AgSnO2 / Cu / CuNi precise contact composite strip and preparation method thereof

Abstract

The invention provides an AgSnO2 / Cu / CuNi precision contact composite strip and a preparation method thereof, and the method comprises the steps: thermally compounding a silver tin oxide strip and a silver strip, and then carrying out heat treatment and rolling to obtain an AgSnO2 / Ag strip; grooving the surface of the copper strip; the AgSnO2 / Ag strip, a copper strip with a groove structure in the surface and a copper-nickel alloy strip are subjected to solid-phase composite machining according to a preset proportion, and a first composite strip is obtained; performing heat treatment on the first composite strip to obtain a second composite strip; performing multi-pass cold rolling on the second composite strip to obtain a third composite strip; the third composite strip is brushed and subjected to striping treatment, and an AgSnO2 / Cu / CuNi composite strip semi-finished product is obtained; and carrying out finish rolling on the semi-finished product of the AgSnO2 / Cu / CuNi composite strip to obtain the AgSnO2 / Cu / CuNi precision contact composite strip. The composite strip provided by the invention can meet the requirements of long service life, high reliability and environmental protection of a high-end multi-layer electric contact material.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrical contact materials, in particular, to an AgSnO2 / Cu / CuNi precision contact composite strip and a preparation method thereof. BACKGROUND

[0002] AgSnO2 composite layer electrical contact material has been widely used in various low-voltage electrical appliances such as small power relays and switches due to its excellent electrical conductivity, anti-welding property, arc erosion resistance, and safety and non-toxicity. However, the working layer of the electrical contact material used in high-power AC / DC contactors and other electrical appliances has a high thickness, and the consumption of noble metal silver is large, resulting in high cost.

[0003] In order to save the use of noble metal silver while ensuring the comprehensive performance of the electrical contact material, domestic and foreign experts have carried out research on various composite layer electrical contact materials. Through retrieval, it is found that patent CN101034632A discloses a silver-based three-layer metal composite electrical contact material, the working layer of which is AgMeO or AgMe silver-based material, the transition layer is copper alloy or silver alloy solder, and the base layer is copper or copper alloy material. This patent connects the working layer and the base layer by using a transition solder layer in a vacuum furnace, and then cold-rolled to the thickness of the finished product to obtain the three-layer composite electrical contact material. However, due to the poor plasticity of AgMeO material, it is not easy to be combined with Cu, and there is a difference in ductility between the solder layer and AgMeO material and copper alloy material. After welding the three layers of materials, cold rolling with a large deformation is carried out, which can easily cause cracks and delamination at the interface of the composite layer, or edge cracking of the AgMeO region, thereby significantly reducing the service life of the electrical contact material.

[0004] Patent CN207611683U discloses a silver-based multi-layer composite electrical contact material, which comprises four layers of materials arranged in the following order: AgMeO working layer, silver or silver alloy solder layer, copper or copper alloy intermediate layer, and iron or iron alloy welding layer with a bubble point. The composite layer electrical contact material in this patent contains a high resistivity iron or iron alloy welding layer, which will generate a large resistance heat when carrying a large current, thereby causing the temperature of the electrical appliance product such as a relay to rise too high, which brings failure risk to the product. SUMMARY

[0005] In view of the defects in the prior art, the purpose of the present application is to provide an AgSnO2 / Cu / CuNi precision contact composite strip and a preparation method thereof.

[0006] In a first aspect of the present application, a preparation method of an AgSnO2 / Cu / CuNi precision contact composite strip is provided, which comprises:

[0007] hot-combining silver tin oxide strip and silver strip, and then performing heat treatment and rolling to obtain AgSnO2 / Ag strip;

[0008] slotting the surface of the copper strip to form a copper strip with a grooved structure on the surface;

[0009] solid-phase compounding the AgSnO2 / Ag strip, the copper strip with a grooved structure on the surface, and the copper-nickel alloy strip according to a preset ratio to obtain a first composite strip;

[0010] heat-treating the first composite strip to obtain a second composite strip;

[0011] cold-rolling the second composite strip in multiple passes to obtain a third composite strip;

[0012] cleaning and slitting the third composite strip to obtain an AgSnO2 / Cu / CuNi composite strip semi-product;

[0013] finely rolling the AgSnO2 / Cu / CuNi composite strip semi-product to obtain an AgSnO2 / Cu / CuNi precision contact composite strip.

[0014] Optionally, the silver tin oxide strip and the silver strip are heat-treated and rolled to obtain the AgSnO2 / Ag strip, which comprises:

[0015] heat-treating and rolling the silver tin oxide strip and the silver strip in a protective atmosphere by induction or resistance heating;

[0016] placing the materials in a heat treatment furnace, introducing a protective gas, and heat-treating;

[0017] placing the heat-treated materials in a rolling mill and cold-rolling the materials in multiple passes in a normal temperature and atmospheric environment to obtain the AgSnO2 / Ag strip.

