Method for manufacturing external electrode and external electrode manufactured thereby

Abstract

The present disclosure relates to a method for manufacturing an external electrode, the method comprising the steps of: (a) preparing a copper powder; (b) preparing a binder solution; (c) mixing the copper powder in step (a), the binder solution in step (b), diethylene glycol butyl ether, terpineol, and kerosene to prepare a paste; (d) screen printing the paste in step (c) on a ceramic substrate to prepare an intermediate; and (e) post-treating the intermediate in step (d).

Description

Manufacturing method of external electrode and external electrode according to the method

[0001] The present disclosure relates to a method for manufacturing an external electrode and an external electrode produced thereby.

[0002] In general, copper alloys are used as semiconductor materials, such as transistors, integrated circuits (ICs), large-scale integration (LSI), very large scale integration (VLSI), diode lead frame materials, heat dissipation materials, lead frame materials for electronic components, and parts materials for electronic devices.

[0003] Copper alloys can also be used as ceramic elements. Ceramic elements have fast response and precision, and can be made small and lightweight, so their applications are expanding to micro-displacement control devices, valves, and pumps.

[0004] In relation to this, Korean Patent Publication No. 10-2020-0033167 (Ceramic element using metal oxide and manufacturing method thereof) discloses a technology of using a metal oxide such as copper oxide, forming a core-shell powder composed of a core made of the metal oxide and a shell made of metal surrounding the core, coating glass on the surface of the core-shell powder, and then mixing it with a binder to form an electrode paste, and then printing and laminating the electrode paste on a ceramic tape to form a ceramic laminate, and then subjecting the ceramic laminate to a first heat treatment in an oxidizing atmosphere and then a second heat treatment in a reducing atmosphere containing hydrogen.

[0005] That is, conventional technologies have attempted to prevent shrinkage and expansion of electrodes during heat treatment by using metal oxides to prevent metal oxidation reactions from occurring, and to provide a method for ultimately reducing metal oxides into metals having a nanoporous structure.

[0006] However, heat treatment typically requires large furnace equipment that takes up a significant amount of workspace. Furthermore, the dry reaction of metal oxides requires a high-temperature process with a large amount of hydrogen, requiring prolonged use. This inevitably entails significant costs, making mass production difficult. Furthermore, particle size control is difficult, leading to segregation when applied to wet processes.

[0007] Therefore, a technology is required that allows easy particle size control through a simple method while preventing problems such as segregation from occurring, and a technology is also required to manufacture electrodes that exhibit characteristics equivalent to those of conventional electrodes.

[0008] [Prior Art Literature]

[0009] [Patent Document]

[0010] (Patent Document 1) Republic of Korea Patent Publication No. 10-2020-0033167 (Published on March 27, 2020)

[0011] The technical problem of the present disclosure is to provide a method for manufacturing a copper-heterometal alloy powder having a desired particle size in a simple manner and using the powder to manufacture an external electrode.

[0012] However, the problems to be solved by the present disclosure are not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the description below.

[0013] The present disclosure provides, in one embodiment, a method for manufacturing an external electrode, comprising the steps of (a) preparing copper powder, (b) preparing a binder solution, (c) mixing the copper powder of step (a), the binder solution of step (b), diethylene glycol butyl ether, terpineol, and keratin to prepare a paste, (d) screen-printing the paste of step (c) onto a ceramic substrate to prepare an intermediate, and (e) post-treating the intermediate of step (d).

[0014] In addition, in step (a), the copper powder may be a copper-heterometal alloy powder in which copper is combined with one or more heterometals selected from the group consisting of nickel, manganese, tin, zinc, and aluminum.

[0015] In addition, step (a) may include (1) a step of introducing copper and at least one heterometal selected from the group consisting of nickel, manganese, tin, zinc, and aluminum into a solvent and mixing them to produce a copper-heterometal mixture, (2) a step of alloying the copper-heterometal mixture by heat-treating it under an inert atmosphere and exposing it to air to produce a copper-heterometal oxide alloy powder, (3) a step of milling the copper-heterometal oxide alloy powder and then performing a first filtering to produce a first-filtered copper-heterometal oxide alloy powder, (4) a step of wet-reducing the first-filtered copper-heterometal oxide alloy powder and then performing a second filtering to produce a copper-heterometal alloy powder, and (5) a step of densifying the second-filtered copper-heterometal alloy powder by immersing it in a copper sulfide solution.

