JPH036974B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a Ni-Au-Cu based electrical resistance alloy and a method for producing the same.The purpose of the present invention is to obtain an alloy with extremely little change in electrical resistance over a wide temperature range and a relatively low electrical resistance. The purpose of the present invention is to obtain an electrical resistance alloy that is relatively easy to finely adjust the component composition and heat treatment, can be processed into fine wires and thin films, and has excellent stability. In recent years, temperatures under delicate environmental conditions have been measured with very high resolution (0.01°C) in temperature control during storage and drying of fresh foods, process control for solar plants, air conditioning equipment, disaster prevention equipment, biological equipment and biotechnology, and physical property research. It has become necessary to stably measure the following). As a temperature sensor to meet this demand, thick film or thin film platinum resistance thermometers are being developed that are compact, have quick thermal response, and are highly resistant to vibration and impact. Compared to thermocouple or thermistor type sensors, this type of sensor has many advantages such as a nearly linear change in resistance value between -200℃ and +500℃, large output, high reliability and accuracy, etc. There are advantages. However, the resolution for temperature is currently 0.1℃
This is a limit, and in order to further increase the resolution, it is necessary to reconsider the overall structure of the temperature sensor. In other words, if we explain the resolution with respect to temperature using the resistance-voltage conversion circuit shown in Figure 1, the resolution will depend on the structural factors of the temperature sensor as well as the platinum resistance thermometer.
It is greatly affected by the accuracy of R _t and the performance of the reference resistor R _S , which is composed of this and a bridge circuit. The most important condition required for the reference resistance R _S is that the resistance does not change with temperature. In addition, it must have an appropriate resistance value (R _t /R _S 1), no hysteresis during thermal cycles, no resistance change during thermal aging,
Examples include chemical stability and good processability. This reference resistor uses manganin-based wire-wound resistors (Cu-Mn-based alloy) and nichrome-based metal film resistors (Ni-Ci-based alloy), which are conventionally used as standard resistors, and provides stable output. can get.
However, although the former can obtain a suitable electrical resistance value, the heat treatment for adjusting the temperature coefficient of electrical resistance is not only complicated but also changes significantly over time, and the latter is compact and easy to mass produce, but Since the resistance value is very large and R _t /R _S is extremely small,
They not only have inferior temperature resolution, but also have drawbacks such as large variations in quality, and both have their advantages and disadvantages, making it difficult to say that they are sufficient. In addition to these, Ni-Cu alloys are also considered, which are used as resistors in communication devices and potentiometers. This alloy has a specific electrical resistance ρ close to the value of manganin (approximately 45 to 48 μΩ-cm), a small temperature coefficient of ρ, and since the alloy is entirely a solid solution, it does not require difficult heat treatment like manganin. However, on the other hand, the C _f
The biggest drawback is the large variation in materials due to the steep slope. A method for alleviating the above-mentioned drawbacks of C _f has already been disclosed in Japanese Patent Publication No. 18911/1973. According to this, as can be seen from Figure 5,
By adding a small amount of Fe or Ge as a third element to a Cu-Ni alloy, an alloy with a temperature coefficient of electrical resistance C _f -0 was obtained. However, the change in C _f with respect to composition is still quite large; for example, in order to obtain an alloy with a temperature coefficient of electrical resistance C _f within ±20 ppm/°C, the Ge content must be limited to an extremely narrow composition range of ±0.5%. Therefore, when mass production is considered, it is extremely difficult to manufacture a product without variation in C _f . As a result of numerous studies, the inventors of the present invention have removed and improved the defects of the above-mentioned alloy to create a highly stable electrical resistor with very little change in electrical resistance in a wide temperature range from low to high temperatures, as well as good workability. They were able to provide the alloy. That is, the present invention has a weight ratio of 22 to 59 nickels.
%, gold 0.01~30% and copper 39~68%, contains a small amount of impurities, and has a temperature coefficient of electrical resistance of ±100ppm/℃ over a wide temperature range of -100℃ to +250℃.
This relates to an electrical resistance alloy having the following characteristics. Furthermore, the present invention has a weight ratio of nickel of 22 to 59.
%, gold 0.01-30% and copper 39-68%, containing a small amount of impurities, is cast into a shape such as a wire or plate by hot working or cold working, in a non-oxidizing atmosphere or in a vacuum. at least
The temperature coefficient of electrical resistance changes from -100℃ to +250℃ by heating for 2 seconds or more at a temperature of 250℃ or higher and below the melting point.
