CN114985507B - Silver-nickel alloy and preparation method thereof - Google Patents

Abstract

The invention provides a silver-nickel alloy and a preparation method thereof, and belongs to the technical field of silver-nickel alloys. The preparation method of the silver-nickel alloy provided by the invention comprises the following steps: (1) After melting silver, adding nickel-magnesium intermediate alloy for alloying, and then carrying out continuous casting to obtain an alloy round rod; the alloying time is 0.5-5 min; the supercooling degree of the continuous casting is delta 20-80 ℃; (2) Carrying out large plastic deformation rolling on the alloy round rod to obtain an alloy wire; the total deformation of the large plastic deformation rolling is more than or equal to 80 percent; (3) And drawing the alloy wire to obtain the silver-nickel alloy. The results of the examples show that the silver-nickel alloy provided by the invention comprises 5-20 wt.% of nickel, 1-5 wt.% of magnesium and the balance of silver, wherein the silver-nickel alloy contains nickel distributed in a fibrous shape, the tensile strength of the silver-nickel alloy is more than or equal to 340MPa, and the resistivity of the silver-nickel alloy is 2.0-2.3 mu omega cm.

Description

Silver-nickel alloy and preparation method thereof

Technical Field

The present invention relates to the technical field of silver-nickel alloys, and in particular to a silver-nickel alloy and a preparation method thereof.

Background Art

Silver-nickel alloy is a silver alloy made by adding nickel to silver. By adding a small amount of nickel, the grains can be refined, the hardness, wear resistance and burning resistance of silver can be improved, and the contact resistance is also slightly increased. Silver-nickel alloy electrical contact materials have good electrical conductivity and thermal conductivity, strong resistance to metal transfer, arc burning, electrical erosion, good wear resistance, high strength, good ductility and cutting ability, and higher contact resistance than silver. As a contact material, it is widely used in various switches, controllers, voltage regulators, circuit breakers, automotive electrical appliances, magnetic starters, etc.

Since silver and nickel are not mutually soluble, and the solubility of nickel in molten liquid silver is very limited, powder metallurgy is often used for preparation. Powder metallurgy generally adopts chemical co-precipitation to obtain silver and nickel mixed powder, and then uses chemical method to make silver and nickel coated powder. With the development of powder making technology, there has been a method of first using mechanical atomization to obtain ultra-fine powder, and then preparing silver-nickel alloy, as well as a method of using silver and nickel co-spraying powder making and mechanical alloying technology to prepare silver-nickel alloy. However, in the process of preparing silver-nickel alloy by powder metallurgy, it is easy to introduce other impurities during mixing, and the density of the prepared silver-nickel alloy is low, which will cause the conductivity, tensile strength and other properties of the silver-nickel alloy to decrease.

In recent years, due to the development of electric vehicles, artificial intelligence, and 5G base stations, the requirements for the strength and electrical wear resistance of silver-nickel electrical alloys have become increasingly higher. Silver-nickel alloys prepared by powder metallurgy can no longer meet the existing technical requirements.

Therefore, providing a method for preparing a silver-nickel alloy with high strength and excellent electrical wear resistance has become a technical problem to be solved urgently in the field.

Summary of the invention

The object of the present invention is to provide a silver-nickel alloy and a preparation method thereof. The silver-nickel alloy provided by the present invention has the characteristics of high tensile strength, contact resistance meeting the requirements, and excellent electrical wear resistance.

In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

The present invention provides a method for preparing a silver-nickel alloy, comprising the following steps:

(1) melting silver, adding nickel-magnesium master alloy to alloy, and then continuously casting to obtain alloy round rods;

The alloying time is 0.5 to 5 minutes; the undercooling degree of the continuous casting is Δ20 to 80°C;

(2) performing large plastic deformation rolling on the alloy round rod obtained in step (1) to obtain alloy wire; the total deformation amount of the large plastic deformation rolling is ≥80%;

(3) Drawing the alloy wire obtained in step (2) to obtain a silver-nickel alloy.

Preferably, the nickel-magnesium intermediate alloy in step (1) is a nickel-magnesium alloy ball.

Preferably, the diameter of the nickel-magnesium alloy ball is 2 to 30 mm.

Preferably, the nickel content in the nickel-magnesium alloy ball is ≥80wt.%.

