Precise resistance alloy foil and preparation method thereof

Abstract

The invention belongs to the technical field of precision resistors, and particularly relates to a precision resistor alloy foil and a preparation method thereof. Aiming at the defect that the performance of the existing precise resistance alloy foil has a space for improving, the invention adopts the following technical scheme: the precise resistance alloy foil comprises the following elements in percentage by mass: 20.4-20.8% of Cr, 2.4-2.8% of Al, 1-2% of Fe, 6.5-7.0% of W, 4.2-4.7% of Ti, 3.5-3.9% of Zr, 0.2-0.6% of Ce and the balance of Ni. The preparation method comprises the following steps: preparing raw materials; smelting and casting to obtain as-cast alloy; carrying out three-way free forging after homogenizing annealing treatment; carrying out five-pass hot rolling; aging treatment is carried out after solution treatment; performing three-pass cold rolling treatment; aging treatment is carried out after solution treatment; and carrying out annealing treatment. The precision resistance alloy foil prepared by the invention has higher resistivity, lower resistance temperature coefficient and better resistance stability.

Description

Technical Field

[0001] The invention belongs to the technical field of precision resistors, and in particular relates to a precision resistor alloy foil and a preparation method thereof. Background Art

[0002] Precision resistors generally refer to resistors with a resistance value of 0.1-20MΩ and an allowable deviation of ±2%-±0.001%. Precision resistors mainly play the role of controlling voltage, current limiting protection and monitoring power in circuits. They can also be used as time circuit components and sensors. They play a very important role in electronic instruments, mobile communications, aerospace and automatic control.

[0003] Precision resistor alloys are the core materials of precision resistors, and their resistance must be highly accurate and stable. Accuracy means that the resistance value remains within a small range when external parameters such as temperature change; stability means that the resistance value changes over time and is controlled within a certain range. In addition, in order to adapt to the development trend of miniaturization of electronic devices, precision resistor alloys are also required to have high resistivity to reduce the size of resistor elements.

[0004] Precision resistance alloys are mainly divided into Cu-Mn, Ag-Mn, Au-Cr, Cu-Ni, Ni-Cr, Fe-Cr-Al and other series. The performance of precision resistance alloys of different series and different parameter ratios are different, and their applicable occasions are also different. For example, 6J20 alloy (with nickel, copper, manganese and zinc as main components) has higher resistivity, lower resistance temperature coefficient, and slightly poor conductivity, which is suitable for making various measuring instruments, meters and other resistance elements; 6J22 alloy (with nickel, chromium, aluminum and iron as main components) has excellent resistivity and stability, lower resistance temperature coefficient and thermoelectric potential to copper, which is suitable for making various measuring instruments and meters in precision resistance elements.

[0005] With the rapid development of cutting-edge science and technology, electronic devices are becoming more and more sophisticated, and the requirements for precision resistor elements are also getting higher and higher. Therefore, it is necessary to further reduce the temperature coefficient of resistance and reduce the annual rate of change of resistance value to obtain higher accuracy and stability. Two problems need to be solved in the implementation process: one is the raw materials and proportions of precision resistor alloys; the other is the preparation process of foil. In the prior art, although the composition and proportion of some precision resistor alloys have been disclosed, there is still room for improvement in various performances. There is little disclosure on precision resistor alloy foils. Summary of the invention

[0006] The present invention aims at the shortcomings of the existing precision resistance alloy foil materials, which have room for improvement in performance, and provides a precision resistance alloy foil material, which improves at least one of the following aspects: the resistance temperature coefficient, resistivity, annual change rate of resistance value, and processing performance of the precision resistance alloy foil material. The present invention also aims at the shortcomings of the existing precision resistance alloy foil material processing technology, and provides a method for preparing the precision resistance alloy foil material.

[0007] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a precision resistor alloy foil is composed of Cr, Al, Fe, W, Ti, Zr, Ce, and Ni, wherein the mass percentage of each element is: 20.4-20.8% Cr, 2.4-2.8% Al, 1-2% Fe, 6.5-7.0% W, 4.2-4.7% Ti, 3.5-3.9% Zr, 0.2-0.6% Ce, and the balance is Ni.