It is characterized by obtaining a value within ±100 ppm/°C in the temperature range of . The method for producing the alloy of the present invention will be explained below. In the present invention, first, nickel 22-59%, gold 0.01%
After melting an appropriate amount of ~30% copper and 39~68% copper in an appropriate melting furnace in air, preferably in a non-oxidizing atmosphere or in vacuum, small amounts of magnesium, manganese, silicon, titanium, calcium, etc. (approximately 1 g or less) to remove harmful impurities and stir thoroughly to create a compositionally uniform molten alloy. Next, this is poured into a mold of an appropriate shape and size to obtain a sound ingot, which is then subjected to various processing such as casting at room temperature or at a temperature below 1100°C to form an object of an appropriate shape, such as a rod. Or build a board. Further, this is subjected to cold working by methods such as swaging, wire drawing, rolling, or crushing to obtain a desired shape, such as a thin wire or a thin plate. Finally, in order to remove the internal strain caused by processing and stabilize the properties, heat and hold them at a temperature of 250℃ or higher and lower than the melting point in a non-oxidizing atmosphere or vacuum for 2 seconds or more and 100 hours or less. For example 5
It is necessary to cool down at a rate of ~300°C/h and sufficiently anneal. This annealing treatment also has features such as improved weldability and wettability during brazing, and ease of handling. One of the major features of the alloy of the present invention is that it has excellent stability because it forms a solid solution throughout the entire composition and does not generate segregation or compounds. Next, when the above alloy is used as an electric resistor element or a sensor coil, there are the following three types of insulation methods. (A) The alloy of the present invention is processed by casting, forging, rolling, wire drawing, etc. into a desired shape such as a wire rod or plate, and is then embedded in a heat-resistant insulator such as a high-purity ceramic paste. mosquito,
It is fixed by attaching it directly to a heat-resistant insulator with alumina adhesive, by wrapping it around a cylindrical ceramic, or by sandwiching it between two insulating plates. (B) Inorganic materials such as silica, alumina, magnesia, fluorides, borides, or nitrides with good heat resistance are added to the surface of wire rods or plates made by casting, forging, rolling, wire drawing, etc. of the alloy of the present invention. After applying or coating an insulating film by an appropriate method such as electrodeposition, vapor deposition, plating, or sputtering, the wire is formed into a desired shape. (C) Electrodepositing a film of the invention alloy on the surface of a heat-resistant insulator;
After being deposited by a suitable method such as vapor deposition, plating or sputtering, etching, punching or trimming is performed into the desired shape, and if necessary, an insulating film is further applied as described above.
Application or coating treatment is performed using method (B). The product manufactured by the above process may be used as is, but if necessary, in order to stabilize the product, it can be annealed again using the method described above to exhibit the same characteristics as the electrical resistance alloy itself. It is possible to manufacture excellent electrical resistor elements or sensor coils. Next, embodiments of the present invention will be described. Example 1 Alloy number No. 102 (alloy composition Ni-30%, Au-15
%, Cu-55%) The raw materials for production are nickel with a purity of 99.9% or higher,
Gold and copper were used. To make a sample, the total weight is 100
The raw material g was placed in an alumina crucible and melted in a high frequency induction electric furnace while blowing high purity argon gas to prevent oxidation, and stirred well to obtain a homogeneous molten alloy. At this time, 0.05% magnesium was added as a deoxidizing agent and cast into an iron mold with an inner diameter of 7 mm and a height of 180 mm. Thereafter, defects on the surface of the ingot were removed, and a round bar with a diameter of 5 mm was produced by hot forging. After carefully removing oxides from the surface of the round bar, it was cold-worked to a wire diameter of 0.5 mm using a swaging and wire drawing machine. This was cut to a length of 100 mm and used as a sample for measuring electrical resistance. Electrical resistance was measured in a temperature range of -190°C to +700°C. As shown in Figure 2, the change in electrical resistance during processing (broken line) is due to the unstable structure, so if the temperature is maintained at point b (300°C) for 1 hour, the electrical resistance changes to d. decreases to a point. Then, if heating and cooling are repeated at a temperature below 300℃, d→
It does not follow the original path like e→f→g and hysteresis occurs. However, curves de and fg follow the same path without hysteresis even if heating and cooling are repeated at temperatures below 250°C. Figure 3A shows a more detailed investigation of this phenomenon. The figure shows samples annealed at 1000℃, then 245℃ and 300℃.
