Contact material containing Ag alloy as main component, contact using the contact material, and electric device

文档序号：1942634 发布日期：2021-12-07 浏览：20次中文

阅读说明：本技术 以Ag合金为主要成分的接点用材料、使用该接点用材料的接点及电气设备 (Contact material containing Ag alloy as main component, contact using the contact material, and electric device ) 是由田中纯一三角修一森哲也于 2020-05-29 设计创作，主要内容包括：提供一种难以使接点由于在接点开闭时产生的电弧而损伤的接点用材料。以Ag合金为主要成分的接点用材料包含：Ag合金；以及主添加物,其以与Ag合金不同的相存在,选自由氧化锡、镍、氧化镍、铁、氧化铁、钨、碳化钨、氧化钨、氧化锌和碳组成的组中的至少一种,Ag合金以0.01重量％以上且固溶于Ag的固溶极限以下的范围含有固溶元素,所述固溶元素具有比作为构成主添加物的金属原子或者主添加物为碳的情况下的碳与Ag金属内的空穴的结合能的空穴结合能低的空穴结合能。(A contact material is provided which is less likely to cause contact damage due to an arc generated when a contact is opened and closed. The material for contacts containing an Ag alloy as a main component comprises: ag alloy; and a main additive which exists in a phase different from that of the Ag alloy, and which is at least one selected from the group consisting of tin oxide, nickel oxide, iron oxide, tungsten carbide, tungsten oxide, zinc oxide, and carbon, wherein the Ag alloy contains a solid solution element having a hole binding energy lower than the hole binding energy of carbon and holes in the Ag metal in the case where the metal atom constituting the main additive or the main additive is carbon, in a range of 0.01 wt% or more and not more than the solid solution limit of Ag.)

1. A contact material containing an Ag alloy as a main component, comprising:

ag alloy; and

a main additive present in a phase different from the Ag alloy, at least one selected from the group consisting of tin oxide, nickel oxide, iron oxide, tungsten carbide, tungsten oxide, zinc oxide, and carbon,

the Ag alloy contains 0.01 wt% or more of a solid solution element having a hole binding energy lower than the hole binding energy of carbon and holes in the Ag metal when the metal atoms constituting the main additive or the main additive is carbon.

2. A material for contacts comprising an Ag alloy as a main component according to claim 1,

the main additive is tin oxide, and is contained in an amount of 5 to 20 wt% in terms of metal,

the solid solution element is at least one selected from the group consisting of Be, C, P, K, Ca, Se, Rb, Sr, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Tl, Pb and Bi, and is contained in an amount of 0.01 to 2 wt%.

3. A material for contacts comprising an Ag alloy as a main component according to claim 1,

when the main additive is nickel or nickel oxide, the content is 5 to 20 wt% in terms of metal,

the solid solution element is at least one selected from the group consisting of Li, Be, C, Na, Mg, Al, Si, P, K, Ca, Cu, Zn, Ga, Ge, Se, Rb, Sr, Y, In, Sn, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Tl, Pb and Bi, and is contained In an amount of 0.01 to 2 wt%.

4. A material for contacts comprising an Ag alloy as a main component according to claim 1,

the main additive is iron or iron oxide, and is contained in an amount of 5 to 20 wt% in terms of metal,

the solid solution element is at least one selected from the group consisting of Li, Be, C, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, Co, Ni, Cu, Zn, Ga, Ge, Se, Rb, Sr, Y, Zr, Rh, Pd, In, Sn, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ir, Pt, Tl, Pb and Bi, and is contained In an amount of 0.01 to 2 wt%.

5. A material for contacts comprising an Ag alloy as a main component according to claim 1,

the main additive is at least one selected from the group consisting of tungsten, tungsten carbide and tungsten oxide, and is contained in an amount of 5 to 20 wt% in terms of metal,

the solid solution element is at least one selected from the group consisting of Li, Be, C, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Se, Rb, Sr, Y, Zr, Ru, Rh, Pd, In, Sn, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, Ir, Pt, Tl, Pb, and Bi, and is contained In an amount of 0.01 to 2 wt%.

6. A material for contacts comprising an Ag alloy as a main component according to claim 1,

the main additive is zinc oxide, and is contained in an amount of 5 to 20 wt% in terms of metal,

the solid solution element is at least one selected from the group consisting of Be, C, Na, Si, P, K, Ca, Ga, Ge, Se, Rb, Sr, Y, In, Sn, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Yb, Tl, Pb and Bi, and is contained In an amount of 0.01 to 2 wt%.

7. A material for contacts comprising an Ag alloy as a main component according to claim 1,

the main additive is carbon, and is contained in an amount of 0.01 to 2 wt% in terms of element,

the solid solution element is selected from the group consisting of Be, K, Ca, Se, Rb, Sr, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Eu, Pb, and Bi, and is contained in an amount of 0.01 wt% to 2 wt%.

8. The material for a contact containing an Ag alloy as a main component according to any one of claims 2 to 4 and 6 to 7,

and at least one selected from the group consisting of tungsten, tungsten carbide, tungsten oxide, and zirconium oxide, which is present in a phase different from the Ag alloy, is contained in an amount of 0.1 to 5 wt% in terms of metal.

9. The material for a contact containing an Ag alloy as a main component according to any one of claims 1 to 7, wherein,

and at least one of molybdenum oxide and tellurium dioxide present in a phase different from the Ag alloy in an amount of 0.1 to 5 wt% in terms of metal.

10. The material for a contact containing an Ag alloy as a main component according to any one of claims 1 to 7, wherein,

and at least one of lithium oxide, lithium carbonate, and lithium cobaltate present in a phase different from the Ag alloy in an amount of 0.01 to 1 wt% in terms of metal.