[0008] As an improvement, the mass percentage of each element is: 20.6% Cr, 2.5% Al, 1.5-1.8% Fe, 6.6% W, 4.4-4.5% Ti, 3.6-3.7% Zr, 0.3-0.5% Ce, and the balance is Ni.

[0009] The method for preparing the precision resistance alloy foil comprises the following steps:

[0010] Step S1, preparing metal raw materials according to the aforementioned components and proportions;

[0011] Step S2, melting and casting the prepared metal raw materials to obtain a cast alloy;

[0012] Step S3, performing homogenization annealing treatment on the cast alloy, then performing surface treatment to remove oxides on the alloy surface, and then performing three-way free forging to obtain a forged alloy;

[0013] Step S4, performing surface treatment on the forged alloy to remove oxides on the alloy surface, and then performing multiple hot rolling passes, wherein the temperature of each hot rolling pass is higher than the temperature of the previous pass, and an annealing treatment is performed after each hot rolling pass. After the second-to-last hot rolling pass is completed, the forged alloy is successively subjected to a solution treatment and an aging treatment, and the second-to-last annealing treatment step is performed after the aging treatment;

[0014] Step S5: After hot rolling is completed, the alloy is subjected to a solid solution treatment and an aging treatment in succession;

[0015] Step S6: After aging is completed, multiple cold rolling passes are performed, and the temperature of each cold rolling pass is lower than the temperature of the previous pass;

[0016] Step S7: After the cold rolling is completed, a solution treatment and an aging treatment are performed successively;

[0017] Step S8: After the aging is completed, annealing treatment is performed to obtain a precision resistor alloy foil.

[0018] As an improvement to the preparation method, step S1 further includes pretreatment of the metal raw material for impurity removal, and the specific method of the pretreatment for impurity removal is: ultrasonic cleaning with deionized water, acid washing, alcohol washing, and finally drying for standby use.

[0019] As an improvement to the preparation method, in step S2, the specific method of smelting and casting treatment is: controlling the temperature at 1200-1300°C, stirring for a period of time after all the metal raw materials are melted, casting into a mold after standing, and then demolding by rapid cooling using water quenching to obtain a cast resistance alloy.

[0020] As an improvement to the preparation method, in step S3, the temperature of homogenization annealing is 960-1050°C, and the holding time is 2.5-3h; the temperature of three-way free forging is 850-950°C, and after forging, the forging temperature is maintained for 2-2.5h as incomplete annealing treatment.

[0021] As an improvement to the preparation method, in step S4, the deformation amount of the first hot rolling pass is 60-65%, and the deformation amount of each subsequent pass is reduced by 4-5%; the thickness of the material after hot rolling is 1.00-2.00 mm; the temperature of the first hot rolling pass is 800°C, and the temperature of each subsequent pass is increased by 50°C compared to the previous pass.

[0022] As an improvement to the preparation method, the solution treatment temperature in step S4, step S5 and step S7 is 900-950°C and maintained for 7-8h; the aging treatment temperature is 400-450°C and maintained for 0.4-0.6h.

[0023] As an improvement to the preparation method, in step S4, the annealing temperature is 450-550°C, maintained for 1-1.5 hours, and annealing is performed at the furnace temperature; the annealing temperature in step S8 is 300-350°C, maintained for 1-1.5 hours, and annealing is performed at the furnace temperature.

[0024] As an improvement to the preparation method, in step S6, the first cold rolling process uses an eight-roll mill to roll the material into a sheet of 0.10-0.50 mm; the second cold rolling process uses a twenty-roll mill to roll the material into a foil of 0.005-0.01 mm; the third cold rolling process uses a thirty-six-roll mill to roll the material into a foil of 0.001-0.005 mm; the temperature of the first cold rolling process is 400°C, and the temperature of each subsequent process is reduced by 50°C compared to the previous process.