350° C. and 350° C. for one month, the change in electrical resistance with respect to the number of days of holding is shown in %. When held at 245°C for one month, the electrical resistance did not change at all, but at temperatures above this temperature a decrease of 1 to 1.4% was observed. Therefore, as can be seen from Figures 2 and 3A,
Curve de and curve fg follow the same path even if heating and cooling are repeated at temperatures below 250°C, so there is no problem in practical use. Furthermore, as can be seen from the characteristic curve of the annealed state (solid line) in Figure 2, when heated to a temperature above point c (470°C), the alloy is stabilized and no hysteresis is observed. However, even in this case, as shown in Figure 3A, if the temperature is kept at a temperature higher than 250°C for a long time, the electrical resistance will change.
Must be set at ℃. The specific electrical resistance ρ at 20°C is 41μΩ-cm, and the temperature coefficient C _f of ρ is -
4ppm/℃ (-50℃~+250℃) and -5ppm/℃
(0°C to +100°C). Example 2 Alloy number No. 176 (alloy composition Ni-28%, Au-24
%, Cu-48%) Nickel, gold, and copper of the same purity as in Example 1 were used as raw materials for production. The method of manufacturing the sample was the same as in Example 1. The sample has a wire diameter of 0.5 mm,
The remaining wire rod was drawn to a wire diameter of 0.03 mm and cold rolled into a ribbon-like thin plate with a thickness of 7 μm and a width of 0.74 mm, which was then annealed at 1000°C. The characteristic curves are as shown in FIGS. 2 and 3B, and show similar trends to those of Example 1. In this case, no difference was observed in the measurement results between the linear sample and the thin plate sample. Furthermore, the specific electrical resistance ρ at 20℃ is
43μΩ-cm, temperature coefficient of ρ C _f is -4ppm/℃ (-50
℃ ~ +250℃) and -12ppm/℃ (0℃ ~ +100℃)
It was hot. Example 3 Alloy number No. 3 (alloy composition Ni-30%, Au-10%,
Cu-60%) The manufacturing raw materials and manufacturing method are the same as in Example 2. The characteristic curves of the sample are as shown in FIGS. 2 and 3C, and show similar trends to those of Examples 1 and 2. The specific electrical resistance ρ at 20℃ is 40μΩ−
cm, temperature coefficient of ρ C _f is 2ppm/℃ (-50℃~+250℃
℃) and 10 ppm/℃ (0℃ to +100℃). 1 in Table 1 and 2 in Table 1 are Cu-Ni-Au
-100~ for Cu-Ni comparative alloy, Cu-Ni-Fe comparative alloy, and Cu-Ni-Ge comparative alloy.
Average temperature coefficient of electrical resistance C _f between +250℃
=ΔR/RΔT is shown. In the case of Cu-Ni-Au alloy, there are 36 types of alloy samples, and their composition range is
25-80%, Ni 10-65% and Au 0-40%
A thin wire with a wire diameter of 0.5 mm and a length of 100 mm is placed in a vacuum.
After heating at 1000°C for 1 hour, it was cooled to room temperature at 300°C/h.

【table】

[Table] Figure 4 shows an experiment similar to Examples 1 to 3 in which the gold content was 0 to 50% in a nickel-gold-copper ternary system.
The average temperature coefficient of electrical resistance C _f −ΔR/RΔT, i.e., −100 ppm/℃, 0, +100 ppm/℃, +
200ppm/°C and +500ppm/°C isovalue curves are shown. Note that points a, b, c, and d in the figure indicate the composition positions of Cu-Ni comparison alloys A, B, C, and D, respectively. Further, points e and f indicate the composition position of the alloy on the curve where C _f is -100 ppm/°C and +100 ppm/°C, respectively. As shown in the figure, for example, alloys with C _f within ±100 ppm/°C are between points a and b (Ni = 32 to 39%), between points a and b (Ni = 32 to 39%), and between points c and However, in the Cu-Ni-Au alloy of the present invention, the composition range is very wide between points e and f (Au = 4 to 30%). It is characterized in that it can be obtained within a range of compositions. Figure 5 shows straight lines A, B and C in Figure 4,
That is, the variation of C _f with respect to gold composition is shown for constant concentrations of 28%, 30% and 32% nickel. Here, in order to compare the change in C _f of the present invention alloy, CU-Ni-Fe comparison alloy and Cu-Ni-Ge alloy are shown.
