TW202041689A - Copper alloy bar, production method for copper alloy bar, resistor resistive material using copper alloy bar, and resistor - Google Patents

Abstract

This copper alloy bar has a composition that contains 3-20 mass% of manganese (Mn), the remainder comprising copper (Cu) and unavoidable impurities. The copper alloy bar is characterized in that the ratio (the surface layer [Mn/Cu] ratio) of Mn content to Cu content as measured by Auger electron spectroscopy for a surface layer region that is demarcated by the surface of the copper alloy bar and locations 0.05 [mu]m from the surface in the depth direction is less than 0.030 in terms of mass. The copper alloy bar has stable resistance, even if the ambient temperature changes, and has favorable solder mountability.

Description

Copper alloy strip and its manufacturing method, resistance material for resistor using the copper alloy strip and resistor

The present invention relates to a copper alloy strip and a manufacturing method thereof, a resistance material for resistors and resistors using the copper alloy strip, and particularly relates to a copper alloy strip that has stable resistance even if the ambient temperature changes.

For the metal material of the resistance material used in the resistor, it is required that its index, that is, the temperature coefficient of resistance (TCR), be so small that the resistance of the resistor is stable even if the ambient temperature changes. The temperature coefficient of resistance is the change in resistance value caused by temperature, expressed in parts per million (ppm) per 1℃, and is expressed by TCR (×10 ^-6 /K) = (RR ₀ ) /R ₀ ×1/(TT ₀ )×10 ⁶ is expressed by the mathematical formula. Here, T in the formula represents the test temperature (unit: ℃), T ₀ represents the reference temperature (unit: ℃), R represents the resistance value at the test temperature T (unit: Ω), R ₀ represents the reference temperature T ₀ The resistance value (unit: Ω).

As metal materials constituting the resistance material, copper-manganese-nickel (Cu-Mn-Ni) alloys and copper-manganese-tin (Cu-Mn-Sn) alloys have been proposed (for example, refer to Patent Document 1). The TCR of these metal materials is very small.

However, although the copper alloy material containing a prescribed amount of manganese shown in Patent Document 1 has a stable temperature coefficient of resistance, in this copper alloy, the surface is oxidized, so an oxide film is easily formed. The oxide of manganese will cause the solder wettability to decrease, so the adhesion to the solder is low.

In order to prevent the oxidation of the surface of the copper alloy material used in the resistance material and suppress the change in the resistance value of the copper alloy material, for example, Patent Document 2 proposes a material in which a copper alloy material added with aluminum and tin is subjected to heat treatment And made by oxidizing its surface. [Prior Technical Literature] (Patent Document)

Patent Document 1: Japanese Patent Laid-Open No. 2016-69724 Patent Document 2: Japanese Patent Laid-Open No. 2006-270078

[The problem to be solved by the invention]

However, in the copper alloy material of Patent Document 2, the addition of aluminum adversely affects the structure of solder and the like, so there is still room for improvement in the structure.

The present invention has been completed in view of the above-mentioned actual situation, and its object is to provide a copper alloy material which has stable electrical resistance even when the ambient temperature changes, and has good solder structure. [Technical means to solve the problem]

The inventors have repeated the results of in-depth research and found that the composition of the copper alloy strip contains 3% by mass or more and 20% by mass or less of manganese, and the remainder is composed of copper and inevitable impurities. Among them, by Oujie Electronics Energy spectroscopy (Auger electron spectroscopy, AES), the manganese (Mn) content relative to the copper (Cu) content measured in the surface area and the surface area demarcated from the surface at a position 0.05 micrometers (μm) in the depth direction The ratio (the ratio of surface layer [Mn/Cu]), which is converted to mass ratio, is less than 0.030. Thereby, the copper alloy strip has stable electrical resistance even when the ambient temperature changes, and has good solder build-up properties, and the present invention has been completed based on this knowledge.

