CN109763128B - A method for preparing ultrafine scaly copper powder by alloy corrosion method - Google Patents

Abstract

The invention relates to a method for preparing ultra-fine scaly copper powder by an alloy corrosion method, belonging to the field of metal powder materials. The concentration is 5%-10% hydrochloric acid solution, the solution is heated to 35°C-45°C, stirred with oxygen blowing, reacted for 1-3 hours, washed with deionized water, dried, and ball-milled to obtain ultra-fine scaly copper powder . Compared with the preparation of flaky copper powder by pure copper ball milling, the ultrafine scaly copper powder obtained by the method of the invention has low production cost, easily available raw materials, simple preparation process, short ball milling time, regular shape and diameter-to-thickness ratio of the flaky copper powder. Large, uniform particle size distribution, with high economic benefits.

Description

A method for preparing ultrafine scaly copper powder by alloy corrosion method

technical field

The invention relates to the field of metal powder materials, in particular to a method for preparing ultra-fine scaly copper powder by an alloy corrosion method.

Background technique

As an important part of the conductive phase in electronic paste, copper powder is widely used in conductive paste, conductive adhesive and so on. The morphology and particle size of copper powder have a great influence on the conductivity of the slurry. The copper powder prepared by people generally includes spherical and flake. Among them, the spherical copper powder is mainly in point contact, and the contact area is small, while the flake copper powder is generally in surface contact, and the specific surface area is large, so the copper conductor paste prepared from the flake copper powder has better conductivity. At present, flaky copper powder is prepared by mechanical ball milling of pure copper, and the obtained flaky copper powder has different shapes and sizes, poor surface flatness and weak conductivity. Therefore, preparing a flake copper powder with uniform particle size and regular shape has an important influence on improving the conductivity of copper conductor paste.

SUMMARY OF THE INVENTION

In view of the deficiencies of the existing technology, the present invention provides a method for preparing ultra-fine scaly copper powder by an alloy corrosion method. production cost and improve production efficiency.

Copper-zinc alloy is a mixture of copper metal element Cu and zinc metal element Zn. Since the hardness of the alloy is greater than that of the metals in its components, the hardness of the brass alloy composed of copper and zinc is greater than that of pure copper; if the copper-zinc alloy is immersed in a hydrochloric acid solution, the copper in the alloy does not react with hydrochloric acid, and the The zinc reacted with hydrochloric acid is corroded and dissolved, and only copper remains in the whole copper-zinc alloy. At this time, the metal sheet shows a mesh structure after corrosion, which is relatively brittle. After ball milling, the mesh copper can be prepared into sheets. copper powder. Compared with the preparation of flaky copper powder by pure copper ball milling, the ultrafine scaly copper powder obtained by the method of the invention has low production cost, easily available raw materials, simple preparation process, short ball milling time, regular shape and diameter-to-thickness ratio of the flaky copper powder. Large, uniform particle size distribution, with high economic benefits.

The technical scheme of the present invention is as follows:

Step (1), cutting the copper-zinc alloy into alloy sheets with an area of about 0.8-2cm ² ;

Step (2), prepare a hydrochloric acid solution, and put the cut alloy pieces into the hydrochloric acid solution;

Step (3), heating the hydrochloric acid solution to a certain temperature with a water bath;

Step (4), introducing oxygen into the hydrochloric acid solution through a plastic conduit, and stirring the hydrochloric acid solution by a stirrer at the same time;

Step (5), react for 1-3 hours to obtain mesh copper sheets, wash with deionized water and then dry;

Step (6), adding the dried mesh copper sheet and the medium ball into the ball mill, adding the ball milling medium, setting the ball milling speed and time, and obtaining the mixture after ball milling;

Step (7): After grinding, the mixture in the ball mill is sieved, and the obtained copper powder is washed 3-5 times with deionized water, and dried in a vacuum drying box at 100° C. for 2 hours to obtain ultra-fine scaly copper powder.

Preferably, in step (1), the mass percentage of zinc is between 5% and 55%.

Preferably, the mass percentage concentration of the hydrochloric acid solution in step (2) is 5%-10%.

Preferably, the hydrochloric acid in step (3) is heated to 35°C-45°C.

Preferably, the oxygen introduced in step (4) is high-purity oxygen of more than 99.9%. The stirring speed was 200 rpm.

Preferably, in step (5), the copper sheet is washed 3-4 times with deionized water, and then dried in a vacuum drying oven at 100° C. for 10-15 minutes.

