High-performance composite silver alloy electrical contact material and preparation method thereof

Abstract

The invention provides a high-performance composite silver alloy electrical contact material and a preparation method thereof, and relates to an electrical contact material, and the high-performance composite silver alloy electrical contact material mainly comprises 5-55 parts by mass of silver-plated first mixed powder and 45-95 parts by mass of silver-plated second mixed powder. The preparation method comprises the steps of smelting atomization and powder electroplating of copper alloy powder, preliminary mixing and electroplating of nickel and nitride powder, and subsequent powder mixing, sintering, extrusion and processing to form a final product. According to the material, key elements are introduced, so that the comprehensive performance is remarkably improved, the contradiction between the high silver content and economic benefits is successfully reconciled, and the material becomes an economical, efficient and excellent-performance contact material and shows wide market application potential and remarkable social and economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of electrical contact materials, and in particular to a high-performance composite silver alloy electrical contact material and a preparation method thereof. Background Art

[0002] In modern industrial applications, relays and small contactors are indispensable components in low-voltage electrical equipment. Their contacts generally adopt a riveted structure and are formed by wire stamping. Although silver-copper alloys have been widely used in medium-load relays and low-current contactors, they are inferior to silver-nickel alloys in terms of arc welding resistance; however, the higher cost of silver-nickel alloys has become one of the factors restricting its application. The silver content of silver-nickel contact materials on the market is as high as 70% to 97%. The use of such a high content is a huge consumption of the precious and increasingly scarce silver resources. It also significantly increases production costs, which in turn affects the overall improvement of the economic benefits and social benefits of the products.

[0003] At present, although copper-based contact materials have shown certain advantages in the field of circuit breakers, further exploration is still needed in the application of relays and contactors. However, these materials generally face the problem of easy oxidation of copper, which leads to increased contact resistance on the contact surface and a sharp increase in temperature, which can easily cause welding failures, thereby damaging electrical equipment and possibly causing safety accidents and economic losses.

[0004] In contrast, although copper-based electrical contact materials have lower costs, their electrical properties are slightly inferior to those of silver-based materials, especially in terms of oxidation resistance and resistance to welding. Given the continued growth in demand for silver for contacts and the urgent need for electrical appliance manufacturers to reduce costs, the market is in urgent need of a new high-performance and economical alloy material. This material should be able to effectively solve the oxidation resistance problem of copper-based materials, while having excellent resistance to welding, and the cost should be controlled at an appropriate level, in order to replace traditional silver-copper alloys, silver-nickel alloys and copper-based alloy materials. Summary of the invention

[0005] The purpose of the present invention is to overcome the high cost of current silver-nickel alloy materials, the application limitations of silver-copper alloy materials, as well as the poor anti-welding performance and the problem of contact resistance fluctuation and easy fusion welding caused by the easy oxidation of copper-based alloy materials. To this end, the first purpose of the present invention is to propose a high-performance composite silver alloy electrical contact material with high efficiency and significant economic benefits, which is particularly suitable for application scenarios of medium-load relays and light-load contactors. In addition, the second purpose of the present invention is to provide an efficient preparation method to produce a high-performance composite silver alloy electrical contact material with excellent performance, significant cost-effectiveness, and specially designed for medium-load relays and light-load contactors.

[0006] To achieve the first purpose of the present invention, the technical solution adopted by the present invention is as follows: a high-performance composite silver alloy electrical contact material, comprising the following components: 5 to 55 parts by mass of a first silver-plated mixed powder, 45 to 95 parts by mass of a second silver-plated mixed powder, wherein the first mixed powder is a uniform mixture of nickel and nitride powders, and the second mixed powder is a copper alloy powder.

[0007] Furthermore, in the first mixed powder, the nitride is titanium nitride, niobium nitride and tantalum nitride.

[0008] Furthermore, the nickel accounts for 5% to 40% by mass, and the nitride accounts for 0.05% to 6% by mass.