[0016] In addition, in step (b), the binder solution is prepared by mixing a water-soluble binder resin into a solvent, and the solvent is at least one selected from the group consisting of methanol, ethanol, toluene, isopropyl alcohol, dimethyl sulfoxide, ethyl carbitol, ethyl cellosolve, methyl pyrrolidone (NMP), and water (H2O), and the water-soluble binder resin may be at least one selected from the group consisting of a cellulose polymer, a starch polymer, polyvinyl pyrrolidone, polyvinyl alcohol, a novolak resin, and an acrylate resin.

[0017] In addition, step (c) can be performed by mixing and stirring 100 parts by weight of copper powder, 10 to 30 parts by weight of diethylene glycol butyl ether, 5 to 20 parts by weight of binder solution, and 0.1 to 2 parts by weight of keratin.

[0018] In addition, step (e) may include a step of drying the intermediate of step (d) at a temperature of 100 to 200°C for 30 to 120 minutes, a step of sintering the dried intermediate at a temperature of 700 to 750°C for 5 to 20 minutes, and a step of subjecting the sintered intermediate to a low-temperature heat treatment or a wet heat treatment.

[0019] In addition, low-temperature heat treatment can be performed at a temperature of 250 to 350 ℃ for 6 to 10 hours in a reducing atmosphere of N2 / H2.

[0020] In addition, wet heat treatment can be performed by placing the sintered intermediate in a mixed solvent of a hydrogen solution and distilled water and heat treating it in a dryer at a temperature of 40 to 90°C for 10 to 60 minutes.

[0021] The present disclosure provides an external electrode manufactured by the method described above in another embodiment.

[0022] According to the present disclosure, a copper-heterometal alloy powder having a desired particle size can be manufactured in a simple manner, and by manufacturing an external electrode using the same, the characteristics of the external electrode can be improved.

[0023] In addition, the equipment required for manufacturing copper-dielectric alloy powder is simplified compared to conventional methods, and it is environmentally friendly.

[0024] In addition, since there is no segregation phenomenon that occurs in conventional wet processes, copper-heterometal alloy powder can be mass-produced easily, thereby reducing the manufacturing cost when manufacturing external electrodes.

[0025] The effects of the present disclosure are not limited to the effects described above, and effects not mentioned can be clearly understood by those skilled in the art from the present specification and the attached drawings.

[0026] FIG. 1 is a flowchart showing a method for manufacturing an external electrode according to one embodiment of the present disclosure.

[0027] Figure 2 shows an SEM image of the copper-nickel alloy powder after the reduction process.

[0028] Figure 3 shows an SEM image of copper-nickel alloy powder after the densification process.

[0029] Figure 4 shows the results of analyzing the electrical conductivity of examples and comparative examples.

[0030] The present disclosure provides, in one embodiment, a method for manufacturing an external electrode, comprising the steps of (a) preparing copper powder, (b) preparing a binder solution, (c) mixing the copper powder of step (a), the binder solution of step (b), diethylene glycol butyl ether, terpineol, and keratin to prepare a paste, (d) screen-printing the paste of step (c) onto a ceramic substrate to prepare an intermediate, and (e) post-treating the intermediate of step (d).

[0031] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be implemented in various different embodiments and is not limited to the embodiments described herein. Like reference numerals designate similar parts throughout the specification.

[0032] The present disclosure provides a method for manufacturing an external electrode, comprising, in one embodiment, (a) a step of preparing copper powder (S100), (b) a step of preparing a binder solution (S200), (c) a step of preparing a paste by mixing the copper powder of step (a), the binder solution of step (b), diethylene glycol butyl ether, terpineol, and keratin (S300), (d) a step of preparing an intermediate by screen-printing the paste of step (c) on a ceramic substrate (S400), and (e) a step of post-processing the intermediate of step (d) (S500).

