Silver-nickel intermediate alloy and preparation method and application thereof

Abstract

The invention relates to the technical field of intermediate alloys, in particular to a silver-nickel intermediate alloy and a preparation method and application thereof. The content of Ni in the silver-nickel intermediate alloy is 1%-20%, the content of O is smaller than 30 ppm, the content of N is smaller than 10 ppm, the content of H is smaller than 8 ppm, and the nickel content deviation is smaller than or equal to 0.05%. The preparation method comprises the following steps: melting a first silver-nickel alloy with low nickel content to prepare alloy liquid; cooling to obtain semi-solid alloy liquid, adding nickel particles, stirring, and cooling to obtain a cast ingot; and forging to obtain an intermediate alloy blank, and then processing the intermediate alloy blank into a silver-nickel intermediate alloy wire or alloy foil. The silver-nickel intermediate alloy prepared through the method is high in nickel content, good in nickel distribution uniformity, high in cleanliness and good in mechanical property; the technical problem that the high-nickel-content silver-nickel intermediate alloy cannot be obtained through a conventional method is solved, and the defects that the silver-nickel intermediate alloy obtained through a powder metallurgy method is high in impurity content and poor in mechanical property are overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of master alloys, and in particular to a silver-nickel master alloy and a preparation method and application thereof. Background Art

[0002] Silver-nickel master alloy is an alloy made by adding nickel to silver. Adding a small amount of nickel to pure silver can refine the grains. When the nickel content is ≥1wt%, the hardness, wear resistance and burning resistance of pure silver can be significantly improved. Therefore, silver-nickel master alloy with a nickel content of ≥1wt% has good mechanical properties, electrical conductivity, thermal conductivity, and strong resistance to metal transfer, arc burning and electrical erosion. It is widely used in silver bonding wires, various switches, controllers, and voltage regulators.

[0003] However, since nickel and silver are not mutually soluble, the solubility of nickel in silver in the solid state is very limited, only 0.3wt%, and conventional smelting methods cannot obtain silver-nickel intermediate alloys with a nickel content of ≥1wt%. At present, powder metallurgy processes are often used in the industry to prepare silver-nickel intermediate pseudoalloys (i.e., physically uniform pseudoalloys) with high nickel content. The powder metallurgy process generally first uses a chemical co-precipitation method to obtain a silver-nickel mixed powder, and then uses a chemical method to make a silver-nickel coated powder. With the development of powder making technology, there has been a method of first using a mechanical atomization method to obtain an extremely fine powder, and then preparing a silver-nickel alloy, as well as a method of using silver and nickel co-spraying powder making and mechanical alloying technology to prepare a silver-nickel alloy. However, in the process of preparing a silver-nickel intermediate alloy using a powder metallurgy process, mixing, pressing and sintering are required. It is very easy to introduce other impurities into the powder during mixing, and the pressed silver-nickel intermediate alloy has a high porosity and a low density, resulting in a decrease in the hardness, tensile strength, conductivity and other properties of the silver-nickel intermediate alloy.

[0004] In view of this situation, it is necessary to provide a conventional preparation method for a high-nickel content silver-nickel intermediate alloy with high cleanliness and good mechanical properties.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The first purpose of the present invention is to provide a silver-nickel master alloy to solve the technical problems that the existing silver-nickel master alloy has low nickel content or the high-nickel silver-nickel master alloy prepared by powder metallurgy has high impurity content, high porosity and low density, resulting in reduced hardness, tensile strength, electrical conductivity and other properties of the silver-nickel master alloy; the silver-nickel master alloy provided by the present invention has high nickel content, good nickel distribution uniformity, high cleanliness and good mechanical properties.

[0007] The second purpose of the present invention is to provide a method for preparing the silver-nickel intermediate alloy as described above. The method of the present invention solves the processing problem of silver-nickel alloy with high nickel content. The prepared silver-nickel intermediate alloy has the advantage of high cleanliness and good mechanical properties when used for silver bonding wires.