[0009] Furthermore, the composition of the second mixed powder, in terms of mass percentage, is as follows: 0.03% to 1% vanadium, 0.08% to 10% rare earth copper alloy, 0.02% to 1.5% alkaline earth metal, and the balance is copper.

[0010] Furthermore, the rare earth copper alloy is a lanthanum-rich rare earth copper alloy or a cerium-rich rare earth copper alloy, and the mass ratio of the components of the rare earth copper alloy is 5% to 25%, and the remainder is mainly copper.

[0011] Furthermore, the alkaline earth metal is calcium or magnesium.

[0012] Furthermore, the sum of the silver contents of the first silver-plated mixed powder and the second silver-plated mixed powder accounts for 5% to 40% of the total.

[0013] To achieve the second object of the present invention, the technical solution adopted by the present invention is as follows: a method for preparing a high-performance composite silver alloy electrical contact material, the method comprising the following steps:

[0014] Step (1): Preparation of the second silver-plated mixed powder:

[0015] Step (1-1) smelting: in the smelting process of the copper alloy powder, firstly, copper is melted according to the mass percentage at a temperature of 1100° C. to 1900° C., then vanadium, rare earth copper alloy and alkaline earth metal elements are added in sequence, and a fusion treatment is performed for 1 to 3 minutes by alloying static refining technology, and finally the melt is atomized into a fine copper alloy powder of 400 to 800 mesh;

[0016] Step (1-2) silver plating: a silver layer is coated on the surface of the copper alloy powder, and silver and copper alloy constitute the basic formula;

[0017] The silver plating process includes the following steps:

[0018] (1-2-1) Cleaning and removing impurities: The copper alloy powder obtained by atomization in step (1-1) is placed in a dilute acid solution to remove surface oxides, and is stirred for 8 to 12 minutes. The clean copper alloy powder is then washed with pure water and filtered out;

[0019] (1-2-2) Dispersion and reduction: gradually add the dispersant solution to the powder obtained in step (1-2-1), and simultaneously add the reducing agent solution, while continuously stirring;

[0020] (1-2-3) Silver plating process: slowly dripping a silver nitrate solution containing a complexing agent into the solution containing the copper alloy powder in step (1-2-2) under stirring, and controlling the reaction time to be 20 to 45 minutes to form a uniform silver plating layer on the surface of the copper alloy powder;

[0021] (1-2-4) Post-treatment stage: After the silver plating process of step (1-2-3) is completed, the powder obtained in step (1-2-3) is washed with pure water, centrifuged and vacuum dried to finally obtain a silver-plated second mixed powder;

[0022] Step (2): Preparation of the first silver-plated mixed powder:

[0023] Step (2-1): reducing the nickel powder in a reduction furnace, wherein the temperature of the reduction furnace is set at 300° C. to 500° C.;

[0024] Step (2-2): Preliminarily mixing the nickel powder reduced in step (2-1) with the nitride powder according to weight percentage for 1.5 to 5 hours to obtain a first mixed powder;

[0025] Step (2-3): adding a silver ammonia solution into an ultrasonic plating tank, subjecting the first mixed powder of step 2-2 to ultrasonic oscillation treatment in the ultrasonic plating tank for 15 to 30 minutes to obtain a silver-plated first mixed powder, and washing with pure water and vacuum drying for later use;

[0026] In step (2), the nitride powder is titanium nitride, niobium nitride and tantalum nitride;

[0027] Step (3) ball milling mixed powder: the silver-plated second mixed powder prepared in step (1) and step (2) and the silver-plated first mixed powder are prepared according to weight percentage, and mixed and ball milled for 1.5 hours to 4 hours;

[0028] Step (4) forming and sintering: isostatically pressing the powders uniformly mixed in step (3) into a primary ingot at a pressure of 100Mp to 300Mp, and then sintering the primary ingot in a sintering furnace, wherein the sintering furnace is evacuated and filled with inert gas, the temperature is set at 820°C to 940°C, and the sintering time is 4 hours to 8 hours. After the sintering is completed, the sintering furnace is cooled to room temperature, and then the powder is taken out of the furnace and the surface is cleaned;

[0029] Step (5) re-pressing and extruding: re-pressing the ingot after surface cleaning in step (4) to a theoretical density of more than 90% under pressure, and then hot-extruding the re-pressed ingot in a gas-protected electric furnace, setting the heating temperature of the electric furnace to 760° C. to 930° C., and the extrusion ratio to 1:30 to 1:350, to extrude wire or sheet;

[0030] Furthermore, the diameter of the wire extruded in step (5) is φ4.0mm~φ6.5mm, and the width of the plate is 45mm~85mm and the thickness is 4mm~8mm.

