WO2024048851A1 - Method for producing co-firable copper-zinc alloy powder for multilayer ceramic device, copper-zinc alloy powder produced thereby, electrode paste comprising same, and multilayer ceramic device - Google Patents

Abstract

The present invention is technically characterized in that copper and zinc are alloyed by comprising: a first step of mixing a copper or copper oxide powder and a zinc powder to prepare a mixture powder; a second step of thermally treating the mixture powder in a reducing atmosphere to prepare a copper-zinc alloy powder; a third step of thermally treating the copper-zinc alloy powder in an oxidizing atmosphere to prepare a copper oxide-zinc oxide alloy powder; a fourth step of pulverizing the copper oxide-zinc oxide alloy powder to prepare a pulverized copper oxide-zinc oxide alloy powder; and a fifth step of thermally treating the pulverized copper oxide-zinc oxide alloy powder in a reducing atmosphere to re-reduce the pulverized copper oxide-zinc oxide alloy powder to a copper-zinc alloy powder.

Description

Method for manufacturing copper-zinc alloy powder for multilayer ceramic devices capable of simultaneous firing, copper-zinc alloy powder manufactured therefrom, electrode paste containing the same, and multilayer ceramic device

The present invention relates to a method for manufacturing a copper-zinc alloy powder for a multilayer ceramic device capable of simultaneous firing, a copper-zinc alloy powder manufactured therefrom, an electrode paste containing the same, and a multilayer ceramic device.

Ceramic elements have fast response and precision, can be made small and lightweight, and their application is expanding to micro-displacement control devices, valves and pumps. However, they have limitations due to their smaller displacement than electric elements. To overcome this, electrodes are used. A multilayer ceramic device in which several layers of thin ceramics are formed is being developed.

Multilayer ceramic elements are manufactured by first making ceramic materials into a thin ceramic form, forming electrodes with conductive materials on the surface of the ceramic, and then stacking multiple pieces. At this time, since the strength of the laminated ceramics is weak, they are hardened through heat treatment. It will be done.

Regarding electrode materials, silver (Ag) has a very low melting point of 961°C, so it is used as silver palladium (AgPd) and silver platinum (AgPt) by dissolving it in solid solution with palladium (Pd) or platinum (Pt), which have high melting points. However, precious metals such as palladium are very expensive, so although it is used as an electrode material by increasing the proportion of relatively inexpensive silver, it is a critical difficulty in mass production of multilayer ceramic devices for economic reasons.

There are cases where copper (Cu) or nickel (Ni) is used as an electrode material. The 'multilayer ceramic part (KR 10-1580350 B1)' is a multilayer ceramic part that can control the content or size of the co-material added to the internal electrode layer and increase the connectivity of the internal electrode by using the high sintering driving force of the co-material, Copper or nickel was applied as the internal electrode.

However, in the process of alloying copper and nickel, there is a problem that segregation, in which copper or nickel elements precipitate easily in certain areas, tends to separate copper and nickel. In order to solve this problem, the sintering behavior of copper is examined. Even with changes, there have been limitations in manufacturing multilayer ceramic devices. In particular, nickel is used as an electrode material for secondary batteries and is difficult to use due to its high price. Therefore, copper-based alloy powder that can maintain stable electrical conductivity by using a metal that is cheaper than nickel, electrode paste containing it, and There is a need for technology development for multilayer ceramic devices.

The present invention was invented to solve the above problems, and is a method for producing copper-zinc alloy powder for a multilayer ceramic device capable of simultaneous firing so that electrical conductivity can be maintained stably by alloying copper and zinc, and the method for manufacturing copper-zinc alloy powder therefrom The technical problem is to provide manufactured copper-zinc alloy powder, electrode paste containing it, and multilayer ceramic device.