[0025] The precision resistance alloy foil of the present invention has a reasonable design of alloy composition and ratio, thereby improving the performance and processing performance of the alloy:

[0026] It is made of Ni, Cr, Al, Fe, Ti, W, Zr and Ce through reasonable proportion design. Ni, Cr, Fe, Ti, W and Zr belong to transition metal elements. Secondly, the outer orbit is not filled. When forming an alloy, the outer electrons of heterogeneous atoms enter the unfilled outer orbit to form an ordered structure, which makes the interaction energy between heterogeneous atoms stronger than the interaction energy between similar atoms, which is more conducive to the outer electrons entering the inner orbit, reducing the number of free electrons and increasing the resistivity.

[0027] The atomic radius of Fe (0.127nm), Ni (0.124nm), and Cr (0.127nm) is similar, and the lattice distortion caused by solid solution in the lattice is small. It is easier to be evenly distributed in the crystal and will not have a dragging effect on the grain boundary. The atomic radius of Al (0.143nm), Ti (0.147nm), W (0.137nm), and Zr (0.160nm) is quite different from that of Fe, Ni, and Cr. In order to reduce distortion and reduce energy, the solid solution of Al, Ti, W, and Zr tends to be concentrated at the grain boundary, thereby inhibiting the grain boundary migration during the recrystallization process and producing the effect of grain refinement. The size of the grain is proportional to the temperature coefficient of resistance. After the grain is refined, the temperature coefficient of resistance decreases;

[0028] As a rare earth element, Ce has a greater affinity with impurity elements such as S (sulfur), and preferentially combines with impurity elements to form refractory compounds, which can eliminate the brittle phase on the alloy grain boundary and refine the size of inclusions, thereby improving the hot working properties of the alloy.

[0029] The method for preparing the precision resistance alloy foil of the present invention has the following advantages:

[0030] The alloy is rolled into a metal foil that meets the thickness standard requirements by hot rolling followed by cold rolling. After the penultimate and last passes of hot rolling, solid solution and aging treatments are performed respectively. Solid solution treatment is beneficial to improving the processing properties of the alloy. In the solid solution process, the vacancy concentration of the alloy increases, which is beneficial to improving the resistivity. Also, due to the increase in vacancy concentration, excess vacancies are generated. The excess vacancies themselves are highly unstable, resulting in an increase in vacancy mobility. Vacancies are annihilated by diffusion during the migration process, and the annihilation of excess vacancies will cause the resistivity to decrease. Therefore, aging treatment is performed immediately after solid solution. During the rapid cooling of the solid solution, the vacancies are eliminated before they have time to diffuse and annihilate, which is beneficial to retaining the high resistivity performance of the alloy and improving the resistance stability. After the last cold rolling, the temperature is immediately raised for solid solution treatment and then aging and annealing. The high resistivity and low resistivity coefficient of the alloy are also stabilized by using the alloy characteristics and the above principles.

[0031] The grain boundary movement accompanying the solution treatment will cause the grain size to gradually increase, and the increase in grain size will lead to an increase in the temperature coefficient of resistance. Therefore, the present invention makes a fine ratio of the alloy components, and uses the interaction of the above metals to weaken or even eliminate the defects accompanying the solution treatment, so that the metal foil prepared by the present invention retains a low temperature coefficient of resistance and has a high resistivity.

[0032] The preparation of foil is more difficult than that of strip, wire and silk, and has higher requirements on process parameters and process conditions. The preparation method of the present invention has easy-to-operate preparation steps, is suitable for industrial production, and can produce precision resistor alloy foil with stable quality. DETAILED DESCRIPTION

[0033] The technical solutions of the embodiments of the present invention are explained and described below, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the present invention.