[0031] Furthermore, the step (5) further includes a drawing process and a rolling process, specifically, the wire or plate extruded in step (5) is annealed at 540° C. to 750° C. and drawn to the wire diameter to be used, or the plate is rolled to the required thickness.

[0032] The beneficial effects of the present invention are as follows:

[0033] 1. Atomization technology is used to prepare copper alloy powder with mesh sizes of 400 to 800. By introducing rare earth copper alloy, high alloying is achieved during the smelting process, which promotes the formation of a more uniform solid solution and component distribution, thereby achieving precise control of the rare earth content; the addition of rare earth and alkaline earth metal elements refines the alloy structure, enhances the oxidation resistance of copper and helps to extinguish the arc, while the incorporation of vanadium optimizes the processing performance;

[0034] 2. Nickel and nitride powders are treated with ultrasonic chemical silver plating, which significantly improves their bonding strength and wettability, demonstrating excellent conductivity and self-lubricating properties, thereby improving the wear resistance, oxidation resistance, and electrical corrosion resistance of the contact material, and has excellent anti-welding performance;

[0035] 3. The addition of a small amount of alkaline earth metal further refines the grain structure and promotes the arc transfer speed, so that the generated oxides decompose quickly, effectively reducing the surface contact resistance and ensuring a lower temperature rise. DETAILED DESCRIPTION

[0036] In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0037] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. The subsequent embodiments will not explain this one by one.

[0039] Embodiment 1:

[0040] The method for preparing a high-performance composite silver alloy electrical contact material comprises the following steps:

[0041] Step (1): Preparation of the second silver-plated mixed powder:

[0042] Step (1-1) smelting: in the smelting process of the copper alloy powder, firstly, copper is melted according to the mass percentage at a temperature of 1100° C. to 1900° C., then vanadium, rare earth copper alloy and alkaline earth metal elements are added in sequence, and a fusion treatment is performed for 1 to 3 minutes by alloying static refining technology, and finally the melt is atomized into a fine copper alloy powder of 400 to 800 mesh;

[0043] Step (1-2) silver plating: a silver layer is coated on the surface of the copper alloy powder, and silver and copper alloy constitute the basic formula;

[0044] The silver plating process includes the following steps:

[0045] (1-2-1) Cleaning and removing impurities: The copper alloy powder obtained by atomization in step (1-1) is placed in a dilute acid solution to remove surface oxides, and is stirred for 8 to 12 minutes. The clean copper alloy powder is then washed with pure water and filtered out;

[0046] (1-2-2) Dispersion and reduction: gradually add the dispersant solution to the powder obtained in step (1-2-1), and simultaneously add the reducing agent solution, while continuously stirring;

[0047] (1-2-3) Silver plating process: slowly dripping a silver nitrate solution containing a complexing agent into the solution containing the copper alloy powder in step (1-2-2) under stirring, and controlling the reaction time to be 20 to 45 minutes to form a uniform silver plating layer on the surface of the copper alloy powder;

[0048] (1-2-4) Post-treatment stage: After the silver plating process of step (1-2-3) is completed, the powder obtained in step (1-2-3) is washed with pure water, centrifuged and vacuum dried to finally obtain a silver-plated second mixed powder;

[0049] Step (2): Preparation of the first silver-plated mixed powder:

[0050] Step (2-1): reducing the nickel powder in a reduction furnace, wherein the temperature of the reduction furnace is set at 300° C. to 500° C.;