[0033] Hereinafter, the manufacturing method of the present disclosure will be described in detail with reference to FIG. 1.

[0034] Step (a) of preparing copper powder

[0035] First, as shown in Fig. 1, a step (S100) of preparing copper powder is performed.

[0036] In step (a), the copper powder may be a copper-diverse metal alloy powder combined with copper and one or more dissimilar metals selected from the group consisting of nickel, manganese, tin, zinc, and aluminum, specifically a copper-nickel alloy powder or a copper-aluminum alloy powder combined with copper and nickel or copper and aluminum, and more specifically a copper-nickel alloy powder combined with copper and nickel.

[0037] Step (a) may include (1) a step of introducing copper and at least one heterometal selected from the group consisting of nickel, manganese, tin, zinc, and aluminum into a solvent and mixing them to produce a copper-heterometal mixture, (2) a step of alloying the copper-heterometal mixture by heat-treating it under an inert atmosphere and exposing it to air to produce a copper-heterometal oxide alloy powder, (3) a step of milling the copper-heterometal oxide alloy powder and then performing a first filtering to produce a first-filtered copper-heterometal oxide alloy powder, (4) a step of wet-reducing the first-filtered copper-heterometal oxide alloy powder and then performing a second filtering to produce a copper-heterometal alloy powder, and (5) a step of densifying the second-filtered copper-heterometal alloy powder by immersing it in a copper sulfide solution.

[0038] Step (1) is a step for manufacturing a copper-heterometal mixture, and copper and the heterometal can be manufactured by mixing them in a weight ratio of 10 to 90:90 to 10.

[0039] If the copper content is less than 10 weight ratio, it is difficult to exhibit the properties of copper due to the low copper content, and if the copper content exceeds 90 weight ratio, it is difficult to stably manufacture a copper-heterometal mixture during manufacturing.

[0040] Step (1) can be manufactured by mixing copper and a dissimilar metal in the aforementioned weight ratio to manufacture a mixed powder, and then sufficiently mixing the mixed powder and a solvent in a weight ratio of 30 to 40:60 to 70.

[0041] Additionally, the solvent may be distilled water, alcohol, or a mixture thereof.

[0042] In step (1), if the content of the mixed powder is less than 30 weight ratio, the production rate is not good, and if the content of the mixed powder is more than 40 weight ratio, the copper and the heterometal are not uniformly mixed due to the relatively small amount of solvent.

[0043] After producing a copper-heterometal mixture through sufficient mixing, a dried copper-heterometal mixture can be produced by drying at a temperature of room temperature to 100°C.

[0044] The drying method is not limited as long as it can sufficiently dry the copper-dielectric mixture.

[0045] Step (2) is a step of manufacturing a copper-heterometal oxide powder using the copper-heterometal mixture manufactured in step (1). The copper-heterometal mixture may be heat-treated under an inert atmosphere to alloy it and exposed to air to manufacture a copper-heterometal alloy powder (copper-heterometal oxide alloy powder) with an oxidized surface.

[0046] The term “inert atmosphere” as used herein refers to “reducing atmosphere”.

[0047] In this step, a reducing atmosphere can be created by selecting one type of gas selected from the group consisting of nitrogen gas, hydrogen gas, and a mixed gas thereof. Specifically, a mixed gas in which nitrogen gas and hydrogen gas are mixed in a volume ratio of 0 to 100:0 to 100 can be used, and more specifically, a mixed gas in which nitrogen gas and hydrogen gas are mixed in a volume ratio of 95:5 can be used.

[0048] In step (2), the heat treatment can be performed for 30 to 360 minutes at a heating rate of 2°C per minute to reach a temperature of 500 to 650°C, and specifically, can be performed at a temperature of 550°C for 120 minutes.

[0049] If the heat treatment temperature is less than 500 ℃, the copper-diverse metal mixture is not alloyed, and if it exceeds 650 ℃, the temperature is high and the oxidation rate of copper or diverse metal is faster than the alloying rate, making it impossible to manufacture copper-diverse metal oxide alloy powder.

[0050] That is, a copper-heterometal mixture can be alloyed through heat treatment under a reducing atmosphere within the aforementioned range.

[0051] Afterwards, the copper-heterometal alloy powder can be manufactured by exposing the manufactured copper-heterometal alloy powder to air (oxygen atmosphere) to oxidize the surface.

[0052] The particle size of the copper-dielectric oxide alloy powder obtained in step (2) may be 0.1 to 100 μm. The particle size can be measured using a laser particle size analyzer.

[0053] Step (3) is a step for manufacturing a primary filtered copper-heterometal oxide alloy powder, which can be manufactured by first filtering the copper-heterometal oxide alloy powder obtained in step (2) after milling.

[0054] In step (3), milling can be performed using zirconia balls having a diameter of 10 mm or less, and specifically, the copper-diverse metal oxide alloy powder and the zirconia balls can be mixed at a weight ratio of 1:1 to 10 and performed at a speed of 120 to 1,000 rpm, and specifically, the zirconia balls and the copper-diverse metal oxide alloy powder can be mixed at a weight ratio of 1:1 to 5 and performed at a speed of 80 to 500 rpm. The copper-diverse metal oxide alloy powder milled under the conditions described above can have a particle size of 1 to 20 ㎛.

[0055] Afterwards, the milled copper-dielectric oxide alloy powder can be first filtered to select the particle size of the powder to be 10 ㎛ or less.

[0056] As described above, step (3) is a step of milling and selecting the copper-dielectric oxide alloy powder so that the particle size is at most 10 ㎛ or less.

[0057] The method of primary filtering is not limited, but can be performed using a wet or dry method, and in some cases, an ultrasonic sedimentation method can be used. For example, in the wet method, a copper-dielectric alloy powder milled in water is added to prepare a mixed solution, and then a paper mesh filter is used to select copper-dielectric alloy powder with a particle size of up to 10 ㎛. In the dry method, a mesh screen can be used for selection.

[0058] Step (4) is a secondary filtering step, and the secondary filtered copper-heterometal oxide alloy powder can be obtained by secondary filtering after wet reduction of the primary filtered copper-heterometal oxide alloy powder obtained in step (3).

[0059] In step (4), wet reduction can be performed by impregnating the primary filtered copper-dielectric oxide alloy powder into a hydrazine solution (N2H4·H2O) and maintaining the temperature at 50 to 150 ℃ for 30 to 120 minutes.

[0060] The term “wet reduction” used in this disclosure refers to “hydrazine solution reduction method.”

[0061] The copper-heterometal oxide alloy powder that has been first filtered through step (4) is reduced to produce a copper-heterometal alloy powder.

[0062] In addition, the copper-diverse metal alloy powder produced by reduction of the copper-diverse metal oxide alloy powder is produced as a fine powder with small and uniform particle sizes. Specifically, it can have a particle size of several hundred nanometers to micrometers.

[0063] The wet reduction process of step (4) can be carried out at a temperature of 30 to 150°C for 30 to 120 minutes, specifically at a temperature of 30 to 120°C, and more specifically at a temperature of 60°C. That is, the wet reduction process is carried out while the hydrazine solution used in the wet reduction process is heated to 30 to 150°C.

[0064] If the temperature of the hydrazine solution is below 30°C, the reduction reaction cannot proceed, and if it exceeds 150°C, there is a problem that the stability of the hydrazine solution may be reduced.

[0065] Additionally, the hydrazine solution in step (4) may have a pH of 13 or less and may contain 1 mol% or less of sodium chloride.

[0066] If the wet reduction time is less than 20 minutes, the reduction may not be complete, or the reduction may not occur, preventing fine powder formation and making mass production impossible. If the time exceeds 120 minutes, not only may the reduction not occur, but there is also the problem of deterioration in physical properties.

[0067] Afterwards, the fine copper-heterometal alloy powder can be selected through secondary filtering, and in this case, the secondary filtering can select the copper-heterometal alloy powder with a size of less than 1 ㎛ or less than 1 to 5 ㎛ using an ultrasonic sedimentation method, depending on the wet or dry case, as described above.

[0068] Step (5) is a step for densifying the manufactured copper-heterometal alloy powder, and the process can be carried out by putting the copper-heterometal alloy powder into a copper sulfide solution (Cu2SO4·H2O) at a temperature of 30 to 70 ℃ and maintaining it for 30 to 120 hours.

[0069] If the temperature of the copper sulfide solution is less than 30°C and the time is less than 30 minutes, densification of the copper-dielectric alloy powder cannot be achieved, and if the temperature of the solution exceeds 70°C and the time exceeds 120 minutes, a problem may occur with the stability of the solution, so the above range is preferable.

[0070] Step (a) can be performed repeatedly in steps (3) and (4), and specifically, can be performed repeatedly 2 to 5 times depending on the particle size of the copper-heterometal alloy powder or the state of the powder, and through repeated performance, a copper-heterometal alloy powder having a desired particle size can be manufactured.

[0071] A copper-dielectric alloy powder having a particle size of less than 1 ㎛ or a particle size of 1 to 5 ㎛ can be manufactured through a subsequent drying step, and the drying method is not limited.

[0072]

[0073] Step (b) of preparing a binder solution

[0074] Next, as shown in Fig. 1, a step (S200) of preparing a binder solution is performed.

[0075] In step (b), the binder solution can be prepared by adding a water-soluble binder resin to a solvent and mixing them.

[0076] The water-soluble binder resin may be at least one selected from the group consisting of a cellulose-based polymer, a starch-based polymer, polyvinylpyrrolidone, polyvinyl alcohol, a novolak-based resin, and an acrylate-based resin, and may be specifically a cellulose-based polymer, and more specifically, may be ethylcellulose.

[0077] The weight average molecular weight of the water-soluble binder resin can be 2,000 to 30,000.

[0078] If the weight average molecular weight of the water-soluble binder resin is less than 2,000, it is difficult to control the viscosity of the paste as described below, and if it exceeds 30,000, the viscosity control is easy, but it may cause defects during screen printing.

[0079] The solvent may be at least one selected from the group consisting of methanol, ethanol, toluene, isopropyl alcohol, dimethyl sulfoxide, ethyl carbitol, ethyl cellosolve, methyl pyrrolidone, and water, and specifically, may be a mixed solvent of toluene and ethanol, and more specifically, may be a mixed solvent of ethanol (EP grade) and toluene (Daejeong Reagent, 99.5%, EP grade) in a weight ratio of 1:1 to 5, or a weight ratio of 1:1 to 3.

[0080] For example, in step (b), the binder solution can be prepared by mixing and stirring ethyl cellulose in a mixed solvent of ethanol and toluene in a volume ratio of 1:3 to 5, at a concentration of 10 to 30 wt%, preferably 20 wt%.

[0081] The stirring method can be performed until the binder resin is sufficiently dissolved in the mixed solvent, and is not limited thereto.

[0082]

[0083] Step (c) of preparing paste

[0084] Next, as shown in Fig. 1, a step (S300) of manufacturing a paste is performed.

[0085] In step (c), the paste can be obtained by mixing and stirring the copper powder obtained in step (a), the binder solution obtained in step (b), diethylene glycol butyl ether, terpineol, and keratin.

[0086] The copper powder mentioned in step (c) may be a copper-dielectric alloy powder obtained in step (a).

[0087] Specifically, a paste can be obtained by mixing and stirring 100 parts by weight of copper powder, 10 to 30 parts by weight of diethylene glycol butyl ether, 5 to 20 parts by weight of binder solution, and 0.1 to 2 parts by weight of keratin, and specifically, by mixing and stirring 100 parts by weight of copper powder, 20 parts by weight of diethylene glycol butyl ether, 10 parts by weight of binder solution, and 0.1 to 1 part by weight of keratin.