[0008] The third object of the present invention is to provide an application of the silver-nickel master alloy as described above or the silver-nickel master alloy prepared by the method for preparing the silver-nickel master alloy as described above in the preparation of silver bonding wires.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] A silver-nickel master alloy, wherein, by mass percentage, the Ni content of the silver-nickel master alloy is 1%-20%, the O content is less than 30ppm, the N content is less than 10ppm, the H content is less than 8ppm, and the nickel content deviation does not exceed 0.05%;

[0011] The nickel content deviation refers to the difference between the nickel content at any point on the surface or inside of the silver-nickel master alloy and the theoretical nickel content in the silver-nickel master alloy.

[0012] A method for preparing the silver-nickel master alloy as described above comprises the following steps:

[0013] S1. Weighing raw materials, the raw materials comprising a first silver-nickel alloy and nickel particles, the nickel content of the first silver-nickel alloy being 0.1wt%-0.3wt%;

[0014] S2. melting the first silver-nickel alloy into a liquid alloy for standby use;

[0015] S3. lowering the temperature of the alloy liquid to make it a semi-solid alloy liquid, adding the nickel particles, stirring and cooling to obtain an ingot;

[0016] S4. Forging the ingot to obtain an intermediate alloy billet, and processing the intermediate alloy billet into a silver-nickel intermediate alloy wire or a silver-nickel intermediate alloy foil.

[0017] A use of the silver-nickel master alloy as described above or the silver-nickel master alloy prepared according to the method for preparing the silver-nickel master alloy as described above in preparing silver bonding wires.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The silver-nickel master alloy provided by the present invention has high nickel content, good nickel distribution uniformity, high cleanliness and good mechanical properties.

[0020] (2) The present invention adopts low-nickel silver-nickel alloy (nickel content 0.1wt%-0.3wt%) as raw material, adds nickel particles in semi-solid state, and evenly embeds the semi-solid melt of the low-nickel silver-nickel alloy, i.e., paste-like alloy liquid, through mechanical stirring, to obtain an ingot with uniform distribution of nickel particles, and obtains silver-nickel intermediate alloy wire or foil with high nickel content through repeated forging, hot extrusion, drawing or rolling at high temperature. The nickel content in the obtained silver-nickel intermediate alloy can be as high as 20wt%, the Ni content deviation is ≤0.05wt%, and the cleanliness is high, thereby overcoming the technical bottleneck that conventional methods cannot obtain silver-nickel intermediate alloys with high nickel content, and avoiding the shortcomings of high impurity content and poor mechanical properties in the silver-nickel intermediate alloy obtained by powder metallurgy method.

[0021] (3) The silver-nickel intermediate alloy provided by the present invention is used to prepare silver bonding wires, which can significantly improve the tensile strength of the bonding wires. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A macroscopic morphology of the silver-nickel master alloy wire provided in an embodiment of the present invention;

[0024] Figure 2 It is a comparison diagram of the microscopic morphology of the silver-nickel master alloy in comparative example 1 (left figure) and embodiment 3 (right figure) of the present invention. DETAILED DESCRIPTION

[0025] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0026] The first aspect of the present invention provides a silver-nickel master alloy, wherein, by mass percentage, the Ni content in the silver-nickel master alloy is 1%-20%, the O content is less than 30ppm, the N content is less than 10ppm, the H content is less than 8ppm, and the nickel content deviation does not exceed 0.05%.

[0027] The nickel content deviation refers to the difference between the nickel content at any point on the surface or inside of the silver-nickel master alloy and the theoretical nickel content in the silver-nickel master alloy; the theoretical nickel content is the nickel content calculated based on the amount of raw material added.

[0028] The silver-nickel master alloy provided by the present invention has high nickel content, small nickel content deviation, good nickel distribution uniformity, low N, H and O contents, high cleanliness and good mechanical properties. It can be used for silver bonding wires to improve the accuracy of nickel content addition and significantly improve the mechanical properties of the bonding wires.

[0029] In some embodiments, typically but not limiting, for example, the nickel content in the silver-nickel master alloy can be any point value of 1%, 5%, 10%, 15%, 20%, or a range value consisting of any two point values; the O content can be any point value of 29ppm, 28.5ppm, 28.0ppm, 27.4ppm, 26.5ppm, 25.3ppm, 23ppm, 20ppm, 15ppm, 10ppm, 5ppm, or a range value consisting of any two point values; the N content can be any point value of 9.5ppm, 9.0ppm, 8.7ppm, 8.6ppm, 8.5ppm, 8.3ppm, 8.0ppm, 7.0ppm, 6.0ppm, or a range value consisting of any two point values; the H content can be any point value of 7.5ppm, 7.0ppm, 6.5ppm, 6.0ppm, 5.8ppm, 5.6ppm, 5.5ppm, 5.0ppm, 3ppm, or a range value consisting of any two point values.