That is, the main structure of the present invention is as follows. (1) A copper alloy strip, the composition of which contains 3% by mass or more and 20% by mass or less of manganese (Mn), and the remainder is composed of copper (Cu) and inevitable impurities. The copper alloy strip is characterized by : The ratio of the Mn content to the Cu content measured in the surface area divided by the surface and the position 0.05μm in the depth direction from the surface by the Oujie electron spectroscopy method (the ratio of the surface layer [Mn/Cu] Ratio), which is converted to mass ratio, which is less than 0.030. (2) The copper alloy strip as described in (1) above, wherein, by Ogee electron spectroscopy, relative to the inner region demarcated from the surface at a position of 5 μm and a position of 10 μm in the depth direction The measured Mn content, the ratio of the Mn content measured in the aforementioned surface region (the ratio of surface Mn content/internal Mn content), converted into mass ratio, is 0.50 or less. (3) The copper alloy strip as described in (1) or (2) above, which contains 5% by mass or more and 20% by mass or less of manganese. (4) The copper alloy strip according to any one of (1) to (3) above, which contains one or more elements selected from the group consisting of: 0.01% by mass or more and 5 Mass% or less nickel; 0.01 mass% or more and 5 mass% or less tin; 0.01 mass% or more and 5 mass% or less zinc; 0.01 mass% or more and 0.5 mass% or less iron; 0.01 mass% or more and 0.5 mass% The following silicon; 0.01 mass% to 0.5 mass% chromium; 0.01 mass% to 0.5 mass% zirconium; 0.01 mass% to 0.5 mass% titanium; 0.01 mass% to 0.5 mass% Silver; 0.01% by mass or more and 0.5% by mass or less of magnesium; 0.01% by mass or more and 0.5% by mass or less of cobalt; and 0.01% by mass or more and 0.5% by mass or less of phosphorus. (5) A method of manufacturing copper alloy strips, which is a method of manufacturing the copper alloy strips described in any one of (1) to (4) above, characterized in that the manufacturing method is characterized by having the following in order Steps: casting step [step 1], homogenization treatment step [step 2], hot rolling step [step 3], surface grinding step [step 4], first cold rolling step [step 5], first oxide film The formation step [Step 6] and the first oxide film removal step [Step 7]; wherein, in the foregoing first oxide film formation step, in a neutral gas atmosphere containing 0.01 to 2.00 vol% oxygen, the temperature is 200 The first cold-rolled sheet obtained in the first cold rolling step is heated at a temperature above 800°C and below 800°C to form a first oxide film; in the foregoing first oxide film removal step, the first oxide film is removed by the sulfuric acid aqueous solution. The first oxide film of the first cold-rolled sheet formed in the oxide film forming step. (6) The method for manufacturing a copper alloy strip as described in (5) above, wherein after the first oxide film removal step [step 7], there is further a second cold rolling step [step 8]. (7) The method of manufacturing a copper alloy strip as described in (6) above, wherein after the aforementioned second cold rolling step [step 8], there is further a second oxide film forming step [step 9] and a second Oxide film removal step [Step 10]; and, in the foregoing second oxide film formation step, in a neutral gas atmosphere containing 0.01 to 2.00% by volume of oxygen, at a temperature of 200°C or more and 800°C or less, The second cold-rolled sheet obtained in the second cold rolling step is heated to form a second oxide film; in the foregoing second oxide film removal step, the sulfuric acid aqueous solution is used to remove the second oxide film formed in the foregoing second oxide film forming step The second oxide film of the second cold rolled sheet. (8) A resistance material for resistors, which uses the copper alloy strip according to any one of (1) to (4) above. (9) A resistor having the resistive material described in (8) above. [Effect of Invention]

According to the present invention, the composition of the copper alloy strip contains 3% by mass or more and 20% by mass or less of manganese, and the remainder is composed of copper and unavoidable impurities. Among them, by OJ electron spectroscopy, The ratio of the Mn content to the Cu content (the ratio of the surface layer [Mn/Cu]) measured in the surface area divided from the surface at a position 0.05 μm in the depth direction from the surface is converted to a mass ratio, which is less than 0.030, whereby the copper alloy strip has stable electrical resistance even if the ambient temperature changes, and has good solder buildability.

(1) Copper alloy strip Hereinafter, the preferred embodiments of the copper alloy strip of the present invention will be described in detail. According to the copper alloy strip of the present invention, its composition is 3% by mass or more and 20% by mass or less of manganese, and the remainder is composed of copper and inevitable impurities. The copper alloy strip is characterized by: Energy spectroscopy, the ratio of the Mn content to the Cu content (the ratio of the surface layer [Mn/Cu]) measured in the surface area divided by the surface and the position 0.05 μm in the depth direction from the surface is converted into The mass ratio is less than 0.030.

In such a copper alloy strip, the Mn on the surface is small, and it has high adhesion to the solder. On the other hand, in the inside of the copper alloy strip, Mn is abundantly present at 3% by mass or more as a whole. Therefore, the alloy strip as a whole bears electrical characteristics and has a lower temperature coefficient of resistance. Therefore, this copper alloy strip has stable electrical resistance even if the ambient temperature changes, and has good solder structure.