In order to solve the above technical problem, the present invention includes a first step of mixing copper or copper oxide powder and zinc powder to produce a mixed powder; A second step of heat treating the mixed powder in a reducing atmosphere to produce copper-zinc alloy powder; A third step of heat-treating the copper-zinc alloy powder in an oxidizing atmosphere to produce copper oxide-zinc oxide alloy powder; A fourth step of pulverizing the copper oxide-zinc oxide alloy powder to produce pulverized copper oxide-zinc oxide alloy powder; And a fifth step of heat-treating the pulverized copper oxide-zinc oxide alloy powder in a reducing atmosphere to re-reduce the pulverized copper oxide-zinc oxide alloy powder to copper-zinc alloy powder, including alloying between copper and zinc. Provided is a method for producing copper-zinc alloy powder for a multilayer ceramic device capable of simultaneous firing, characterized in that:

In the present invention, the first step is characterized in that the copper or copper oxide powder and the zinc powder are mixed at a weight ratio of 5 to 9.9:0.1 to 5.

In the present invention, the second step is characterized in that the mixed powder is heat-treated at a temperature of 500 to 650 ° C. in a hydrogen or hydrogen/nitrogen mixed gas atmosphere.

In the present invention, the third step is characterized in that the copper-zinc alloy powder is heat-treated at a temperature of 500 to 900 ° C. in an oxygen or atmospheric atmosphere.

In the present invention, the fifth step is characterized in that the pulverized copper oxide-zinc oxide alloy powder is heat-treated at a temperature lower than the heat treatment temperature of the second step in a hydrogen or hydrogen/nitrogen mixed gas atmosphere.

In order to solve the above other technical problems, the present invention provides a copper-zinc alloy powder, which is produced by the above method.

In order to solve the above technical problem, the present invention includes an organic vehicle formed by mixing an organic solvent and a binder; And it provides an electrode paste, characterized in that it includes the copper-zinc alloy powder.

In order to solve the above technical problem, the present invention is a multilayer ceramic, which is formed by printing the electrode paste on a ceramic tape to form a ceramic laminate, heat treating it in an oxidizing atmosphere, and then heat treating it in a reducing atmosphere. Devices are provided.

In the present invention, the ceramic element is made by heat-treating the ceramic laminate at 100 to 650°C in an oxidizing atmosphere to burn-out and degrease the binder, and then heat-treating the ceramic laminate at 800 to 1,100°C in an oxidizing atmosphere. Sintering; and heat treating the sintered ceramic laminate at 100 to 300° C. in a reducing atmosphere.

According to the present invention as a means of solving the above problem, simultaneous firing is possible even in an oxidizing atmosphere using dissimilar metals of copper and zinc, thereby controlling the shrinkage rate between dissimilar metals, ultimately preventing shrinkage and delamination. Copper-zinc alloy powder can be manufactured, and it has a dense structure by alloying with zinc compared to pure copper, which has the effect of improving heat resistance up to 1,050 ℃.

In particular, the copper-zinc alloy powder of the present invention maintains stable electrical conductivity compared to bulk copper (Bulk Cu) and expensive silver palladium (AgPd) materials, so it can be used to manufacture electrode paste instead of expensive silver palladium (AgPd). It has the effect of increasing economic efficiency by using it as an electrode for a post-laminated ceramic device.

1 is a flowchart showing a method of manufacturing copper-zinc alloy powder according to the present invention.

Figure 2 is a flowchart showing a method of manufacturing an electrode paste and a multilayer ceramic device according to the present invention.

Figure 3 is a schematic diagram showing a method for manufacturing electrodes of a multilayer ceramic device according to the present invention.

Figure 4 is an SEM photograph showing surface changes of copper-zinc alloy powder.

Figure 5 is a graph comparing electrical conductivity according to electrode material.

Since the present invention can make various changes and take various forms, specific embodiments will be described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of a combination of features, numbers, steps, components, etc. described in the specification, but are not intended to indicate the presence of one or more other features, numbers, or steps. , it should be understood that the existence or addition possibility of combinations of components, etc. is not excluded in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless clearly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

Here, repeated descriptions, known functions that may unnecessarily obscure the gist of the present invention, and detailed descriptions of configurations are omitted. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