[0018] Optionally, at least one of the following features is present:

[0019] - the heat-treating temperature is 700-850°C, and the heat-treating deformation is 55-80%;

[0020] - the heat-treating temperature is 550-650°C, and the heat-treating time is 1-3 hours;

[0021] - the deformation reduction of each pass is 3-5%, and the cumulative deformation reduction is 10-20%.

[0022] Optionally, the slotting the surface of the copper strip to form a copper strip with a grooved structure on the surface comprises: slotting one surface of the copper strip to obtain a copper strip with a grooved structure on one surface;

[0023] The AgSnO2 / Ag strip, the copper strip with a groove structure on the surface, and the copper-nickel alloy strip are solid-phase compounded at a preset ratio to obtain a first composite strip, including: embedding the AgSnO2 / Ag strip in the groove structure on one surface of the copper strip, and then stacking the copper-nickel alloy strip on the other surface of the copper strip to perform cold rolling compounding.

[0024] Optionally, the grooving treatment on the surface of the copper strip to form the copper strip with a groove structure on the surface includes: performing grooving treatment on both the upper and lower surfaces of the copper strip to form the copper strip with groove structures on both the upper and lower surfaces, and the grooves are symmetrically distributed.

[0025] The AgSnO2 / Ag strip, the copper strip with a groove structure on the surface, and the copper-nickel alloy strip are solid-phase compounded at a preset ratio to obtain a first composite strip, including: embedding the AgSnO2 / Ag strip in the groove structure on one surface of the copper strip, and then stacking the copper-nickel alloy strip on the other surface of the copper strip to perform cold rolling compounding.

[0026] Optionally, the preset ratio includes: the thickness ratio of the AgSnO2 / Ag strip, the copper strip with a groove structure on the surface, and the copper-nickel alloy strip is (15%-40%):(50%-80%):(5%-15%).

[0027] Optionally, the first composite strip is heat treated to obtain a second composite strip, including: heat treatment under a protective atmosphere, and the heat treatment temperature is 350-450°C.

[0028] Optionally, the second composite strip is cold rolled in multiple passes to obtain a third composite strip, including: the deformation reduction of each pass is 3%-5%, and the cumulative deformation reduction is 10%-20%.

[0029] Optionally, the AgSnO2 / Cu / CuNi composite strip semi-product is finish-rolled to obtain an AgSnO2 / Cu / CuNi precision contact composite strip, including: in-mold rolling the AgSnO2 / Cu / CuNi composite strip semi-product according to the requirements of the finished strip.

[0030] In a second aspect, the application provides an AgSnO2 / Cu / CuNi precision contact composite strip prepared by the method.

[0031] The application provides a preparation method of the AgSnO2 / Cu / CuNi precision contact composite strip, which improves the plasticity of the AgSnO2 material layer in the composite layer electric contact material through the pre-combination of pure silver and the inlaid composite mode, realizes the good combination of the AgSnO2 and the copper layer, and improves the consistency and reliability of the product. Through the multi-layer material structure design of the AgSnO2 / Cu / CuNi, a large amount of silver is saved, and the advantages of the AgSnO2, copper and CuNi multi-layer material are combined, so that the high-end composite layer electric contact material can be efficiently and cleanly produced in a high-speed automatic welding equipment, and the requirements of long service life, high reliability and environmental protection are met.

[0032] Other technical effects brought by additional features will be further described in corresponding embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0033] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments with reference to the attached drawings:

[0034] Figure 1 A flow chart of the preparation method of the AgSnO2 / Cu / CuNi precision contact composite strip according to an exemplary embodiment is shown. DETAILED DESCRIPTION

[0035] The application will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be pointed out that, for those skilled in the art, without departing from the concept of the application, a number of modifications and improvements can be made, which are within the scope of protection of the application. The parts not described in detail in the following embodiments can be realized by using the prior art.

[0036] The existing composite layer electric contact material has problems such as difficulty in combination of AgSnO2 and Cu layer, delamination and cracking of the composite layer interface, and large heat generation of the welding layer. Based on the above problems, the application provides a preparation method of an AgSnO2 / Cu / CuNi precision contact composite strip to solve the above problems.