＜Composition of copper alloy strips＞ [Manganese: 3% by mass or more and 20% by mass or less] The copper alloy strip of the present invention contains 3% by mass or more and 20% by mass or less of manganese (Mn). When the content of manganese is within this range, the temperature coefficient of resistance can be reduced without reducing the solder wettability of the surface of the copper alloy material. In contrast, if the manganese content is less than 3% by mass, the effect of lowering the temperature coefficient of resistance cannot be sufficiently obtained. In addition, when the content of manganese is more than 20% by mass, the surface properties may be significantly reduced. From the viewpoint of the temperature coefficient of resistance, the content of manganese is preferably 5% by mass or more.

＜Composition distribution of copper alloy bars＞ The copper alloy strip of the present invention is the ratio of the Mn content to the Cu content measured in the surface area divided by the surface and the position 0.05 μm in the depth direction from the surface by Oge electron spectroscopy (The ratio of surface layer [Mn/Cu]), which is converted into mass ratio, is less than 0.030. As a result, when the ratio of [Mn/Cu] of the surface layer is less than 0.030, Mn will be reduced on the surface, and therefore, the surface will have high solder wettability and good solder buildability. The ratio of the surface layer [Mn/Cu], for example, is preferably 0.028 or less, more preferably 0.025 or less, and still more preferably 0.022 or less.

In addition, the alloy strip of the present invention, by Ogee electron spectroscopy, is compared with the Mn content measured in the internal region partitioned from the surface to the depth direction of 5 μm and 10 μm. The ratio of the Mn content measured in the surface region (the ratio of the surface Mn content/the internal Mn content), which is converted into a mass ratio, is preferably 0.50 or less, more preferably 0.45 or less, and still more preferably 0.4 or less. When the ratio of surface Mn content/internal Mn content is 0.50 or less, the concentration of manganese will rise from the surface of the alloy bar toward the inside, but the concentration gradient will become steeper. If manganese is present in the surface layer, its oxidation will cause the wettability of the copper alloy strip to decrease. Therefore, it is necessary to reduce the concentration of manganese in the surface layer as much as possible. On the other hand, the material contains a large amount of manganese as a whole to reduce the wettability. Temperature coefficient of resistance. That is, the smaller the ratio of surface Mn content/internal Mn content, the greater the concentration gradient of manganese, so in the surface layer, manganese becomes sparsely distributed, and inside, manganese becomes densely distributed. As a result, it becomes more dense. While good solder wettability, it also has a lower temperature coefficient of resistance.

＜Optional ingredients＞ In addition, the alloy strip of the present invention can contain one or more elements selected from the group consisting of: 0.01 mass% or more and 5 mass% or less nickel; 0.01 mass% or more and 5 mass% tin or less; 0.01 mass% or more and 5 mass% or less zinc; 0.01 mass% or more and 0.5 mass% or less iron; 0.01 mass% or more and 0.5 mass% or less silicon; 0.01 mass% or more and 0.5 mass% % Chromium; 0.01 mass% to 0.5 mass% zirconium; 0.01 mass% to 0.5 mass% titanium; 0.01 mass% to 0.5 mass% silver; 0.01 mass% to 0.5 mass%的magnesium; 0.01% by mass or more and 0.5% by mass or less of cobalt; and, 0.01% by mass or more and 0.5% by mass or less of phosphorus. Any of these elements are added for the purpose of improving the temperature coefficient of resistance, adjusting the volume resistivity, etc. However, if the addition exceeds the respective prescribed ranges, there is a risk that solder wettability decreases and raw material costs increase. Hereinafter, each metal element will be described separately.