The C _f of the comparative alloys is also shown. As is clear from the figure, the C _f of the comparative alloy changes rapidly with the addition amount of Fe or Ge, whereas in the case of the invention alloy, the small value of C _f changes over a wide range of additive elements. Available over a range of compositions. For example, C _f is ±
In order to obtain an alloy within 20ppm/℃, Cu-Ni
In the -Ge comparison alloy, the composition is limited to an extremely narrow composition range of 2 to 3% Ge, but in the case of the invention alloy, the Au content is 4.5 to 22.5% in the Ni = 30% curve.
%, which is approximately 18 times wider than that of the comparative alloy. That is, as shown in FIGS. 4 and 5, the alloy of the present invention has a lower C _f composition dependence than the Cu-Ni comparative alloy, Cu-Ni-Fe comparative alloy, Cu-Ni-Ge comparative alloy, etc. It can be said that there are extremely few. As described in Examples 1 to 3 above, the alloy of the present invention not only exhibits a very small change in electrical resistance with respect to temperature, but also has excellent stability with no variation in properties because its alloy composition spans a wide range. Moreover, it exhibits many characteristics such as not only good workability but also excellent reproducibility because it forms a solid solution in all compositions, and good weldability and brazing properties. These properties are suitable for mass production of electrical resistance alloys for reference resistors and sensor coil materials, and fully satisfy the required properties. Next, regarding the composition of the alloy of the present invention, nickel is 22
The reason for limiting gold to ~50% and 0.01 to 30% is that
As is clear from each example, FIG. 2, FIG. 4, and FIG. 5, in the composition range of -100
The temperature coefficient of electrical resistance in the temperature range from °C to +250 °C is within ±100 ppm/°C, but if the composition exceeds this range, it becomes larger than the above value, which is the purpose of the present invention. This is because it is contrary to alloys with small changes. In addition, the temperature range of the alloy of the present invention is -50°C to +250°C.
The reason for this limitation is that within this temperature range, the temperature coefficient of electrical resistance changes within ±100 ppm/°C for all compositions of the alloy of the present invention, but at temperatures above 250°C, the temperature coefficient changes as shown in Figures 2 and 3. As is clear from the above, not only is there a problem in stability due to thermal aging, but it also lacks oxidation resistance. Also, at temperatures below -100°C, the temperature coefficient of electrical resistance may increase depending on the alloy.
This is because it is 100 ppm/°C or more, which is contrary to the purpose of the present invention of creating an alloy that has a small change in electrical resistance over a wide range of temperatures. The reason why the heating temperature and heating time of the alloy of the present invention are limited to 250° C. or higher and lower than the melting point and 2 seconds or higher and 100 hours or lower, respectively, will be explained with reference to FIG. Figure 6 shows the degree of removal of machining strain (hardness of 50% or less) that affects the stabilization of electrical properties (resistance-temperature curve, temperature coefficient of electrical resistance, time change of electrical resistance, etc.) for alloy No. 11. This shows the relationship between the amount by which the temperature decreases and the heating temperature or heating holding time. Area in the diagram
In (A), the growth of crystal grains during the recrystallization process associated with heating is controlled and softened. However, in the outer region (B), softening progresses very quickly, but not only does the crystal grain become coarse and the mechanical strength becomes weak, but also the Au contained in the alloy is liberated. Electrical characteristics deteriorate. Therefore, it is preferable to process in area (A). Furthermore, when the treatment is carried out at 250° C. or below or for 2 seconds or below, the above-mentioned effects are hardly observed and this is inappropriate as a method for producing the alloy of the present invention. Furthermore, the cooling rate after heating of the alloy of the present invention was
The reason for limiting the temperature to ~300°C/h is that by processing within this range, the growth of crystal grains during the recrystallization process is controlled, and the release of Au does not occur, so the excellent electrical properties of the alloy of the present invention are achieved. Although the properties will not be impaired, if it deviates from this range, not only will the desired electrical properties not be obtained, but the stabilization of the electrical properties will be impaired, making it inappropriate as a method for producing the alloy of the present invention. In short, the alloy of the present invention has -100 over a wide range of compositions.