[0030] In some specific embodiments of the present invention, the hardness of the silver-nickel master alloy is greater than 70 HV 0.2 , for example, it can be 71HV 0.2 、80HV 0.2 、90HV 0.2 , 100HV 0.2 、110HV 0.2 、120HV 0.2 Any point value or a range of values ​​consisting of any two point values ​​in .

[0031] In some specific embodiments of the present invention, the tensile strength of the silver-nickel master alloy is greater than 240 MPa, for example, it can be any point value among 245 MPa, 278 MPa, 300 MPa, 350 MPa, 382 MPa, or a range value consisting of any two point values.

[0032] In some specific embodiments of the present invention, the density of the silver-nickel master alloy is greater than 10 g / cm 3 , for example, can be 10.1 g / cm 3 、10.2g / cm 3 , 10.3g / cm 3 , 10.4g / cm 3 , 10.5g / cm 3 、10.6g / cm 3 Any point value or a range of values ​​consisting of any two point values ​​in .

[0033] Compared with the silver-nickel master alloy with high nickel content prepared by the traditional powder metallurgy method, the silver-nickel master alloy provided by the present invention has high density and low porosity, and therefore has high hardness, high tensile strength and better mechanical properties.

[0034] The silver-nickel intermediate alloy provided by the present invention can be used for the preparation of high-tensile-strength silver bonding wires, and can also be used as contact materials for various switches, controllers, circuit breakers, and the like. The mechanical properties of the bonding wires are the key to the bonding quality, and the higher tensile strength enables the bonding wires to resist certain mechanical stresses and have stable arc-forming properties. Since the pure silver bonding wire has low hardness (softer), poor wear resistance and tensile strength, and is prone to wire breakage during the drawing process, nickel elements need to be added for strengthening, but nickel elements are difficult to be evenly distributed in silver. Therefore, the silver-nickel intermediate alloy wire in the present invention can be used as a nickel-containing silver bonding wire with high hardness and high tensile strength; it can also be added to silver as an intermediate alloy, and the "inherited" effect of the mechanical properties of the silver-nickel intermediate alloy is utilized to improve the mechanical properties of the silver bonding wire.

[0035] A second aspect of the present invention provides a method for preparing a silver-nickel master alloy as described in any one of the aforementioned embodiments, comprising the following steps:

[0036] S1. Weigh the raw materials by mass percentage, the raw materials comprising a first silver-nickel alloy and nickel particles, the nickel content of the first silver-nickel alloy being 0.1wt%-0.3wt%;

[0037] S2. The first silver-nickel alloy is melted to form a liquid alloy for standby use;

[0038] S3. lowering the temperature of the alloy liquid to make it a semi-solid alloy liquid, adding nickel particles, stirring evenly and then rapidly cooling to obtain an ingot;

[0039] S4. The ingot is repeatedly subjected to high-temperature forging to obtain an intermediate alloy billet, and the intermediate alloy billet is subjected to multiple passes of hot extrusion, drawing or rolling to obtain a silver-nickel intermediate alloy wire or a silver-nickel intermediate alloy foil.

[0040] The present invention uses nickel particles to be uniformly embedded in a semi-solid low-nickel silver-nickel alloy liquid, obtains an ingot with uniform nickel particles through mechanical stirring and rapid cooling, and then obtains a high-nickel silver-nickel intermediate alloy through forging and extrusion. The present invention uses a relatively easy-to-obtain silver-nickel alloy with a low nickel content (i.e., a first silver-nickel alloy) as a raw material, utilizes the semi-solid state of the alloy during the heating process, and uniformly embeds nickel particles in a low-nickel silver-nickel alloy liquid to prepare a high-nickel intermediate alloy. The reason for using a semi-solid alloy liquid is that when the alloy liquid is in a semi-solid state (the melt temperature is between the liquidus line and the solidus line), the alloy liquid is "paste-like", has a high density, and has a certain holding force on the nickel particles. The nickel particles will not move due to gravity or buoyancy, which helps to obtain a uniform intermediate alloy. The purpose of high-temperature forging of the ingot is to make the nickel particles evenly distributed, because repeated forging of the ingot is similar to repeated "kneading dough", which further evens out the distribution of the nickel particles.