[0037] Referring to Figure 1 In an embodiment of the application, the preparation method of the AgSnO2 / Cu / CuNi precision contact composite strip includes:

[0038] S1, hot-combining a silver tin oxide strip and a silver strip, and then performing heat treatment and rolling to obtain an AgSnO2 / Ag strip;

[0039] S2, slotting the surface of the copper strip to form a copper strip with a groove structure on the surface;

[0040] S3, AgSnO2 / Ag strip, copper strip with groove structure on the surface, copper-nickel alloy strip are solid-phase compounded according to a preset ratio to obtain a first composite strip;

[0041] S4, heat treating the first composite strip to obtain a second composite strip;

[0042] S5, cold rolling the second composite strip in multiple passes to obtain a third composite strip;

[0043] S6, brushing and slitting the third composite strip to obtain an AgSnO2 / Cu / CuNi composite strip semi-product;

[0044] S7, finishing the AgSnO2 / Cu / CuNi composite strip semi-product to obtain an AgSnO2 / Cu / CuNi precision contact composite strip.

[0045] The embodiment of the application increases the processability of the strip by pre-compounding AgSnO2 and Ag material, improves the plasticity and toughness of the AgSnO2 material layer of the composite layer electrical contact material, and meanwhile, adds a layer of pure silver transition layer between AgSnO2 and copper layer, solves the difficulty in compounding AgSnO2 and copper, and realizes good combination of AgSnO2 and copper layer. The embodiment of the application embeds AgSnO2 / Ag pre-compounded material strip in copper strip and then solid-phase compounds, so that AgSnO2 is subjected to upward and downward rolling force and four lateral forces at the same time, thereby making AgSnO2 be subjected to multi-directional force at the same time, and reducing the cracking caused by local stress unevenness of AgSnO2.

[0046] In the embodiments of the present application, the AgSnO2 layer is an electrical contact working layer, which enables the electrical contact to resist arc ablation and avoids welding failure at the moment of switch opening and closing. The Cu layer is a transition layer, which mainly functions to conduct current and quickly dissipate heat of the working layer. The plasticity of the AgSnO2 and CuNi layers is obviously different, and the addition of the Cu transition layer makes the two layers more workable. The CuNi layer is a welding layer, which can be firmly welded with the copper support without additional solder. The CuNi layer can also prevent rust and the occurrence of copper green on the welding layer of the assembly product due to long storage time. The multi-layer material structure design of AgSnO2 / Cu / CuNi not only saves a large amount of silver, but also combines the advantages of the multi-layer materials. The AgSnO2 / Cu / CuNi material has the advantages of AgSnO2, such as excellent electrical conductivity, welding resistance, arc erosion resistance, safety and non-toxicity, and the advantages of copper, such as high electrical conductivity, high thermal conductivity and high plasticity. The CuNi material also has the advantages of firm welding, corrosion resistance and rust prevention. The AgSnO2 / Cu / CuNi material can be applied to special application scenarios such as the ocean, coastal areas and high altitudes. When a large current flows through the material, the electrical contact material prepared in the embodiments of the present application does not contain a low-melting-point high-resistance solder layer. The copper layer in the middle layer is a high-conductivity high-thermal-conductivity material, which reduces the overall resistance of the electrical contact and the temperature rise of the multi-layer electrical contact, avoids the problem of solder layer melting and working layer falling off caused by resistance heat, and meets the requirements of long service life, high reliability and environmental protection for high-end multi-layer electrical contact materials.

[0047] The AgSnO2 / Cu / CuNi precision contact (i.e., the electrical contact composed of the three layers of materials) prepared in the embodiments of the present application can be produced continuously at high speed, high efficiency and cleanliness in a high-speed automatic welding device, avoids secondary pollution caused by the assembly process, improves the consistency and reliability of the switch product, and thus realizes the large-scale preparation of environmentally friendly, silver-saving and high-performance electrical contact materials.

[0048] The above embodiments of the present application improve the plasticity of the AgSnO2 material layer in the multi-layer electrical contact material by pre-combining pure silver and inlaying, realize the good combination of AgSnO2 and the copper layer, and improve the consistency and reliability of the product. The above embodiments of the present application also design the multi-layer material structure of AgSnO2 / Cu / CuNi, which not only saves silver, but also has the advantages of AgSnO2, such as environmental protection and high welding resistance, the advantages of copper, such as high electrical conductivity and high thermal conductivity, and the advantages of CuNi, such as rust prevention and firm welding. The AgSnO2 / Cu / CuNi material can be produced continuously at high efficiency and cleanliness in a high-speed automatic welding device, meets the requirements of long service life, high reliability and environmental protection for high-end multi-layer electrical contact materials, and has significant economic benefits.

[0049] In order to realize the preparation of the AgSnO2 / Ag strip, in some specific embodiments of the present application, the following steps can be used for the hot compounding of the silver tin oxide strip and the silver strip, and then heat treatment and rolling to obtain the AgSnO2 / Ag strip:

[0050] S11, using induction or resistance heating, hot compounding the silver tin oxide strip and the silver strip in a protective atmosphere;

[0051] S12, placing the material in a heat treatment furnace, introducing a protective gas, and performing heat treatment;

[0052] S13, placing the heat-treated material in a rolling mill, and performing multi-pass cold rolling compounding in a normal temperature and atmospheric environment to obtain the AgSnO2 / Ag strip.