[0034] The precision resistor alloy foil of the present invention is composed of Cr, Al, Fe, W, Ti, Zr, Ce and Ni, wherein the mass percentage of each element is: 20.4-20.8% Cr, 2.4-2.8% Al, 1-2% Fe, 6.5-7.0% W, 4.2-4.7% Ti, 3.5-3.9% Zr, 0.2-0.6% Ce, and the balance is Ni.

[0035] In some specific embodiments, the mass percentage of each element is preferably: 20.6% Cr, 2.5% Al, 1.5-1.8% Fe, 6.6% W, 4.4-4.5% Ti, 3.6-3.7% Zr, 0.3-0.5% Ce, and the balance is Ni.

[0036] The precision resistance alloy foil of the present invention has a reasonable design of alloy composition and ratio, thereby improving the performance and processing performance of the alloy:

[0037] It is made of Ni (nickel), Cr (chromium), Al (aluminum), Fe (iron), Ti (titanium), W (tungsten), Zr (zirconium), and Ce (cerium) in a reasonable ratio. Ni, Cr, Fe, Ti, W, and Zr belong to transition metal elements. Secondly, the outer orbit is not filled. When forming an alloy, the outer electrons of heterogeneous atoms enter the unfilled outer orbit to form an ordered structure, which makes the interaction energy between heterogeneous atoms stronger than the interaction energy between similar atoms, which is more conducive to the outer electrons entering the inner orbit, reducing the number of free electrons and increasing the resistivity.

[0038] The atomic radius of Fe (0.127nm), Ni (0.124nm), and Cr (0.127nm) is similar, and the lattice distortion caused by solid solution in the lattice is small. It is easier to be evenly distributed in the crystal and will not have a dragging effect on the grain boundary. The atomic radius of Al (0.143nm), Ti (0.147nm), W (0.137nm), and Zr (0.160nm) is quite different from that of Fe, Ni, and Cr. In order to reduce distortion and reduce energy, the solid solution of Al, Ti, W, and Zr tends to be concentrated at the grain boundary, thereby inhibiting the grain boundary migration during the recrystallization process and producing the effect of grain refinement. The size of the grain is proportional to the temperature coefficient of resistance. After the grain is refined, the temperature coefficient of resistance decreases;

[0039] As a rare earth element, Ce has a greater affinity with impurity elements such as S, and preferentially combines with impurity elements to form refractory compounds, which can eliminate the brittle phase on the alloy grain boundary and refine the size of inclusions, thereby improving the hot working properties of the alloy.

[0040] The method for preparing the precision resistance alloy foil comprises the following steps:

[0041] Step S1, preparing metal raw materials according to the aforementioned components and proportions;

[0042] Step S2, melting and casting the prepared metal raw materials to obtain a cast alloy;

[0043] Step S3, performing homogenization annealing treatment on the cast alloy, then performing surface treatment to remove oxides on the alloy surface, and then performing three-way free forging to obtain a forged alloy;

[0044] Step S4, performing surface treatment on the forged alloy to remove the oxide on the alloy surface, and then performing 5 passes of hot rolling, wherein the temperature of each pass of hot rolling is higher than the temperature of the previous pass, and an annealing treatment is performed after each pass of hot rolling. After the second-to-last pass of hot rolling is completed, the forged alloy is successively subjected to a solution treatment and an aging treatment, and the second-to-last annealing treatment step is after the aging treatment;

[0045] Step S5: After hot rolling is completed, the alloy is subjected to a solid solution treatment and an aging treatment in succession;

[0046] Step S6: After aging is completed, three cold rolling passes are performed, and the temperature of each cold rolling pass is lower than the temperature of the previous pass;

[0047] Step S7: After the cold rolling is completed, a solution treatment and an aging treatment are performed successively;

[0048] Step S8: After the aging is completed, annealing treatment is performed to obtain a precision resistor alloy foil.

[0049] In some specific embodiments, step S1 also includes pretreatment of the metal raw material for impurity removal, and the specific method of the pretreatment is: first ultrasonic cleaning with deionized water to remove dust on the surface of the metal raw material; then pickling with 6 mol / L hydrochloric acid solution to remove oxides on the surface of the metal raw material; then washing with anhydrous ethanol to remove impurities remaining on the surface of the metal raw material; finally drying in a vacuum drying oven for use.