Preferably, in step (6), the mass ratio of the meshed copper to the dielectric ball is 1:60-80. The medium ball is a stainless steel ball with a diameter of φ25mm, and 5%-20% of the weight of the copper sheet is added with hexadecanol as the ball milling medium.

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

The invention adopts copper-zinc alloy as raw material, when the cut sheet alloy is immersed in hydrochloric acid solution, the copper in the alloy does not react with hydrochloric acid, the zinc in the alloy reacts with hydrochloric acid and is corroded and dissolved, and the whole copper-zinc alloy only remains Copper, at this time, the metal sheet is corroded and presents a network structure, which is relatively brittle. After ball milling, the network copper can be prepared into flake copper powder. After the corrosion reaction, the mesh copper sheet is washed with deionized water, dried, and ball-milled to obtain ultra-fine scaly copper powder. The method is easy to obtain raw materials, simple in preparation process and low in cost; the prepared ultrafine scaly copper powder has regular shape, large diameter-to-thickness ratio and uniform particle size distribution. The process is simple, the ball milling time is short, the production cost is low, and it has high economic benefits.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

Fig. 1 Process flow chart of preparation of ultra-fine scaly copper powder by alloy etching method;

Fig. 2 SEM photo of ultra-fine scaly copper powder, the text below Fig. 2 is unclear and does not affect the content expression of the drawing.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with specific examples. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

Step (1): Use a cutting tool to cut a copper-zinc alloy with a bulk or columnar zinc content of 50% into alloy sheets of about 1 cm ² .

Step (2), configure a hydrochloric acid solution with a mass percentage concentration of 10%, and put the cut alloy pieces into the hydrochloric acid solution.

Step (3), use a water bath to heat the hydrochloric acid solution to a temperature of 45°C.

In step (4), high-purity oxygen with a purity of more than 99.9% is introduced into the hydrochloric acid solution through a plastic conduit, and the hydrochloric acid solution is stirred by a stirrer at a rotational speed of 200 rpm.

Step (5), when the reaction time is 3 hours, take out the copper sheet, wash the mesh copper sheet with ionized water 3-4 times, and dry it in a vacuum drying oven at 100° C. for 12 minutes before use.

Step (6), add the dried mesh copper sheet and the medium ball into the ball mill at a weight ratio of 1:80. The medium ball is a stainless steel ball with a diameter of φ 25 mm, and hexadecanol is added according to 20% of the weight of the mesh copper sheet. As a grinding medium, the speed of ball milling is 1200 rpm, and the ball milling is 5 hours.

Step (7): After grinding, sieve the copper powder mixture in the ball mill, and the obtained copper powder is first washed with 10% concentration of hydrochloric acid repeatedly for 3-5 times, and then washed with deionized water for 3-5 times. The desired ultra-fine scaly copper powder can be obtained by drying at 100°C for 2 hours in a vacuum drying oven.

The flake copper powder obtained by this method is uniformly dispersed, the particle size is about 1-2 μm, and there is no agglomeration phenomenon. It was found by XRD test that there were no peaks of zinc and copper oxide, which proved that the prepared powder was pure copper powder. The properties of the prepared slurry were measured after sintering. The resistance was 6-8mΩ and the adhesion was 19-23N. Better than the slurry prepared by 2μm spherical copper powder under the same conditions.

Example 2

Step (1): Use a cutting tool to cut a copper-zinc alloy with a bulk or columnar zinc content of 50% into alloy sheets of about 1 cm ² .

Step (2), configure a hydrochloric acid solution with a mass percentage concentration of 10%, and put the cut alloy pieces into the hydrochloric acid solution.

Step (3), use a water bath to heat the hydrochloric acid solution to a temperature of 45°C.

In step (4), high-purity oxygen with a purity of more than 99.9% is introduced into the hydrochloric acid solution through a plastic conduit, and the hydrochloric acid solution is stirred by a stirrer at a rotational speed of 200 rpm.

Step (5), when the reaction time reaches 1 hour, take out the mesh copper sheet, use deionized water to wash the copper sheet 3-4 times, and dry it in a vacuum drying box at 100°C for 15 minutes before use.

Step (6), add the dried copper sheet and the medium ball into the ball mill at a weight ratio of 1:60, and the medium ball is a stainless steel ball with a diameter of φ25 mm. Cetyl alcohol was added as a grinding medium according to 5% of the weight of the copper flakes, the rotational speed was 1100 rpm during ball milling, and the ball milled for 3 hours to obtain a copper powder mixture.