[0053] For example, in S11 and S12, the protective atmosphere is nitrogen or argon.

[0054] Specifically, the thickness ratio of the AgSnO2 material layer and the Ag material layer in the AgSnO2 / Ag strip is (80-95):(15-5), wherein the mass percentage of each component of the AgSnO2 material layer is: SnO2: 6%-18%, additive X: 0-4%, and the balance is Ag, the additive X is one or more of In2O3, ZnO, Bi2O3, CuO, W, Ni, Re, and rare earth elements, and the additive functions to regulate the comprehensive electrical or mechanical properties of the AgSnO2 material, such as In2O3 improving the wettability of the reinforcing phase and the silver matrix, Bi2O3 improving the resistance to welding of the AgSnO2 material; Ce rare earth elements refining the SnO2 reinforcing phase particles and improving the electrical conductivity of the material, adding additive X to the AgSnO2 material improves the bonding strength of the reinforcing phase and the matrix, etc., which is beneficial to further improve its toughness, plasticity, arc ablation resistance and welding resistance. The Ag material layer needs to meet the requirements of good and stable electrical conductivity, good processability, and the material of the Ag material layer is pure silver or fine-grained silver. The material of the silver material layer is set based on factors such as material conductivity and formability. When the AgSnO2 and Ag strips are rolled, the silver strip deforms uniformly, has high surface quality, and does not appear wrinkles and other phenomena, and its electrical conductivity is stable, has good high-temperature creep resistance, and is not prone to high-temperature creep when the electric contact assembly is made and installed in the switch.

[0055] In the above embodiments of the present application, by means of oxide reinforcement and addition of trace elements, the segregation of AgSnO2 material, poor bonding of the reinforcing phase and the silver matrix, etc. can be improved, and the interface bonding strength, material conductivity, arc erosion resistance, mechanical wear resistance, etc. of the AgSnO2 material can be improved.

[0056] In order to improve the plasticity and toughness of the AgSnO2 material layer of the multi-layer electrical contact material and realize good combination of AgSnO2 and copper layer, in some specific embodiments of the present application, for heat compounding, heat treatment and rolling, specifically: the temperature of heat compounding is 700-850°C, the deformation amount of heat compounding is 55%-80%; the temperature of heat treatment is 550-650°C, the time of heat treatment is 1-3 hours; the deformation reduction of each pass of cold rolling is 3%-5%, and the cumulative deformation reduction is 10%-20%.

[0057] In the above embodiments of the present application, the heat compounding is performed above the recrystallization temperature of silver, and the combination is enhanced by atomic diffusion at high temperature, the compounding interface is wavy, and the machinability is good. The effect of heat treatment is to change the microstructure of the material, eliminate internal stress and internal defects of the material, and improve the mechanical properties of the material. Multi-pass cold rolling compounding is performed below the recrystallization temperature, mainly through plastic deformation to enhance the interface combination, and it is easier to accurately control the size. By setting the deformation reduction, the two materials are fully extruded and deformed at the AgSnO2 / Ag contact interface during rolling, and a fresh AgSnO2 / Ag interface forms a preliminary physical and mechanical engagement.

[0058] It should be noted that the base material of the silver tin oxide strip is still pure silver, so the heat compounding is set with the recrystallization temperature of silver as the lower limit. The recrystallization temperature of fine-grained silver or pure silver has a difference, generally in the range of 200-400°C, so the heat compounding usually needs to be greater than 400°C. AgSnO2 contains SnO2 hard phase, in order to realize the purpose that the strengthening phase and silver matrix do not dislocate or even crack during the rolling of AgSnO2, the upper limit of the heat compounding temperature needs to be close to the sintering temperature of AgSnO2.

[0059] In order to form a copper strip with a groove structure on the surface, in some specific embodiments of the present application, one surface of the copper strip can be slotted to obtain a copper strip with a groove structure on one surface; or the upper and lower surfaces of the copper strip are both slotted to form a copper strip with a groove structure on the upper and lower surfaces, and the grooves are symmetrically distributed.

[0060] Specifically, the surface groove shape is consistent with the structure of the AgSnO2 / Ag strip and the copper-nickel alloy strip, and the geometric structure is a long strip. During rolling, the AgSnO2 / Ag strip and the copper-nickel alloy strip are placed at the bottom of the groove, and the AgSnO2 / Ag and copper-nickel alloy materials extend horizontally to the groove side wall, so that the AgSnO2 / Ag and copper material, and the copper-nickel alloy and copper material are tightly combined at the compounding interface, without defects such as delamination or gap.

