阅读说明：本技术 一种银氧化锌电接触材料及其制备方法 (Silver zinc oxide electric contact material and preparation method thereof ) 是由 陈杨方 李�杰 颜小芳 柏小平 张明江 杨昌麟 陈松扬 于 2020-12-24 设计创作，主要内容包括：本发明公开了一种银氧化锌电接触材料及其制备方法,包括Ag86.5～92wt.％,ZnO5～10wt.％,SnO-22～3wt.％,CuO 1～3wt.％,Li-2O 0.5～2wt.％,其他添加物0.5～2wt.％,制备方法如下：首先利用Ag锭、Zn锭、Sn、Cu、Li及添加物,制备AgZn合金锭子,经过车削表皮、加热挤成丝材、拉拔至直径2.0mm、冲成断丝、氧化、压制成锭、烧结、热挤压、拉拔等工序,最终做成成品丝材。本发明优点是：通过在材料中添加Li、Cu、Sn元素的方法,获得了更细小的球形氧化物颗粒,同时使氧化物颗粒弥散分布在Ag基体上,提高了材料的致密度,增加了材料的抗电弧侵蚀性,抗熔焊性。同时所制成的丝材做成铆钉触点,铆钉冷镦过程开裂比例明显降低,其在直流或交流条件下,获得的电寿命均可达到10万次以上,拥有较高的抗烧损能力和电寿命。(The invention discloses a silver zinc oxide electrical contact material and a preparation method thereof, wherein the silver zinc oxide electrical contact material comprises Ag86.5-92 wt.%, ZnO 5-10 wt.%, and SnO 2 2～3wt.％，CuO 1～3wt.％，Li 2 0.5-2 wt.% of O and 0.5-2 wt.% of other additives, and the preparation method comprises the following steps: firstly, preparing an AgZn alloy spindle by utilizing Ag ingot, Zn ingot, Sn, Cu, Li and additives, turning a surface skin, heating and extruding into a wire material, drawing to the diameter of 2.0mm, punching into a broken wire, oxidizing, pressing into an ingot, sintering, hot extruding, drawing and the like, and finally preparing a finished wire material. The invention has the advantages that: by adding Li and C to the materialThe method of u and Sn elements obtains finer spherical oxide particles, and simultaneously, the oxide particles are dispersed and distributed on the Ag matrix, so that the density of the material is improved, and the arc erosion resistance and the fusion welding resistance of the material are increased. Meanwhile, the manufactured wire is used for manufacturing a rivet contact, the cracking proportion of the rivet in the cold heading process is obviously reduced, the obtained electric service life can reach more than 10 ten thousand times under the direct current or alternating current condition, and the rivet contact has higher burning loss resistance and longer electric service life.)

1. The preparation method of the silver zinc oxide electric contact material is characterized by comprising the following steps:

(1) preparing a smelting alloy ingot: according to the formula of the silver zinc oxide electric contact material, adding an Ag plate, a Zn plate and additives, wherein the additives are Li, Cu and Sn, smelting AgZn alloy in advance, and casting the solution into a mold to prepare an AgZn alloy spindle;

(2) turning treatment: removing a layer of oxide skin on the surface of a cast AgZn alloy ingot by using a lathe, wherein the lower amount of a single side lathe is 1-2 mm;

(3) and (3) extrusion treatment: preheating the turned ingot blank at 700 +/-10 ℃, and then loading the ingot blank into an oil pressure extruder at the temperature to extrude the ingot blank into a first wire material;

(4) drawing and cutting; according to the drawing process, the first wire is drawn into a second wire with smaller diameter by a wire drawing machine, and then the second wire is cut into small sections;

(5) internal oxidation: adding the cut small material sections into an internal oxidation furnace, introducing oxygen, starting the oxidation furnace, heating to 800 ℃ at 700-;

(6) and (3) ingot pressing treatment: pressing the oxidized material section into an AgZnO ingot blank by using a hydraulic press, wherein the pressure of the hydraulic press is 30 +/-2 MPa;

(7) sintering treatment: placing the AgZnO ingot blank into a sintering furnace, and sintering at 700-800 ℃ for 2-6 h;

(8) extruding: heating the sintered AgZnO spindle at the temperature of 700-800 ℃ for 3-5 hours, and then forming the sintered AgZnO spindle into a semi-finished wire by using an extruder;

(9) drawing treatment: according to the drawing process, the semi-finished wire is drawn into a finished wire with smaller diameter by a medium-frequency wire drawing machine.

2. The method of claim 1, wherein: and (4) the ingot pressing pressure maintaining time of the step (6) is 15 s.

3. The method of claim 1, wherein: and (4) the process parameters of the intermediate frequency wire drawing machine in the drawing process of the step (9) are wire drawing speed of 4.5Hz and current intensity of 12A.

4. The silver zinc oxide electric contact material is characterized in that: the paint comprises the following components in percentage by weight:

Ag 83.5～91.5wt.％，ZnO 5～10wt.％，SnO₂ 2～3wt.％，CuO 0.5～1wt.％，Li₂0.5-1 wt% of O and 0.5-1.5 wt% of other additives.

Technical Field

The invention belongs to the field of manufacturing of electrical materials, and particularly relates to a silver zinc oxide electrical contact material and a preparation method thereof.

Background

Silver-based electrical contact materials have excellent electrical and thermal conductivity, and due to the low hardness and poor resistance to electrical wear of pure silver, it is usually necessary to add other additives to the silver matrix to enhance the electrical properties of the material, such as the welding resistance, electrical life, and resistance to arc burning of the contacts. The silver zinc oxide (AgZnO) is one of the silver zinc oxide and the AgZnO, has better fusion welding resistance and arc erosion resistance, and can be applied to power relays and general relays. The main methods for preparing AgZnO at present comprise a powder metallurgy method, an alloy internal oxidation method and an atomization process, wherein the atomization process is to atomize alloy melt into powder by air or cooling water, prepare alloy oxidation powder by powder preoxidation and high-temperature oxidation processes, and finally press-form the powder to prepare an electrical contact material; the alloy internal oxidation method is used for preparing the electric contact material by alloy fusion casting and alloy oxidation. However, the electric contact materials manufactured by the processes have the problems of small material density, cracking during cold heading forming of contact rivets and influence on the service performance of the materials, and in addition, the conventional materials have low sintering density and need to be improved in the formula or manufacturing process of the conventional electric contact materials.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the silver zinc oxide electric contact material and the preparation method thereof.

In order to achieve the purpose, the technical scheme of the invention is a preparation method of a silver zinc oxide electric contact material, which is characterized by comprising the following steps:

(1) preparing a smelting alloy ingot: according to the formula of the silver zinc oxide electric contact material, adding an Ag plate, a Zn plate and additives, wherein the additives are Li, Cu and Sn, smelting AgZn alloy in advance, and casting the solution into a mold to prepare an AgZn alloy spindle;

(2) turning treatment: removing a layer of oxide skin on the surface of a cast AgZn alloy ingot by using a lathe, wherein the lower amount of a single side lathe is 1-2 mm;

(3) and (3) extrusion treatment: preheating the turned ingot blank at 700 +/-10 ℃, and then loading the ingot blank into an oil pressure extruder at the temperature to extrude the ingot blank into a first wire material;

(4) drawing and cutting; according to the drawing process, the first wire is drawn into a second wire with smaller diameter by a drawing machine, and then the second wire is cut into small sections.

(5) Internal oxidation: adding the cut small material sections into an internal oxidation furnace, introducing oxygen, starting the oxidation furnace, heating to 800 ℃ at 700-;

(6) and (3) ingot pressing treatment: pressing the oxidized material section into an AgZnO ingot blank by using a hydraulic press, wherein the pressure of the hydraulic press is 30 +/-2 MPa;

(7) sintering treatment: placing the AgZnO ingot blank into a sintering furnace, and sintering at 700-800 ℃ for 2-6 h;

(8) extruding: heating the sintered AgZnO spindle at the temperature of 700-800 ℃ for 3-5 hours, and then forming the sintered AgZnO spindle into a semi-finished wire by using an extruder;

(9) drawing treatment: according to the drawing process, the semi-finished wire is drawn into a finished wire with smaller diameter by a medium-frequency wire drawing machine.

Further setting the ingot pressing pressure maintaining time of the step (6) to be 15 s.

Further setting the process parameters of the medium-frequency wire drawing machine in the drawing process of the step (9) as wire drawing speed 4.5Hz and current intensity 12A.

The invention also provides a silver zinc oxide electrical contact material which comprises the following components in percentage by weight:

Ag 83.5～91.5wt.％，ZnO 5～10wt.％，SnO₂ 2～3wt.％，CuO 0.5～1wt.％，Li₂0.5-1 wt.% of O and 0.5-1.5 wt.% of other additives, wherein the other additives refer to elements such as Ni and Te.

The invention can achieve the following beneficial effects:

(1) compared with the existing silver zinc oxide material, the method for adding the elements Li, Cu and Sn has the advantages that the addition of the element Li is to activate the sintering process of AgZnO, so that the compactness of the material is improved, ZnO particles in the material are spherical, meanwhile, trace Sn can enable the oxide particles to be finer, the Cu element can enable the oxide particles to be dispersedly distributed on a silver substrate, the influence of a flaky structure in the original AgZnO material on the electrical property can be eliminated under the combined action of the Sn and Cu elements, the fusion welding resistance and the burning resistance of the material are improved under the combined action of the three trace elements, and the electrical life of the material is further prolonged;

(2) the shape and distribution of oxide particles in the material and the compactness of the material are improved, so that the cracking proportion of the rivet contact during forming is further reduced.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the following examples.

Example 1:

(1) preparing a smelting alloy ingot: manufacturing according to 25kg in a 1 furnace, firstly putting 86 wt.% of Ag plate, 9.5 wt.% of Zn plate, 2 wt.% of Sn, 1 wt.% of Cu, 1 wt.% of Li and 0.5 wt.% of additives, smelting in a medium-frequency smelting furnace, setting the smelting temperature at 1200 ℃, smelting for 0.5h, stirring by using a graphite rod in the smelting process, then reducing the temperature to 1100 ℃ for refining for 12min, finally pouring the refined alloy melt into a mold, putting the mold into water for cooling after solidification, and finally manufacturing an AgZn alloy spindle;

(2) turning treatment: removing a layer of oxide skin on the surface of the cast alloy ingot by using a lathe, wherein the quantity of the single side lathe is 1-2mm, and the rotating speed of the lathe is 2000 rpm;

(3) and (3) extrusion treatment: preheating the turned ingot blank at 700 +/-10 ℃, and then loading the ingot blank into an oil pressure extruder at the temperature to extrude the ingot blank into 6.0mm phi wires;

(4) drawing and cutting; according to the drawing process, drawing the wire with the diameter of 6.0mm into the wire with the diameter of 2.0mm by a wire drawing machine, and cutting the wire with the diameter of 2.0mm into small sections with the diameter of 10-15mm by a punch.

(5) Internal oxidation: adding the cut small material sections into an internal oxidation furnace, introducing oxygen, starting the oxidation furnace, heating to 800 ℃ at 700-;

(6) and (3) ingot pressing treatment: pressing the oxidized material section into a spindle with the diameter of phi 90mm by using a hydraulic machine, wherein the pressure of the hydraulic machine is 30 +/-2 MPa;

(7) sintering treatment: putting the ingot blank into a sintering furnace, and sintering at 700-800 ℃ for 2-6 h;

(8) extruding: heating the sintered AgZnO spindle at 800 ℃ at 700-;

(9) drawing treatment: according to the drawing process, drawing the wire with the diameter of 6mm into the wire with the diameter of 1.88mm by a medium-frequency wire drawing machine, wherein the drawing process comprises the following steps:

Φ6.0Δ→→Φ5.6→→Φ5.2→→Φ4.9Δ→→Φ4.5→→Φ4.2Δ→→Φ3.9→→Φ3.6→→Φ3.4Δ→→Φ3.2→→Φ3.0→→Φ2.9Δ→→Φ2.7→→Φ2.5→→Φ2.3Δ→→Φ2.1→→Φ2.0→→Φ1.88

Δ represents annealing, annealing temperature: keeping the temperature at 850 +/-10 ℃ for 2-6 h, and annealing in air. Wherein "→ →" represents hot drawing and "→" represents cold drawing.

The process parameters of the medium-frequency wire drawing machine in the drawing process are wire drawing frequency of 5.0Hz and current intensity of 10A; example 2:

the difference from example 1 was that, in the case of the charge of raw materials, 88.5 wt.% Ag plate and 7 wt.% Zn plate, and 2 wt.% Sn, 1 wt.% Cu, 1 wt.% Li, and 0.5 wt.% additive were charged in accordance with the configuration of 1 furnace of 25 kg.

Example 3:

the difference from examples 1 and 2 is that the charge of raw materials was varied in the amount of 1 furnace 25kg, 90.5 wt.% Ag plate and 5 wt.% Zn plate, and 2 wt.% Sn, 1 wt.% Cu, 1 wt.% Li, and 0.5 wt.% of additives.

The AgZnO/Cu rivet contact prepared by the above embodiment is used for carrying out simulated electrical property experiments, and the specifications of the rivet are moving contact R3.2x1.4(0.5) +1.5x1.2SR20 and static contact F3.2x1.4(0.5) +1.5x 2.5. The experimental conditions for simulating the electrical properties are as follows: 250VAC, 10A, closing force of 100g, breaking force of 60g and contact frequency of 90 times/min; 20VDC, 9A, 100g closing force, 50g breaking force and 90 contact frequencies/min, and the experimental results are shown in Table 1.

TABLE 1 Electrical Performance test results for AgZnO/Cu rivet contacts

The experimental results show that the electrical property of the example 2 in the three examples is the best, and compared with the comparative example, the electrical property of the material has good performance under both direct current conditions and alternating current conditions, the contact resistance is low, the electrical life exceeds 11 ten thousand times, and the electrical life of other examples reaches more than 9.9 ten thousand times, which is mainly attributed to the fact that the Li element is added in the invention, the electrical life of the material can be effectively prolonged, and the tissue of the prepared wire material and even the prepared rivet contact material is effectively improved.

By adopting the technical scheme, the invention can obtain the following technical effects:

(1) compared with the traditional silver zinc oxide formula, the contact made of the material produced by the invention has better electric service life under the direct current condition, and the material has the advantages of longer service life of more than 10 ten thousand times under a certain current through testing, higher fusion welding resistance and burning loss resistance;

(2) by adding Li element into the material, the density of the material is improved, and the plastic deformation capacity of the material is improved;

(3) the rivet made of the wire material prepared by the invention has the electric service life of more than 10 ten thousand times, has lower contact resistance, the lowest contact resistance is 0.5m omega, and the highest electric service life can reach about 11 ten thousand times.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention, and it is therefore to be understood that the invention is not limited by the scope of the appended claims.