Preferably, the melting temperature in step (1) is 980-1100° C., and the melting atmosphere is vacuum.

Preferably, the alloying temperature in step (1) is 980-1100°C.

Preferably, the diameter of the alloy round rod in step (1) is 5 to 9 mm.

Preferably, the deformation amount of a single pass of the large plastic deformation rolling in step (2) is ≥10%.

Preferably, the diameter of the alloy wire in step (2) is 1 to 3 mm.

The present invention provides a silver-nickel alloy prepared by the preparation method described in the above technical solution, wherein the silver-nickel alloy comprises 5-20wt.% nickel, 1-5wt.% magnesium and the balance silver.

The invention provides a preparation method of a silver-nickel alloy, comprising the following steps: (1) melting silver, adding a nickel-magnesium intermediate alloy to perform alloying, and then continuously casting to obtain an alloy round rod; the alloying time is 0.5 to 5 minutes; the undercooling degree of the continuous casting is Δ20 to 80° C.; (2) performing large plastic deformation rolling on the alloy round rod obtained in the step (1) to obtain an alloy wire; the total deformation amount of the large plastic deformation rolling is ≥80%; (3) performing wire drawing on the alloy wire obtained in the step (2) to obtain a silver-nickel alloy. The present invention adds a nickel-magnesium master alloy to molten silver for alloying in a short time, and the nickel in the nickel-magnesium master alloy cannot be completely dissolved, so that part of the nickel-magnesium alloy remains in the alloy round rod, which can not only play a role in refining grains, but also lay a foundation for the subsequent fibrous distribution of nickel in the silver-nickel alloy; the magnesium in the nickel-magnesium master alloy can form solid solution strengthening with silver, thereby further improving the strength of the alloy; by casting under a certain undercooling condition, the solid solution amount of nickel in silver can be increased, and silver and nickel can form solid solution strengthening, thereby improving the strength of the alloy; by large plastic deformation rolling, the diameter of the alloy round rod can be greatly reduced under the action of external force, and in this process, the nickel-magnesium alloy remaining in the alloy round rod gradually forms a fibrous distribution as the alloy round rod is deformed, thereby further improving the hardness, wear resistance and burning resistance of the silver-nickel alloy. The results of the embodiments show that the silver-nickel alloy provided by the present invention comprises 5-20wt.% nickel, 1-5wt.% magnesium and the balance silver, wherein the silver-nickel alloy contains nickel distributed in a fibrous form, and the tensile strength of the silver-nickel alloy is ≥340MPa and the resistivity is 2.0-2.3μΩ·cm.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a microstructure diagram of the silver-nickel alloy provided in Example 1 of the present invention.

DETAILED DESCRIPTION

The present invention provides a method for preparing a silver-nickel alloy, comprising the following steps:

(1) melting silver, adding nickel-magnesium master alloy to alloy, and then continuously casting to obtain alloy round rods;

The alloying time is 0.5 to 5 minutes; the undercooling degree of the continuous casting is Δ20 to 80°C;

(2) performing large plastic deformation rolling on the alloy round rod obtained in step (1) to obtain alloy wire; the total deformation amount of the large plastic deformation rolling is ≥80%;

(3) Drawing the alloy wire obtained in step (2) to obtain a silver-nickel alloy.

The invention melts silver and then adds nickel-magnesium master alloy for alloying, and then continuously casts the alloy round rod.

In the present invention, the nickel-magnesium master alloy is preferably a nickel-magnesium alloy ball. The present invention has no particular limitation on the specific sources of the silver and the nickel-magnesium master alloy, and commercial products well known to those skilled in the art or self-prepared products can be used. The present invention can reduce the content of impurities in the alloy by using the above raw materials to prepare the alloy round rod.

In the present invention, the diameter of the nickel-magnesium alloy ball is preferably 2 to 30 mm, more preferably 5 to 25 mm, and further preferably 10 to 20 mm; the nickel content in the nickel-magnesium alloy ball is preferably ≥ 80 wt.%, more preferably 80 to 90 wt.%; the magnesium content in the nickel-magnesium alloy ball is preferably ≤ 20 wt.%, more preferably 10 to 20 wt.%. The present invention controls the nickel content of the nickel-magnesium alloy ball within the above range, which can avoid the negative impact of excessive magnesium content on the conductive properties of the silver-nickel alloy; by controlling the size of the nickel-magnesium alloy ball, it is beneficial to control the residual nickel-magnesium alloy to form spherical aggregation during alloying, and it is more beneficial to make the nickel form a fibrous distribution during deformation.