[0041] The nickel content in the silver-nickel master alloy prepared by the method of the present invention can be as high as 20wt%, and the deviation of the Ni content is small, breaking through the technical bottleneck that the conventional smelting method cannot obtain the silver-nickel master alloy with high nickel content. Compared with the traditional powder metallurgy method (using the mechanical mixing, pressing and sintering of silver and nickel powders to obtain the alloy), the silver-nickel master alloy prepared by the method of the present invention has high density and low porosity, so it has good hardness, tensile strength and electrical conductivity; and also has the advantage of high cleanliness. It overcomes the defects of high impurity content and poor mechanical properties in the silver-nickel master alloy prepared by the powder metallurgy method.

[0042] In some specific embodiments of the present invention, the particle size of the nickel particles used is 30-50 μm, for example, it can be any point value among 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, or a range value consisting of any two point values, and the nickel particles used are hollow nickel particles or solid nickel particles.

[0043] Silver grain size refers to the average diameter or equivalent diameter of silver grains in the material. The range of silver grain size varies depending on factors such as the preparation process and heat treatment conditions. For the present invention, the silver alloy solidified after melting is in a cast state, and its silver grain size is approximately between tens and hundreds of microns. Therefore, when the nickel particle size is between 30-50μm (much smaller than the maximum size of the silver grains), the nickel particles can be evenly distributed in the gaps between the silver grains through the size effect to form an interstitial solid solution. If the nickel particle size is large, it is not easy to form an interstitial solid solution; on the contrary, if the particle size is too small, the nickel particles will agglomerate and cannot be evenly distributed.

[0044] In some specific embodiments of the present invention, in step S3, the temperature of the semi-solid alloy liquid is 970-1050°C, for example, it can be any point value among 970°C, 980°C, 990°C, 1000°C, 1010°C, 1020°C, 1030°C, 1040°C, and 1050°C, or a range value consisting of any two point values; the solid phase volume percentage of the semi-solid alloy liquid is 20%-40%, for example, it can be any point value among 20%, 25%, 30%, 35%, and 40%, or a range value consisting of any two point values.

[0045] Temperature affects the solid content of the semi-solid alloy liquid. If the solid content is too low, the viscosity of the semi-solid alloy liquid is low, and the nickel particles cannot be evenly distributed. If the solid content is too high, it is difficult for the nickel particles to enter the first silver-nickel alloy, which will also affect the uniformity of the nickel particle distribution. Reasonable control of the temperature and solid content of the semi-solid alloy liquid is conducive to improving the uniformity of the nickel particle distribution.

[0046] In some specific embodiments of the present invention, in step S3, the stirring speed is 500-800r / min, for example, it can be any point value among 500r / min, 550r / min, 600r / min, 650r / min, 700r / min, 750r / min, 800r / min or a range value consisting of any two point values; the stirring time is 6-10min, for example, it can be any point value among 6min, 7min, 8min, 9min, 10min or a range value consisting of any two point values; the nickel particles are evenly distributed in the semi-solid alloy liquid through high-speed stirring.

[0047] The two parameters of stirring speed and stirring time are to ensure the uniformity of the slurry. If the stirring speed is too low, the nickel particles cannot be suspended in the solution; if the stirring speed is too high, the melt is easy to splash and easily bring in gas; if the stirring time is too short, the nickel particles cannot be evenly distributed; if the stirring time is too long, the melt is easy to oxidize at high temperature and the efficiency is low.

[0048] In some specific embodiments of the present invention, in step S3, the cooling rate is 20-30°C / s, and the temperature is cooled to ≤150°C. For example, the cooling rate can be any point value of 20°C / s, 22°C / s, 24°C / s, 25°C / s, 26°C / s, 28°C / s, and 30°C / s, or a range value composed of any two point values. If the cooling rate is too high (higher than 30°C / s), the molten mold will be easily stress cracked due to sudden cooling; if the cooling rate is too low (lower than 20°C / s), the nickel particles that have been stirred and evenly distributed will not have time to solidify, and may sink or float, resulting in unevenness. Therefore, after the slurry is stirred evenly, it needs to be rapidly cooled to form an ingot to avoid the uniformly distributed nickel particles embedded in the semi-solid slurry from being segregated due to density differences. However, in order to avoid mold cracking, the cooling rate cannot be too fast and needs to be controlled within a reasonable range.