11. The material for a contact containing an Ag alloy as a main component according to any one of claims 1 to 7, wherein,

and at least one of copper oxide and copper present in a phase different from the Ag alloy in an amount of 0.1 to 2 wt% in terms of metal.

12. The material for a contact containing an Ag alloy as a main component according to any one of claims 2 and 4 to 7,

and at least one of nickel oxide and nickel present in a phase different from the Ag alloy in an amount of 0.1 to 2 wt% in terms of metal.

13. The material for a contact containing an Ag alloy as a main component according to any one of claims 1 to 7, wherein,

and indium oxide present in a phase different from the Ag alloy in an amount of 0.1 to 5 wt% in terms of metal.

14. The material for a contact containing an Ag alloy as a main component according to any one of claims 1 to 7, wherein,

and bismuth oxide present in a phase different from the Ag alloy in an amount of 0.1 to 5 wt% in terms of metal.

15. The material for a contact containing an Ag alloy as a main component according to any one of claims 3 to 7, wherein,

and tin oxide present in a phase different from the Ag alloy in an amount of 0.1 to 5 wt% in terms of metal.

16. The material for a contact containing an Ag alloy as a main component according to any one of claims 2 to 5 or 7, wherein,

and at least one of zinc oxides present in a phase different from the Ag alloy in an amount of 0.1 to 5 wt% in terms of metal.

17. The material for a contact containing an Ag alloy as a main component according to any one of claims 2 to 6, wherein,

also, carbon present in a phase different from the Ag alloy is contained in an amount of 0.01 wt% or more and 2 wt% or less in terms of element.

18. A material for contacts comprising an Ag alloy as a main component according to claim 1,

further comprising at least one selected from the group consisting of tungsten, tungsten carbide, tungsten oxide, zirconium oxide, molybdenum oxide, tellurium dioxide, lithium oxide, lithium carbonate, lithium cobaltate, copper oxide, copper, nickel oxide, nickel, indium oxide, bismuth oxide, tin oxide, zinc oxide, and carbon, which is present in a phase different from the Ag alloy.

19. A contact using the material for a contact comprising an Ag alloy as set forth in any one of claims 1 to 18 as a main component.

20. An electrical device selected from the group consisting of a relay device, an electromagnetic contactor, an electromagnetic switch, a relay, a switch, and a switch, using the contact according to claim 19.

Technical Field

The present invention relates to a contact material containing an Ag alloy as a main component and a contact using the contact material. And more particularly to a contact material containing an Ag alloy and a main additive selected from at least one of the group consisting of tin oxide, nickel oxide, iron oxide, tungsten carbide, tungsten oxide, zinc oxide, and carbon, and a contact using the contact material.

Background

Contacts used in power relays and switches are made of a material containing Ag as a main component. In recent years, the market price of Ag is about 2.5 times as high as 20 years ago, and in order to save silver by reducing the amount of Ag used, it has been previously compounded with inexpensive copper. In order to further save silver, the contact needs to be made smaller.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 53-149667

Disclosure of Invention

Technical problem to be solved by the invention

However, if the current contact is made smaller, the number of times the contacts 2A and 2B are opened and closed before welding occurs due to the arc 4 generated when the contacts are opened and closed becomes shorter, and the life becomes shorter (fig. 2A and 2B).

On the other hand, in order to improve the soldering resistance and the like of an electrical contact using Ag, a material for an electrical contact in which an oxide such as tin oxide is dispersed in a matrix phase of Ag is known (for example, see patent document 1).

However, as the number of times of opening and closing of the contact increases, there is a problem that, as shown in fig. 3A to 3C, tin oxide 12 dispersed in a parent phase 14 of an Ag alloy moves to the surface of the contact 2 due to an arc at the time of opening and closing of the contact, and aggregates 16 are formed, thereby accelerating damage of the contact. In addition, the arrow in the drawing indicates the moving direction of the tin oxide.

Accordingly, an object of the present invention is to provide a contact material which can reduce the movement of oxides and hardly damage a contact even when an arc is generated at the time of opening and closing the contact.

Means for solving the problems

The contact material mainly composed of an Ag alloy according to the present invention comprises: ag alloy; and

Effects of the invention

According to the contact material containing an Ag alloy as a main component according to the present invention, the Ag alloy contains a solid solution element having a hole-binding energy lower than that of the constituent element of the main additive. Therefore, even when the contact material is used for the contact, the movement of the main additive such as tin oxide due to an arc or the like generated when the contact is opened or closed can be suppressed. This reduces the migration and aggregation of the main additive from the Ag alloy, and reduces contact damage caused by arcing during opening and closing of the contact.

Drawings

Fig. 1 is a bar graph showing a comparison between the hole binding energy of a rare earth element dissolved in a solid solution element of an Ag alloy and the hole binding energy (-0.202eV) of tin oxide in the contact material mainly composed of an Ag alloy according to embodiment 1.

Fig. 2A is a schematic view showing a state where an arc is generated between contacts when the contacts are opened and closed.

Fig. 2B is a schematic view showing a state where welding occurs between the contacts.

Fig. 3A is a schematic cross-sectional view showing a state in which tin oxide is dispersed in silver of a mother phase in a contact.

Fig. 3B is a schematic cross-sectional view showing a state in which tin oxide moves to the contact surface side due to repeated opening and closing of the contact, and agglomerates are formed.

Fig. 3C is a schematic cross-sectional view showing a case where tin oxide moves to the contact surface side and a larger aggregate is formed by further repeating opening and closing of the contact.

Fig. 4A is a schematic view showing a state of tin oxide and voids dispersed in the matrix phase Ag in the contact.

Fig. 4B is a schematic view showing a state where Sn atoms constituting tin oxide move in the voids in Ag due to an arc when the contact is opened and closed.