The present invention relates to a method of manufacturing copper-zinc alloy powder for a multilayer ceramic device capable of simultaneous firing. In relation to this, Figure 1 is a flowchart showing a method of manufacturing copper-zinc alloy powder according to the present invention. Referring to Figure 1, the copper-zinc alloy powder of the present invention includes a first step (S10) of mixing copper or copper oxide powder and zinc powder to produce a mixed powder, and heat treating the mixed powder in a reducing atmosphere, A second step (S20) of producing a copper-zinc alloy powder, a third step (S30) of producing a copper oxide-zinc oxide alloy powder by heat-treating the copper-zinc alloy powder in an oxidizing atmosphere, and the copper oxide -A fourth step (S40) of pulverizing the zinc oxide alloy powder to produce pulverized copper oxide-zinc oxide alloy powder, and heat-treating the pulverized copper oxide-zinc oxide alloy powder in a reducing atmosphere to oxidize the pulverized copper oxide alloy powder. It is manufactured through the fifth step (S50) of reducing copper-zinc oxide alloy powder to copper-zinc alloy powder, and is particularly characterized by alloying between copper and zinc.

According to the above-described manufacturing method, the first step is to prepare a mixed powder by mixing copper or copper oxide powder and zinc powder (S10).

The copper or copper oxide powder and the zinc powder may be mixed at a weight ratio of 5 to 9.9:0.1 to 5. If the copper or copper oxide powder is less than 5 weight ratio or the zinc powder is more than 5 weight ratio, it is difficult to tune in terms of improving electrical conductivity, and if the copper or copper oxide powder exceeds 9.9 weight ratio or the zinc powder is less than 0.1 weight ratio, shrinkage between copper and zinc occurs. It is undesirable because it may cause shrinkage or delamination.

Next, the second step is to heat-treat the mixed powder in a reducing atmosphere to produce copper-zinc alloy powder (S20).

The mixed powder is heat-treated at a temperature of 500 to 650° C. in a hydrogen or hydrogen/nitrogen mixed gas atmosphere. The melting point of zinc is approximately 419 ℃, and for alloying copper and zinc, it must be above the minimum melting point of zinc, and for process efficiency, it is desirable to be above 500 ℃. Reduction heat treatment below 500°C has the disadvantage of requiring a long time for alloying between copper and zinc, and exceeding 650°C may result in deterioration of the physical properties of the copper-zinc alloy powder due to the high temperature. Since the melting point of copper is as high as 1,085°C, when heat-treated at a temperature of 500 to 650°C in a reducing atmosphere, zinc, which has a low melting point of about 419°C, melts and forms an alloy powder covering the surface of copper. However, the oxidation rate of zinc may be relatively faster than that of copper, and in this case, an oxide film may be formed on the surface of the alloy powder.

Next, the third step is to heat-treat the copper-zinc alloy powder in an oxidizing atmosphere to produce copper oxide-zinc oxide alloy powder (S30).

The copper-zinc alloy powder is heat-treated at a temperature of 500 to 900° C. in an oxygen or atmospheric atmosphere. In order to oxidize copper-zinc alloy powder, heat treatment must be performed in an oxygen or air atmosphere at a temperature of at least 500 ℃. If it exceeds 900 ℃, copper and zinc are peroxidized, which is undesirable.

Next, the fourth step is to grind the copper oxide-zinc oxide alloy powder to produce pulverized copper oxide-zinc oxide alloy powder (S40).

The copper oxide-zinc oxide alloy powder is ground to a particle size of 0.5 to 10 μm. In order to be applied as an electrode of a multilayer ceramic device, it can be ground into particles with a size of 0.5 to 10 ㎛, preferably 1 to 5 ㎛, and more preferably 1 ㎛ or less. can do.

Next, the fifth step is a step of heat treating the pulverized copper oxide-zinc oxide alloy powder in a reducing atmosphere to re-reduce the pulverized copper oxide-zinc oxide alloy powder to the copper-zinc alloy powder (S50).

When the pulverized copper oxide-zinc oxide alloy powder is stabilized by heat treatment in a hydrogen or hydrogen/nitrogen mixed gas atmosphere at a temperature relatively lower than the heat treatment temperature of the second step, the oxide film formed on the surface of the copper-zinc alloy powder can be removed. It comes true. In the case of heat treatment, it can be carried out at 100 to 300 ℃. If the temperature is less than 100 ℃, it takes a lot of time for the oxide form of copper oxide or zinc oxide to be completely reduced to the metal form, so the amount of hydrogen / nitrogen mixed gas must be increased. There are disadvantages in the process, and temperatures exceeding 300°C cannot be said to be a stable temperature for re-reduction to copper-zinc alloy powder.