[0049] In some specific embodiments of the present invention, in step S3, the cooling medium includes any one of water, alcohol or powdered rare earth coolant.

[0050] In some specific embodiments of the present invention, in step S4, the forging temperature is 600-700°C, for example, it can be any point value among 600°C, 620°C, 650°C, 680°C, and 700°C, or a range value consisting of any two point values; the repeated forging is multi-directional upsetting, and the forging time is 15-30min, for example, it can be any point value among 15min, 18min, 22min, 25min, and 30min, or a range value consisting of any two point values; the deformation degree is ≥30%, for example, it can be any point value among 30%, 35%, 40%, 45%, and 50%, or a range value consisting of any two point values.

[0051] The forging temperature is generally above the recrystallization temperature of the alloy, 50-100°C higher than the alloy recrystallization temperature, and 100-200°C lower than the alloy solidus temperature. Since the recrystallization temperature of the silver-nickel alloy is about 550-600°C and the solidus temperature is 960°C, the forging temperature is 600-700°C. Multi-directional forging is to make the nickel particles evenly distributed. If the forging time is short, the nickel particles are less evenly distributed. If the forging time is long, manpower is wasted. The purpose of controlling the degree of deformation is to ensure that large particles are broken and the nickel particles are evenly distributed. The above conditions are coordinated to achieve uniform distribution of nickel in the high-nickel silver-nickel intermediate alloy.

[0052] A third aspect of the present invention provides an application of a silver-nickel intermediate alloy as described in any of the aforementioned embodiments or a silver-nickel intermediate alloy prepared by the method for preparing a silver-nickel intermediate alloy as described in any of the aforementioned embodiments in preparing silver bonding wires.

[0053] By using the present invention, a nickel-containing silver bonding wire with high hardness and high tensile strength can be directly prepared; the silver-nickel intermediate alloy in the present invention can also be added to silver as an intermediate alloy, and the mechanical properties of the silver bonding wire can be improved by utilizing the "inheritance" effect of the mechanical properties of the silver-nickel intermediate alloy.

[0054] The silver-nickel master alloy of the present invention is used to prepare silver bonding wires, which can significantly improve the tensile strength of the silver bonding wires.

[0055] The following is a detailed description of some embodiments of the present invention in conjunction with specific examples. The raw materials used in the examples can be purchased from the market unless otherwise specified.

[0056] Example 1

[0057] The nickel content in the silver-nickel master alloy provided in this embodiment accounts for 1wt% of the entire alloy.

[0058] 5 kg of silver-nickel intermediate alloy was prepared. The Ni content in the first silver-nickel alloy used in this embodiment was 0.1 wt% (i.e., Ag-0.1% Ni alloy). The nickel particles used were solid nickel particles with a particle size of 30 μm. The required amount of Ag-0.1% Ni alloy was calculated to be 4954.95 g and the amount of nickel particles was 45.05 g.

[0059] The preparation method comprises the following steps:

[0060] S1. Weigh 4954.95 g of Ag-0.1% Ni alloy and 45.05 g of nickel particles for later use;

[0061] S2. The Ag-0.1% Ni alloy is melted into a liquid alloy in a high-purity graphite mold for later use;

[0062] S3. Lower the temperature of the alloy liquid to 970°C, so that the Ag-0.1%Ni alloy liquid becomes semi-solid, the solid phase volume percentage is 40%, nickel particles are added, and the stirring device is started at the same time, the slurry is stirred at a high speed of 500r / min, and after stirring for 6 minutes, the heating is stopped, the lifting platform is started, and the graphite mold is immersed in a cooling tank filled with cooling water, and the ingot is cooled to 150°C at a cooling rate of 20°C / s to obtain an ingot;

[0063] S4. The ingot is repeatedly subjected to high temperature forging at 600°C, wherein the repeated forging is multi-directional upsetting and drawing, the forging time is 15 minutes, and the deformation degree is 30%, to obtain an intermediate alloy billet; and a silver-nickel intermediate alloy wire is obtained by multiple hot extrusion and drawing.