[0050] In some specific embodiments, in step S2, the specific method of smelting and casting treatment is: controlling the temperature at 1200-1300°C, stirring for a period of time after all the metal raw materials are melted, casting into a mold after standing, and then demolding by rapid cooling with water quenching to obtain a cast resistance alloy.

[0051] In some specific embodiments, in step S3, the temperature of homogenization annealing is 960-1050°C, and the holding time is 2.5-3h; the temperature of three-way free forging is 850-950°C, and the forging temperature is maintained for 2-2.5h after forging as incomplete annealing treatment.

[0052] In some specific embodiments, in step S4, the deformation amount of the first hot rolling pass is 60-65%, and the deformation amount of each subsequent pass is reduced by 4-5%; the thickness of the material after hot rolling is 1.00-2.00 mm; the temperature of the first hot rolling pass is 800°C, and the temperature of each subsequent pass is increased by 50°C compared to the previous pass.

[0053] In some specific embodiments, the solution treatment temperature in step S4, step S5 and step S7 is 900-950° C. and maintained for 7-8 hours; the aging treatment temperature is 400-450° C. and maintained for 0.4-0.6 hours.

[0054] In some specific embodiments, in step S4, the annealing temperature is 450-550°C, maintained for 1-1.5 hours, and annealing is performed at the furnace temperature; in step S8, the annealing temperature is 300-350°C, maintained for 1-1.5 hours, and annealing is performed at the furnace temperature.

[0055] In some specific embodiments, in step S6, the first cold rolling process uses an eight-roll mill to roll the material into a sheet of 0.10-0.50 mm; the second cold rolling process uses a twenty-roll mill to roll the material into a foil of 0.005-0.01 mm; the third cold rolling process uses a thirty-six-roll mill to roll the material into a foil of 0.001-0.005 mm; the temperature of the first cold rolling process is 400°C, and the temperature of each subsequent process is reduced by 50°C compared to the previous process.

[0056] The method for preparing the precision resistance alloy foil of the present invention has the following advantages:

[0057] The alloy is rolled into a metal foil that meets the thickness standard requirements by hot rolling followed by cold rolling. After the penultimate and last passes of hot rolling, solid solution and aging treatments are performed respectively. Solid solution treatment is beneficial to improving the processing properties of the alloy. In the solid solution process, the vacancy concentration of the alloy increases, which is beneficial to improving the resistivity. Also, due to the increase in vacancy concentration, excess vacancies are generated. The excess vacancies themselves are highly unstable, resulting in an increase in vacancy mobility. Vacancies are annihilated by diffusion during the migration process, and the annihilation of excess vacancies will cause the resistivity to decrease. Therefore, aging treatment is performed immediately after solid solution. During the rapid cooling of the solid solution, the vacancies are eliminated before they have time to diffuse and annihilate, which is beneficial to retaining the high resistivity performance of the alloy and improving the resistance stability. After the last cold rolling, the temperature is immediately raised for solid solution treatment and then aging and annealing. The high resistivity and low resistivity coefficient of the alloy are also stabilized by using the alloy characteristics and the above principles.

[0058] The grain boundary movement accompanying the solution treatment will cause the grain size to gradually increase, and the increase in grain size will lead to an increase in the temperature coefficient of resistance. Therefore, the present invention makes a fine ratio of the alloy components, and uses the interaction of the above metals to weaken or even eliminate the defects accompanying the solution treatment, so that the metal foil prepared by the present invention retains a low temperature coefficient of resistance and has a high resistivity.

[0059] The preparation of foil is more difficult than that of strip, wire and silk, and has higher requirements on process parameters and process conditions. The preparation method of the present invention has easy-to-operate preparation steps, is suitable for industrial production, and can produce precision resistor alloy foil with stable quality.