FIG. 4C is a schematic view showing a case where holes are formed in Ag and Sn atoms move in the holes, following FIG. 4B.

FIG. 4D is a schematic view showing the case where holes are repeatedly formed in Ag and Sn atoms are moved in the holes and Sn atoms are moved, following FIG. 4C.

FIG. 5A is a schematic view showing that in comparative example 1, a tin oxide SnO as a main additive is added to Ag which does not substantially contain a solid solution element other than tin as a main additive₂And a field emission scanning electron microscope (FE-SEM) image of a cross section of the contact in a state where the contact is heated by repeating opening and closing of the contact, and aggregates are formed near the surface of the contact.

FIG. 5B is an image of Electron back scatter analysis (EBSD) enlarging the field of view of FIG. 5A.

FIG. 6B is a diagram showing a binarized image of the FE-SEM photograph of FIG. 6A.

FIG. 7A is a schematic view showing that tin oxide SnO as a main additive is added to an Ag alloy obtained by adding a rare earth element as a solid solution element to Ag as a base material in example 1₂A field emission scanning electron micrograph (FE-SEM) of the cross section of the film after the heat treatment of the resulting film.

FIG. 7B is a diagram showing a binarized image of the FE-SEM photograph of FIG. 7A.

FIG. 8B is a diagram showing a binarized image of the FE-SEM photograph of FIG. 8A.

FIG. 9A is a diagram showing SnO in which tin oxide is added as a main additive to Ag which does not substantially contain solid solution elements other than tin as the main additive in comparative example 1₂A field emission scanning electron micrograph (FE-SEM) of the cross section of the film after the heat treatment of the resulting film.

FIG. 9B is a diagram showing a binarized image of the FE-SEM photograph of FIG. 9A.

Fig. 10 is a graph showing the relationship between the heat treatment temperature (annealing temperature) and the sheet resistance change rate of the thin films of example 1 and comparative example 1.

Detailed Description

< Process of the present invention >

As described above, in the material for an electrical contact in which an oxide such as tin oxide is dispersed in a matrix phase of Ag for the purpose of improving the soldering resistance, there is also a problem that tin oxide moves to the surface of a contact due to repeated opening and closing of the contact, and thus, a fine aggregate is formed.

The present inventors investigated the hypothesis of the movement mechanism related to the holes with respect to the movement of tin oxide in the parent phase Ag. Fig. 4A is a schematic view showing the states of Sn atoms 22, O atoms 23, and holes 26 of tin oxide dispersed in the matrix phase Ag24 in the contact 2. Fig. 4B is a schematic view showing a state where Sn atoms 22 constituting tin oxide move in voids 26 in Ag24 due to an arc when the contact is opened and closed. Fig. 4C is a schematic view showing a case where holes 26 are formed in Ag24 and Sn atoms 22 move in the holes, following fig. 4B. Fig. 4D is a schematic view showing a case where, following fig. 4C, formation of holes 26 in Ag24 and movement of Sn atoms 22 in the holes 26 are repeated, and the Sn atoms 22 move upward.

The present inventors considered that Sn atoms constituting tin oxide moved to the vicinity of the surface of the contact by the action of hole diffusion in Ag.

As the energy relating to the hole, there is a hole binding energy E_B. The hole binding energy is an energy change when substitution by an additive element and formation of holes occur simultaneously/adjacently with respect to the case where substitution by an additive element and formation of holes occur separately. When the hole binding energy is low, holes are difficult to move due to the effect of the additive.

Therefore, the present inventors have considered that the migration of the constituent elements of the main additive such as tin oxide can be suppressed by dissolving a solid solution element having a hole binding energy lower than that of the main additive in the Ag alloy, and have completed the present invention. The present inventors have also found that the movement of silver as a base material can be suppressed by dissolving a solid solution element having a hole binding energy lower than that of the main additive in an Ag alloy, and that coarsening of silver crystals can be prevented to suppress contact damage, and have completed the present invention.

Further, the method of calculating the above-mentioned hole binding energy is described in, for example, Chun Yu, et Al, "First principles calculation of the effects of the solvent on electron emission resistance of Al interconnects", J.Physics D: appl.Phys.42(2009)125501(6 pp).

Specifically, the hole binding energy E can be calculated from the following formula (1)_B. The E (number of Ag atoms, number of holes, number of additive atoms) can be calculated by changing the number of additives and holes in order to remove energy of Ag and additive elements themselves based on the face centered cubic lattice (FCC) of Ag. As the calculation tool, for example, commercial software such as WIEN2K, CASEP, VASP (https:// www.vasp.at /) and free software such as Abinit, Quantaum express, etc. can be used. By the first principle calculation, it is possible to input the spatial coordinates of atoms in the target system, the atomic number of each atom, and the like, and output the total energy of the state in which the energy of the target system is minimum.

The structural optimization in the first principle calculation is performed by, for example, sequentially performing the following steps.

(a) The crystal structure of the target parent material atom is set to a model shape.

(b) The atomic positions and the electron densities in the model shape are changed to calculate the total energy of the model shape.

Here, as the model shape, the crystal structure of silver as a base material is unified into a face centered cubic lattice.

E_BE (4, 0, 0) × 8-E (31, 0, 1) -E (31, 1, 0) + E (30, 1, 1) · · formula (1)

E (30, 1, 1): energy of 30 Ag atoms, 1 hole, 1 additive atom

E (4, 0, 0): energy of 4 Ag atoms

E (31, 1, 0): energy of 31 Ag atoms and 1 hole

E (31, 0, 1): energy of 31 Ag atoms and 1 additive atom

In the case of E (30, 1, 1), E (31, 0, 1), E (31,1, 0), the initial crystal structure is set to a face-centered cubic lattice. The multiplying power of the unified lattice constant is 1, and the translation vector of the primitive translation is The position of the hole is arranged to be closest to the position of the added atom.