[0061] Preferably, the copper strip is made of any one of oxygen-free copper, pure copper, or red copper, so that the subsequently prepared multi-layer electric contact material can quickly conduct and dissipate heat when carrying a large current, thereby improving the temperature rise of electric products such as relays.

[0062] In order to inlay the AgSnO2 / Ag pre-composite material strip in the copper strip, in some embodiments of the present application, for S3, the AgSnO2 / Ag strip is inlaid in the groove structure on one surface of the copper strip, and then the copper-nickel alloy strip is stacked on the other surface of the copper strip, and cold rolling is performed for composite. Alternatively, the AgSnO2 / Ag strip and the copper-nickel alloy strip are inlaid in the groove structures on the upper surface and the lower surface of the copper strip, respectively, and then cold rolling is performed for composite.

[0063] In order to improve the bonding strength of the material composite interface and reduce the cracking caused by local stress unevenness of AgSnO2, in some embodiments of the present application, the preset ratio includes: the thickness ratio of the AgSnO2 / Ag strip, the copper strip with a groove structure on the surface, and the copper-nickel alloy strip is (15% to 40%):(50% to 80%):(5% to 15%).

[0064] Specifically, the thickness of the copper-nickel welding layer is set to be firm and not too thick to cause high temperature rise of the contact assembly. The thickness of the silver tin oxide working layer is generally set according to the product's electrical life and temperature rise requirements and production cost, so that the service life of the AgSnO2 / Cu / CuNi contact assembly after welding with the copper piece meets the requirements and has high cost performance. The thickness of the copper intermediate layer is determined according to the temperature rise of the AgSnO2 / Cu / CuNi contact assembly and the cost, and the thicker the intermediate layer, the better the heat dissipation and the lower the temperature rise.

[0065] It should be noted that the preset ratio is mainly set according to the material type and silver content of AgSnO2 / Ag, and the processability and weldability of the multi-layer electric contact material.

[0066] Specifically, the copper-nickel alloy is any one of CuNi5, CuNi10, CuNi20, CuNi25, or CuNi30. Through the copper-nickel alloy layer with a convex structure (i.e., the outer surface of the CuNi layer parallel to the working surface has a convex rib or a convex pattern), the AgSnO2 / Cu / CuNi contact strip is realized. Convex welding with copper material, no additional solder is needed throughout the process, no cleaning of welding slag is needed subsequently, and the electric contact product after welding can be directly assembled into an electric switch. Moreover, due to the rust-proof property of CuNi, the AgSnO2 / Cu / CuNi electric contact product can be used in high-rust-resistant working environments such as the ocean.

[0067] In the above embodiments of the present application, the AgSnO2 / Ag strip is placed in the groove on the upper surface of the copper strip, and in some embodiments, the copper-nickel alloy strip is placed in the groove on the lower surface of the copper strip, and then the composite rolling is performed by using the roll set with positioning grooves, with a cold rolling deformation reduction of 65% to 75%, and the pulling speed of the material strip is 1 m / s to 5 m / s, so as to improve the bonding strength of the composite interface. The width (transverse dimension) of the positioning groove of the roll set matches the width of the copper strip to be rolled, the roll positioning groove restricts the material to be rolled, limits the transverse expansion of the material, so that the strip does not expand transversely during rolling, and the composite interface is subjected to a lateral force, which promotes the close combination of the composite interface.

[0068] In some embodiments of the present application, the first composite strip is heat treated to obtain a second composite strip, including: heat treatment under a protective atmosphere, and the heat treatment temperature is 350°C to 450°C.

[0069] For example, the protective atmosphere is nitrogen or argon.

[0070] In the above embodiments of the present application, the heat treatment parameters are determined according to the interface bonding strength (diffusion interface formation condition) and other factors, so as to eliminate the residual stress in the material after cold rolling, promote the diffusion of the material at the interface, improve the mechanical properties of the material and the interface bonding strength, and avoid material cracking or delamination.

[0071] In some embodiments of the present application, the second composite strip is cold rolled in multiple passes to obtain a third composite strip, including: a deformation reduction of 3% to 5% for each pass, and a cumulative deformation reduction of 10% to 20%.

[0072] In the above embodiments of the present application, the specific parameters of cold rolling are determined according to the interface bonding strength (diffusion interface formation condition) and the work hardening requirement of the material, and through multiple small deformation cold rolling, a good diffusion layer can be formed, so that the two layers of materials are firmly combined, and the size can be accurately controlled.

[0073] Specifically, in S6, the surface of the strip obtained in step S5 is first brushed to remove surface oxides and other impurities, and then according to the width requirement, the strip is cut into multiple strips with smaller width by using a slitting knife, to obtain an AgSnO2 / Cu / CuNi composite strip semi-product.