[Nickel: 0.01 mass% or more and 5 mass% or less] The content of nickel (Ni) is not particularly limited, but it is preferably 0.01% by mass to 5% by mass relative to 100% by mass of the copper alloy strip. If the nickel content is less than 0.01%, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of nickel exceeds 5% by mass, the solder wettability may decrease. In addition, the content of nickel may be, for example, 0% by mass or more (including the case where nickel is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Tin: 0.01 mass% or more and 5 mass% or less] The content of tin (Sn) is not particularly limited, but is preferably 0.01% by mass to 5% by mass relative to 100% by mass of the copper alloy strip. If the tin content is less than 0.01%, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of tin exceeds 5% by mass, the manufacturability of the copper alloy strip may be significantly reduced. In addition, the content of tin may be, for example, 0% by mass or more (including the case where tin is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Iron: 0.01% by mass or more and 0.5% by mass or less] The content of iron (Fe) is not particularly limited, but it is preferably 0.01% by mass to 0.5% by mass relative to 100% by mass of the copper alloy strip. If the iron content is less than 0.01%, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of iron exceeds 0.5% by mass, the solder wettability may decrease. In addition, the iron content may be, for example, 0% by mass or more (including the case where iron is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Zinc: 0.01 mass% or more and 5 mass% or less] The content of zinc (Zn) is not particularly limited, but it is preferably 0.01% by mass to 5% by mass relative to 100% by mass of the copper alloy strip. If the zinc content is less than 0.01%, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of zinc exceeds 5% by mass, dezincification may cause changes in performance over time. In addition, the content of zinc may be, for example, 0% by mass or more (including the case where zinc is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Silicon: 0.01% by mass or more and 0.5% by mass or less] The content of silicon (Si) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the content of silicon is less than 0.01% by mass, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of silicon exceeds 0.5% by mass, the solder wettability may decrease. In addition, the content of silicon may be, for example, 0 mass% or more (including the case where silicon is not included), 0.001 mass% or more, or 0.005 mass% or more.

[Chromium: 0.01% by mass or more and 0.5% by mass or less] The content of chromium (Cr) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the chromium content is less than 0.01% by mass, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of chromium exceeds 0.5% by mass, the solder wettability may decrease. In addition, the content of chromium may be, for example, 0% by mass or more (including the case where chromium is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Zirconium: 0.01% by mass or more and 0.5% by mass or less] The content of zirconium (Zr) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the content of zirconium is less than 0.01% by mass, the effects of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of zirconium exceeds 0.5% by mass, solder wettability may decrease. In addition, the content of zirconium may be, for example, 0% by mass or more (including the case where zirconium is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Titanium: 0.01% by mass or more and 0.5% by mass or less] The content of titanium (Ti) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the titanium content is less than 0.01% by mass, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of titanium exceeds 0.5% by mass, the solder wettability may decrease. In addition, the content of titanium may be, for example, 0% by mass or more (including the case where titanium is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Silver: 0.01% by mass or more and 0.5% by mass or less] The content of silver (Ag) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the silver content is less than 0.01%, there is a possibility that the effects of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of silver exceeds 0.5% by mass, the cost of raw materials will increase, but the effect commensurate with it will not be obtained. In addition, the content of silver can be, for example, 0% by mass or more (including the case where silver is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Magnesium: 0.01% by mass or more and 0.5% by mass or less] The content of magnesium (Mg) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the content of magnesium is less than 0.01% by mass, there is a possibility that the effects of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of magnesium exceeds 0.5% by mass, the solder wettability may decrease. In addition, the content of magnesium may be, for example, 0% by mass or more (including the case where magnesium is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Cobalt: 0.01% by mass or more and 0.5% by mass or less] The content of cobalt (Co) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the content of cobalt is less than 0.01% by mass, there is a possibility that the effects of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the content of cobalt exceeds 0.5% by mass, the solder wettability may decrease. In addition, the content of cobalt may be, for example, 0% by mass or more (including the case where cobalt is not included), 0.001% by mass or more, or 0.005% by mass or more.

[Phosphorus: 0.01% by mass or more and 0.5% by mass or less] The content of phosphorus (P) is not particularly limited, but it is preferably 0.01% by mass or more and 0.5% by mass or less with respect to 100% by mass of the copper alloy strip. If the phosphorus content is less than 0.01%, there is a possibility that the effect of improving the temperature coefficient of resistance and adjusting the volume resistivity may not be sufficiently obtained. On the other hand, if the phosphorus content exceeds 0.5% by mass, the manufacturability of the copper alloy strip may be significantly reduced. In addition, the content of phosphorus may be, for example, 0% by mass or more (including the case where phosphorus is not included), 0.001% by mass or more, or 0.005% by mass or more.

[The rest: copper and inevitable impurities] In addition to the aforementioned essential components and optional additional components, the remainder is composed of copper (Cu) and inevitable impurities. In addition, the term "unavoidable impurities" here means that most of the copper-based products are present in the raw materials or inevitably mixed in the manufacturing process. They are originally unnecessary components, but they are very small and do not affect The characteristics of the copper-based products affect, so the impurities can be tolerated. Examples of components that can be cited as unavoidable impurities include non-metal elements such as sulfur (S) and oxygen (O), and metal elements such as aluminum (Al) and antimony (Sb). In addition, the upper limit of the content of these components may be 0.05% by mass for each of the above components, and 0.20% by mass based on the total amount of the components.