In E (4, 0, 0), the magnification of the lattice constant is set to 1, and the primitive translation vector is set to

Next, the k-point pitch is explained. The k point in the first principle calculation corresponds to the wave number of the wave function. The k-point pitch corresponds to a range of wave numbers to be reflected in the calculation, and is set for each axis of the initial translational vectors a, b, and c. Since the wave function in which the wave number is larger as the k-point pitch is larger is also considered, the calculation accuracy of the electron density is high. On the other hand, the calculation required for the calculation becomes long. The k-point pitch is set to k points in the inverted lattice space. Here, the setting is performed as follows. In E (30, 1, 1), E (31, 0, 1), and E (31, 1, 0), 8 × 8 × 8 is set. In addition, E (4, 0, 0) is 16 × 16 × 16. Further, the Monkhorst Pack method is used as a method for selecting k points. The Monkhorst Pack method is a commonly used spacing generation method in first-principle computing software.

Further, the description is made with respect to the calculation. In the structure optimization calculation, (1) atom positions, (2) shapes of lattices, and (3) lattice constants are targeted for optimization. The method of calculating the electronic state (trajectory) uses the Blocked-Davidson method. In addition, the quasi-Newton method is used as an atomic position and ion structure relaxation algorithm. These are all common methods in first principles computing software. As a convergence condition of the structure optimization calculation, the energy difference before and after the repeated calculation satisfies 10^-4The magnitude of the force generated per 1 atom is below eV/cellThe following. Here, the cell (cell) corresponds to a model shape.

A contact material containing an Ag alloy as a main component according to a first aspect includes: ag alloy; and

The contact material containing an Ag alloy as a main component according to the second aspect may be such that, in the first aspect, the main additive is tin oxide and is contained in an amount of 5 wt% or more and 20 wt% or less in terms of metal,

The contact material containing an Ag alloy as a main component according to the third aspect may be such that, in the first aspect, the main additive is nickel or nickel oxide and is contained in an amount of 5 wt% or more and 20 wt% or less in terms of metal,

In the contact material containing an Ag alloy as a main component according to the fourth aspect, the main additive may be iron or iron oxide, and may be contained in an amount of 5 wt% or more and 20 wt% or less in terms of metal,

In the contact material containing an Ag alloy as a main component according to the fifth aspect, the main additive may be at least one selected from the group consisting of tungsten, tungsten carbide, and tungsten oxide, and may be contained in an amount of 5 wt% or more and 20 wt% or less in terms of metal,

In the contact material containing an Ag alloy as a main component according to the sixth aspect, the main additive may be zinc oxide, and the content thereof may be 5 wt% or more and 20 wt% or less in terms of metal,

The contact material containing an Ag alloy as a main component according to the seventh aspect may be such that, in the first aspect, the main additive is carbon and is contained in an amount of 0.01 wt% or more and 2 wt% or less in terms of element,

the solid solution element is selected from the group consisting of Be, K, Ca, Se, Rb, Sr, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Eu, Pb, and Bi, and is contained in an amount of 0.01 wt% to 2 wt%.

The contact material containing an Ag alloy as a main component according to the eighth aspect may further contain at least one selected from the group consisting of tungsten, tungsten carbide, tungsten oxide, and zirconium oxide present in a phase different from the Ag alloy in an amount of 0.1 wt% or more and 5 wt% or less in terms of metal in any one of the second to fourth aspects and the sixth to seventh aspects.

A contact material containing an Ag alloy as a main component according to a ninth aspect may further contain at least one of molybdenum oxide and tellurium dioxide present in a phase different from the Ag alloy in an amount of 0.1 wt% to 5 wt% in terms of metal in any one of the first to seventh aspects.

The contact material containing an Ag alloy as a main component according to the tenth aspect may further contain at least one of lithium oxide, lithium carbonate, and lithium cobaltate present in a phase different from the Ag alloy in an amount of 0.01 wt% to 1 wt% in terms of metal in any one of the first to seventh aspects.

The contact material containing an Ag alloy as a main component according to the eleventh aspect may further contain at least one of copper oxide and copper present in a phase different from the Ag alloy in an amount of 0.1 wt% or more and 2 wt% or less in terms of metal in any one of the first to seventh aspects.

A contact material containing an Ag alloy as a main component according to a twelfth aspect may further contain 0.1 wt% or more and 2 wt% or less, in terms of metal, of at least one of nickel oxide and nickel present in a phase different from the Ag alloy in any one of the second aspect, the fourth aspect, and the seventh aspect.

The contact material containing an Ag alloy as a main component according to the thirteenth aspect may further contain 0.1 wt% or more and 5 wt% or less of indium oxide present in a phase different from the Ag alloy in terms of metal in any one of the first to seventh aspects.

A contact material containing an Ag alloy as a main component according to a fourteenth aspect may further contain 0.1 wt% or more and 5 wt% or less of bismuth oxide present in a phase different from the Ag alloy in terms of metal in any one of the first to seventh aspects.

The contact material containing an Ag alloy as a main component according to the fifteenth aspect may further contain 0.1 wt% or more and 5 wt% or less of tin oxide present in a phase different from the Ag alloy in terms of metal in any one of the third to seventh aspects.

The contact material containing an Ag alloy as a main component according to the sixteenth aspect may further contain at least one of zinc oxide present in a phase different from the Ag alloy in an amount of 0.1 to 5 wt% in terms of metal in any one of the second to fifth and seventh aspects.

A contact material containing an Ag alloy as a main component according to a seventeenth aspect may further contain, in any one of the second to sixth aspects, 0.01 wt% or more and 2 wt% or less, in terms of element, of carbon present in a phase different from the Ag alloy.