In the present invention, the heating method for melting is preferably electromagnetic heating or natural gas heating; the melting temperature is preferably 980-1100°C, more preferably 1000-1080°C, and further preferably 1020-1050°C; the melting atmosphere is preferably vacuum; the melting vacuum is preferably 1×10 ^-3 Pa to 1×10 ^-5 Pa, and more preferably 1×10 ^-4 Pa to 1×10 ^-5 Pa. The present invention is conducive to further improving the melting effect by controlling the melting parameters.

After melting, the present invention preferably allows the molten product to stand. In the present invention, the standing time is preferably 0.5 to 3 minutes, more preferably 1 to 2 minutes. By standing, the present invention can make the molten silver heat more evenly.

In the present invention, the alloying temperature is preferably 980-1100°C, more preferably 1000-1080°C, and further preferably 1020-1050°C; the alloying time is 0.5-5 min, preferably 1-4 min, and more preferably 2-3 min. The present invention can make the molten silver have good fluidity and facilitate uniform mixing by alloying at the above temperature; by controlling the alloying time, the nickel-magnesium alloy ball can be not completely melted in the molten silver, so that it can be deformed with the deformation of the alloy round rod during the subsequent rolling and wire drawing process, and finally form a fibrous distribution.

In the present invention, the alloying is preferably carried out under electromagnetic stirring conditions. The present invention can make the nickel-magnesium alloy balls disperse more evenly in the molten silver by electromagnetic stirring.

After alloying, the present invention preferably allows the alloyed product to stand. In the present invention, the standing time is preferably 0.5 to 5 minutes, more preferably 1 to 4 minutes. By standing, the present invention can make each component more uniform.

In the present invention, the undercooling degree of continuous casting is Δ20-80° C., preferably Δ40-60° C. The present invention can increase the solid solution amount of nickel in silver and make silver, nickel and magnesium form solid solution strengthening by continuous casting under a certain undercooling condition, thereby improving the strength of the alloy, thereby further improving the strength and conductivity of the alloy.

The present invention has no special limitation on the specific operation of the continuous casting, as long as the diameter of the alloy round rod can meet the requirements.

In the present invention, the diameter of the alloy round rod is preferably 5-9 mm, more preferably 6-8 mm, and further preferably 7 mm. By controlling the diameter of the alloy round rod within the above range, the present invention facilitates subsequent large plastic deformation rolling, thereby further improving the performance of the alloy.

After obtaining the alloy round rod, the present invention performs large plastic deformation rolling on the alloy round rod to obtain the alloy wire.

In the present invention, the total deformation of the large plastic deformation rolling is ≥80%, preferably 80-90%, more preferably 85-90%; the single-pass deformation of the large plastic deformation rolling is preferably ≥10%, more preferably 10-20%, and further preferably 12-15%. The present invention uses large plastic deformation rolling to significantly reduce the diameter of the alloy round rod under the action of external force, and at the same time, the nickel-magnesium alloy remaining inside the alloy round rod is deformed with the deformation of the alloy round rod, and finally forms a fibrous distribution, thereby improving the mechanical properties of the alloy.

In the present invention, the diameter of the alloy wire is preferably 1-3 mm, more preferably 2 mm. The present invention controls the diameter of the alloy wire within the above range to facilitate subsequent wire drawing.

After obtaining the alloy wire, the present invention draws the alloy wire to obtain the silver-nickel alloy.

The present invention has no special limitation on the specific operation of the wire drawing, and the wire drawing can be performed according to the required size specifications of the silver-nickel alloy.

The present invention adds a nickel-magnesium master alloy to molten silver for alloying in a short time, and the nickel-magnesium master alloy cannot be completely dissolved, so that part of the nickel-magnesium alloy remains in the alloy round rod, which can not only play a role in refining grains, but also lay a foundation for the subsequent fibrous distribution of nickel in the silver-nickel alloy; the magnesium in the nickel-magnesium master alloy can form solid solution strengthening with silver, thereby further improving the strength of the alloy; by casting under a certain undercooling condition, the solid solution amount of nickel in silver can be increased, and silver and nickel can form solid solution strengthening, thereby improving the strength of the alloy; by large plastic deformation rolling, the diameter of the alloy round rod can be greatly reduced under the action of external force, and in this process, the nickel-magnesium alloy remaining in the alloy round rod gradually forms a fibrous distribution as the alloy round rod is deformed, thereby further improving the hardness, wear resistance and burning resistance of the silver-nickel alloy.

The preparation method of the invention is simple and can make the silver-nickel alloy have the characteristics of high strength and high contact resistance, which lays a foundation for the subsequent research and preparation of the silver-nickel alloy.

The present invention provides a silver-nickel alloy prepared by the preparation method described in the above technical solution, wherein the silver-nickel alloy comprises 5-20wt.% nickel, 1-5wt.% magnesium and the balance silver, preferably 10-15wt.% nickel, 2-4wt.% magnesium and the balance silver. In the present invention, the silver-nickel alloy contains nickel distributed in a fibrous form.

The silver-nickel alloy provided by the present invention has the characteristics of high tensile strength, good wear resistance, high contact resistance and excellent electrical wear resistance, and can be used as a contact material in switches, controllers, voltage regulators, circuit breakers, automotive electrical appliances and magnetic starters.

The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Example 1

A method for preparing a silver-nickel alloy comprises the following steps:

(1) After melting silver, let it stand for 3 minutes, add nickel-magnesium alloy balls for alloying, let it stand for 2 minutes, and then continuously cast to obtain alloy round rods; the melting heating method is natural gas heating, the melting temperature is 1050°C, and the melting vacuum is 1× ^10-4 Pa; the diameter of the nickel-magnesium alloy balls is 6 mm; the nickel content in the nickel-magnesium alloy is 80wt.%, and the magnesium content is 20wt.%; the alloying method is electromagnetic stirring, the alloying temperature is 1050°C, and the alloying time is 0.5 min; the undercooling degree of continuous casting is Δ40°C; the diameter of the alloy round rod is 6 mm;

(2) performing large plastic deformation rolling on the alloy round rod obtained in step (1) to obtain an alloy wire; the total deformation of the large plastic deformation rolling is 80%; the deformation of a single pass of the large plastic deformation rolling is 12%; and the diameter of the alloy wire is 2 mm;

(3) Drawing the alloy wire obtained in step (2) to obtain a silver-nickel alloy.

The silver content in the silver-nickel alloy prepared in Example 1 is 85wt.%, the nickel content is 12wt.%, and the magnesium content is 3wt.%. The microstructure diagram of the silver-nickel alloy is shown in Figure 1. As can be seen from Figure 1, the silver-nickel alloy prepared by the present invention contains nickel distributed in a fibrous form.

The tensile strength and contact resistance of the silver-nickel alloy prepared in Example 1 were tested, and it was finally measured that the tensile strength of the silver-nickel alloy was 390 MPa and the resistivity was 2.1 μΩ·cm, indicating that the silver-nickel alloy prepared by the preparation method of the present invention has high tensile strength and excellent electrical wear resistance.

Example 2

A method for preparing a silver-nickel alloy comprises the following steps:

(1) After melting silver, let it stand for 1 minute, add nickel-magnesium alloy balls for alloying, let it stand for 5 minutes, and then continuously cast to obtain alloy round rods; the melting heating method is natural gas heating, the melting temperature is 1000°C, and the melting vacuum is 1× ^10-4 Pa; the diameter of the nickel-magnesium alloy balls is 2 mm; the nickel content in the nickel-magnesium alloy is 80wt.%, and the magnesium content is 20wt.%; the alloying method is electromagnetic stirring, the alloying temperature is 1000°C, and the alloying time is 3 minutes; the undercooling degree of continuous casting is Δ20°C; the diameter of the alloy round rod is 5 mm;

(2) performing large plastic deformation rolling on the alloy round rod obtained in step (1) to obtain an alloy wire; the total deformation of the large plastic deformation rolling is 80%; the deformation of a single pass of the large plastic deformation rolling is 15%; and the diameter of the alloy wire is 2 mm;

(3) Drawing the alloy wire obtained in step (2) to obtain a silver-nickel alloy.