[0060] Embodiment 1

[0061] Precision resistor alloy foil is composed of Cr, Al, Fe, W, Ti, Zr, Ce, and Ni, wherein the mass percentage of each element is: 20.4% Cr, 2.4% Al, 1% Fe, 6.5% W, 4.2% Ti, 3.6% Zr, 0.2% Ce, and the balance is Ni.

[0062] The method for preparing the precision resistance alloy foil comprises the following steps:

[0063] Step S1, preparing metal raw materials according to the above ingredients and proportions, first ultrasonically cleaning the metal raw materials with deionized water to remove dust on the surface of each metal raw material; then pickling with 6 mol / L hydrochloric acid solution to remove oxides on the surface of each metal raw material; then washing with anhydrous ethanol to remove impurities remaining on the surface of each metal raw material; finally drying in a vacuum drying oven for standby use; cleaning and other impurity removal pretreatment operations can be performed before or after weighing;

[0064] Step S2, maintaining the temperature at 1200°C, and after all the metal raw materials are melted, stirring them to make the melt composition more uniform; after the alloy liquid is stirred, standing for 2 hours, casting it into a mold, and then demolding; during the demolding process, water quenching is used for rapid cooling to obtain a cast resistance alloy;

[0065] Step S3, performing homogenization annealing treatment at 960° C. on the as-cast alloy for 2.5 hours, then performing milling treatment to remove oxides on the surface of the alloy, and then performing three-way free forging at a temperature of 850° C. After forging, the alloy is kept at the forging temperature for 2.5 hours as an incomplete annealing treatment;

[0066] Step S4, performing milling treatment on the forged alloy to remove the oxide on the alloy surface, and then performing 5 passes of hot rolling, the first pass hot rolling temperature is 800°C, the hot rolling deformation is 60%, and then the temperature of each pass is 50°C higher than the previous pass, and the deformation of each pass is reduced by 4%. After the second to last pass of hot rolling is completed, the forged alloy is subjected to a solid solution treatment, the solid solution treatment temperature is 900°C, and it is maintained for 8 hours, and then an aging treatment is performed again, the aging treatment temperature is 400°C, and it is maintained for 0.4 hours. After each hot rolling, an annealing treatment is performed, and the second to last annealing treatment step is after the aging treatment, the annealing treatment temperature is 450°C, and it is maintained for 1 hour. Annealing is performed at the furnace temperature, and the material thickness after hot rolling is 1.00-2.00 mm;

[0067] Step S5, after hot rolling is completed, the alloy is subjected to another solution treatment, the solution treatment temperature is 900°C, and maintained for 7 hours, and then an aging treatment is performed again, the aging treatment temperature is 400°C, and maintained for 0.6 hours;

[0068] Step S6, after aging is completed, three cold rolling processes are performed, the first cold rolling temperature is 400°C, the cold rolling process uses an eight-roll rolling mill to roll the material into a sheet of 0.10-0.50 mm; the second cold rolling temperature is 350°C, the cold rolling process uses a twenty-roll rolling mill to roll the material into a sheet of 0.005-0.01 mm; the second cold rolling temperature is 300°C, the cold rolling process uses a thirty-six-roll rolling mill to roll the material into a foil of 0.001-0.005 mm;

[0069] Step S7, after the cold rolling is completed, a solution treatment is performed again, the solution treatment temperature is 900°C, and it is maintained for 8 hours, and then an aging treatment is performed again, the aging treatment temperature is 400°C, and it is maintained for 0.6 hours;

[0070] Step S8: After the aging is completed, annealing treatment is performed at a temperature of 300° C. for 1.5 hours, and annealing is performed at the furnace temperature to obtain a precision resistor alloy foil.

[0071] After testing, the resistivity of the finished alloy foil is 134μΩ·cm, the temperature coefficient of resistance is 1.5ppm, and the annual change rate of resistance value is 1.8ppm.