[0051] Step (2-2): Preliminarily mixing the nickel powder reduced in step (2-1) with the nitride powder according to weight percentage for 1.5 to 5 hours to obtain a first mixed powder;

[0052] Step (2-3): adding a silver ammonia solution into an ultrasonic plating tank, subjecting the first mixed powder of step (2-2) to ultrasonic oscillation treatment in the ultrasonic plating tank for 15 to 30 minutes to obtain a silver-plated first mixed powder, and washing with pure water and vacuum drying for later use;

[0053] In step (2), the nitride powder is titanium nitride, niobium nitride and tantalum nitride;

[0054] Step (3) ball milling mixed powder: the silver-plated second mixed powder prepared in step (1) and step (2) and the silver-plated first mixed powder are prepared according to weight percentage, and mixed and ball milled for 1.5 hours to 4 hours;

[0055] Step (4) forming and sintering: isostatically pressing the powders uniformly mixed in step (3) into a primary ingot at a pressure of 100Mp to 300Mp, and then sintering the primary ingot in a sintering furnace, wherein the sintering furnace is evacuated and filled with inert gas, the temperature is set at 820°C to 940°C, and the sintering time is 4 hours to 8 hours. After the sintering is completed, the sintering furnace is cooled to room temperature, and then the powder is taken out of the furnace and the surface is cleaned;

[0056] Step (5) re-pressing and extruding: re-pressing the ingot after surface cleaning in step (4) to a density of more than 90% of the theoretical density under pressure, and then hot-extruding the re-pressed ingot in a gas-protected electric furnace (the heating temperature of the electric furnace is set to 760° C. to 930° C., and the extrusion ratio is 1:30 to 1:350) to extrude wire or sheet;

[0057] Step (6) Drawing and rolling: The wire or plate extruded in step (5) is subjected to vacuum annealing at 540° C. to 750° C. and then drawn to the wire diameter to be used, or the thickness required for rolling the plate.

[0058] It is further arranged that the diameter of the wire extruded in step (5) is φ4.0mm~φ6.5mm, and the width of the plate is 50mm.

[0059] Embodiment 2:

[0060] According to the preparation method of a high-performance composite silver alloy electrical contact material described in Example 1, a high-performance composite silver alloy electrical contact material is prepared, and its components, by mass percentage, are: 30% silver, 9.8% nickel, 0.2% niobium nitride, 0.03% vanadium, 1.5% rare earth metal lanthanum, 0.02% alkaline earth metal calcium, and the balance is copper.

[0061] The performance indicators of the contact material include:

[0062] Density ≥10.15g / cm 3 ; Resistivity ≤2.05μΩ·cm; Hardness (HV) 600~785Mp; Tensile strength 305~380Mp; Elongation ≥5% (soft state).

[0063] Embodiment three:

[0064] According to the method for preparing a high-performance composite silver alloy electrical contact material described in Example 1, a high-performance composite silver alloy electrical contact material is prepared, and its components, by mass percentage, are: 25% silver, 15% nickel, 0.3% titanium nitride, 2.0% rare earth copper alloy, 0.025% alkaline earth metal, and the balance is copper.

[0065] The performance indicators of the contact material include:

[0066] Density ≥10.10g / cm 3 ; Resistivity ≤ 2.20μΩ·cm; Hardness (HV) 530~770Mp;

[0067] Tensile strength 280~380Mp; elongation ≥4.5% (soft state).

[0068] Embodiment 4:

[0069] According to the preparation method of a high-performance composite silver alloy electrical contact material described in Example 1, a high-performance composite silver alloy electrical contact material is prepared, and its components, by mass percentage, are: 20% silver, 20% nickel, 0.4% titanium nitride, 2.5% rare earth copper alloy, 0.03% alkaline earth metal, and the balance is copper.

[0070] The performance indicators of the contact material include:

[0071] Density ≥10.00g / cm 3 ; Resistivity ≤2.30μΩ·cm; Hardness (HV) 570~790Mp; Tensile strength 290~405Mp; Elongation ≥4.2% (soft state).