[0064] Example 2

[0065] The nickel content in the silver-nickel master alloy provided in this embodiment accounts for 5wt% of the entire alloy.

[0066] 5 kg of silver-nickel intermediate alloy was prepared. The Ni content in the first silver-nickel alloy used in this embodiment was 0.2 wt% (i.e., Ag-0.2% Ni alloy). The nickel particles used were solid nickel particles with a particle size of 40 μm. The required amount of Ag-0.2% Ni alloy was calculated to be 4759.5 g and the amount of nickel particles was 240.5 g.

[0067] The preparation method of this embodiment is similar to that of embodiment 1, except that:

[0068] In step S3, the temperature of the semi-solid alloy liquid is 980° C., the solid phase volume percentage in the semi-solid alloy liquid is 35%, the stirring speed is 600 r / min, and the stirring time is 7 min; the cooling medium is alcohol, the cooling rate is 30° C. / s, and the ingot is obtained by cooling to 150° C.;

[0069] In step S4, the forging temperature is 650° C., the repeated forging is multi-directional upsetting, the forging time is 18 minutes, and the deformation degree is 35%; the silver-nickel intermediate alloy foil is obtained by multiple passes of hot extrusion and rolling;

[0070] The remaining process steps and parameters are the same as those in Example 1.

[0071] Example 3

[0072] The nickel content in the silver-nickel master alloy provided in this embodiment accounts for 10 wt % of the entire alloy.

[0073] 5 kg of silver-nickel intermediate alloy was prepared. The Ni content in the first silver-nickel alloy used in this embodiment was 0.3 wt% (i.e., Ag-0.3% Ni alloy). The nickel particles used were solid nickel particles with a particle size of 45 μm. The required amount of Ag-0.3% Ni alloy was calculated to be 4513.54 g and the amount of nickel particles was 486.46 g.

[0074] The preparation method of this embodiment is similar to that of embodiment 1, except that:

[0075] In step S3, the temperature of the semi-solid alloy liquid is 990° C., the solid phase volume percentage in the semi-solid alloy liquid is 30%, the stirring speed is 700 r / min, and the stirring time is 8 min; the cooling medium is rare earth cooling medium powder, and the cooling rate is 25° C. / s.

[0076] In step S4, the forging temperature is 700° C., the repeated forging is multi-directional upsetting, the forging time is 22 minutes, and the deformation degree is 40%; the silver-nickel intermediate alloy wire is obtained by multiple hot extrusion and drawing;

[0077] The remaining process steps and parameters are the same as those in Example 1.

[0078] Example 4

[0079] The nickel content in the silver-nickel master alloy provided in this embodiment accounts for 20wt% of the entire alloy.

[0080] 5 kg of silver-nickel intermediate alloy was prepared. The Ni content in the first silver-nickel alloy used in this embodiment was 0.1 wt% (i.e., Ag-0.1% Ni alloy). The nickel particles used were solid nickel particles with a particle size of 50 μm. The required amount of Ag-0.1% Ni alloy was calculated to be 4004 g and the amount of nickel particles was 996 g.

[0081] The preparation method of this embodiment is similar to that of embodiment 1, except that:

[0082] In step S3, the temperature of the semi-solid alloy liquid is 1000° C., the solid phase volume percentage in the semi-solid alloy liquid is 25%, the stirring speed is 750 r / min, and the stirring time is 9 min;

[0083] The forging time in step S4 is 25 minutes, and the degree of deformation by forging is 45%; the silver-nickel intermediate alloy foil is obtained by multiple passes of hot extrusion and rolling;

[0084] The remaining process steps and parameters are the same as those in Example 1.

[0085] Example 5

[0086] The nickel content in the silver-nickel master alloy provided in this embodiment accounts for 20wt% of the entire alloy.

[0087] 5 kg of silver-nickel intermediate alloy was prepared. The Ni content in the first silver-nickel alloy used in this embodiment was 0.1 wt% (i.e., Ag-0.1% Ni alloy). The nickel particles used were solid nickel particles with a particle size of 50 μm. The required amount of Ag-0.1% Ni alloy was calculated to be 4004 g and the amount of nickel particles was 996 g.