[0074] In some embodiments of the present application, for S7, the AgSnO2 / Cu / CuNi composite strip semi-product is in-mold rolled according to the requirements of the finished strip.

[0075] Specifically, the in-mold rolling processing includes processing convex ribs or welding patterns on the surface of CuNi, etc., to prepare for subsequent welding of AgSnO2 / Cu / CuNi precision contact composite strip products and copper pieces; also includes adjusting the geometry and structure of the AgSnO2 working surface of the AgSnO2 / Cu / CuNi composite strip, which is more conducive to high-speed, efficient, and clean continuous production in high-speed automatic welding equipment, avoiding secondary pollution during the turnover of original rivet electrical contacts and other materials.

[0076] The above embodiments of the present application obtain AgSnO2 / Cu / CuNi precision contact composite strip through pre-purified silver layer combined with inlaid composite secondary composite method. Compared with the existing preparation method, the composite interface of the prepared electrical contact material is subjected to lateral force, and a pure silver transition layer is added to promote the combination of the AgSnO2 layer and the Cu layer to be more closely, the material has higher bonding strength, better material plasticity, higher material yield, and the welding layer uses CuNi with anti-rust function, the prepared material has better anti-rust and corrosion resistance. Therefore, the quality stability and product life of the electrical contact assembly prepared by using the AgSnO2 / Cu / CuNi precision contact composite strip are significantly improved. The method of the above embodiments of the present application is easy to mass produce, has high material yield, stable performance, and can be continuously produced on a high-speed automatic welding machine.

[0077] The preferred features in the above embodiments can be used alone in any embodiment, and can also be used in combination without conflict. In addition, parts not described in detail in the embodiments can be implemented by existing technology.

[0078] The present application will be further described below in combination with specific application examples / comparative examples, so that the above technical solutions of the present application can be better understood. It should be understood that the following are only some examples and do not limit the present application.

[0079] Embodiment 1:

[0080] The preparation method of the AgSnO2(12) / Cu / CuNi20 precision contact strip provided in Embodiment 1 includes the following steps:

[0081] S1: first, using inductive heating method, hot composite AgSn02(12) strip and pure silver strip at 800℃ under nitrogen atmosphere, the hot composite deformation is 75%; then the material is placed in a heat treatment furnace, heat treated at 650℃ under nitrogen for 1 hour; then the heat treated material is placed in a roller mill, cold rolled four times under atmospheric environment at room temperature, each pass cold rolling deformation reduction is 3%, the cumulative deformation reduction is 12%, to obtain AgSn02(12) / Ag strip with thickness ratio of 95:5, wherein the composition of AgSn02(12) material layer is 12wt% Sn02, 0.5% additive X (additive X contains In203 and Ce), and the balance is Ag.

[0082] S2: one surface of the T2 copper strip is subjected to slotting treatment to form a T2 copper strip with a groove structure on one surface; wherein the surface groove shape is long strip-shaped and consistent with the structure of the AgSn02(12) / Ag strip.

[0083] S3: first, the AgSn02(12) / Ag strip is embedded in the surface groove of the T2 copper strip, and then the CuNi20 strip is stacked on the other surface of the copper strip. Subsequently, the AgSn02(12) / Ag strip, the T2 copper strip with the groove depth removed, and the CuNi20 strip are cold rolled with a deformation reduction of 65% according to a preset thickness ratio of 30:60:10, and the material strip is drawn at a speed of 1m / s.

[0084] S4: the strip obtained in step S3 is placed in a heat treatment furnace and heat treated at 450℃ under nitrogen atmosphere for 2 hours.

[0085] S5: five times of cold rolling of the strip obtained in step S4; each pass cold rolling deformation reduction is 3%, and the cumulative deformation reduction is 15%.

[0086] S6: first, brushing the surface of the strip obtained in step S5, then according to the customer's width requirement, using a slitting knife to cut the strip into 8 smaller width strips to obtain AgSn02(12) / Cu / CuNi20 composite strip semi-finished product.

[0087] S7: according to the requirement of finished strip, in-mold rolling processing AgSn02(12) / Cu / CuNi20 composite strip semi-finished product to form welding ribs on the CuNi20 welding surface to obtain the required AgSn02(12) / Cu / CuNi20 precision contact composite strip product.

[0088] Example 2

[0089] The preparation method of the AgSn02(8) / Cu / CuNi10 precision contact strip provided in this embodiment 2 comprises the following steps:

[0090] S1: first, using resistance heating method, hot-composite AgSnO2(8) strip and fine-grained silver strip at 700℃ under nitrogen atmosphere, the hot-composite deformation is 65%; then, put the material into a heat treatment furnace, heat treatment for 1.5 hours at 600℃ under nitrogen; then, put the heat-treated material into a roller mill, cold-rolled three times under atmospheric environment at room temperature, the deformation reduction of each pass is 4%, the cumulative deformation reduction is 12%, to obtain AgSnO2(8) / Ag strip with a thickness ratio of 90:10, wherein the composition of the AgSnO2(8) material layer is 8wt% SnO2, 1% additive X (additive X contains Bi2O3 and CuO), and the balance is Ag.

[0091] S2: groove processing is performed on the upper and lower surfaces of the T3 copper strip to form a T3 copper strip with groove structures on both the upper and lower surfaces, and the grooves are symmetrically distributed; wherein the upper surface groove shape is consistent with the structure of the AgSnO2(8) / Ag strip, and the lower surface groove shape is consistent with the CuNi10 strip.

[0092] S3: first, embed the AgSnO2(8) / Ag strip in the upper surface groove of the T3 copper strip, and embed the CuNi10 strip in the lower surface groove of the T3 copper strip. Then, cold-rolled composite the AgSnO2(8) / Ag strip, the T3 copper strip with the groove depth removed, and the CuNi10 strip according to a preset thickness ratio of 20:65:15, with a deformation reduction of 70%, and the material strip is drawn at a speed of 2m / s.

[0093] S4: put the strip obtained in step S3 into a heat treatment furnace and heat treat at 400℃ under nitrogen atmosphere for 2 hours.

[0094] S5: four-pass cold rolling of the strip obtained in step S4; the deformation reduction of each pass is 5%, and the cumulative deformation reduction is 20%.

[0095] S6: first, brush the surface of the strip obtained in step S5, then according to the customer's width requirement, use a slitting knife to cut the strip into 10 smaller width strips to obtain AgSnO2(8) / Cu / CuNi10 composite strip semi-finished product.

[0096] S7: according to the requirements of the finished strip, in-mold rolling process AgSnO2(8) / Cu / CuNi10 composite strip semi-finished product to form a single boss-shaped welding ridge on the CuNi10 welding surface to obtain the required AgSnO2(8) / Cu / CuNi10 precision contact composite strip product.

[0097] The AgSnO2(12) / Cu / CuNi20 precision contact composite strip material prepared by welding the AgSnO2(12) / Cu / CuNi20 precision contact composite strip material prepared in the above embodiment 1 and embodiment 2 was compared with the AgSnO2(12) / Ag15CuP / Cu / Fe electrical contact assembly prepared by using the prior method (CN207611683U), and the material electrical life test, corrosion resistance and processable length evaluation were carried out. The performance characterization results of embodiment 2 and embodiment 1 were similar, and the detailed results of embodiment 1 and the comparative example were shown in table 1.

[0098] Table 1 Performance comparison of electrical contact assembly

[0099]

[0100] As can be seen from table 1, the electrical contact assembly in embodiment 1 is obviously superior to the electrical contact assembly in the comparative example in terms of electrical life test, processable length and corrosion resistance, and has the characteristics of long service life and high reliability. Compared with the comparative example, the secondary compounding in embodiment 1 makes the electrical contact assembly have higher density, a pre-compounded silver layer, promotes the close combination of the silver tin oxide working layer and the copper layer, thereby improving the service life of the electrical contact assembly, and the corrosion resistance is also superior to the comparative example by using corrosion-resistant CuNi20 instead of Fe as the welding layer. The above-mentioned embodiment method of the present application prepares the AgSnO2 / Cu / CuNi precision contact composite strip material for low-voltage electrical appliances, which has long service life, silver-saving, rust-proof corrosion resistance and high reliability. In addition, AgSnO2, Cu and CuNi are all environmentally friendly materials, and there is no risk of cadmium poisoning. The electrical contact assembly in the above-mentioned embodiment of the present application also has the characteristics of environmental protection.

[0101] In the description of the embodiments of the present application, it should be understood that the orientations or positional relationships indicated by the terms “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “bottom”, “inner”, “outer”, “clockwise”, “counterclockwise” and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0102] In addition, the terms “first” and “second” are only for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with “first” and “second” can explicitly or implicitly include one or more of the features.

[0103] In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited. In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, can also be detachably connected, or integrally connected; can be mechanically connected, can also be electrically connected; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0104] In the embodiments of the present application, the terms "including" and "having" and any variants thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally further comprises steps or units not listed, or optionally further comprises other steps or units inherent to the process, method, product or device.

[0105] The above describes some specific embodiments of the present application. It should be understood that the present application is not limited to the above specific embodiments, and those skilled in the art can make various modifications or modifications within the scope of the claims, which does not affect the essential content of the present application. The above preferred features can be used in combination in the case of not conflicting with each other.