[0088] In step (c), stirring can be performed at 700 to 1,000 rpm for 3 to 6 minutes. For example, stirring can be performed at 700 rpm for 3 minutes, 800 rpm for 1 minute, 900 rpm for 30 seconds, and 1,000 rpm for 20 seconds. In other words, stirring can be performed by sequentially increasing the stirring speed.

[0089] Step (c) may further include, but is not limited to, a step of grinding and homogenizing the paste using a three-roll mill after mixing and stirring each component.

[0090]

[0091] Step (d) of manufacturing an intermediate

[0092] Next, as shown in Fig. 1, a step (S400) is performed to manufacture an intermediate by screen printing the paste obtained in step (c) onto a ceramic substrate.

[0093] In step (d), screen printing can be performed using a conventional method of the same technology by applying paste to a screen mesh and then applying pressure with a squeegee to print a desired pattern on a substrate.

[0094]

[0095] Step (e) of post-processing the intermediate

[0096] Finally, as shown in Fig. 1, a step (S500) of post-processing the intermediate of step (d) is performed.

[0097] Step (e) may include a step of drying the intermediate obtained in step (d) at a temperature of 100 to 200°C for 30 to 120 minutes, a step of sintering the dried intermediate at a temperature of 700 to 750°C for 8 to 15 minutes, and a step of subjecting the sintered intermediate to a low-temperature heat treatment or a wet heat treatment.

[0098] Low-temperature heat treatment can be performed at a temperature of 250 to 350°C in a reducing atmosphere of N2 / H2 for 6 to 10 hours, and specifically, can be performed at a temperature of 300°C in a reducing atmosphere of N2 / H2 for 8 hours.

[0099] Wet heat treatment can be performed by adding the sintered intermediate to a mixed solvent of a hydrogen peroxide solution and distilled water in a weight ratio of 1:2 to 10 and heat treating it in a dryer at a temperature of 40 to 80°C for 20 to 60 minutes.

[0100] In case of wet heat treatment of the sintered intermediate in step (e), a step of removing the hydrazine solution by washing it by immersing it in distilled water for 5 to 15 minutes can be performed.

[0101]

[0102] The present disclosure provides an external electrode manufactured by the method described above in another embodiment.

[0103]

[0104] Hereinafter, the present disclosure will be described in more detail using examples. It will be apparent to those skilled in the art that these examples are intended solely to illustrate the present disclosure more specifically and that the scope of the present disclosure is not limited by them.

[0105]

[0106] <Preparation of Materials>

[0107] 1. Production of copper-nickel alloy powder

[0108] A copper-nickel powder was prepared by mixing 35 wt% of a mixture of copper powder and nickel powder and 65 wt% of alcohol and then drying at 100°C.

[0109] Next, the copper-nickel mixture was N 2 / A copper-nickel oxide alloy powder was manufactured by heating from room temperature to 550°C at a rate of 2°C / min in an inert atmosphere mixed with a volume ratio of H2=95:5, maintaining the temperature for 1 hour, and then heat-treating. The inert atmosphere was removed, air was sucked in, and cooling was performed.

[0110] Next, the copper-nickel oxide alloy powder was ground into small zirconia balls less than 10 mm in size.

[0111] The particle size of the copper-nickel oxide alloy powder was controlled to 1-20 ㎛ by ball milling at a weight ratio of 1:2 of copper-nickel oxide powder:zirconia ball in the range of 60-800 rpm. Afterwards, the copper-nickel oxide alloy powder having a particle size of 10 ㎛ or less was made into a solution and screened using a paper mesh filter (or mesh sieve in some cases), thereby producing the copper-nickel oxide alloy powder.

[0112] Next, a wet reduction process was performed in which a hydrazine solution having a pH of 13 or less and containing 1 mol% or less of sodium chloride was heated to 100°C, and then copper-nickel oxide alloy powder was added and maintained for 1 hour to produce a copper-nickel alloy powder.

[0113] Finally, copper-nickel alloy powder with a particle size of 5 ㎛ or less was selected using a paper mesh filter and dried to produce copper-nickel alloy powder.

[0114]

[0115] 2. Preparation of binder solution

[0116] A mixed solvent was prepared by mixing ethanol (EP grade) and toluene (Daejeong Reagent, 99.5%, EP grade) in a volume ratio of 1:4, and the binder solution was prepared by mixing and stirring so that ethyl cellulose was 20 wt% based on 100 wt% of the binder solution.

[0117]

[0118] <Example>

[0119] Example 1: Manufacturing of external electrodes

[0120] A 300 ml mixture was prepared by adding 200 g of copper-nickel alloy powder, 40 g of diethylene glycol butyl ether, 20 g of binder solution, and a small amount of keratin, and stirring was performed at 700 rpm for 3 minutes, 800 rpm for 1 minute, 900 rpm for 30 seconds, and 1,000 rpm for 20 seconds to prepare a paste. Thereafter, the paste was homogenized by ball milling using a 3-roll mill.

[0121] An intermediate was manufactured by screen printing on a ceramic substrate using the paste manufactured thereafter.

[0122] The manufactured intermediate was dried at a temperature of about 150°C for 1 hour, annealed at a temperature of 725°C for 10 minutes, and then subjected to low-temperature heat treatment at a temperature of 300°C for 8 hours in a reducing atmosphere of N2 / H2, to manufacture an external electrode.

[0123]

[0124] Example 2: Preparation of external electrodes

[0125] The external electrode was manufactured in the same manner as in Example 1, but wet heat treatment was performed instead of low-temperature heat treatment.

[0126] For wet heat treatment, the sintered intermediate was placed in a mixed solvent of a hydrogen peroxide solution and distilled water in a weight ratio of 1:5, heat-treated in a dryer at a temperature of 70°C for 1 hour, and then washed by immersion in distilled water for 10 minutes.

[0127]

[0128] <Comparative Example>

[0129] Comparative Example 1

[0130] External electrodes manufactured using commercially available silver-lead (Ag-Pd) alloy powder were purchased and prepared.

[0131]

[0132] Comparative Example 2

[0133] External electrodes manufactured using commercially available Bulk Cu were purchased and prepared.

[0134]

[0135] Comparative Example 3

[0136] External electrodes manufactured using commercially available Bulk Ag were purchased and prepared.

[0137]

[0138] <Example of an exam>

[0139] Test Example 1: Particle size analysis of copper-nickel alloy powder

[0140] To analyze the particle size of the manufactured copper-nickel alloy powder, SEM measurements were performed.

[0141] Figure 2 shows an SEM image of copper-nickel alloy powder after a reduction process, and Figure 3 shows an SEM image of copper-nickel alloy powder after a densification process.

[0142] Referring to Fig. 2, it can be confirmed that the copper-nickel alloy powder that has undergone the reduction process has a particle size of 10 ㎛ or less, and as can be confirmed in Fig. 3, it can be confirmed that the copper-nickel alloy powder has been densified through the densification process.

[0143]

[0144] Test Example 2: Electrical Conductivity Analysis

[0145] The electrical conductivity values ​​of the external electrodes manufactured according to Examples and Comparative Examples 1 to 3 were measured using an electrical conductivity meter, and are shown in Table 1 and Figure 4 below.

[0146] Electrical Conductivity (1 / Ω·m) Comparative Example 259,600,000 Comparative Example 363,000,000 Comparative Example 16,000,000 Example 7,400,000

[0147] As can be seen in Table 1 and Figure 4 above, the example exhibited a lower conductivity value than Comparative Examples 2 and 3, but it can be seen that it was superior to the electrical conductivity value of the external electrode using the conventional silver-lead alloy (Comparative Example 1).

[0148]

[0149] Test Example 3: Electrical Resistivity Analysis

[0150] The electrical resistivity values ​​of the external electrodes manufactured according to Example and Comparative Example 1 were measured using an electrical resistivity meter and are shown in Table 2 below.

[0151] Electrical resistivity (μΩcm) Examples 20-40 Comparative example 150

[0152] As can be seen in Table 2, it can be confirmed that the external electrode of the present disclosure manufactured according to the example has a superior electrical resistivity value than that of Comparative Example 1 manufactured using a conventional silver-lead alloy.

[0153] According to the present disclosure, a copper-heterometal alloy powder having a desired particle size can be manufactured in a simple manner, and an external electrode having improved properties can be manufactured using the same.

[0154] In addition, since there is no segregation phenomenon that occurs in conventional wet processes, copper-heterometal alloy powder can be mass-produced easily, thereby reducing the manufacturing cost when manufacturing external electrodes.

Claims

1. (a) Step of preparing copper powder, (b) a step of preparing a binder solution; (c) a step of preparing a paste by mixing the copper powder of step (a), the binder solution of step (b), diethylene glycol butyl ether, terpineol, and kerosene; (d) a step of manufacturing an intermediate by screen printing the paste of step (c) on a ceramic substrate; and (e) comprising a step of post-processing the intermediate of step (d); Method for manufacturing an external electrode.

2. In paragraph 1, In the above step (a), the copper powder, A copper-dissimilar metal alloy powder in which copper is combined with one or more dissimilar metals selected from the group consisting of nickel, manganese, tin, zinc and aluminum. Method for manufacturing an external electrode.

3. In paragraph 2, The above step (a) is, (1) A step of producing a copper-heterometal mixture by introducing and mixing copper and one or more heterometals selected from the group consisting of nickel, manganese, tin, zinc, and aluminum into a solvent. (2) A step of alloying the copper-heterometal mixture by heat-treating it in an inert atmosphere and exposing it to the air to produce a copper-heterometal oxide alloy powder. (3) A step of manufacturing a first-filtered copper-heterometal oxide alloy powder by first filtering the above copper-heterometal oxide alloy powder after milling it. (4) A step of manufacturing a copper-heterometal alloy powder by wet-reducing the first filtered copper-heterometal oxide alloy powder and then secondarily filtering it. (5) A step of densifying the second filtered copper-dissimilar metal alloy powder by immersing it in a copper sulfide solution. Method for manufacturing an external electrode.

4. In paragraph 1, In the above step (b), the binder solution is It is manufactured by mixing a water-soluble binder resin into a solvent. The solvent is at least one selected from the group consisting of methanol, ethanol, toluene, isopropyl alcohol, dimethyl sulfoxide, ethyl carbitol, ethyl cellosolve, methyl pyrrolidone and water. The above water-soluble binder resin is, At least one selected from the group consisting of cellulose polymers, starch polymers, polyvinylpyrrolidone, polyvinyl alcohol, novolac resins and acrylate resins. Method for manufacturing an external electrode.

5. In paragraph 1, The above step (c) is, Mix and stir 10 to 30 parts by weight of the diethylene glycol butyl ether, 5 to 20 parts by weight of the binder solution, and 0.1 to 2 parts by weight of the keratin with 100 parts by weight of the copper powder. Method for manufacturing an external electrode.

6. In paragraph 1, The above step (e) is, A step of drying the intermediate of the above step (d) at a temperature of 100 to 200 ℃ for 30 to 120 minutes, A step of sintering the above dried intermediate at a temperature of 700 to 750 ℃ ​​for 8 to 15 minutes, and Comprising a step of performing low-temperature heat treatment or wet heat treatment on the above sintered intermediate. Method for manufacturing an external electrode.

7. In paragraph 6, The above low temperature heat treatment is, N 2 / H reducing atmosphere, carried out at a temperature of 250~350℃ for 6~10 hours, Method for manufacturing an external electrode.

8. In paragraph 6, The above wet heat treatment is, The sintered intermediate is added to a mixed solvent of a hydrogen solution and distilled water and heat-treated in a dryer at a temperature of 60 to 80°C for 30 to 60 minutes. Method for manufacturing an external electrode.

9. An external electrode manufactured by any one of the methods in clauses 1 to 8.

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