The change in electrical resistance over a wide temperature range from ℃ to +250℃ is extremely small, within ±100ppm/℃, and since it forms a solid solution in all compositions, it has excellent reproducibility and stability, and has good weldability and brazing. Not only that, but it also has many advantages such as good workability of ultra-fine wires and thin plates, making it highly suitable for mass production.
Therefore, it is suitable for various reference resistors, as well as electrical resistor elements and sensor coil materials for precision measuring instruments and the like. In particular, when the alloy of the present invention is applied to a reference resistor for a high-resolution temperature sensor, its specific electrical resistance value is slightly smaller than that of a manganin-based alloy, so it can exhibit even more excellent characteristics.

[Brief explanation of the drawing]

Figure 1 is a basic configuration diagram of the resistance-voltage conversion method used in temperature sensors, Figure 2 is alloy number No. 102,
For No. 176 and No. 3, the characteristic curve diagram showing the change in electrical resistance with respect to the measured temperature.
245℃, 300℃ and 350℃ for the same alloy as shown
Figure 4 shows the average electrical resistance of the nickel-gold-copper alloy in the temperature range of -100°C to +250°C. Temperature coefficient of -
100ppm/℃, 0, +100ppm/℃, +200ppm/℃
and +500ppm/℃, Figure 5 is a characteristic curve diagram showing the change in the temperature coefficient of electrical resistance with respect to the composition of gold, assuming that 28%, 30%, and 30% of nickel in Figure 4 is constant. Figure 6 shows alloy No.
11 is a characteristic curve diagram showing the relationship between the degree of removal of processing strain and heating temperature or heating holding time for No. 11. FIG. 1... Constant current circuit, 2... Differential amplifier, 3...
Signal conversion circuit.

Claims (1)

[Claims] 1. Nickel 22-59%, gold 0.01-30% by weight
and an electrical resistance alloy characterized by having a composition of 39 to 68% copper and containing a small amount of impurities. 2. Nickel 22-59%, gold 0.01-30% by weight
An alloy with a composition of 39-68% copper and a small amount of impurities is cast and hot-worked or cold-worked into a shape such as a wire or plate, with a melting point of at least 250℃ or higher in a non-oxidizing atmosphere or vacuum. 1. A method for producing an electrical resistance alloy, characterized in that an electrical resistance alloy having a temperature coefficient of electrical resistance within ±100 ppm/°C in a temperature range of -100°C to +250°C is obtained by heating at the following temperature for 2 seconds or more. 3 Nickel 22-59%, gold 0.01-30% by weight
The wire rod or plate material obtained by casting an alloy with a composition of 39 to 68% copper and containing a small amount of impurities is subjected to winding processing or punched into the desired shape, and it is used as is to provide heat-resistant insulation. After embedding them in the body or fixing them on a heat-resistant insulator, they are held at a temperature of 250°C or higher and below the melting point in a non-oxidizing atmosphere or vacuum for 2 seconds or more and 100 hours or less, and then heated at 5 to 300°C/h. By cooling at a cooling rate and performing sufficient annealing, the temperature coefficient of electrical resistance becomes -
A method for manufacturing an electric resistor element or a sensor coil, characterized in that it produces an electrical resistor element or sensor coil with a tolerance of within ±100 ppm/°C in a temperature range of 100°C to +250°C. 4 Nickel 22-59%, gold 0.01-30% by weight
After applying or coating a heat-resistant insulator on the surface of a fine wire or thin plate obtained by casting an alloy consisting of 39 to 68% copper and containing a small amount of impurities, the wire is formed into the desired shape. in a non-oxidizing atmosphere or in a vacuum.
A method for manufacturing an electric resistor element or a sensor coil, which comprises holding at a temperature of 250° C. or more and below the melting point for 2 seconds or more and 100 hours or less, and then cooling at a cooling rate of 5 to 300° C./h to perform sufficient annealing. 5 Nickel 22-59%, gold 0.01-30% by weight
After applying an alloy film with a composition of 39 to 68% copper and containing a small amount of impurities to the surface of the heat-resistant insulator by an appropriate method, it is formed into the desired shape, and then the heat-resistant insulator is coated on top of it. The coated, applied, or coated material is maintained at a temperature of 250℃ or higher and lower than the melting point in a non-oxidizing atmosphere or vacuum for 2 seconds or more and 100 hours or less, and then cooled at a cooling rate of 5 to 300℃/h for sufficient annealing. A method of manufacturing an electric resistor element or a sensor coil, characterized in that: