JP2024090765A - Copper alloy material, and resistor material and resistor using the same - Google Patents

Abstract

To provide a copper alloy material that is large in a ratio of a shear surface occupying on a press-punched surface generated at the time of press-punching, has sufficiently high volume resistivity, has a resistance temperature coefficient (TCR) that is negative and small in the absolute value, and has a small absolute value of copper thermoelectromotive force (EMF) as well as a resistive material for resistors therewith and a resistor.SOLUTION: A copper alloy material contains Mn: 20.0 mass% or more and 35.0 mass% or less, and Ni: 6.5 mass% or more and 17.0 mass% or less, and the remaining portion is a copper alloy material having an alloy composition composed of Cu and unavoidable impurities. In a longitudinal section containing a drawing direction and a thickness direction of the copper alloy, when a crystal orientation distribution function (ODF) obtained from crystal orientation analysis due to a SEM-EBSD method is expressed by Euler angle (Φ1, Φ, Φ2), Φ1=0-90°, Φ=0-90°, and Φ2 is 15°-20°and a maximum value of orientation density at 25°exceeds 6.0.SELECTED DRAWING: Figure 1

Description

The present invention relates to a copper alloy material and a resistor material and resistor using the same.

It is desirable that the metallic material of the resistive material used in a resistor has a stable resistance even when the environmental temperature changes. For this reason, the resistive material is required to have a small absolute value of the temperature coefficient of resistance (TCR), which is an index showing the characteristic of a stable resistance value against temperature changes. The temperature coefficient of resistance is expressed in parts per million (ppm) per degree Celsius, and is expressed by the formula TCR (×10 ⁻⁶ /° C.) = {(R-R ₀ )/R ₀ }×{1/(T-T ₀ )}×10 ^6. Here, in the formula, T is the test temperature (° C.), T ₀ is the reference temperature (° C.), R is the resistance value (Ω) at the test temperature T, and R ₀ is the resistance value (Ω) at the reference temperature T _0. In particular, Cu-Mn-Ni alloys and Cu-Mn-Sn alloys have a very small TCR and are therefore widely used as alloy materials constituting resistive materials.

However, when these Cu-Mn-Ni alloys and Cu-Mn-Sn alloys are used as resistive materials in resistors designed to have a predetermined resistance value by forming a circuit (pattern) using the resistive material, the volume resistivity is small, less than 50×10 ⁻⁸ (Ω·m), so it is necessary to reduce the cross-sectional area of the resistive material to increase the resistance value of the resistor. In such resistors, when a large current flows temporarily in the circuit or when a relatively large current continues to flow all the time, Joule heat generated in the resistive material with a small cross-sectional area becomes high and heat is generated, and as a result, the resistive material is easily broken (melted) by the heat.

For this reason, there is a demand for resistive materials with higher volume resistivity to prevent the cross-sectional area of the resistive material from becoming smaller.

For example, Patent Document 1 describes a copper alloy containing Mn in the range of 23 mass % to 28 mass % and Ni in the range of 9 mass % to 13 mass %, and by configuring the mass fractions of Mn and Ni so that the thermoelectromotive force against copper is less than ±1 μV/°C at 20°C, it is possible to obtain a copper alloy having a high electrical resistance (volume resistivity ρ) of 50× ^10-8 [Ω·m] or more, a small thermoelectromotive force against copper (copper thermoelectromotive force, EMF), a low temperature coefficient of electrical resistance, and high stability over time of the intrinsic electrical resistance (time invariance).

Patent Document 2 also claims that by including 33% by mass or more and 38% by mass or less of Mn and 8% by mass or more and 15% by mass or less of Ni in an alloy for resistors containing copper, manganese, and nickel, it is possible to obtain a copper-manganese-nickel alloy that has properties (particularly resistivity) similar to those of nickel-chromium alloys and has superior workability compared to nickel-chromium alloys.

JP 2016-528376 A JP 2021-161512 A

As electrical and electronic components have become smaller and more highly integrated in recent years, resistors and the resistive materials used in them have also become smaller. The resistive materials used in resistors are generally formed by cutting processes such as press punching, so in order to reduce the variation in resistance value, it is required that the copper alloy material has excellent press punching workability. In particular, when press punching is performed on the copper alloy material, it is required that the cut surface, which is the punched surface, is formed in a fixed position in order to reduce the variation in resistance value.

Copper alloys that contain high concentrations of Mn and Ni to increase the volume resistivity are characterized by high mechanical strength and strong bonding between the atoms that make up the copper alloy due to solid solution strengthening. However, when such copper alloys are produced into a plate and then punched by a press, the area of the cut surface, especially the sheared surface, tends to become small due to the strong bonding between the atoms and poor ductility. Here, the performance of resistors made of copper alloy material is easily influenced by the dimensions of the resistor obtained after press punching. In particular, in copper alloy material with poor ductility, if the proportion of the sheared surface in the cut surface, which is the punched surface, is small, the proportion of the fractured surface increases, etc., and errors are likely to occur in the dimensions of the obtained resistor, which could impair the accuracy of the electrical resistance of the resistance material.

Furthermore, in recent years, in the electrical equipment systems of electric vehicles, resistors such as shunt resistors and chip resistors are required to have a high volume resistivity ρ as well as high precision resistors that can withstand higher temperature environments, and copper alloys used in such resistors are also required to have high precision resistors that can withstand higher temperature environments. More specifically, there is a demand for copper alloy materials that have a high volume resistivity ρ, and when considering the wide temperature range from room temperature to high temperatures, a negative temperature coefficient of resistance (TCR) with a small absolute value, and a small absolute value of thermal electromotive force (EMF) against copper.

The object of the present invention is therefore to provide a copper alloy material having a large proportion of the shear surface on the punched surface generated during press punching, a sufficiently high volume resistivity, a negative temperature coefficient of resistance (TCR) with a small absolute value, and a small absolute value of the thermoelectromotive force (EMF) against copper, as well as a resistor material and a resistor using the same.

The inventors have discovered that a copper alloy material having an alloy composition containing 20.0% by mass or more and 35.0% by mass or less of Mn, 6.5% by mass or more and 17.0% by mass or less of Ni, with the balance being Cu and unavoidable impurities, and having a maximum orientation density exceeding 6.0 when the crystal orientation distribution function (ODF) is expressed in Euler angles (φ1, Φ, φ2) at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 = 15°, 20°, and 25°, increases the ratio of the shear surface occupying the punched surface generated during press punching, has a sufficiently high volume resistivity ρ as a resistance material, and is capable of being used in a wide temperature range from room temperature (e.g., 20°C) to high temperature (e.g., 150°C), has a negative temperature coefficient of resistance (TCR) with a small absolute value, and has a small absolute value of thermal electromotive force (EMF) against copper, and has been completed.

In order to achieve the above object, the gist of the present invention is as follows.
(1) A copper alloy material having an alloy composition containing 20.0 mass% or more and 35.0 mass% or less of Mn, and 6.5 mass% or more and 17.0 mass% or less of Ni, with the balance being Cu and unavoidable impurities, wherein, in a longitudinal section including an elongation direction and a thickness direction of the copper alloy material, a crystal orientation distribution function (ODF) obtained by a crystal orientation analysis by a SEM-EBSD method is expressed as Euler angles (φ1, Φ, φ2), the maximum value of the orientation density at φ1=0 to 90°, Φ=0 to 90°, and φ2 of 15°, 20°, and 25° exceeds 6.0.
(2) In a longitudinal section including the stretching direction and the thickness direction of the copper alloy material, when a crystal orientation distribution function (ODF) obtained by a crystal orientation analysis by a SEM-EBSD method is expressed in terms of Euler angles (φ1, Φ, φ2), the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 is 15°, 20°, and 25° is 7.0 or more. The copper alloy material according to (1) above.
(3) The copper alloy material according to (1) or (2) above, wherein the alloy composition further contains one or both of Fe: 0.01 mass% or more and 0.50 mass% or less and Co: 0.01 mass% or more and 2.00 mass% or less.
(4) The copper alloy material according to any one of (1) to (3), further comprising at least one selected from the group consisting of Sn: 0.01% by mass or more and 5.00% by mass or less, Zn: 0.01% by mass or more and 5.00% by mass or less, Cr: 0.01% by mass or more and 0.50% by mass or less, Ag: 0.01% by mass or more and 0.50% by mass or less, Al: 0.01% by mass or more and 1.00% by mass or less, Mg: 0.01% by mass or more and 0.50% by mass or less, Si: 0.01% by mass or more and 0.50% by mass or less, and P: 0.01% by mass or more and 0.50% by mass or less.
(5) A resistance material for a resistor, comprising the copper alloy material according to any one of (1) to (4) above.
(6) A resistor, which is a shunt resistor or a chip resistor, comprising the resistive material for resistors according to (5) above.

According to the present invention, it is possible to provide a copper alloy material having a large proportion of the shear surface generated during press punching on the punched surface, a sufficiently high volume resistivity, a negative temperature coefficient of resistance (TCR) with a small absolute value, and a small absolute value of the thermoelectromotive force (EMF) against copper, as well as a resistor material for resistors and a resistor using the same.

FIG. 1 is a schematic diagram of a polished surface of the punched copper alloy material of the present invention, which is viewed from a direction parallel to the cut surface, when the punched copper alloy material is subjected to a press punching process, and a surface including a thickness direction perpendicular to the cut surface is embedded in resin and polished in order to understand the contour shape (right edge portion) of the cut surface. FIG. 2 is a schematic diagram for explaining a method for determining the thermoelectromotive force (EMF) against copper for each of the test materials of the invention examples and the comparative examples. FIG. 3 is a graph showing the crystal orientation distribution function (ODF) of the copper alloy material of Example 9 of the present invention, expressed as Euler angles (φ1, Φ, φ2), with φ1 on the horizontal axis and Φ on the vertical axis, showing the orientation density in the ranges of φ1=0 to 90° and Φ=0 to 90°, where FIG. 3(a) is a graph when φ2=15°, FIG. 3(b) is a graph when φ2=20°, and FIG. 3(c) is a graph when φ2=25°.

Below, preferred embodiments of the copper alloy material of the present invention will be described in detail. Note that in the component composition of the alloy of the present invention, "mass %" may be simply indicated as "%".

The copper alloy material according to the present invention has an alloy composition containing Mn: 20.0% by mass to 35.0% by mass, Ni: 6.5% by mass to 17.0% by mass, with the balance being Cu and unavoidable impurities. When the crystal orientation distribution function (ODF) obtained from crystal orientation analysis by SEM-EBSD method in a longitudinal section including the elongation direction and thickness direction of the copper alloy material is expressed in terms of Euler angles (φ1, Φ, φ2), the maximum orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 of 15°, 20°, and 25° exceeds 6.0.

In this way, in the copper alloy material according to the present invention, for a copper alloy material containing 20.0% by mass or more and 35.0% by mass or less of Mn and 6.5% by mass or more and 17.0% by mass or less of Ni, when the crystal orientation distribution function (ODF) is expressed as Euler angles (φ1, Φ, φ2), the maximum orientation density exceeds 6.0 at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 = 15°, 20°, and 25°. This increases the proportion of crystal grains oriented in the S orientation or copper orientation, suppressing the presence of crystal grains not oriented in these orientations, which are the starting point of fracture during press punching, thereby suppressing fracture of the copper alloy material during press punching, and thereby making it possible to increase the proportion of the shear surface in the punched surface.

In addition, in the copper alloy material according to the present invention, Mn is contained in the range of 20.0 mass% to 35.0 mass% and Ni is contained in the range of 6.5 mass% to 17.0 mass%, thereby increasing the volume resistivity ρ, reducing the absolute value of the temperature coefficient of resistance (TCR) (hereinafter sometimes simply referred to as "temperature coefficient of resistance") in the temperature range of 20°C to 150°C, and reducing the absolute value of the thermoelectromotive force against copper. In addition, in the copper alloy material according to the present invention, the absolute value of the thermoelectromotive force against copper (EMF) (hereinafter sometimes simply referred to as "thermoelectromotive force against copper") generated between temperature environments of 20°C and 80°C is reduced, so that the precision of resistors can be improved even in high-temperature environments.

In this regard, in the copper alloy described in the above-mentioned Patent Document 1, in order to reduce the absolute value of the copper thermoelectromotive force (EMF), it is necessary to increase the Ni content, and in that case, the absolute value of the temperature coefficient of resistance (TCR) tends to increase. In addition, in the copper alloy described in the above-mentioned Patent Document 1, the temperature coefficient of resistance (TCR) becomes a large negative number in the temperature range from 20°C to 150°C, including the higher temperature range, as shown in, for example, FIG. 3 of Patent Document 1, with respect to the temperature dependence of the electrical resistance, so that the resistance value tends to be prone to errors in the high temperature range. However, in the copper alloy material according to the present invention, the absolute value of the temperature coefficient of resistance (TCR) in the temperature range from 20°C to 150°C can be suppressed from increasing, so that the copper alloy material has a sufficiently high volume resistivity as a resistance material, and is also excellent in that it has a small absolute value of the temperature coefficient of resistance and a small absolute value of the thermoelectromotive force against copper, taking into account the use environment in a wide temperature range from room temperature (e.g., 20°C) to high temperature (e.g., 150°C).

As a result, by using the copper alloy material according to the present invention, it is possible to provide a copper alloy material in which the proportion of the shear surface generated during press punching is large on the punched surface, which has a sufficiently high volume resistivity ρ, a negative temperature coefficient of resistance (TCR) with a small absolute value, and a small absolute value of the thermoelectromotive force (EMF) against copper, as well as a resistor material for resistors and resistors using the same.

[1] Composition of copper alloy material <Essential additive components>
The alloy composition of the copper alloy material of the present invention contains, as essential additive components, Mn: 20.0 mass % or more and 35.0 mass % or less, and Ni: 6.5 mass % or more and 17.0 mass % or less.

(Mn: 20.0 mass% or more and 35.0 mass% or less)
Mn (manganese) is an element that increases the volume resistivity ρ. In order to exert this effect and obtain a homogeneous copper alloy material, Mn is preferably contained in an amount of 20.0 mass% or more, more preferably 22.0 mass% or more, and even more preferably 24.0 mass% or more. Here, by increasing the Mn content to 22.0 mass% or more or 24.0 mass% or more, the volume resistivity ρ of the copper alloy material can be further increased. On the other hand, if the Mn content exceeds 35.0 mass%, the melting point of the copper alloy material decreases, making it difficult to control the manufacture of the copper alloy material, especially hot working, and therefore making it difficult to obtain uniform characteristics. In addition, if the Mn content exceeds 35.0 mass%, the absolute value of the copper thermoelectromotive force (EMF) tends to be large. For this reason, the Mn content is set to a range of 20.0 mass% to 35.0 mass%.

(Ni: 6.5 mass% or more and 17.0 mass% or less)
Ni (nickel) is an element that adjusts the electromotive force (EMF) to a positive direction. To exert this effect, Ni is preferably contained in an amount of 6.5 mass% or more. On the other hand, if the Ni content exceeds 17.0 mass%, it becomes difficult to obtain a uniform structure, and the volume resistivity ρ and electromotive force (EMF) to copper may change. In particular, the Ni content is set to a range of 6.5 mass% to 17.0 mass% or less, preferably 6.5 mass% to 12.0 mass% or less, and more preferably 6.5 mass% to 9.0 mass% or less, from the viewpoint of obtaining a copper alloy material having desired characteristics and from the viewpoint of obtaining a copper alloy material that is easy to manufacture.

<First optional component>
The alloy composition of the copper alloy material of the present invention may further contain, as a first optional additive component, one or both of Fe: 0.01 mass% or more and 0.50 mass% or less and Co: 0.01 mass% or more and 2.00 mass% or less. In particular, by containing one or both of Fe and Co, it is possible to further reduce at least the absolute value of the temperature coefficient of resistance (TCR) among the absolute values of the thermoelectromotive force (EMF) against copper and the temperature coefficient of resistance (TCR).

(Fe: 0.01 mass% or more and 0.50 mass% or less)
Fe (iron) is an element that adjusts the thermoelectromotive force (EMF) against copper in a positive direction. To exert this effect, it is preferable that Fe is contained in an amount of 0.01 mass% or more. On the other hand, if the content of Fe exceeds 0.50 mass%, it becomes difficult to obtain a uniform structure, and thus the electrical performance is likely to vary. In addition, while Fe is an inexpensive element, it is an element that increases the fluctuation of electrical properties over time. Therefore, it is preferable that the Fe content is 0.50 mass% or less. In particular, from the viewpoint of further increasing the stability of electrical properties against heat, etc., and thereby further increasing reliability when used for a long period of time as a resistance material, etc., the Fe content is more preferably 0.30 mass% or less, and even more preferably 0.20 mass% or less. Therefore, the Fe content is preferably in the range of 0.01 mass% or more and 0.50 mass% or less, more preferably in the range of 0.01 mass% or more and 0.30 mass% or less, and even more preferably in the range of 0.01 mass% or more and 0.20 mass% or less.

(Co: 0.01% by mass or more and 2.00% by mass or less)
Co (cobalt) is an element that adjusts the electromotive force (EMF) against copper in a positive direction. To exert this effect, it is preferable that Co is contained in an amount of 0.01 mass% or more. On the other hand, if the content of Co exceeds 2.00 mass%, it becomes difficult to obtain a uniform structure, and the electrical performance is likely to vary. On the other hand, Co is an expensive element, but unlike Fe, if the content of Co is in the range of 2.00 mass% or less, it is difficult for the electrical properties to fluctuate over time. Therefore, it is preferable that the content of Co is in the range of 0.01 mass% or more and 2.00 mass% or less.

<Second optional component>
The alloy composition of the copper alloy material of the present invention may further contain at least one selected from the group consisting of Sn: 0.01% by mass or more and 5.00% by mass or less, Zn: 0.01% by mass or more and 5.00% by mass or less, Cr: 0.01% by mass or more and 0.50% by mass or less, Ag: 0.01% by mass or more and 0.50% by mass or less, Al: 0.01% by mass or more and 1.00% by mass or less, Mg: 0.01% by mass or more and 0.50% by mass or less, Si: 0.01% by mass or more and 0.50% by mass or less, and P: 0.01% by mass or more and 0.50% by mass or less, as a second optional added component.

(Sn: 0.01% by mass or more and 5.00% by mass or less)
Sn (tin) is a component that can be used to adjust the volume resistivity ρ. In order to exert this effect, it is preferable to contain 0.01 mass% or more of Sn. On the other hand, by making the Sn content 5.00 mass% or less, it is possible to make it difficult for the copper alloy material to become brittle and thereby reduce the deterioration of manufacturability.

(Zn: 0.01% by mass or more and 5.00% by mass or less)
Zn (zinc) is a component that can be used to adjust the volume resistivity ρ. To achieve this effect, it is preferable to contain Zn at 0.01 mass% or more. On the other hand, the Zn content is preferably 5.00 mass% or less because it may adversely affect the stability of the electrical performance of the resistor, such as the volume resistivity ρ and the electromotive force (EMF) against copper.

(Cr: 0.01% by mass or more and 0.50% by mass or less)
Cr (chromium) is a component that can be used to adjust the volume resistivity ρ. To achieve this effect, it is preferable to contain 0.01 mass% or more of Cr. On the other hand, the Cr content is preferably 0.50 mass% or less because it may adversely affect the stability of the electrical performance of the resistor, such as the volume resistivity ρ and the thermal electromotive force (EMF) against copper.

(Ag: 0.01% by mass or more and 0.50% by mass or less)
Silver (Ag) is a component that can be used to adjust the volume resistivity ρ. To achieve this effect, it is preferable to contain 0.01 mass% or more of Ag. On the other hand, the Ag content is preferably 0.50 mass% or less because it may adversely affect the stability of the electrical performance of the resistor, such as the volume resistivity ρ and the thermal electromotive force (EMF) against copper.

(Al: 0.01% by mass or more and 1.00% by mass or less)
Al (aluminum) is a component that can be used to adjust the volume resistivity ρ. To achieve this effect, it is preferable to contain 0.01 mass% or more of Al. On the other hand, the Al content is preferably 1.00 mass% or less because there is a risk of embrittlement of the copper alloy material.

(Mg: 0.01% by mass or more and 0.50% by mass or less)
Mg (magnesium) is a component that can be used to adjust the volume resistivity ρ. To achieve this effect, it is preferable to contain 0.01 mass% or more of Mg. On the other hand, the Mg content is preferably 0.50 mass% or less because there is a risk of embrittlement of the copper alloy material.

(Si: 0.01 mass% or more and 0.50 mass% or less)
Si (silicon) is a component that can be used to adjust the volume resistivity ρ. In order to exert this effect, it is preferable to contain 0.01 mass% or more of Si. On the other hand, the Si content is preferably 0.50 mass% or less because there is a risk of embrittlement of the copper alloy material.

(P: 0.01% by mass or more and 0.50% by mass or less)
P (phosphorus) is a component that can be used to adjust the volume resistivity ρ. To achieve this effect, it is preferable to contain 0.01 mass% or more of P. On the other hand, since the P content may embrittle the copper alloy material, it is preferable to set it to 0.50 mass% or less.

(Total amount of second optional added components: 0.01% by mass or more and 5.00% by mass or less)
In order to obtain the effects of the second optional components, which are at least one component selected from the group consisting of Sn, Zn, Cr, Ag, Al, Mg, Si, and P, it is preferable to contain them in a total amount of 0.01 mass% or more. On the other hand, if these second optional components are contained in a large amount, the electrical characteristics become unstable and it becomes difficult to manufacture the copper alloy material, so that it is preferable to limit the total amount to 5.00 mass% or less.

<Balance: Cu and inevitable impurities>
Other than the above-mentioned essential components and optional additive components, the remainder is composed of Cu (copper) and inevitable impurities. The "unavoidable impurities" referred to here are generally those present in raw materials in copper-based products or those inevitably mixed in during the manufacturing process, and are essentially unnecessary impurities that are allowed because they are in small amounts and do not affect the properties of copper-based products. Examples of components that can be cited as inevitable impurities include nonmetallic elements such as sulfur (S) and metallic elements such as antimony (Sb). The upper limit of the content of these components can be 0.05 mass% for each of the above components, and 0.10 mass% for the total amount of the above components.

[2] Maximum orientation density when crystal orientation distribution function (ODF) is expressed as Euler angles at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 is 15°, 20°, and 25° In the copper alloy material of the present invention, when a crystal orientation distribution function (ODF) obtained from crystal orientation analysis by SEM-EBSD method is expressed as Euler angles (φ1, Φ, φ2) in a longitudinal section including the elongation direction and thickness direction of the copper alloy material, the maximum orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 is 15°, 20°, and 25° exceeds 6.0. Here, by manufacturing the copper alloy material so that the crystal grains are oriented in the S orientation {123}<634> or the Copper orientation {112}<111>, the maximum value of the orientation density at φ1=0-90°, Φ=0-90°, and φ2=15°, 20°, and 25° can exceed 6.0. In the copper alloy material of the present invention, since many crystal grains oriented in the S orientation or the Copper orientation are accumulated, the presence of crystal grains having different orientations and different mechanical properties, which are the starting points of fracture during press punching, can be suppressed, and therefore fracture of the copper alloy material during press punching can be suppressed. As a result, a cut surface with a small proportion of fracture surfaces that cause errors in the dimensions of the resistor and a large proportion of smooth shear surfaces can be obtained, so that a copper alloy material suitable for obtaining a resistor with higher accuracy can be obtained.

Therefore, from the viewpoint of increasing the proportion of the shear plane in the punched surface generated during press punching and obtaining a copper alloy material suitable for obtaining resistors with higher precision, when the crystal orientation distribution function (ODF) is expressed as Euler angles (φ1, Φ, φ2), it is preferable that the maximum value of the orientation density (orientation) at φ1 = 0 to 90°, Φ = 0 to 90°, φ2 = 15°, 20°, and 25° exceeds 6.0, and is particularly preferable to be 7.0 or more.

When the crystal orientation distribution function (ODF) is expressed in terms of Euler angles (φ1, Φ, φ2), the maximum orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 = 15°, 20°, and 25° is the value obtained from the inverse pole figure, which shows the intensity distribution of the crystal orientation and is drawn from the crystal orientation analysis data obtained by the SEM-EBSD method.

Here, the crystal orientation analysis data of the SEM-EBSD method can be obtained by preparing a cross-sectional sample by mirror-polishing a cross-section parallel to the elongation direction of the copper alloy material, observing the cross-sectional sample using a field emission scanning electron microscope (FE-SEM), and performing EBSD measurement (measurement by electron backscatter diffraction method). The area to be measured in the EBSD measurement can be ^0.02 mm2 or more, and the measurement step can be 0.5 μm.

From the EBSD measurement results, the maximum orientation density can be obtained using an ODF map obtained using the data analysis software "OIM ANALYSIS". More specifically, the intensity is calculated using the harmonic series expansion with a series rank of 16 and a Gaussian half-width of 5° when fitting to a Gaussian distribution, and texture analysis is performed on the calculation results obtained by selecting Enforce Orthotropic Sample Symmetry to create an ODF map showing the intensity distribution of the crystal orientation when expressed in Euler angles (φ1, Φ, φ2). Using this, the maximum orientation density can be obtained for φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 = 15°, 20°, and 25°.

When the crystal orientation distribution function (ODF) is expressed in terms of Euler angles (φ1, Φ, φ2), the maximum orientation density at φ1 = 0-90°, Φ = 0-90°, φ2 = 15°, 20°, and 25° is expressed as a relative value when the density of crystal grains oriented at the corresponding Euler angles (φ1, Φ, φ2) when the crystal grains are completely randomly oriented is set to 1.

[3] Shape of copper alloy material The shape of the copper alloy material of the present invention is not particularly limited, but is preferably a plate material from the viewpoint of facilitating the hot or cold processing step and cutting processing such as press punching, which will be described later. Here, in the copper alloy material formed by rolling, such as a plate material, the rolling direction can be the stretching direction. On the other hand, the copper alloy material of the present invention may be a wire material, a rectangular wire material, a ribbon material, a strip material, or a bar material, and by forming these shapes with the copper alloy material of the present invention, it is possible to facilitate cutting processing of the terminal. Here, in the copper alloy material of these shapes formed by wire drawing, drawing, or extrusion, any of the wire drawing direction, drawing direction, and extrusion direction can be the stretching direction.

[4] An example of a manufacturing method for a copper alloy material The above-mentioned copper alloy material can be realized by controlling a combination of alloy composition and manufacturing process, and the manufacturing process is not particularly limited. Among them, the following method can be mentioned as an example of a manufacturing process that can obtain the above-mentioned copper alloy material.

As an example of the manufacturing method of the copper alloy material of the present invention, at least the casting process [step 1], the homogenization heat treatment process [step 2], the hot working process [step 3], the first cold stretching process [step 4], the first annealing process [step 5], the second cold stretching process [step 6], and the second annealing process [step 7] are sequentially performed on a copper alloy material having substantially the same alloy composition as the above-mentioned copper alloy material. Among these, in the homogenization heat treatment process [step 2], the heating temperature is set to a range of 700°C or more and 900°C or less, and the temperature holding time at the heating temperature is set to a range of 10 minutes or more and 10 hours or less. In addition, in the first cold stretching process [step 4], the total processing rate is set to a range of 30% or more and 50% or less, and in the first annealing process [step 5], the heating temperature is set to a range of 300°C or more and 500°C or less, and the temperature holding time at the heating temperature is set to a range of 1 hour or more and 2 hours or less. In addition, in the second cold stretching step [step 6], the total processing rate including the first cold stretching step [step 4] is set to 90% or more, and in the second annealing step [step 7], the heating temperature is set to a range of 600°C or more and 800°C or less, and the temperature holding time at the heating temperature is set to a range of 1 minute or more and 2 hours or less.

(i) Casting process [Step 1]
In the casting process [Step 1], a copper alloy material having the above-mentioned alloy composition is melted in an inert gas atmosphere or in a vacuum using a high-frequency melting furnace, and then cast into an ingot of a predetermined shape (e.g., 300 mm thick, 500 mm wide, and 3000 mm long). Note that the alloy composition of the copper alloy material may not necessarily be completely identical to that of the copper alloy material produced due to the adhesion or volatilization of additives in the melting furnace in each manufacturing process, but it has substantially the same alloy composition as that of the copper alloy material.

(ii) Homogenization heat treatment step [Step 2]
The homogenization heat treatment step [step 2] is a step of performing a homogenizing heat treatment on the ingot after the casting step [step 1]. Here, the conditions of the heat treatment in the homogenization heat treatment step [step 2] are preferably a heating temperature in the range of 700°C to 900°C and a holding time in the range of 10 minutes to 10 hours from the viewpoint of suppressing the coarsening of crystal grains.

(iii) Hot working step [Step 3]
The hot working step [step 3] is a step in which the ingot that has been subjected to the homogenization heat treatment is subjected to elongation processing such as hot rolling and wire drawing until it has a predetermined thickness, thereby producing a hot-rolled material. The conditions of the hot working step [step 3] are that the working temperature is preferably in the range of 700°C to 900°C, and may be the same as the heating temperature in the homogenization heat treatment step [step 2]. In addition, the working rate in the hot working step [step 3] is preferably 50% or more.

Here, the "processing rate" is a value obtained by subtracting the cross-sectional area after processing from the cross-sectional area before elongation processing such as rolling or wire drawing, dividing the result by the cross-sectional area before processing, multiplying the result by 100, and expressed as a percentage, and is expressed by the following formula.
[Processing rate] = {([Cross-sectional area before processing] - [Cross-sectional area after processing]) / [Cross-sectional area before processing]} x 100 (%)

The hot-rolled material after the hot working step [step 3] is preferably cooled. Here, the means for cooling the hot-rolled material is not particularly limited, but from the viewpoint of, for example, making it difficult for the crystal grains to become coarse, it is preferable to use a means for increasing the cooling rate as much as possible, and for example, it is preferable to use a means such as water cooling to make the cooling rate 50°C/sec or more.

Here, facing may be performed on the cooled hot-rolled material to remove the surface. By performing facing, it is possible to remove the oxide film and defects on the surface that occurred in the hot working step [step 3]. The conditions for facing may be any conditions that are normally used, and are not particularly limited. The amount of material removed from the surface of the hot-rolled material by facing can be appropriately adjusted based on the conditions of the hot working step [step 3], and can be, for example, about 0.5 mm to 4 mm from the surface of the hot-rolled material.

(iv) First cold stretching step [Step 4]
The first cold stretching step [step 4] is a step of performing stretching such as cold rolling or wire drawing on the hot rolled material after the hot stretching step [step 3]. The conditions of the stretching such as rolling or wire drawing in the first cold stretching step [step 4] can be set according to the thickness and size of the hot rolled material before stretching and the cold rolled material after stretching. In particular, from the viewpoint of promoting the orientation of the crystal grains in the S orientation {123}<634> and the Copper orientation {112}<111>, it is preferable that the total processing rate in the first cold stretching step [step 4] is in the range of 30% to 50%.

(v) First annealing step [Step 5]
The first annealing step [step 5] is a step of annealing in which the cold-rolled material after the first cold stretching step [step 4] is subjected to a heat treatment. Here, the conditions of the heat treatment in the first annealing step [step 5] are that the heating temperature is in the range of 300°C to 500°C, and the holding time at the heating temperature is in the range of 1 hour to 2 hours. In particular, after the first cold stretching step [step 4] in which the total processing rate is in the range of 30% to 50%, annealing is performed at a heating temperature of 300°C to 500°C for a heating time of 1 hour to 2 hours, thereby reducing the equipment load when performing the cold stretching step in the subsequent step. In addition, by accumulating many crystal grains oriented in the S orientation and Copper orientation in the copper alloy material, the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 = 15°, 20°, and 25° can be increased. On the other hand, if the heating temperature in the first annealing step [step 5] is less than 300°C, the equipment load when performing the subsequent cold stretching step cannot be reduced, and if the heating temperature in the first annealing step [step 5] exceeds 500°C, the maximum value of the orientation density becomes small.

(vi) Second cold stretching step [Step 6]
The second cold stretching step [step 6] is a step of performing stretching such as cold rolling or wire drawing on the cold rolled material after the first annealing step [step 5]. The conditions of the stretching such as rolling or wire drawing in the second cold stretching step [step 6] can be set according to the thickness and size of the cold rolled material before stretching and the product after stretching. In particular, from the viewpoint of further strengthening the orientation of the crystal grains in the S orientation {123}<634> and the Copper orientation {112}<111>, the total processing rate in the second cold stretching step [step 6] including the processing rate in the first cold stretching step [step 4] is preferably 90% or more, more preferably 92% or more, and even more preferably 95% or more.

(vii) Second annealing step [step 7]
The second annealing step [step 7] is a step of annealing in which the cold-rolled material after the second cold stretching step [step 6] is heat-treated to recrystallize it. Here, the conditions of the heat treatment in the second annealing step [step 7] are a heating temperature in the range of 600°C to 800°C and a holding time in the range of 1 minute to 2 hours. On the other hand, when the heating temperature is less than 600°C or the holding time is less than 1 minute, it becomes difficult to recrystallize the copper alloy material, so that it becomes difficult to accumulate crystal grains having the desired orientation. In addition, when the heating temperature exceeds 800°C or the holding time exceeds 2 hours, the crystal grains become coarse and the number decreases, so that at least one of the volume resistivity, the temperature coefficient of resistance, and the thermoelectromotive force against copper becomes inappropriate.

[5] Uses of copper alloy material The copper alloy material of the present invention is extremely useful as a resistor material for resistors, for example, shunt resistors or chip resistors. That is, the resistor material is preferably made of the above-mentioned copper alloy material. Moreover, resistors such as shunt resistors or chip resistors preferably have the resistor material made of the above-mentioned copper alloy material.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and includes all aspects included in the concept of the present invention and the scope of the claims, and can be modified in various ways within the scope of the present invention.

Next, to further clarify the effects of the present invention, examples of the present invention and comparative examples will be described, but the present invention is not limited to these examples.

(Inventive Examples 1 to 17 and Comparative Examples 1 to 6)
A copper alloy material having the alloy composition shown in Table 1 was melted, and the molten copper alloy material was cooled and cast in a casting step [Step 1] to obtain an ingot having a thickness of 30 mm. Here, the alloy composition of Comparative Example 1 has the same alloy composition as the copper alloy described in the above-mentioned Patent Document 1 and Example 2 of the above-mentioned Patent Document 2.

This ingot was subjected to a homogenization heat treatment process [Step 2] in which heat treatment was performed at a heating temperature of 800°C and a holding time of 5 hours, and then a hot processing process [Step 3] in which it was rolled along the longitudinal direction at a processing temperature of 800°C so that the total processing rate was 67% (thickness before processing: 30 mm, thickness after processing: 10 mm) was performed to obtain a hot-rolled material. It was then cooled to room temperature by water cooling, and facing was performed by removing 1 to 3.5 mm from both sides to remove the oxide film that had formed on the surface. The thickness of the hot-rolled material after facing was 3 to 8 mm.

The hot-rolled material after the hot working process [step 3] was subjected to the first cold working process [step 4] in which it was rolled in the longitudinal direction at the total working ratio shown in Table 2.

Here, for present invention examples 1 to 17 and comparative examples 1 to 3, 5, and 6, the cold-rolled material after the first cold working step [step 4] was subjected to a first heat treatment step [step 5] in which heat treatment was performed under the heat treatment conditions shown in Table 2, and then a second cold working step [step 6] was performed in which the cold-rolled material was rolled in the longitudinal direction at a total processing rate including the first cold stretching step [step 4] shown in Table 2. Then, the cold-rolled material after the second cold working step [step 6] was subjected to a second heat treatment step [step 7] in which heat treatment was performed under the heat treatment conditions shown in Table 2.

On the other hand, in Comparative Example 4, the cold-rolled material after the first cold stretching step [step 4] was subjected to the second heat treatment step [step 7] without performing the first heat treatment step [step 5] and the second cold working step [step 6].

In this manner, the copper alloy materials (copper alloy sheet materials) of invention examples 1 to 17 and comparative examples 1 to 6 were produced.

In Table 1, the columns for components that are not included in the alloy composition of the copper alloy material are marked with a horizontal line "-" to indicate that the component is not included, or if it is included, it is below the detection limit.

[Various measurement and evaluation methods]
The copper alloy materials (copper alloy sheet materials) according to the above-mentioned examples of the present invention and comparative examples were used to carry out the following characteristic evaluations. The evaluation conditions for each characteristic were as follows.

[1] Measurement of maximum orientation density when crystal orientation distribution function (ODF) is expressed in Euler angles at φ1=0-90°, Φ=0-90°, and φ2=15°, 20°, and 25°. For the copper alloy sheets obtained in the present invention and comparative examples, a cross section parallel to the rolling direction (stretching direction) was mirror-polished to prepare a cross-sectional sample, which was then observed using a field emission scanning electron microscope (FE-SEM) and subjected to EBSD measurement (measurement by electron backscatter diffraction method) to obtain crystal orientation analysis data by the SEM-EBSD method. Here, the area to be measured in the EBSD measurement was 0.02 ^mm2 , and the step during measurement was 0.5 μm. From the EBSD measurement results, a data analysis software "OIM ANALYSIS" was used to perform intensity calculations using harmonic series expansion, with the expansion order (Series Rank) set to 16, and the half-width (Gaussian Half-Width) when fitting to a Gaussian distribution set to 5°. The calculation results were analyzed by selecting Enforce Orthotropic Sample Symmetry to create an ODF map showing the intensity distribution of the crystal orientation when expressed by Euler angles (φ1, Φ, φ2). For each of the cases where φ2 was set to 15°, 20°, and 25°, the maximum orientation density was obtained from the intensity distribution of the crystal orientation displayed on a graph showing the orientation density in the ranges of φ1=0 to 90° and Φ=0 to 90°, with φ1 on the horizontal axis and Φ on the vertical axis.

[2] Method for evaluating the ratio of the thickness of the sheared surface generated in the copper alloy material during press punching to the thickness of the copper alloy material In order to evaluate the thickness of the sheared surface generated when the prepared copper alloy material was subjected to press punching, a shear test was performed as described in the shear test method for copper and copper alloy thin plate strips specified in the Japan Copper and Brass Association Technical Standard JCBA T310:2019. That is, the die was adjusted so that the clearance between the upper die (punch) and the lower die (die) was 10 μm, and the copper alloy material was punched into a square shape having a size of 10 mm along the stretching direction and a size of 10 mm along the plate width direction perpendicular to the stretching direction, to prepare a copper alloy material specimen having a cut surface on the outer periphery.

Figure 1 is a schematic diagram of the cut surface of the punched copper alloy material of the present invention, in which the surface including the thickness direction perpendicular to the cut surface is filled with resin and polished, viewed from a direction parallel to the cut surface, in order to understand the outline shape (right edge portion) of the cut surface when the punched copper alloy material is subjected to press punching processing. In Figure 1, the outline shape of the cut surface 2 that appears on a plane including the direction X perpendicular to the cut surface 2 and the thickness direction Y is shown. The copper alloy material 1 shown in Figure 1 shows the cut surface 2 after press punching processing, which is performed by lowering an upper die (punch) while the copper alloy material 1 is fixed on a lower die (die) not shown. Here, the cut surface 2 is formed with a sag 3, a shear surface 4, and a fracture surface 5 in this order from the upper surface 1a side of the press punched copper alloy material 1. Here, a burr 6 is often formed on the lower edge of the cut surface 2 so as to extend outward from the fracture surface 5.

In this example, in order to understand the contour shape (right edge portion) of the cut surface 2 when the copper alloy material 1 of the present invention example and the comparative example was subjected to press punching, the test material made of the punched copper alloy material 1 was polished by filling a surface including the thickness direction perpendicular to the cut surface with resin, and the polished surface was observed from a direction parallel to the cut surface 2 using an optical microscope (manufactured by Olympus Corporation, model number: GX71) at a magnification of 300 times. Then, from the obtained optical microscope photograph, the ratio of the thickness _t2 of the shear surface 4 to the thickness _t1 of the copper alloy material was calculated in percentage (%).

Regarding the calculated ratio of the thickness t2 of the sheared surface ₄ to the thickness _t1 of the copper alloy material 1, when it was 50% or more, the ratio of the sheared surface 4 to the cut surface 2, which is the punched surface, was sufficiently large, and the ratio of the fractured surface 5 to the cut surface 2 was sufficiently small, so that it was evaluated as "◎". In addition, when the ratio of the thickness _t2 of the sheared surface 4 to the thickness t1 of the copper alloy material ₁ was 40% or more and less than 50%, it was evaluated as "○" because it was good in that the ratio of the fractured surface 5 to the cut surface 2 was small. On the other hand, when the ratio of the thickness t2 of the sheared surface ₄ to the thickness _t1 of the copper alloy material 1 was less than 40%, it was evaluated as "×" because it was poor in that the ratio of the fractured surface 5 to the cut surface 2 was not within the appropriate range. The results are shown in Table 3.

[3] Measurement of Volume Resistivity The prepared copper alloy material was cut into a plate having a thickness of 0.3 mm into a width of 10 mm and a length of 300 mm to prepare a test material.

The volume resistivity ρ was measured by measuring the voltage at a room temperature of 20°C using the four-terminal method according to the method specified in JIS C2525, with the distance between the voltage terminals set at 200 mm and the measurement current set at 100 mA, and the volume resistivity ρ [μΩ·cm] was calculated from the obtained value.

When the measured volume resistivity ρ was 80 μΩ·cm or more, the volume resistivity ρ was evaluated as being sufficiently large and excellent as a resistive material, with a rating of "◎". When the volume resistivity ρ was 70 μΩ·cm or more but less than 80 μΩ·cm, the volume resistivity ρ was evaluated as being large and good as a resistive material, with a rating of "○". On the other hand, when the volume resistivity ρ was less than 70 μΩ·cm, the volume resistivity ρ was evaluated as being small and poor as a resistive material, with a rating of "×". In this example, the evaluations were made with "◎" and "○" as pass levels. The results are shown in Table 3.

[4] Method for measuring thermoelectromotive force (EMF) against copper For the prepared copper alloy material, the obtained plate material having a thickness of 0.3 mm was cut into a width of 10 mm and a length of 1000 mm to prepare a test material.

The copper thermoelectromotive force (EMF) of the test material was measured according to JIS C2527. More specifically, as shown in FIG. 2, the copper thermoelectromotive force (EMF) of the test material 11 was measured by using a fully annealed pure copper wire with a diameter of 1 mm as a standard copper wire 21, immersing a temperature measuring junction _P1 , to which one end of the test material 11 and the standard copper wire 21 were connected, in hot water kept warm in a thermostatic bath 41 at 80° C., and measuring the electromotive force when the reference junctions _P21 and _P22 , to which the other ends of the test material 11 and the standard copper wire 21 were connected to copper wires 31 and 32, respectively, were immersed in ice water at 0° C. kept cold in a freezing point device 42, using a voltage measuring device 43. The obtained electromotive force was divided by the temperature difference of 80° C. to obtain the copper thermoelectromotive force EMF (μV/° C.).

When the absolute value of the measured copper thermoelectromotive force (EMF) was 0.5 μV/℃ or less, the absolute value of the copper thermoelectromotive force (EMF) was evaluated as "◎", which means that the absolute value of the copper thermoelectromotive force (EMF) was sufficiently small and the material was deemed to be good as a resistive material. When the absolute value of the copper thermoelectromotive force (EMF) was greater than 0.5 μV/℃ and less than 1.0 μV/℃, the absolute value of the copper thermoelectromotive force (EMF) was small and the material was deemed to be good as a resistive material. On the other hand, when the absolute value of the copper thermoelectromotive force (EMF) was greater than 1.0 μV/℃, the absolute value of the copper thermoelectromotive force (EMF) was large and the material was deemed to be poor as a resistive material, which was evaluated as "×". The results are shown in Table 3.

[5] Method for measuring temperature coefficient of resistance (TCR) The prepared copper alloy material was cut into a plate having a thickness of 0.3 mm into a width of 10 mm and a length of 300 mm to prepare a test material.

The temperature coefficient of resistance (TCR) was measured by a four-terminal method according to the method specified in JIS C2525 and JIS C2526, with a voltage terminal distance of 200 mm and a measurement current of 100 mA, and the voltage was measured when the temperature of the test material was heated to 150 ° C., and the resistance value R _{150 ° C.} [μΩ] at 150 ° C. was obtained from the obtained value. Next, the voltage was measured when the temperature of the test material was cooled to 20 ° C., and the resistance value R _{20 ° C.} [μΩ] at 20 ° C. was obtained from the obtained value. Then, from the obtained resistance values R _{150 ° C.} and R _{20 ° C.} , the temperature coefficient of resistance (ppm / ° C.) was calculated from the formula TCR = {(R _{150 ° C.} [μΩ] - R _{20 ° C.} [μΩ]) / R _{20 ° C.} [μΩ]} × {1 / (150 [° C.] - 20 [° C.])} × 10 ⁶ .

When the absolute value of the measured temperature coefficient of resistance (TCR) was 50 ppm/℃ or less, the absolute value of the temperature coefficient of resistance (TCR) was evaluated as "◎", which means that the absolute value of the temperature coefficient of resistance (TCR) was sufficiently small and excellent as a resistive material. When the absolute value of the temperature coefficient of resistance (TCR) was greater than 50 ppm/℃ and less than 75 ppm/℃, the absolute value of the temperature coefficient of resistance (TCR) was evaluated as "◯", which means that the absolute value of the temperature coefficient of resistance (TCR) was small and good as a resistive material. On the other hand, when the absolute value of the temperature coefficient of resistance (TCR) was greater than 75 ppm/℃, the absolute value of the temperature coefficient of resistance (TCR) was evaluated as "×", which means that the absolute value of the temperature coefficient of resistance (TCR) was too large and poor as a resistive material. The results are shown in Table 3.

[6] Overall Evaluation Among these evaluation results, the ratio of the thickness of the sheared surface to the thickness of the copper alloy material, the volume resistivity ρ, the thermal electromotive force against copper (EMF) and the temperature coefficient of resistance (TCR) were all evaluated as "◎" when all four were evaluated as "◎" in terms of the difficulty of generating a sheared surface during press punching, the volume resistivity ρ, the thermal electromotive force against copper (EMF) and the temperature coefficient of resistance (TCR). In addition, when at least one of these four evaluation results was evaluated as "○" or "△" and the remaining was evaluated as "◎", these four characteristics were at least good and evaluated as "○". On the other hand, when the evaluation result of at least one of the ratio of the thickness of the sheared surface to the thickness of the copper alloy material, the volume resistivity ρ, the thermal electromotive force against copper (EMF) and the temperature coefficient of resistance (TCR) was "×", at least one of these four characteristics was evaluated as "×" in terms of failing. The results are shown in Table 3.

[7] Reliability when copper alloy material is used for a long period of time In addition to the items evaluated in the above [6] Overall evaluation, for the present invention examples 1 to 17 and comparative examples 1 to 6, in order to examine the reliability when the copper alloy material is used for a long period of time as a resistance material, in particular the stability of electrical properties against heat, an accelerated test was performed on the test material after the volume resistivity was measured in the above [3] Measurement of volume resistivity by heating at 400 ° C for 2 hours to examine the stability of electrical properties against heat. After the accelerated test by heating, the volume resistivity of the test material was measured in the same manner as in the above [3] Measurement of volume resistivity, and the difference in volume resistivity was calculated by subtracting the volume resistivity after heating from the volume resistivity before heating. The results are shown in Table 2.

From the results of Tables 1 to 3, the copper alloy materials of Examples 1 to 17 of the present invention have alloy compositions and maximum orientation densities within the appropriate ranges of the present invention, and the ratios of the thickness _t2 of the sheared surface 4 to the thickness _t1 of the copper alloy material 1 are all evaluated as "◎" or "◯", so that the ratio of the sheared surface in the punched surface generated during press punching is large. In addition, the copper alloy materials of Examples 1 to 17 of the present invention were also evaluated as "◎" or "◯" for the volume resistivity ρ, the thermal electromotive force (EMF) against copper, and the temperature coefficient of resistance (TCR).

On the other hand, the copper alloy materials of Comparative Examples 1, 2, and 3 had small maximum values of orientation density at φ1=0-90°, Φ=0-90°, and φ2=15°, 20°, and 25° when the crystal orientation distribution function (ODF) was expressed as Euler angles, which were outside the appropriate range of the present invention. Therefore, the copper alloy materials of Comparative Examples 1, 2, and 3 were evaluated as "x" for the ratio of the thickness _t2 of the shear surface 4 to the thickness _t1 of the copper alloy material 1.

In addition, the copper alloy material of Comparative Example 3 had a low Ni content and the alloy composition was outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 3 was rated as "X" in terms of copper thermoelectromotive force (EMF).

In addition, the copper alloy material of Comparative Example 4 had low contents of both Mn and Ni, and the alloy composition was outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 4 was evaluated as "x" for volume resistivity ρ. In particular, the copper alloy material of Comparative Example 4 had a low Mn content, and therefore the evaluation result of volume resistivity ρ was "x".

In addition, the copper alloy material of Comparative Example 5 had a high Mn content and the alloy composition was outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 5 was rated as "X" in terms of copper thermoelectromotive force (EMF).

In addition, the copper alloy material of Comparative Example 6 had a high Ni content and the alloy composition was outside the appropriate range of the present invention. Therefore, the copper alloy material of Comparative Example 6 was rated as "X" in terms of copper thermoelectromotive force (EMF) and temperature coefficient of resistance (TCR).

From these results, it was confirmed that, when the maximum orientation density of the alloy composition and the crystal orientation distribution function (ODF) expressed in Euler angles (φ1, Φ, φ2) is within the appropriate range of the present invention, the proportion of the shear surface that occupies the punched surface generated during press punching is large. At the same time, it was confirmed that the volume resistivity ρ, thermoelectromotive force (EMF) to copper, and temperature coefficient of resistance (TCR) of the copper alloy material of the present invention are at least good.

Figure 3 shows the crystal orientation distribution function (ODF) of the copper alloy material of Example 9 of the present invention, expressed as Euler angles (φ1, Φ, φ2), with φ1 on the horizontal axis and Φ on the vertical axis, showing the orientation density in the ranges of φ1 = 0 to 90° and Φ = 0 to 90°. Figure 3(a) shows the graph when φ2 = 15°, Figure 3(b) shows the graph when φ2 = 20°, and Figure 3(c) shows the graph when φ2 = 25°. From these graphs, it can be seen that the maximum orientation density of the copper alloy material of Example 9 of the present invention is 8.9 when φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 is 15°, 20°, and 25° (the measured value of the maximum orientation density was rounded off to one decimal place).

Furthermore, in Examples 1 to 4, 6, 7, 9 to 11, and 13 to 17 of the present invention, when the Fe content was 0.20 mass% or less, the difference in volume resistivity obtained by subtracting the volume resistivity after heating from the volume resistivity before heating, which indicates the reliability when the copper alloy material is used for a long period of time as a resistance material, was 1.0 μΩ·cm or less. From this result, it was found that the copper alloy materials of Examples 1 to 4, 6, 7, 9 to 11, and 13 to 17 of the present invention have improved stability of electrical properties against heat when the Fe content is 0.30 mass% or more, compared to Examples 5, 8, and 12 of the present invention, in which the difference in volume resistivity obtained by subtracting the volume resistivity after heating from the volume resistivity before heating was greater than 1.0 μΩ·cm.

On the other hand, in Examples 5, 8, and 12 of the present invention, the Fe content was 0.30 mass% or more, and the difference in volume resistivity obtained by subtracting the volume resistivity after heating from the volume resistivity before heating was greater than 2.0 μΩ·cm, indicating that the stability of the electrical properties against heat was low.

In addition, in Examples 4 to 17 of the present invention, the addition of either or both of Fe and Co resulted in a smaller absolute value of at least the temperature coefficient of resistance (TCR) among the absolute values of the copper thermoelectromotive force (EMF) and the temperature coefficient of resistance (TCR), compared to Examples 1 to 3 of the present invention, in which the evaluation results of the copper thermoelectromotive force (EMF) and the temperature coefficient of resistance (TCR) were evaluated as "good". Therefore, it was found that both of these evaluation results were evaluated as "◎".

REFERENCE SIGNS LIST 1 Copper alloy material 1a Upper surface of copper alloy material 1b Lower surface of copper alloy material 2 Cut surface 3 Sagging 4 Shear surface 5 Fracture surface 6 Burr 11 Test material 21 Standard copper wire 31, 32 Copper wire 41 Thermostatic chamber 42 Freezing point device 43 Voltage measuring instrument _P1 Temperature measuring junction _P21 , _P22 Reference junction X Direction perpendicular to cut surface Y Thickness direction

Claims (6)

A copper alloy material having an alloy composition containing Mn: 20.0 mass% or more and 35.0 mass% or less, and Ni: 6.5 mass% or more and 17.0 mass% or less, with the balance being Cu and unavoidable impurities,
The copper alloy material has a maximum orientation density of more than 6.0 when a crystal orientation distribution function (ODF) obtained by crystal orientation analysis by a SEM-EBSD method is expressed in terms of Euler angles (φ1, Φ, φ2) in a longitudinal section including the stretching direction and thickness direction of the copper alloy material, and the ODF is expressed in terms of Euler angles (φ1, Φ, φ2). The copper alloy material according to claim 1, in which, when the crystal orientation distribution function (ODF) obtained by crystal orientation analysis using the SEM-EBSD method in a longitudinal section including the stretching direction and thickness direction of the copper alloy material is expressed in terms of Euler angles (φ1, Φ, φ2), the maximum value of the orientation density at φ1 = 0 to 90°, Φ = 0 to 90°, and φ2 = 15°, 20°, and 25° is 7.0 or more. The alloy composition is
The copper alloy material according to claim 1, further containing one or both of Fe: 0.01 mass% or more and 0.50 mass% or less, and Co: 0.01 mass% or more and 2.00 mass% or less. The alloy composition is
Sn: 0.01% by mass or more and 5.00% by mass or less,
Zn: 0.01% by mass or more and 5.00% by mass or less,
Cr: 0.01% by mass or more and 0.50% by mass or less,
Ag: 0.01% by mass or more and 0.50% by mass or less,
Al: 0.01% by mass or more and 1.00% by mass or less,
Mg: 0.01% by mass or more and 0.50% by mass or less,
The copper alloy material according to claim 1, further comprising at least one selected from the group consisting of Si: 0.01 mass% or more and 0.50 mass% or less, and P: 0.01 mass% or more and 0.50 mass% or less. A resistor material for resistors, comprising the copper alloy material according to any one of claims 1 to 4. A resistor that is a shunt resistor or a chip resistor, comprising the resistor material according to claim 5.

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