The silver content in the silver-nickel alloy prepared in Example 2 is 87.5wt.%, the nickel content is 10wt.%, and the magnesium content is 2.5wt.%. The tensile strength and contact resistance of the silver-nickel alloy prepared in Example 2 were tested, and it was finally measured that the tensile strength of the silver-nickel alloy was 340MPa and the resistivity was 2.0μΩ·cm, indicating that the silver-nickel alloy prepared by the preparation method of the present invention has high tensile strength and excellent electrical wear resistance.

Example 3

A method for preparing a silver-nickel alloy comprises the following steps:

(1) After melting silver, let it stand for 1 minute, add nickel-magnesium alloy balls for alloying, let it stand for 3 minutes, and then continuously cast to obtain alloy round rods; the melting heating method is natural gas heating, the melting temperature is 1100°C, and the melting vacuum is 1× ^10-5 Pa; the diameter of the nickel-magnesium alloy balls is 20 mm; the nickel content in the nickel-magnesium alloy is 80 wt.%, and the magnesium content is 20 wt.%; the alloying method is electromagnetic stirring, the alloying temperature is 1000°C, and the alloying time is 5 minutes; the undercooling degree of the continuous casting is Δ60°C; the diameter of the alloy round rod is 9 mm;

(2) performing large plastic deformation rolling on the alloy round rod obtained in step (1) to obtain an alloy wire; the total deformation of the large plastic deformation rolling is 80%; the deformation of a single pass of the large plastic deformation rolling is 10%; and the diameter of the alloy wire is 2 mm;

(3) Drawing the alloy wire obtained in step (2) to obtain a silver-nickel alloy.

The silver content in the silver-nickel alloy prepared in Example 3 is 80wt.%, the nickel content is 16wt.%, and the magnesium content is 4wt.%. The tensile strength and contact resistance of the silver-nickel alloy prepared in Example 2 were tested, and it was finally measured that the tensile strength of the silver-nickel alloy was 410MPa and the resistivity was 2.3μΩ·cm, indicating that the silver-nickel alloy prepared by the preparation method of the present invention has high tensile strength and excellent electrical wear resistance.

It can be seen from the description of Examples 1 to 3 that the silver-nickel alloy prepared by the present invention has high tensile strength, contact resistance that meets the requirements, and excellent electrical wear resistance.

The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims (9)

1. A method for preparing a silver-nickel alloy, comprising the following steps: (1) After melting silver, adding nickel-magnesium master alloy for alloying, and then continuously casting to obtain alloy round rods; The alloying time is 0.5-5 min; the undercooling degree of the continuous casting is Δ20-80° C.; (2) performing large plastic deformation rolling on the alloy round rod obtained in step (1) to obtain alloy wire; the total deformation amount of the large plastic deformation rolling is ≥80%; (3) drawing the alloy wire obtained in step (2) to obtain a silver-nickel alloy; The alloying temperature in step (1) is 980-1100°C; By adding nickel-magnesium master alloy to molten silver for a short period of alloying, the nickel in the nickel-magnesium master alloy cannot be completely dissolved, so that part of the nickel-magnesium alloy remains in the alloy round rod; The silver-nickel alloy includes 5-20 wt.% nickel, 1-5 wt.% magnesium and the balance silver. 2. The preparation method according to claim 1, characterized in that the nickel-magnesium intermediate alloy in step (1) is a nickel-magnesium alloy ball. 3. The preparation method according to claim 2, characterized in that the diameter of the nickel-magnesium alloy ball is 2-30 mm. 4. The preparation method according to claim 2 or 3, characterized in that the nickel content in the nickel-magnesium alloy ball is ≥80wt.%. 5. The preparation method according to claim 1, characterized in that the melting atmosphere in step (1) is vacuum. 6. The preparation method according to claim 1, characterized in that the diameter of the alloy round rod in step (1) is 5-9 mm. 7. The preparation method according to claim 1, characterized in that the deformation amount of a single pass of the large plastic deformation rolling in the step (2) is ≥ 10%. 8. The preparation method according to claim 1, characterized in that the diameter of the alloy wire in step (2) is 1-3 mm. 9. The silver-nickel alloy prepared by the preparation method according to any one of claims 1 to 8.