Step (7): After grinding, sieve the copper powder mixture in the ball mill. The obtained copper powder is first washed with 10% hydrochloric acid repeatedly for 3-5 times, then washed with deionized water for 3-5 times, and dried in vacuum. The desired ultra-fine scaly copper powder is obtained by drying at 100°C for 2 hours in the box.

The flake copper powder obtained by this method has a relatively uniform dispersion and a particle size of about 1-2 μm, and there is a small part of agglomeration. It was found by XRD test that there were no peaks of zinc and copper oxide, which proved that the prepared powder was pure copper powder.

Example 3

Step (1): Use a cutting tool to cut a copper-zinc alloy with a bulk or columnar zinc content of 50% into alloy sheets with an area of about 2 cm ² .

Step (2), configure a hydrochloric acid solution with a mass percentage concentration of 8%, and put the cut alloy pieces into the hydrochloric acid solution.

Step (3), use a water bath to heat the hydrochloric acid solution, and the heating temperature is 45°C.

In step (4), high-purity oxygen with a purity of more than 99.9% is introduced into the hydrochloric acid solution through a plastic conduit, and the hydrochloric acid solution is stirred by a stirrer at a rotational speed of 200 rpm.

Step (5), when the reaction time reaches 3 hours. Take out the copper sheet. Wash the copper sheet 3-4 times with deionized water. Dry in a vacuum drying oven at 100°C for 11 minutes before use.

Step (6): Add the dried copper sheet and the medium ball into the ball mill in a weight ratio of 1.60, and the medium ball is a stainless steel ball with a diameter of φ25 mm. 20% of the weight of the copper flakes was added with cetyl alcohol as a grinding medium, the rotational speed was 1200 rpm during ball milling, and the ball milled for 5 hours to obtain a copper powder mixture.

Step (7): After grinding, sieve the copper powder mixture in the ball mill, and the obtained copper powder is first washed with 10% concentration of hydrochloric acid repeatedly for 3-5 times, and then washed with deionized water for 3-5 times. The desired ultra-fine scaly copper powder can be obtained by drying in a vacuum drying oven at 100°C for 2 hours.

The flake copper powder obtained by this method is uniformly dispersed, the particle size is about 2-4 μm, and there is no agglomeration phenomenon. It was found by XRD test that there were no peaks of zinc and copper oxide, which proved that the prepared powder was pure copper powder. The properties of the prepared slurry were measured after sintering. The resistance was 10-15mΩ and the adhesion was 14-17N. Better than the slurry prepared by 4μm spherical copper powder under the same conditions.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (1)

1. a method for preparing ultra-fine scaly copper powder by alloy corrosion method, is characterized in that comprising the following steps: Step (1), cutting the copper-zinc alloy into an alloy sheet with an area of 0.8-2cm ² , and the zinc in the copper-zinc alloy is 5%-55% by mass percentage; Step (2), preparing a hydrochloric acid solution, and placing the cut alloy sheet into a hydrochloric acid solution with a mass percentage concentration of 5%-10%; Step (3), heating the hydrochloric acid solution with a water bath to a temperature of 35°C-45°C; Step (4), pass high-purity oxygen with a concentration of more than 99.9% into the hydrochloric acid solution through a plastic conduit, and simultaneously perform a stirring reaction on the hydrochloric acid solution through a stirrer, and the stirring speed is 200 rpm; Step (5), stirring and reacting for 1-3 hours to obtain mesh copper sheets, washing the mesh copper sheets with deionized water for 3-4 times, and then drying them in a vacuum drying oven at 100°C for 10-15 minutes; Step (6), put the dried mesh copper sheet and the medium ball into the ball mill, the mass ratio of the mesh copper sheet to the medium ball is 1:60-80, and the medium ball is a stainless steel ball with a diameter of φ25 mm ; Add hexadecanol as the ball milling medium by 5%-20% of the weight of the copper sheet, and the rotating speed during ball milling is 1100-1200 rpm, and the ball milling is 3-5 hours to obtain the copper powder mixture; Step (7): After sieving the copper powder mixture in the ball mill, the obtained copper powder is washed with deionized water for 3-5 times, and dried in a vacuum drying box at 100° C. for 2 hours to obtain ultra-fine scaly copper powder.

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