In the contact material containing an Ag alloy as a main component according to the eighteenth aspect, the contact material may further include at least one selected from the group consisting of tungsten, tungsten carbide, tungsten oxide, zirconium oxide, molybdenum oxide, tellurium dioxide, lithium oxide, lithium carbonate, lithium cobaltate, copper oxide, copper, nickel oxide, nickel, indium oxide, bismuth oxide, tin oxide, zinc oxide, and carbon, which is present in a phase different from the Ag alloy in the first aspect.

A contact according to a nineteenth aspect uses the contact material containing an Ag alloy as a main component according to any one of the first to eighteenth aspects.

The electrical device according to the twentieth aspect is selected from the group consisting of a relay device, an electromagnetic contactor, an electromagnetic switch, a relay, a switch, and a switch, which use the contact according to the nineteenth aspect.

Hereinafter, a contact material containing an Ag alloy as a main component and a contact using the contact material according to the embodiment will be described with reference to the drawings. In the drawings, substantially the same components are denoted by the same reference numerals.

(embodiment mode 1)

< contact Material containing Ag alloy as the main component >

The contact material containing an Ag alloy as a main component according to embodiment 1 contains an Ag alloy and a main additive present in a phase different from the Ag alloy. The main additive is at least one selected from the group consisting of tin oxide, nickel oxide, iron oxide, tungsten carbide, tungsten oxide, zinc oxide, and carbon. The Ag alloy contains 0.01 wt% or more of solid solution elements. The solid solution element has a hole binding energy lower than the hole binding energy of carbon and holes in the Ag metal when the metal atom constituting the main additive or the main additive is carbon.

According to the contact material containing the Ag alloy as a main component, the Ag alloy contains a solid solution element having a hole binding energy lower than that of the constituent element of the main additive. Therefore, even when the contact material is used for the contact, the main additive such as tin oxide can be prevented from moving to the contact surface due to an arc or the like generated when the contact is opened or closed. This can suppress the main additive from migrating from the Ag alloy and condensing on the contact surface, and can suppress contact damage due to arcing generated when the contact is opened and closed.

The contact material containing the Ag alloy as a main component may contain the Ag alloy as a main phase and a main additive present in a phase different from the main phase, and may be in the form of a molded body having a predetermined shape, an amorphous sintered body, or a mixed powder which is amorphous and does not have a predetermined shape.

Hereinafter, each member constituting the contact material mainly composed of the Ag alloy will be described.

< Ag alloy >

The Ag alloy constitutes a main component of the material for contacts. The solid solution element that is solid-soluble in the Ag alloy is contained in Ag in an amount of 0.01 wt% or more. The Ag alloy contains 0.01 wt% or more of a solid solution element having a hole binding energy lower than the hole binding energy of carbon and holes in the Ag metal when the metal atom constituting the main additive or the main additive is carbon. By containing at least 0.01 wt% of the solid solution element, the solid solution element is more likely to bond to the holes in the Ag alloy than the elements constituting the main additive, and therefore the holes can be attracted to the periphery of the solid solution element. This can suppress the movement and aggregation of the main additive. Further, it preferably contains a solid-solution element 1.5 times or less the solid-solution limit of the Ag single phase.

Table 1 shows an element that may be used as a solid solution element and a hole binding energy in Ag of the element.

[ Table 1]

Element(s)	Hole binding energy (eV)	Element(s)	Hole binding energy (eV)		Hole binding energy (eV)
						Li	-0.087	Zn	-0.113	Nd	-0.293
Be	-0.237	Ga	-0.130	Pm	-0.247
						C	-0.235	Ge	-0.177	Sm	-0.217
Na	-0.186	Se	-0.259	Eu	-0.285
						Mg	-0.061	Rb	-0.873	Gd	-0.157
Al	-0.077	Sr	-0.538	Tb	-0.137
						Si	-0.185	Y	-0.124	Dy	-0.116
P	-0.222	Zr	0.036	Ho	-0.099
						K	-0.592	Ru	0.150	Er	-0.083
Ca	-0.252	Rh	0.065	Tm	-0.068
						Sc	0.010	Pd	-0.013	Yb	-0.165
Ti	0.053	In	-0.136	Lu	-0.046
						V	0.074	Sn	-0.202	Hf	0.056
Cr	0.094	Sb	-0.255	Ta	0.102
						Mn	0.084	Te	-0.301	Ir	0.071
Fe	0.073	Ba	-1.010	Pt	-0.021
						Co	0.027	La	-0.461	Tl	-0.213
Ni	-0.030	Ce	-0.367	Pb	-0.242
						Cu	-0.096	Pr	-0.339	Bi	-0.285
W	0.156	Mo	0.162

The relationship between the main additive and the solid solution element will be described later.

< major additives >

The host additive exists in a different phase from the Ag alloy. The main additive is at least one selected from the group consisting of tin oxide, nickel oxide, iron oxide, tungsten carbide, tungsten oxide, zinc oxide, and carbon. Further, a non-integral oxide of tin oxide, nickel oxide, iron oxide, or tungsten oxide may be selected as the main additive.

When the main additive is tin oxide, the content is 5 wt% or more and 20 wt% or less in terms of metal. In this case, the hole-binding energy of Sn, which is a metal element constituting tin oxide, in Ag is-0.202 eV.

As shown in fig. 1, it is known that when tin oxide is used as a main additive, La, Ce, Pr, Nd, Pm, Sm, and Eu in rare earth elements including Sc and Y of scandium have a hole binding energy lower than that of tin oxide. Therefore, La, Ce, Pr, Nd, Pm, Sm, and Eu can be used as solid solution elements.

