroplating sample; the above-mentioned electroplating uses pure aluminum as the anode; the formula of the electroplating solution is: nickel sulfate 100-250 g/L, sodium chloride 10-20 g/L, boric acid 20-20 g/L 40 g/L, cobalt sulfate 10-120 g/L, saccharin 1g/L; constant current during the electroplating process, the current is 0.15A, and the pH value of the plating solution is 4.6; 2) Put the electroplated Co-Ni/Al into the heater, keep it at a temperature of 250°C-600°C for 60-240 hours, diffuse to form a uniform Co-Ni-Al alloy, and take it out after cooling to room temperature with the furnace. 2. The method according to claim 1, characterized in that: the thickness of the pure aluminum substrate in the above step 1) is 0.01mm-0.3mm. 3. The method according to claim 1, characterized in that: the heater in the above step 2) is a muffle furnace or a vacuum furnace; in order to avoid oxidation of the coating, the muffle furnace adopts nitrogen, argon or hydrogen protective gas , or put Co-Ni/Al into the carbon powder reducing substance and heat it. 4. The method according to claim 1, characterized in that: the holding time in the above step 2) is determined according to the pure aluminum substrate and the thickness of the coating, and the Co-Ni-Al alloy with uniform composition is obtained by heating until diffusion.