Meanwhile, electrode paste and a multilayer ceramic device can be manufactured using the copper-zinc alloy powder produced by the above method. In relation to this, Figure 2 is a flowchart showing an electrode paste and a method of manufacturing a multilayer ceramic device according to the present invention, and Figure 3 is a schematic diagram showing a method of manufacturing an electrode of a multilayer ceramic device according to the present invention.

The electrode paste may include an organic vehicle formed by mixing an organic solvent and a binder, and the copper-zinc alloy powder prepared by the above method. At this time, in the copper-zinc alloy powder mixed with the organic vehicle, the fourth stage pulverized copper oxide-zinc oxide alloy powder may be used. That is, the pulverized copper oxide-zinc oxide alloy powder and the organic vehicle are put into a mixer at a weight ratio of 1:1 and mixed first at 600 to 1,000 rpm, then secondly mixed in a three-roll mill, and then filtered to obtain an electrode paste. It becomes possible.

The organic vehicle serves to hold the copper oxide-zinc oxide alloy powder to agglomerate. The organic solvent can be selected from the group consisting of PGME (propylene glycol monomethyl ether), Terpineol (α, b, d, g), Dihydro-Terpineol, and Dihydro-Terpinyl-Acetate. The binder can be manufactured by melting 20% by weight of ethyl cellulose in ethanol, and in some cases, PVB (Polyvinyl Butyral) can be used. When manufacturing an organic vehicle, additional DOP (di-2-ethylhexyl phtalate) plasticizer, BYK-111 (dispersant), borosilicate glass frit, etc. may be added.

Such an organic vehicle can be prepared by mixing an organic solvent and a binder at a weight ratio of 5 to 9:1 to 5. If the organic solvent is less than 4 weight ratio, homogeneous mixing of the binder cannot be achieved, and if it exceeds 9 weight ratio, the physical properties of the organic vehicle may be impaired due to the use of too much organic solvent. If the binder is less than 1 weight ratio or exceeds 5 weight ratio, it is not desirable for electrode paste formation.

To manufacture a multilayer ceramic device using this electrode paste, the electrode paste is printed on a sheet-shaped ceramic tape by screen printing to form a ceramic laminate, and then heat-treated in an oxidizing atmosphere and then in a reducing atmosphere.

In the multilayer ceramic device, the ceramic laminate is heat-treated at 100 to 650° C. in an oxidizing atmosphere to burn-out the binder and degreased through organic burn-out, and then heat-treated at 800 to 1,100° C. in an oxidizing atmosphere. Following the sintering step, the sintered ceramic laminate is stabilized by heat treatment at 100 to 300° C. in a reducing atmosphere. Eventually, the metal oxide is reduced to metal, thereby manufacturing a multilayer ceramic device. In other words, through re-reduction heat treatment, oxygen and hydrogen of copper oxide-zinc oxide combine to form water, and as it evaporates, it is reduced to copper-zinc.

Therefore, when manufacturing a conventional multilayer ceramic device, electrode paste is printed and laminated on a ceramic tape, and then degreasing, sintering (oxygen partial pressure pO ₂ < 10 ^-13 atm) and reoxidation heat treatment in a reducing atmosphere (N ₂ , H ₂ ) from the beginning. (Oxygen partial pressure pO ₂ < 10 ^-6 atm), unlike the need for dedicated equipment and cumbersome processes such as gas injection, the multilayer ceramic device according to the present invention is capable of degreasing and simultaneous firing in an atmospheric atmosphere, There is an advantage that a multilayer ceramic device can be easily manufactured by simply applying heat treatment in a reducing atmosphere in the post-treatment process.

Hereinafter, embodiments of the present invention will be described in more detail as follows. However, the following examples are merely illustrative to aid understanding of the present invention and are not intended to limit the scope of the present invention.