The solid solution element is not limited to the rare earth element, and contains 0.01 wt% to 2 wt% of at least one element having a hole binding energy lower than that of Sn in Ag, selected from the group consisting of Be, C, P, K, Ca, Se, Rb, Sr, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Tl, Pb, and Bi.

< Nickel Ni or Nickel oxide NiO >

When the main additive is nickel or nickel oxide, the content is 5 wt% or more and 20 wt% or less in terms of metal. In this case, the hole-binding energy of Ni, a metal element constituting nickel or nickel oxide, to Ag is-0.030 eV. Therefore, the solid-solution element contains 0.01 wt% to 2 wt% of at least one element having a hole-binding energy lower than that of Ni In Ag, selected from the group consisting of Li, Be, C, Na, Mg, Al, Si, P, K, Ca, Cu, Zn, Ga, Ge, Se, Rb, Sr, Y, In, Sn, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Tl, Pb, and Bi.

When the main additive is iron or iron oxide, the content is 5 wt% or more and 20 wt% or less in terms of metal. In this case, the hole binding energy of the metal element Fe constituting iron or iron oxide in Ag is 0.073 eV. Therefore, the solid-solution element contains 0.01 wt% to 2 wt% of at least one element having a hole-binding energy lower than that of Fe In Ag, selected from the group consisting of Li, Be, C, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, Co, Ni, Cu, Zn, Ga, Ge, Se, Rb, Sr, Y, Zr, Rh, Pd, In, Sn, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ir, Pt, Tl, Pb, and Bi.

When the main additive is at least one selected from the group consisting of tungsten, tungsten carbide, and tungsten oxide, the main additive is contained in an amount of 5 wt% or more and 20 wt% or less in terms of metal. In this case, the hole binding energy of the metal element W constituting tungsten, tungsten carbide, and tungsten oxide in Ag is 0.156 eV. Therefore, the solid-solution element contains 0.01 wt% to 2 wt% of at least one element having a hole-binding energy lower than that of W In Ag and selected from the group consisting of Li, Be, C, Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Se, Rb, Sr, Y, Zr, Ru, Rh, Pd, In, Sn, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, Ir, Pt, Tl, Pb, and Bi.

< Zinc oxide ZnO >

When the main additive is zinc oxide, the content is 5 wt% or more and 20 wt% or less in terms of metal. In this case, the hole-binding energy of Zn, a metal element constituting the zinc oxide, in Ag is-0.113 eV. Therefore, the solid-solution element contains 0.01 wt% to 2 wt% of at least one element selected from the group consisting of Be, C, Na, Si, P, K, Ca, Ga, Ge, Se, Rb, Sr, Y, In, Sn, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Yb, Tl, Pb, and Bi, which has a hole-binding energy lower than that of Zn In Ag.

< carbon C >

When the main additive is carbon, the content of the main additive is 0.01 wt% or more and 2 wt% or less in terms of elemental conversion. The carbon may be any carbon, and may be an allotrope such as graphite, graphene, fullerene, or carbon nanotube. In this case, the hole binding energy of carbon in Ag is-0.235 eV. Therefore, the solid-solution element contains 0.01 wt% or more and 2 wt% or less of a group selected from the group consisting of Be, K, Ca, Se, Rb, Sr, Sb, Te, Ba, La, Ce, Pr, Nd, Pm, Eu, Pb, and Bi, which have a hole binding energy lower than that of carbon in Ag.

< additives >

Like the main additive, the sub-additive exists in a phase different from that of the Ag alloy. The following additives are listed.

The auxiliary additive may be at least one of tungsten, tungsten carbide, tungsten oxide, and zirconium oxide. In this case, the content may be 0.1 wt% or more and 5 wt% or less in terms of metal. Further, the tungsten, tungsten carbide, and tungsten oxide as the auxiliary additive are added when the main additive is not tungsten, tungsten carbide, or tungsten oxide. The tungsten, tungsten carbide, tungsten oxide, and zirconium oxide have high melting points, and the addition of these elements can provide an effect of making the main additive difficult to move.

The sub-additive may be at least one of molybdenum oxide and tellurium dioxide. In this case, the content may be 0.1 wt% or more and 5 wt% or less in terms of metal. Since molybdenum oxide and tellurium dioxide have lower sublimation points or boiling points than Ag, the formation of irregularities can be suppressed by the burning effect, and the solder resistance can be improved.

The secondary additive may be at least one of lithium oxide, lithium carbonate, and lithium cobaltate. In this case, the content may be 0.01 wt% or more and 1 wt% or less in terms of metal. By including lithium oxide, lithium carbonate, and lithium cobaltate, the wear resistance can be improved.

< copper oxide CuO, copper Cu >

The secondary additive may be at least one of copper oxide and copper. In this case, the content may be 0.1 wt% or more and 2 wt% or less in terms of metal. The workability can be improved by including copper oxide or copper.

< NiO and Ni oxides >

The auxiliary additive can be at least one of nickel oxide and nickel. In this case, the content may be 0.1 wt% or more and 2 wt% or less in terms of metal. In addition, nickel oxide and nickel as the auxiliary additives are added when the main additives are not nickel oxide or nickel. The workability can be improved by including nickel oxide or nickel.

The sub-additive may be indium oxide. In this case, the content may be 0.1 wt% or more and 5 wt% or less in terms of metal. By adding indium oxide, wear resistance can be improved and low contact resistance can be achieved.

The secondary additive may be bismuth oxide. In this case, the content may be 0.1 wt% or more and 5 wt% or less in terms of metal. By adding bismuth oxide, the solder resistance can be improved and low contact resistance can be achieved.

The auxiliary additive may be tin oxide. In this case, the content may be 0.1 wt% or more and 5 wt% or less in terms of metal. In addition, the tin oxide of the auxiliary additive is added in the case where the main additive is not tin oxide. The addition of tin oxide can improve the solder resistance.

< Zinc oxide ZnO >

The secondary additive may be zinc oxide. In this case, the content may be 0.1 wt% or more and 5 wt% or less in terms of metal. In addition, the zinc oxide of the sub-additive is added in the case where the main additive is not zinc oxide. By adding zinc oxide, the solder resistance can be improved and low contact resistance can be achieved.

< carbon C >

The secondary additive may be carbon. In this case, the content may be 0.01 wt% or more and 2 wt% or less in terms of element. The carbon may be any carbon, and may be an allotrope such as graphite, graphene, fullerene, or carbon nanotube. The carbon of the auxiliary additive is added when the main additive is not carbon. By adding carbon, the soldering resistance can be improved and low contact resistance can be achieved.

Further, the above-mentioned auxiliary additives may be used in a variety of forms.

< method for producing contact using contact material containing Ag alloy as main component >

A method for manufacturing a contact using a contact material containing an Ag alloy as a main component according to embodiment 1 includes the steps of: a particle production step of producing a powder of Ag alloy particles of the matrix phase, a powder of particles of the main additive, and a powder of particles of the sub additive;

a mixing step of mixing the Ag alloy particle powder, the particle powder of the main additive, and the particle powder of the sub additive to obtain a mixed powder; and

and a sintering step of sintering the mixed powder.

After the sintering step, for example, a molding step of molding into a predetermined shape as a contact may be included. That is, each step not including the step of forming the contact is also a step constituting the method of manufacturing a contact material mainly composed of an Ag alloy. The above-described process is an example, and is not limited thereto. Any commonly used powder metallurgy method can be used.

< Process for producing particles >

In the particle production step, for example, Ag and solid solution elements of the raw materials are weighed, dissolved, and then refined. Further, classification may be performed as necessary. The particle production step can be performed by a gas atomization method, a water atomization method, a PVD method, a CVD method, or the like. Further, the refining may be performed by plasma processing or pulverization from the alloy. Further, it is not essential that the solid solution of the solid-solution element in Ag is carried out in the production process of the particles. For example, Ag particle powder and solid solution element particle powder may be prepared separately in advance. In this case, the solid-solution element is not solid-dissolved in Ag. Then, in the next mixing step, the respective particles may be mixed, and the solid solution element may be made solid solution in Ag in the mixing step or the sintering step to be alloyed. Alternatively, Ag particle powder and oxide particle powder may be mixed and alloyed by reduction in an intermediate step.

< mixing step >

In the mixing step, Ag alloy particle powder, particle powder of the main additive, and particle powder of the sub additive are mixed to obtain mixed powder. For example, mixing can be performed in a mortar. Alternatively, the mixing may be performed in a ball mill.

In this mixing step, a mixed powder in which the main additive particles and the sub-additive particles are dispersed in the matrix phase of the Ag alloy particle powder is obtained.

Further, the method is not limited to the above method, and for example, an alloy of Ag and an element constituting the main additive may be prepared in advance, and then treated by an atomization method to selectively oxidize only the element constituting the main additive, for example, Sn, internally, thereby obtaining Ag in which SnO is dispersed₂A mixed powder of particles. Alternatively, an alloy of Ag and an element constituting the main additive may be prepared in advance, and then the internal oxidation treatment may be performed by a high-temperature treatment in an oxygen atmosphere. Then, the Ag alloy according to embodiment 1 can be mixed with the particles obtained by this method to obtain the alloy of the present invention.

< sintering step >

In the sintering step, for example, the mixed powder is press-molded at room temperature to form a powder compact, and then the powder compact is sintered in a vacuum sintering furnace. In a vacuum sintering furnace, vacuum drawing is performed, for example, by raising the temperature to 800 ℃ and holding for about 30 minutes for sintering.

Alternatively, the internal oxidation treatment may be followed by compression molding and high-temperature treatment at 750 to 900 ℃ in the air.

In the sintering step, a mixed powder in which the main additive particles and the sub-additive particles are dispersed in the matrix phase of the Ag alloy particle powder is obtained.

The above steps of the production method may be performed in an inert atmosphere such as nitrogen or argon. This can suppress oxidation of the element constituting the contact. Further, the reaction may be performed in a reducing atmosphere such as hydrogen gas.

In addition, the sintering step is not limited to one time. For example, sintering and compression molding may be repeated, or after sintering, pulverization, pressing, and sintering may be repeated.

< Molding Process >

In the molding step, the contact is molded into a predetermined shape. For example, the contact can be formed into a rod shape by hot extrusion, and the contact can be formed into a contact shape by rolling, blanking, drawing, or cold stamping. In addition, the copper can be combined with the copper in the rolling and cold pressing process, and after the shape of the contact is formed, barrel polishing and cleaning can be performed. Further, as the shape of the contact, a rivet contact for riveting with a contact piece, a lead press-in contact for riveting cut to a desired size while holding a drawn wire, a longitudinal welded contact attached to a contact piece by welding, a tape press-in contact processed into a rectangular tape and riveted cut to a desired size, a tape contact for attaching a protruding portion to a contact piece by resistance welding, and a post-soldering point formed by further providing a soldering flux on the lower side of the protruding portion, a contact attached to a contact piece by silver soldering after cutting or punching a drawn wire, a rectangular tape, or a plate into a round or rectangular shape into individual pieces, and the like are conceivable, but the shape is not limited thereto.

FIG. 5A is a schematic representation ofTin oxide SnO as main additive added to Ag substantially not containing solid solution elements other than tin as main additive₂The resultant contact was heated by repeating opening and closing of the contact, and an FE-SEM photograph of a cross section of the contact in a state where aggregates were formed near the surface of the contact. Fig. 5B is an EBSD photograph of the same field of view as fig. 5A.