[0088] The preparation method of this embodiment is similar to that of embodiment 1, except that:

[0089] In step S3, the temperature of the semi-solid alloy liquid is 1050° C., the solid phase volume percentage in the semi-solid alloy liquid is 20%, the stirring speed is 800 r / min, and the stirring time is 10 min;

[0090] In step S4, the forging temperature is 700° C., the repeated forging is multi-directional upsetting, the forging time is 30 minutes, and the deformation degree is 50%; the silver-nickel intermediate alloy foil is obtained by multiple passes of hot extrusion and rolling;

[0091] The remaining process steps and parameters are the same as those in Example 1.

[0092] Comparative Example 1

[0093] The silver-nickel intermediate alloy wire with a Ni content of 10wt% is prepared by powder metallurgy process. The specific process parameters are as follows: nickel powder is mixed at a percentage of 10wt%, silver powder and nickel powder are weighed separately, the powders are mechanically mixed by a V-shaped mixer, and a pressure of 3-5MPa is applied on a press to press them into powder ingots of a certain shape, and the intermediate alloy wire is obtained by extrusion at room temperature.

[0094] Comparative Example 2

[0095] A silver-nickel intermediate alloy with a Ni content of 10 wt% was prepared by conventional smelting and extrusion methods. It was found that nickel was easily eluted and could not be completely dissolved in silver, and a silver-nickel intermediate alloy with a Ni content of 10 wt% could not be obtained.

[0096] Comparative Example 3

[0097] Comparative Example 3 is similar to Example 3, except that: the temperature of the semi-solid alloy liquid in step S3 is 1080° C., and the solid phase volume percentage is 10%; the other process conditions are the same as those in Example 3.

[0098] The viscosity of the semi-solid alloy liquid is low at this solid phase content, and the nickel particles cannot be evenly distributed.

[0099] Comparative Example 4

[0100] Comparative Example 4 is similar to Example 3, except that the temperature of the semi-solid alloy liquid in step S3 is 950° C., the solid phase volume percentage is 50%, and the other process conditions are the same as those in Example 3.

[0101] In step S3 of this comparative example, the solid phase contains a large amount of material, resulting in uneven stirring of the nickel particles.

[0102] Comparative Example 5

[0103] Comparative Example 5 is similar to Example 3, except that there is no rapid cooling after stirring, but natural cooling under atmospheric environment, and the other process conditions are the same as those of Example 3.

[0104] Comparative Example 6

[0105] Comparative Example 6 is similar to Example 3, except that the degree of deformation during high temperature forging is lower, 10%, and the other process conditions are the same as those of Example 3.

[0106] Test Example 1

[0107] In order to verify the cleanliness, hardness and tensile strength of the silver-nickel master alloy in each embodiment and comparative example, samples were taken for nitrogen, hydrogen and oxygen content test, hardness test and tensile strength test. The test results are shown in Table 1.

[0108] Table 1

[0109]

[0110]

[0111] From the data in Table 1, it can be seen that the O, N, and H contents of the silver-nickel master alloys in Examples 1-5 are all low. Compared with the conventional alloy (Comparative Example 1), the oxygen content is reduced from hundreds of ppm to tens of ppm, and the gas impurity content in the alloy is significantly reduced. In addition, compared with Comparative Example 1, the tensile strength of the silver-nickel master alloy (Ni content is 10wt%, nickel content is the same) in Example 3 is increased from 198MPa to 350MPa, and the hardness is increased from 55HV to 1000MPa. 0.2 Increased to 110HV 0.2 , significantly improving the mechanical properties of the alloy.

[0112] Figure 1The macroscopic morphology of the silver-nickel master alloy provided by the embodiment of the present invention is shown in FIG. Figure 2 The microscopic morphology comparison diagram of the silver-nickel master alloy prepared in Comparative Example 1 and Example 3 of the present invention is shown in FIG. Figure 2 It can be seen that the silver-nickel intermediate alloy with a nickel content of 10wt% prepared in Comparative Example 1 has many black holes and shrinkage in its microstructure, which is not dense and therefore has poor mechanical properties; while the silver-nickel intermediate alloy with a nickel content of 10wt% prepared in Example 3 has a denser microstructure and better mechanical properties.