<Example 1>

Preparation of copper-zinc alloy powder

Copper oxide powder (Cu ₂ O, CuO) and zinc (Zn) powder were prepared, and the copper (I) oxide powder and zinc powder were added to ethanol at a weight ratio of 9:1 and wet mixed to ensure uniform mixing. The uniformly mixed solution was dried at room temperature or high temperature below 100°C to obtain a uniformly mixed copper-zinc mixed powder.

The uniformly mixed copper-zinc mixed powder was subjected to reduction heat treatment at 600°C in a pure hydrogen atmosphere or a hydrogen/nitrogen mixed gas atmosphere to form copper-zinc alloy powder.

The copper-zinc alloy powder was heat-treated at 600° C. in an air or oxygen atmosphere to form a copper oxide-zinc oxide alloy powder.

The obtained copper oxide (CuO)-zinc oxide (ZnO) alloy powder was ground by ball milling for 24 hours using zirconia balls to obtain copper oxide-zinc oxide alloy powder with an average diameter of 0.5 to 10 ㎛.

By heat-treating the pulverized copper oxide-zinc oxide alloy powder in a hydrogen or hydrogen/nitrogen mixed gas atmosphere by adjusting it to an appropriate temperature in the temperature range of 100 to 300 ° C., which is lower than the reduction heat treatment, the pulverized copper oxide-zinc oxide alloy powder was re-reduced to copper-zinc alloy powder.

Preparation of electrode paste

The organic vehicle was prepared by mixing the organic solvent and binder at a weight ratio of 5 to 9:1 to 5, and showed different viscosity characteristics depending on the mixing ratio. The organic solvent was terpineol, and the binder was prepared by dissolving 20% by weight of ethyl cellulose in ethanol.

An electrode paste was prepared by mixing the pulverized copper oxide-zinc oxide alloy powder and the prepared organic vehicle at a weight ratio of 1:1 at 700 to 1,000 rpm for more than 20 seconds.

Manufacturing of layered ceramic devices

To obtain a copper-zinc electrode, the electrode paste is printed on a substrate, heat treated at 550°C in an atmospheric atmosphere to burn-out and degrease the binder, and then heat treated at 950°C in an atmospheric atmosphere to sinter, followed by hydrogen/hydrogen Copper oxide-zinc oxide was reduced to copper-zinc by re-reduction heat treatment at a temperature of 100 to 300°C in a nitrogen gas atmosphere. Through the heat treatment process, the oxygen and hydrogen of the copper oxide-zinc oxide combined to form water, which was reduced to copper-zinc as it evaporated.

Figure 4 is an SEM photograph showing surface changes of copper-zinc alloy powder. In other words, it can be confirmed that copper-based alloying is achieved through the degreasing, sintering, and reduction post-treatment processes of the multilayer ceramic device.

<Comparative Example 1>

In Comparative Example 1, a multilayer ceramic device was manufactured through the same process as Example 1, except that bulk Cu, rather than copper-zinc alloy, was used as the electrode material.

<Comparative Example 2>

In Comparative Example 2, a multilayer ceramic device was manufactured through the same process as Example 1, except that AgPd, rather than copper-zinc alloy, was used as the electrode material.

Figure 5 is a graph comparing electrical conductivity according to electrode material. Referring to FIG. 5, Comparative Example 1 has an electrical conductivity close to 10 ⁸ (Ω·M) ^{-1 and} Comparative Example 2 has an electrical conductivity close to 10 ⁷ (Ω·M) ^-1 . The copper in the multilayer ceramic device of Example 1 -It was confirmed that the electrical conductivity was relatively greater in the zinc alloy electrode than in Comparative Example 2, and this showed that shrinkage and peeling between copper and zinc in the multilayer ceramic device in which the copper-zinc alloy of the present invention was applied as an electrode ( It can be seen that electrical conductivity is maintained stably as delamination does not occur.

In summary, the present invention mixes copper or copper oxide powder and zinc powder, heat-treats them in a reducing atmosphere, heat-treats them in an oxidizing atmosphere, goes through a grinding process, and heat-treats them in a reducing atmosphere, thereby forming an alloy between copper and zinc and forming a metal oxide film. can be removed, and has the characteristic of maintaining stable electrical conductivity.