Claims

1. A method for producing an AgSn02 / Cu / CuNi precision contact composite strip, characterized by, include: The silver-tin oxide strip and silver strip are thermally composited, and then subjected to heat treatment and rolling to obtain AgSnO2 / Ag strip; The surface of the copper strip is grooved to form a copper strip with a grooved structure on the surface. The AgSnO2 / Ag strip, the copper strip with grooved surface, and the copper-nickel alloy strip are subjected to solid-state composite processing in a preset ratio to obtain the first composite strip. The first composite strip is heat-treated to obtain the second composite strip; The second composite strip is cold-rolled in multiple passes to obtain the third composite strip; The third composite strip is cleaned and slit to obtain a semi-finished AgSnO2 / Cu / CuNi composite strip. The AgSnO2 / Cu / CuNi composite strip semi-finished product is precision rolled to obtain AgSnO2 / Cu / CuNi precision contact composite strip.

2. The preparation method of the AgSn02 / Cu / CuNi precision contact composite strip according to claim 1, characterized in that, The thermally composite silver-tin oxide strip and silver strip are then heat-treated and rolled to obtain AgSnO2 / Ag strip, comprising: The silver-tin oxide strip and the silver strip are thermally bonded using induction or resistance heating under a protective atmosphere. The material is placed in a heat treatment furnace, and a protective gas is introduced for heat treatment. The heat-treated material is placed in a rolling mill and subjected to multiple cold rolling composite processes at room temperature and atmospheric conditions to obtain AgSnO2 / Ag strip.

3. The method for preparing AgSnO2 / Cu / CuNi precision contact composite strip according to claim 2, characterized in that, It has at least one of the following characteristics: - The temperature of the thermal bonding is 700℃~850℃, and the deformation of the thermal bonding is 55%~80%; - The heat treatment temperature is 550℃~650℃, and the heat treatment time is 1 hour~3 hours; - The cold rolling deformation reduction per pass is 3% to 5%, and the cumulative deformation reduction is 10% to 20%.

4. The preparation method of the AgSn02 / Cu / CuNi precision contact composite strip according to claim 1, characterized in that, The method of grooving the surface of the copper strip to form a copper strip with a grooved structure includes: grooving one surface of the copper strip to obtain a copper strip with a grooved structure on the surface. The step of solid-state composite processing of the AgSnO2 / Ag strip, the copper strip with grooved surface, and the copper-nickel alloy strip in a preset ratio to obtain the first composite strip includes: embedding the AgSnO2 / Ag strip into the grooved structure on one surface of the copper strip, and then stacking the copper-nickel alloy strip on the other surface of the copper strip, followed by cold rolling composite processing.

5. The method for preparing AgSnO2 / Cu / CuNi precision contact composite strip according to claim 1, characterized in that, The method of grooving the surface of the copper strip to form a copper strip with a groove structure includes: grooving both the upper and lower surfaces of the copper strip to form a copper strip with groove structures on both the upper and lower surfaces, and the grooves are symmetrically distributed. The step of solid-state composite processing of the AgSnO2 / Ag strip, the copper strip with grooved surface, and the copper-nickel alloy strip in a preset ratio to obtain the first composite strip includes: embedding the AgSnO2 / Ag strip and the copper-nickel alloy strip into the grooved structures on the upper and lower surfaces of the copper strip, respectively, and then performing cold rolling composite processing.

6. The preparation method of the AgSn02 / Cu / CuNi precision contact composite strip of claim 1, characterized in that, The preset ratio includes the following: the thickness ratio of the AgSnO2 / Ag strip, the copper strip with grooved surface, and the copper-nickel alloy strip is (15%~40%):(50%~80%):(5%~15%).

7. The method for preparing AgSnO2 / Cu / CuNi precision contact composite strip according to claim 1, characterized in that, The heat treatment of the first composite strip material obtains a second composite strip material, comprising: heat treatment under a protective atmosphere, and the heat treatment temperature is 350-450 DEG C.

8. The method for preparing AgSnO2 / Cu / CuNi precision contact composite strip according to claim 1, characterized in that, The multi-pass cold rolling of the second composite strip material obtains a third composite strip material, comprising: the deformation reduction of each pass is 3-5%, and the cumulative deformation reduction is 10-20%.

9. The method for preparing AgSnO2 / Cu / CuNi precision contact composite strip according to claim 1, characterized in that, The finish rolling of the AgSnO2 / Cu / CuNi composite strip material semi-product obtains an AgSnO2 / Cu / CuNi precision contact composite strip material, comprising: in-mold rolling processing of the AgSnO2 / Cu / CuNi composite strip material semi-product according to the requirements of the finished strip material.

10. An AgSn02 / Cu / CuNi precision contact composite strip material, characterized by, The method is prepared by any one of claims 1-9.

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