[0072] Embodiment five:

[0073] According to the method for preparing a high-performance composite silver alloy electrical contact material described in Example 1, a high-performance composite silver alloy electrical contact material is prepared, and its components, by mass percentage, are: 15% silver, 30% nickel, 0.5% tantalum nitride, 3.5% rare earth copper alloy, 0.04% alkaline earth metal, and the balance is copper.

[0074] The performance indicators of the contact material include:

[0075] Density ≥9.83g / cm 3 ; Resistivity ≤ 2.65μΩ·cm; Hardness (HV) 605~815Mp;

[0076] Tensile strength 310~415Mp; elongation ≥4% (soft state).

[0077] Embodiment six:

[0078] According to the method for preparing a high-performance composite silver alloy electrical contact material described in Example 1, a high-performance composite silver alloy electrical contact material is prepared, and its components, by mass percentage, are: 10% silver, 40% nickel, 0.6% niobium nitride, 4.0% rare earth copper alloy, 0.05% alkaline earth metal, and the balance is copper.

[0079] The performance indicators of the contact material include:

[0080] Density ≥9.82g / cm 3 ; Resistivity ≤ 3.23μΩ·cm; Hardness (HV) 660~860Mp;

[0081] Tensile strength 360~430Mp; elongation ≥3.5% (soft state).

[0082] Embodiment seven:

[0083] According to the method for preparing a high-performance composite silver alloy electrical contact material described in Example 1, a high-performance composite silver alloy electrical contact material is prepared, and its components, by mass percentage, are: 15% silver, 20% nickel, 0.2% tantalum nitride, 3.0% rare earth copper alloy, 0.03% alkaline earth metal, and the balance is copper.

[0084] The performance indicators of the contact material include:

[0085] Density ≥10.00g / cm 3 ; Resistivity ≤ 2.30μΩ·cm; Hardness (HV) 580~795Mp;

[0086] Tensile strength 290~405Mp; elongation ≥4.2% (soft state).

[0087] Embodiment eight:

[0088] According to the preparation method of a high-performance composite silver alloy electrical contact material described in Example 1, a high-performance composite silver alloy electrical contact material is prepared, and its components, by mass percentage, are: 40% silver, 10% nickel, 0.2% titanium nitride, 0.03% vanadium, 1.5% rare earth metal lanthanum, 0.02% alkaline earth metal calcium, and the balance is copper.

[0089] The performance indicators of the contact material include:

[0090] Density ≥10.15g / cm 3 ; Resistivity ≤2.05μΩ·cm; Hardness (HV) 600~785Mp; Tensile strength 305~380Mp; Elongation ≥5.0% (soft state).

[0091] Examples 2 to 8 A high-performance composite silver alloy electrical contact material was prepared according to the method described in Example 1. The mechanical and physical properties of the obtained high-performance composite silver alloy electrical contact material are shown in the following table:

[0092]

[0093] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A high-performance composite silver alloy electrical contact material, characterized in that: The invention comprises the following components: 5 to 55 parts by mass of a first silver-plated mixed powder and 45 to 95 parts by mass of a second silver-plated mixed powder. The first mixed powder is a uniform mixture of nickel and nitride powders, and the second mixed powder is a copper alloy powder.

2. A high performance composite silver alloy electrical contact material according to claim 1, characterized in that: In the first mixed powder, the nitrides are titanium nitride, niobium nitride and tantalum nitride.

3. A high performance composite silver alloy electrical contact material according to claim 2, characterized in that: The nickel accounts for 5 to 40% by mass, and the nitride accounts for 0.05 to 6% by mass.

4. The high performance composite silver alloy electrical contact material according to claim 1, characterized in that: The composition of the second mixed powder is, by mass percentage, 0.03% to 1% of vanadium, 0.08% to 10% of rare earth copper alloy, 0.02% to 1.5% of alkaline earth metal, and the balance is copper.

5. A high performance composite silver alloy electrical contact material according to claim 4, characterized in that: The rare earth copper alloy is a lanthanum-rich rare earth copper alloy or a cerium-rich rare earth copper alloy. The mass proportion of the rare earth copper alloy components is 5% to 25%, and the remainder is mainly copper.

6. The high performance composite silver alloy electrical contact material according to claim 4, characterized in that: The alkaline earth metal is calcium or magnesium.

7. The high-performance composite silver alloy electrical contact material according to claim 1, characterized in that: The sum of the silver contents of the first silver-plated mixed powder and the second silver-plated mixed powder accounts for 5% to 40% of the total.

8. A method for preparing a high-performance composite silver alloy electrical contact material as claimed in any one of claims 1 to 7, the method comprising the following steps: Step (1): Preparation of the second silver-plated mixed powder: Step (1-1) smelting: in the smelting process of the copper alloy powder, firstly, copper is melted according to the mass percentage, then vanadium, rare earth copper alloy and alkaline earth metal elements are added in sequence, and the fusion treatment is carried out by alloying static refining technology, and finally the melt is atomized into a fine copper alloy powder of 400 to 800 mesh; Step (1-2) silver plating: a silver layer is coated on the surface of the copper alloy powder, and silver and copper alloy constitute the basic formula; The silver plating process includes the following steps: (1-2-1) Cleaning and removing impurities: The copper alloy powder obtained by atomization in step (1-1) is placed in a dilute acid solution to remove surface oxides, ensuring sufficient stirring, and then washed with pure water and filtered to obtain clean copper alloy powder; (1-2-2) Dispersion and reduction: gradually add the dispersant solution to the powder obtained in step (1-2-1), and simultaneously add the reducing agent solution, while continuously stirring; (1-2-3) Silver plating process: under stirring, a silver nitrate solution containing a complexing agent is added dropwise to the solution containing the copper alloy powder in step (1-2-2), so as to form a uniform silver plating layer on the surface of the copper alloy powder; (1-2-4) Post-treatment stage: After the silver plating process of step (1-2-3) is completed, the powder obtained in step (1-2-3) is washed with pure water, centrifuged and vacuum dried to finally obtain a silver-plated second mixed powder; Step (2): Preparation of the first silver-plated mixed powder: Step (2-1): reducing the nickel powder in a reduction furnace; Step (2-2): Preliminarily mixing the nickel powder reduced in step (2-1) and the nitride powder according to weight percentage to obtain a first mixed powder; Step (2-3): adding a silver ammonia solution into an ultrasonic plating tank, subjecting the first mixed powder of step (2-2) to ultrasonic oscillation treatment in the ultrasonic plating tank to obtain a silver-plated first mixed powder, and washing with pure water and vacuum drying for later use; In step (2), the nitride powder is titanium nitride, niobium nitride and tantalum nitride; Step (3) ball milling mixed powder: the silver-plated second mixed powder prepared in step (1) and step (2) and the silver-plated first mixed powder are prepared according to weight percentage, and mixed and ball milled to obtain a uniformly mixed powder; Step (4) forming and sintering: isostatically pressing the uniformly mixed powder obtained in step (3) into a primary ingot, and then sintering the primary ingot in a sintering furnace, wherein the sintering furnace is evacuated and filled with inert gas, and after the sintering is completed, the sintering furnace is cooled to room temperature, and then the powder is taken out of the furnace and the surface is cleaned; Step (5) re-pressing and extruding: the ingot after surface cleaning in step (4) is re-pressed under pressure to a density of more than 90% of the theoretical density, and then the re-pressed ingot is hot-extruded in a gas-protected electric furnace to extrude wire or sheet.

9. The method for preparing a high-performance composite silver alloy electrical contact material according to claim 8, characterized in that: The diameter of the wire extruded in step (5) is φ4.0mm~φ6.5mm, and the width of the plate is 45mm~85mm and the thickness is 4mm~8mm.

10. The method for preparing a high-performance composite silver alloy electrical contact material according to claim 9, characterized in that: The step (5) further includes a drawing process and a rolling process, specifically, the wire or plate extruded in step (5) is annealed at 540° C. to 750° C. and drawn to the wire diameter to be used, or the plate is rolled to the required thickness.

Images