As shown in FIG. 5A, it is understood that Ag containing no solid solution element and SnO, a tin oxide, as a main additive₂In the contact of (3), after Sn has moved to the surface of the contact, a large amount of aggregates of several μm or more are formed in the vicinity of the surface.

In order to verify the effect of the present invention, the coarsening of crystals due to heating was compared between the films shown in (example 1) and (comparative example 1).

(example 1)

FIG. 6A is a schematic view showing an Ag alloy obtained by adding a rare earth element as a solid solution element to Ag as a base material according to example 1, to which tin oxide SnO as a main additive was added₂And a field emission scanning electron microscope (FE-SEM) photograph of the cross section of the film before the heat treatment. Fig. 7A is a field emission scanning electron microscope (FE-SEM) photograph of a cross section of the film after the heat treatment of the film according to example 1. The heat treatment was carried out under vacuum at 600 ℃ for 10 minutes.

Using fig. 6A/7A of the images of the thin film cross section, the luminance of 890nm in width at a position of 250nm in thickness was measured, and the average crystal size as the crystal size of Ag of the base material was calculated from the number of times of peak occurrence corresponding to the luminance of the central portion of the crystal. In addition, since it is difficult to understand the particles in the FE-SEM photograph state of fig. 6A and 7A, binarization as image processing was performed as shown in fig. 6B and 7B, and processing was performed so that the distribution of the particles can be easily understood.

As shown in fig. 6A/6B, in the film before the heat treatment, the average value of the crystal size of Ag as the base material was about 28 nm. On the other hand, as shown in fig. 7A/7B, after heat treatment at 600 ℃ for 10 minutes, the average value of the crystal size of Ag as the base material was about 30 nm. According to embodiment 1, comprisesAg alloy of solid solution rare earth element and SnO₂The change in particle size of the thin film as the main additive before and after the heat treatment was 1.07 times without significant change.

Comparative example 1

FIG. 8A is a diagram showing SnO in which tin oxide is added as a main additive to Ag which does not substantially contain solid solution elements other than tin as the main additive in comparative example 1₂And a field emission scanning electron micrograph (FE-SEM) of the cross section of the film before the heat treatment. FIG. 9A is a field emission scanning electron microscope (FE-SEM) photograph of a cross section of the film after heat treatment of the film according to comparative example 1. The heat treatment was carried out at 600 ℃ for 10 minutes under vacuum in the same manner as in example 1. Fig. 8B is a diagram showing a binarized image of the FE-SEM photograph of fig. 8A. Fig. 9B is a view showing a binarized image of the FE-SEM photograph of fig. 9A.

As shown in fig. 8A, in the film before the heat treatment, the average value of the crystal size of Ag as the base material was about 36 nm. On the other hand, as shown in fig. 9A, after heat treatment at 600 ℃ for 10 minutes, the average value of the crystal size of Ag as the base material was about 47 nm. In comparative example 1, Ag containing no solid solution element and SnO, tin oxide, a main additive₂It is known that the particles of (1.3 times the particle size coarsened before and after the heat treatment.

Next, table 2 is a table showing the relationship between the heat treatment temperature and the change (%) in sheet resistance when the film of example 1 and the film of comparative example 1 were subjected to heat treatment. Fig. 10 is a graph showing the relationship between the heat treatment temperature and the sheet resistance of the thin films of example 1 and comparative example 1. The sheet resistance after the heat treatment was compared with the initial sheet resistance of the single sample, and the change rate (%) was calculated based on the initial sheet resistance of the single sample, and was dimensionless.

[ Table 2]

As shown in Table 2 and FIG. 10, in comparative example 1, the Ag which does not substantially contain solid solution elements other than tin as the main additive contains tin oxide SnO as the main additive₂When the heat treatment temperature of the film (2) exceeded 200 ℃, the sheet resistance began to decrease, and at 300 ℃, the sheet resistance significantly changed to 53.6% before the heat treatment. Thereafter, the sheet resistance was reduced to 71.5% before the heat treatment at a heat treatment temperature of 500 ℃ and no change was observed when the heat treatment temperature was further increased. On the other hand, the Ag alloy containing solid-solution rare earth elements according to example 1 and SnO₂Similarly, in the thin film containing the main additive, the sheet resistance started to decrease when the heat treatment temperature exceeded 200 ℃, but the sheet resistance was suppressed to 28.0% before the heat treatment at 300 ℃, gradually decreased as the heat treatment temperature increased, and decreased to 59.3% before the heat treatment at 500 ℃, after which the sheet resistance was substantially constant.

It is found that the alloy of comparative example 1 contains Ag containing no solid solution element and SnO, a tin oxide, as a main additive₂In comparison with the thin film of (1), the Ag alloy containing a solid-solution rare earth element and SnO₂In the thin film containing the main additive, coarsening of crystals and change in sheet resistance due to heat treatment can be suppressed.

In addition, in the present invention, any of the various embodiments and/or examples described above may be combined as appropriate, and effects of the various embodiments and/or examples may be achieved.

Industrial applicability

According to the contact material containing an Ag alloy as a main component according to the present invention, the Ag alloy contains a solid solution element having a hole-binding energy lower than that of the constituent element of the main additive. Therefore, even when the material for a contact is used for a contact, the main additive such as tin oxide can be prevented from moving to the surface of the contact due to an arc or the like generated when the contact is opened or closed, and the material is useful as a material for an electric contact.

Description of the symbols

2. 2a, 2b contact

4 arc of electricity

12 tin oxide (Main additive)

14 Ag

16 agglomerates

22 Sn atom

23O atom

24 Ag atom

26 cavities

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Contact material containing Ag alloy as main component, contact using the contact material, and electric device

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