[0113] Test Example 2

[0114] In order to verify the composition uniformity of the silver-nickel master alloy in each embodiment and comparative example, the Ni content of different parts on the silver-nickel master alloy wire or silver-nickel master alloy foil was tested by ICP spectrometer. The alloy wire sampling: samples were taken every 1 meter from the silver-nickel alloy wire with a diameter of 2 mm and a length of 5 m; the alloy foil sampling: samples were taken every 1 meter along the center of the strip with a width of 100 mm and a length of 5 m. The test results are shown in Table 2.

[0115] Table 2

[0116]

[0117]

[0118] It can be seen from the data in Table 2 that the Ni element in the silver-nickel master alloy prepared in the embodiment of the present invention is evenly distributed, the Ni content in different samples is highly uniform, and the average deviation is ≤0.05%; while Comparative Example 1 is prepared by traditional powder metallurgy, and the average deviation of Ni content in the silver-nickel master alloy is ≤0.5%, which is 10 times higher than that in the embodiment, and the uniformity is relatively poor; similarly, in Comparative Example 3, due to the low solid content in the semi-solid alloy liquid, the distribution of Ni is uneven, and the Ni content deviation is increased by about 2 times compared with that in the embodiment.

[0119] Although the present invention has been illustrated and described with specific embodiments, it should be appreciated that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents without departing from the spirit and scope of the present invention. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A silver-nickel master alloy, characterized in that: In terms of mass percentage, the Ni content in the silver-nickel master alloy is 1%-20%, the O content is less than 30ppm, the N content is less than 10ppm, the H content is less than 8ppm, and the nickel content deviation does not exceed 0.05%; The nickel content deviation refers to the difference between the nickel content at any point on the surface or inside of the silver-nickel master alloy and the theoretical nickel content in the silver-nickel master alloy.

2. The silver-nickel master alloy according to claim 1, characterized in that: Contains at least one of the following characteristics: (1) The hardness of the silver-nickel master alloy is greater than 70 HV 0.2 ; (2) The tensile strength of the silver-nickel master alloy is greater than 240 MPa; (3) The density of the silver-nickel master alloy is greater than 10 g / cm 3 .

3. The method for preparing the silver-nickel master alloy according to claim 1 or 2, characterized in that: The following steps are involved: S1. Weighing raw materials, the raw materials comprising a first silver-nickel alloy and nickel particles, the nickel content of the first silver-nickel alloy being 0.1wt%-0.3wt%; S2. melting the first silver-nickel alloy into a liquid alloy for standby use; S3. lowering the temperature of the alloy liquid to make it a semi-solid alloy liquid, adding the nickel particles, stirring and cooling to obtain an ingot; S4. Forging the ingot to obtain an intermediate alloy billet, and processing the intermediate alloy billet into a silver-nickel intermediate alloy wire or a silver-nickel intermediate alloy foil.

4. The method for preparing the silver-nickel master alloy according to claim 3, characterized in that: The nickel particles have a particle size of 30-50 μm.

5. The method for preparing the silver-nickel master alloy according to claim 3, characterized in that: In step S3, the temperature of the semi-solid alloy liquid is 970-1050° C., and the solid phase volume percentage of the semi-solid alloy liquid is 20%-40%.

6. The method for preparing the silver-nickel master alloy according to claim 3, characterized in that: In step S3, the stirring speed is 500-800 r / min, and the stirring time is 6-10 min.

7. The method for preparing the silver-nickel master alloy according to claim 3, characterized in that: In step S3, the cooling rate is 20-30°C / s, and the temperature is cooled to ≤150°C.

8. The method for preparing the silver-nickel master alloy according to claim 3, characterized in that: In step S3, the cooling medium includes any one of water, alcohol or powdered rare earth coolant.

9. The method for preparing the silver-nickel master alloy according to claim 3, characterized in that: In step S4, the forging temperature is 600-700° C., the forging is multi-directional upsetting, the forging time is 15-30 minutes, and the deformation degree is ≥30%.

10. Use of the silver-nickel master alloy according to claim 1 or 2 or the silver-nickel master alloy prepared by the method for preparing the silver-nickel master alloy according to any one of claims 3 to 9 in preparing silver bonding wires.

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