According to these characteristics, it is a copper-zinc alloy powder that allows simultaneous firing even in an oxidizing atmosphere using dissimilar metals of copper and zinc, ultimately preventing shrinkage and delamination by controlling the shrinkage rate between dissimilar metals. It has the advantage of being able to manufacture electrode paste and multilayer ceramic elements using this.

In addition, the copper-zinc alloy powder of the present invention maintains stable electrical conductivity compared to bulk copper (Bulk Cu) and silver palladium (AgPd) materials, so it can be used as an electrode for multilayer ceramic devices instead of expensive nickel, making it economical. It can be raised, but it is meaningful.

The above description is merely an illustrative explanation of the technical idea of the present invention, and those skilled in the art will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for explanation, and the scope of the technical idea of the present invention is not limited by these examples. The scope of protection of the present invention should be interpreted in accordance with the scope of the patent claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights of the present invention.

Claims (9)

1. A first step of mixing copper or copper oxide powder and zinc powder to produce a mixed powder;

   A second step of heat treating the mixed powder in a reducing atmosphere to produce copper-zinc alloy powder;

   A third step of heat-treating the copper-zinc alloy powder in an oxidizing atmosphere to produce copper oxide-zinc oxide alloy powder;

   A fourth step of pulverizing the copper oxide-zinc oxide alloy powder to produce pulverized copper oxide-zinc oxide alloy powder; and

   Including a fifth step of heat-treating the pulverized copper oxide-zinc oxide alloy powder in a reducing atmosphere to re-reduce the pulverized copper oxide-zinc oxide alloy powder to a copper-zinc alloy powder,

   A method for producing copper-zinc alloy powder for a multilayer ceramic device capable of simultaneous firing, characterized in that alloying occurs between copper and zinc.
2. According to claim 1,

   The first step is,

   A method for producing a copper-zinc alloy powder for a multilayer ceramic device capable of simultaneous firing, characterized in that the copper or copper oxide powder and the zinc powder are mixed at a weight ratio of 5 to 9.9:0.1 to 5.
3. According to claim 1,

   The second step is,

   A method for producing a copper-zinc alloy powder for a multilayer ceramic device capable of simultaneous firing, characterized in that the mixed powder is heat-treated at a temperature of 500 to 650 ° C. in a hydrogen or hydrogen/nitrogen mixed gas atmosphere.
4. According to claim 1,

   The third step is,

   A method for producing a copper-zinc alloy powder for a multilayer ceramic device capable of simultaneous firing, characterized in that the copper-zinc alloy powder is heat-treated at a temperature of 500 to 900 ° C. in an oxygen or atmospheric atmosphere.
5. According to claim 1,

   The fifth step is,

   A copper-zinc alloy for a multilayer ceramic device capable of simultaneous firing, characterized in that the pulverized copper oxide-zinc oxide alloy powder is heat-treated in a hydrogen or hydrogen/nitrogen mixed gas atmosphere at a temperature lower than the heat treatment temperature of the second step. Method for producing powder.
6. Copper-zinc alloy powder, characterized in that it is produced by the method of any one of claims 1 to 5.
7. An organic vehicle formed by mixing an organic solvent and a binder; and

   The electrode paste comprising the copper-zinc alloy powder of claim 6.
8. A multilayer ceramic device, characterized in that it is formed by printing the electrode paste of claim 7 on a ceramic tape to form a ceramic laminate, heat treating it in an oxidizing atmosphere, and then heat treating it in a reducing atmosphere.
9. According to clause 8,

   The multilayer ceramic device,

   heat-treating the ceramic laminate at 100 to 650°C in an oxidizing atmosphere to burn-out and degrease the binder, and then sintering the ceramic laminate by heat-treating it at 800 to 1,100°C in an oxidizing atmosphere; and

   A multilayer ceramic device, characterized in that it is formed through the step of heat treating the sintered ceramic laminate at 100 to 300 ° C. in a reducing atmosphere.

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