[0072] Embodiment 2

[0073] Precision resistor alloy foil is composed of Cr, Al, Fe, W, Ti, Zr, Ce, and Ni, wherein the mass percentage of each element is: 20.6% Cr, 2.5% Al, 1.65% Fe, 6.6% W, 4.4% Ti, 3.7% Zr, 0.45% Ce, and the balance is Ni.

[0074] The method for preparing the precision resistance alloy foil comprises the following steps:

[0075] Step S1, preparing the raw materials and proportions mentioned above, firstly using deionized water to ultrasonically clean the raw materials to remove dust on the surface of each raw material, then using 6 mol / L hydrochloric acid solution to pickle and remove oxides on the surface of each raw material; then using anhydrous ethanol to wash and remove impurities remaining on the surface of each raw material; finally drying in a vacuum drying oven for standby use;

[0076] Step S2, controlling the temperature to 1250°C, stirring after all the raw materials are melted to make the melt composition more uniform; after the alloy liquid is stirred, it is cast into a mold after standing for 2 hours, and then demolded, and rapidly cooled by water quenching to obtain a cast resistance alloy;

[0077] Step S3, performing homogenization annealing treatment at 1000° C. on the cast alloy for 2.5 hours, then performing milling treatment to remove oxides on the alloy surface, and then performing three-way free forging at a temperature of 900° C. After forging, the alloy is kept at the forging temperature for 2.5 hours as an incomplete annealing treatment;

[0078] Step S4, performing milling treatment on the forged alloy to remove the oxide on the alloy surface, and then performing 5 passes of hot rolling, the first pass hot rolling temperature is 800°C, the hot rolling deformation is 62%, and then the temperature of each pass is 50°C higher than the previous pass, and the deformation of each pass is reduced by 4%. After the second to last pass of hot rolling is completed, the forged alloy is subjected to a solid solution treatment, the solid solution treatment temperature is 920°C, and it is maintained for 8 hours, and then an aging treatment is performed, and the aging treatment temperature is 420°C, and it is maintained for 0.5 hours. After each hot rolling, an annealing treatment is performed, and the second to last annealing treatment step is after the aging treatment, the annealing treatment temperature is 500°C, and it is maintained for 1.25 hours. Annealing is performed at the furnace temperature, and the thickness of the material after hot rolling is 1.00-2.00 mm;

[0079] Step S5, after hot rolling is completed, the alloy is subjected to another solution treatment, the solution treatment temperature is 925°C, and maintained for 7.5 hours, and then an aging treatment is performed again, the aging treatment temperature is 425°C, and maintained for 0.5 hours;

[0080] Step S6, after aging is completed, three cold rolling processes are performed, the first cold rolling temperature is 400°C, the cold rolling process uses an eight-roll rolling mill to roll the material into a sheet of 0.10-0.50 mm; the second cold rolling temperature is 350°C, the cold rolling process uses a twenty-roll rolling mill to roll the material into a sheet of 0.005-0.01 mm; the second cold rolling temperature is 300°C, the cold rolling process uses a thirty-six-roll rolling mill to roll the material into a foil of 0.001-0.005 mm;

[0081] Step S7, after the cold rolling is completed, a solution treatment is performed again, the solution treatment temperature is 925°C, and it is maintained for 8 hours, and then an aging treatment is performed again, the aging treatment temperature is 425°C, and it is maintained for 0.5 hours;

[0082] Step S8: After aging is completed, annealing treatment is performed at a temperature of 325° C. and maintained for 1.25 hours. The precision resistor alloy foil is annealed at the furnace temperature to obtain the precision resistor alloy foil.

[0083] The test results show that the resistivity of the finished alloy foil is 142μΩ·cm, the temperature coefficient of resistance is 1ppm, and the annual change rate of resistance value is 1.3ppm.

[0084] Embodiment 3

[0085] Precision resistor alloy foil is composed of Ni, Cr, Al, Fe, Ti, W, Zr and Ce, wherein the mass percentage of each element is: 20.8% Cr, 2.8% Al, 1.8% Fe, 7.0% W, 4.7% Ti, 3.9% Zr, 0.5% Ce, and the balance is Ni.