The copper alloy strip of the present invention is extremely useful as a resistor, such as a resistor material for shunt resistors and chip resistors.

(2) Manufacturing method of copper alloy strip The method for manufacturing the copper alloy strip according to an embodiment of the present invention will be described in detail. This manufacturing method is characterized by having the following steps in sequence: casting step [step 1], homogenization treatment step [step 2], hot rolling step [step 3], surface grinding step [step 4], first The cold rolling step [step 5], the first oxide film formation step [step 6], and the first oxide film removal step [step 7]; wherein, in the aforementioned first oxide film formation step, 0.01 to 2.00 The first cold-rolled sheet obtained in the first cold rolling step is heated at a temperature above 200°C and below 800°C in an oxygen neutral gas atmosphere of vol% to form a first oxide film; In the oxide film removing step, the first oxide film of the first cold-rolled sheet formed in the first oxide film forming step is removed by a sulfuric acid aqueous solution. In addition, according to requirements, a second cold rolling step [step 8], or a second oxide film formation step [step 9] and a second oxide film removal step [step 10] can be additionally added. The following describes each step.

<Casting Step [Step 1]> In the casting step [Step 1], the raw materials (copper alloy raw materials) of copper alloy sheet materials such as Cu and Si are melted and cast in a casting machine (inner wall) preferably made of carbon, for example, a graphite crucible. In order to prevent the formation of oxides, the atmosphere inside the casting machine during melting is preferably a vacuum or an inert gas atmosphere such as nitrogen and argon. The casting method is not particularly limited, and for example, a horizontal continuous casting machine or an upward-drawn continuous casting method can be used.

＜Homogenization treatment step [Step 2]＞ In the casting [step 1], the solidification segregation and crystallized product produced during the ingot casting are coarse, so in the homogenization treatment step [step 2], make it solid-dissolved in the matrix as small as possible , And make it disappear as much as possible. Specifically, for example, the following homogenization treatment is performed: in an inert gas or the like, heating at 800 to 1000°C for 1 to 24 hours.

＜Hot rolling step [Step 3]＞ In the hot rolling [Step 3], for example, the homogenized ingot is rolled at a temperature of about 800°C to 1000°C so as to have a desired plate thickness. Regarding the hot working, either rolling processing or extrusion processing is not particularly limited.

<Surface Grinding Step [Step 4]> In the surface grinding step [Step 4], the oxide film and the altered layer of the surface of the copper alloy sheet are removed. It can be performed by a generally known method, for example, it can be performed by mechanical polishing. As the thickness of the surface grinding, for example, it may be about 0.1 to 3 millimeters (mm).

<The first cold rolling step [Step 5]> In the first cold rolling step [Step 5], for example, cold rolling with a processing degree of 90% is performed.

<The first oxide film formation step [Step 6]> In the first oxide film forming step [step 6], in a neutral gas atmosphere containing 0.01 to 2.00% by volume of oxygen, heating is performed at a temperature of 200°C or more and 800°C or less in the above-mentioned first cold rolling step The first cold-rolled sheet is obtained to form a first oxide film. The heating time is preferably, for example, 10 seconds to 10 hours. The reason for actively forming the first oxide film is to form an oxide film containing manganese oxide as a main component. In addition, the steps marked with "first" such as "first oxide film forming step" are to distinguish them from the "second oxide film forming step" described later. However, the "second oxide film forming step" is not an essential step, and only the "first oxide film forming step" may be performed.

<The first oxide film removal step [Step 7]> The first oxide film removing step [Step 7] is a step of removing the first oxide film of the first cold-rolled sheet formed in the first oxide film forming step with a sulfuric acid aqueous solution. The concentration of the aqueous sulfuric acid solution is, for example, preferably 1-50%, more preferably 5-30%. Through this first oxide film removal step, the manganese oxide in the surface layer can be chemically dissolved and removed, thereby obtaining a copper alloy strip with a low concentration of manganese at the surface layer.

<The second cold rolling step [Step 8]> After the first oxide film removal step [step 7], a second cold rolling step [step 8] can be further provided. In this second cold rolling step [Step 8], for example, cold rolling with a processing degree of 0 to 75% is performed to make the plate thickness uniform. The thickness of the plate after the second cold rolling depends on the application and the like. For example, it can be set to 0.01 to 10 mm. Thereby, the above-mentioned copper alloy strip of the present invention can be obtained.

<The second oxide film formation step [Step 9]> After the first oxide film removal step [Step 7] or the second cold rolling step [Step 8], a second oxide film forming step [Step 9] may be further provided. This second oxide film forming step is to heat the second cold rolling step obtained in the second cold rolling step in a neutral gas atmosphere containing 0.01 to 2.00% by volume of oxygen at a temperature above 200°C and below 800°C The step of cold rolling the plate to form a second oxide film. The specific operation is the same as the first oxide film forming step.

<Second Oxide Film Removal Step [Step 10]> The second oxide film removing step is a step of removing the second oxide film of the second cold-rolled sheet formed in the second oxide film forming step using a sulfuric acid aqueous solution. The specific operation is the same as the first oxide film removal step.

To make the ratio of the Mn content to the Cu content (the ratio of the surface layer [Mn/Cu]) less than 0.030, it is necessary to preferentially oxidize Mn in a neutral gas atmosphere with controlled oxygen concentration, and then use a wet step to remove The oxide film formed in the previous step is removed. At this time, in order to reduce the ratio of surface layer [Mn/Cu], it is necessary to increase the preferential oxidation amount of Mn, so the heat treatment temperature, time, and oxygen concentration are appropriately adjusted to obtain the desired oxidation amount. Thereafter, by removing the oxide film with a sulfuric acid solution, a surface layer with a small ratio of [Mn/Cu] of the surface layer can be formed. In addition, with regard to electrical properties and especially temperature coefficient of resistance (TCR), a higher Mn concentration is better, which is the opposite of solder wettability. In particular, in order to have both electrical characteristics and solder wettability at a higher level, the internal Mn concentration is required to be high and the surface layer Mn concentration is low. To achieve this, it is necessary to form a surface layer with a small ratio described above in the final step after melting and casting for the internal concentration. Although only cold working can obtain a surface layer with a small ratio of [Mn/Cu], due to cold working, the surface layer with a small ratio of [Mn/Cu] may become thinner. It is better to perform oxidation treatment and removal at the end deal with.

The embodiments of the present invention have been described above, but the present invention is not limited to the above-mentioned embodiments, and includes the concept of the present invention and all aspects included in the scope of the patent application. Various changes can be made within the scope of the present invention. (Example)

Subsequently, in order to further clarify the effect 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.

(Invention Examples 1-22, Comparative Examples 1 and 3) An ingot having the alloy composition described in the "alloy composition" column of Table 1 below was produced by casting. Subsequently, for this ingot, the heating temperature is 800°C or more and 1000°C or less, and the heating time is 10 minutes or more and 10 hours or less. After performing heat treatment to homogenize the alloy composition, it is formed into a plate by hot rolling. Shape and cool with water to obtain a plate.

Subsequently, the plate material obtained by hot rolling is subjected to surface grinding to remove the surface oxide film by 1 mm on each side, and then the plate material is cold rolled at a predetermined processing rate of 90% or more. The thickness of the plate after the first cold rolling was adjusted to 0.15 mm, 0.23 mm, and 0.50 mm, respectively.

Next, in a furnace controlled to consist of a mixed gas of nitrogen and air and an oxygen concentration of 0.01 to 2.00% by volume, the surface is oxidized under predetermined conditions (heating temperature and heating time). After the oxidation treatment, the oxide film on the surface is removed by a 20% sulfuric acid aqueous solution.

Thereafter, for invention examples other than invention examples 1, 4, 7, 10, 13, 16, 19, and 22 where the plate thickness after the first cold rolling is 0.15 mm, 35% (after the first cold rolling) When the plate thickness is 0.23mm) or 70% (when the plate thickness after the first cold rolling is 0.50mm), the second cold rolling is performed. In either case, the plate thickness is 0.15mm. Rolled plates (copper alloy strips). In addition, for Examples 1, 4, 7, 10, 13, 16, 19, and 22 of the present invention and Comparative Examples 1 to 3, the second cold rolling was not performed. Therefore, in the "second cold rolling step" of Table 1 below, "-" is displayed in the field.

In addition, for Examples 5, 6, 8, 9, 12, 14, 15, 17, 18, 20, and 21 of the present invention, after the second cold rolling, oxidation treatment (second oxide film formation step) was performed again, The oxide film on the surface is removed by a 20% sulfuric acid aqueous solution to obtain a copper alloy strip. In addition, for Examples 1 to 4, 7, 10, 11, 13, 16, 19, 22 of the present invention and Comparative Examples 1 to 3, the second oxide film forming step and the second oxide film removal step were not performed, so It is displayed as "-" in the column of "Second Oxide Film Formation Step" in Table 1 below.

(Comparative example 2) By changing the thickness of the plate after the first cold rolling to 0.35mm, and after the oxidation treatment, the surface of the sample is removed by wet grinding with 0.1mm on each side, thereby obtaining a copper alloy with a thickness of 0.15mm Strip sample.

[Composition of the copper alloy strip] The chemical composition of the copper alloy strip was determined by ICP (Inductively Coupled Plasma) analysis and is shown in Table 1 below. In addition, the ratio of the surface layer [Mn/Cu] and the ratio of the surface layer Mn content/internal Mn content were measured by the OJ Electronic Spectrometer PIH 680 (ULVAC-PHI, Inc.). Specifically, after obtaining the atomic percentage (atomic %) from the obtained spectrum of Cu and Mn, the atomic weight of Cu is calculated as 63.546 and the atomic weight of Mn is calculated as 54.938, and the mass percentage of Mn and Cu (mass %) ) Conversion to calculate the content. In addition, the following values are shown in the following table as the ratio of surface layer [Mn/Cu] (the ratio of the surface layer to the average [Mn/Cu] ratio of the surface layer area divided from the surface to a position 0.05 μm in the depth direction) 1: Set the sputtering speed during the measurement to 2kV (10nm/min in terms of SiO ₂ conversion value), and measure it at 0.25 minute intervals from 0 to 5 minutes (Mn The ratio of content)/(Cu content) is the value obtained by converting and averaging the mass ratio, and then measuring and averaging the obtained value by measuring 5 points on each side. At this time, determine the following value as "the Mn content measured in the surface area" (surface Mn content): In this surface area, the Mn content is measured and averaged at 0.25 minute intervals, and further Measure 5 points on the front and back sides and average the obtained values. In addition, calculate the following value as "the Mn content measured in the internal region" (internal Mn content): in the internal area demarcated from a position of 5 μm in the depth direction from the surface and a position of 10 μm in the depth direction from the surface region, the sputtering rate during measurement to 4kV (equivalent value of SiO _2, of 100nm / min), time 50 to 100 minutes until, at intervals of 0.25 minutes while the Mn content will be measured And average the obtained value, and then measure and average the obtained value by 5 points on the front and back. From the numerical values of the surface Mn content and the internal Mn content obtained as described above, the ratio of the surface Mn content/internal Mn content is shown in Table 1. Measuring device: PIH 680 (ULVAC-PHI, Inc.) Analysis area: 10×10μm Sputtering speed: 2.4 kV (10 or 100nm/min in terms of SiO ₂ conversion value)

[Solder wettability] With the solder inspector, the test piece cut into a width of 10mm is immersed in the Sn-3Ag-0.5Cu alloy heated to 245℃ for 10mm at an immersion speed of 25mm/sec, and the maximum wetness is read. Wet load (unit: mN). In addition, in terms of flux, RMA type (RM615) is used, and the case with a wetting load of 5mN or more is evaluated as excellent solder wettability, and the case with 4mN or more and less than 5mN is evaluated as solder The wettability was good and was evaluated as "○", and the case where the wetting load was less than 4 mN was evaluated as "×" as the solder wettability was poor, and the results are shown in Table 1.

[Temperature Coefficient of Resistance (TCR)] According to the method specified in JIS C2526 (1994), the average temperature coefficient of resistance (TCR) of the sheet material in the range of 20°C or more and 50°C or less is measured. When the absolute value of the average temperature coefficient of resistance in the range of 20°C or higher and 50°C or lower is 200ppm/K or less, it is evaluated as "◎" as excellent in electrical characteristics, and when it exceeds 200ppm/K and 400ppm/K or less It was evaluated as "○" as having good electrical characteristics, and the case of exceeding 400 ppm/K was evaluated as "×" as having poor electrical characteristics, and the results are shown in Table 1.

[Table 1]

From Table 1 above, it can be seen that the copper alloy strips of Examples 1-22 of the present invention have both low TCR and good solder wettability. The composition of the copper alloy strips of Examples 1-22 of the present invention contains 3 masses. % Or more and 20% by mass or less of manganese, the remainder is composed of copper and unavoidable impurities. Among them, by Oge electron spectroscopy, it is divided between the surface and the position of 0.05μm in the depth direction from the surface The ratio of the measured Mn content to the Cu content in the surface area (the ratio of the surface layer [Mn/Cu]), which is converted into a mass ratio, is less than 0.030.

In contrast, the copper alloy strip of Comparative Example 1 with a manganese content of 2% by mass less than the appropriate range of the present invention has good solder wettability but high TCR, and thus has poor electrical properties.

In addition, the copper alloy strip of Comparative Example 2 with a surface layer [Mn/Cu] ratio of 0.111 has a low TCR, but has poor solder wettability.

Furthermore, the copper alloy strip of Comparative Example 3 with a manganese content of 25% by mass more than the appropriate range of the present invention has a low TCR but poor solder wettability.

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Claims (9)

A copper alloy strip, the composition of which contains 3% by mass or more and 20% by mass or less of manganese, and the remainder is composed of copper and inevitable impurities. The characteristics of the copper alloy strip are: The ratio of the manganese content to the copper content measured in the surface area divided by the surface and the position 0.05μm in the depth direction from the surface (surface layer [Mn/Cu] ratio ), which is converted into a mass ratio, which is less than 0.030. The copper alloy strip according to claim 1, wherein, by Oge electron spectroscopy, relative to the manganese measured in the inner region divided from the surface to the depth direction of 5 μm and 10 μm The content, the ratio of the manganese content measured in the aforementioned surface layer region (the ratio of the surface layer Mn content/internal Mn content), converted into a mass ratio, is 0.50 or less. The copper alloy strip according to claim 1 or 2, which contains 5% by mass or more and 20% by mass or less of manganese. The copper alloy strip according to any one of claims 1 to 3, which contains one or more elements selected from the group consisting of: 0.01 mass% or more and 5 mass% or less of nickel; 0.01 mass% or more and 5 mass% or less tin; 0.01 mass% or more and 5 mass% or less of zinc; 0.01% by mass or more and 0.5% by mass or less of iron; 0.01% by mass or more and 0.5% by mass or less of silicon; 0.01% by mass or more and 0.5% by mass or less of chromium; 0.01% by mass or more and 0.5% by mass or less of zirconium; 0.01% by mass or more and 0.5% by mass or less of titanium; 0.01% by mass or more and 0.5% by mass or less of silver; 0.01% by mass or more and 0.5% by mass or less of magnesium; 0.01% by mass or more and 0.5% by mass or less of cobalt; and, 0.01% by mass or more and 0.5% by mass or less of phosphorus. A method for manufacturing copper alloy strips, which is a method for manufacturing the copper alloy strips according to any one of Claims 1 to 4, the manufacturing method is characterized in that it has the following steps in sequence: Casting step [step 1], homogenization treatment step [step 2], hot rolling step [step 3], surface grinding step [step 4], first cold rolling step [step 5], first oxide film forming step [Step 6] and the first oxide film removal step [Step 7]; Wherein, in the aforementioned first oxide film forming step, in a neutral gas atmosphere containing 0.01 to 2.00% by volume of oxygen, the temperature obtained in the first cold rolling step is heated at a temperature above 200°C and below 800°C The first cold-rolled plate to form a first oxide film; In the first oxide film removing step, the first oxide film of the first cold-rolled sheet formed in the first oxide film forming step is removed by a sulfuric acid aqueous solution. The method of manufacturing a copper alloy strip according to claim 5, wherein after the first oxide film removal step [step 7], there is further a second cold rolling step [step 8]. The method of manufacturing a copper alloy strip according to claim 6, wherein after the aforementioned second cold rolling step [step 8], there is further a second oxide film forming step [step 9] and a second oxide film removal Step [Step 10]; In addition, in the foregoing second oxide film forming step, in a neutral gas atmosphere containing 0.01 to 2.00% by volume of oxygen, the temperature obtained in the second cold rolling step is heated at a temperature of 200° C. or higher and 800° C. or lower. A second cold-rolled plate to form a second oxide film; In the second oxide film removing step, the second oxide film of the second cold-rolled sheet formed in the second oxide film forming step is removed by a sulfuric acid aqueous solution. A resistance material for a resistor, which uses the copper alloy strip according to any one of claims 1 to 4. A resistor having the resistance material described in claim 8.