[0086] The method for preparing the precision resistance alloy foil comprises the following steps:

[0087] Step S1, preparing the raw materials and proportions mentioned above, firstly using deionized water to ultrasonically clean the raw materials to remove dust on the surface of each metal raw material, then using 6 mol / L hydrochloric acid solution to pickle and remove oxides on the surface of each metal raw material; then using anhydrous ethanol to wash and remove impurities remaining on the surface of each metal raw material; finally drying in a vacuum drying oven for standby use;

[0088] Step S2, controlling the temperature to 1300°C, stirring after all the metal raw materials are melted to make the melt composition more uniform; after the alloy liquid is stirred, it is cast into a mold after standing for 2 hours, and then demolded, and rapidly cooled by water quenching to obtain a cast resistance alloy;

[0089] Step S3, performing homogenization annealing treatment at 1050° C. on the cast alloy for 2.5 hours, then performing milling treatment to remove oxides on the alloy surface, and then performing three-way free forging at a temperature of 950° C. After forging, the alloy is kept at the forging temperature for 2 hours as an incomplete annealing treatment;

[0090] Step S4, performing milling treatment on the forged alloy to remove the oxide on the alloy surface, and then performing 5 passes of hot rolling, the first pass of hot rolling temperature is 800°C, the hot rolling deformation is 65%, and then the temperature of each pass is 50°C higher than the previous pass, and the deformation of each pass is reduced by 5%. After the second to last pass of hot rolling is completed, the forged alloy is subjected to a solid solution treatment, the solid solution treatment temperature is 950°C, and it is maintained for 8 hours, and then an aging treatment is performed, the aging treatment temperature is 450°C, and it is maintained for 0.4 hours. After each hot rolling, an annealing treatment is performed, and the second to last annealing treatment step is after the aging treatment, the annealing treatment temperature is 550°C, and it is maintained for 1 hour. Annealing is performed at the furnace temperature, and the material thickness after hot rolling is 1.00-2.00 mm;

[0091] Step S5, after hot rolling is completed, the alloy is subjected to another solution treatment, the solution treatment temperature is 950°C, and maintained for 7 hours, and then an aging treatment is performed again, the aging treatment temperature is 450°C, and maintained for 0.4 hours;

[0092] Step S6, after aging is completed, three cold rolling processes are performed, the first cold rolling temperature is 400°C, the cold rolling process uses an eight-roll rolling mill to roll the material into a sheet of 0.10-0.50 mm; the second cold rolling temperature is 350°C, the cold rolling process uses a twenty-roll rolling mill to roll the material into a sheet of 0.005-0.01 mm; the second cold rolling temperature is 300°C, the cold rolling process uses a thirty-six-roll rolling mill to roll the material into a foil of 0.001-0.005 mm;

[0093] Step S7, after the cold rolling is completed, a solution treatment is performed again, the solution treatment temperature is 950°C, and it is maintained for 8 hours, and then an aging treatment is performed again, the aging treatment temperature is 450°C, and it is maintained for 0.6 hours;

[0094] Step S8: After the aging is completed, annealing treatment is performed at a temperature of 350° C. for 1.5 hours, and annealing is performed at the furnace temperature to obtain a precision resistor alloy foil.

[0095] The test results show that the resistivity of the finished alloy foil is 139μΩ·cm, the temperature coefficient of resistance is 1.8ppm, and the annual change rate of resistance value is 1.5ppm.

[0096] Comparative Example 1

[0097] The difference between Comparative Example 1 and Example 2 is that only the transition metal Ti is replaced by Co, and the ratio remains unchanged.

[0098] The test results show that the resistivity of the finished alloy foil is 130μΩ·cm, the temperature coefficient of resistance is 5.5ppm, and the annual change rate of resistance value is 2.5ppm.

[0099] Comparative Example 2

[0100] The difference between Comparative Example 2 and Example 2 is that only the transition metal Zr is replaced by Mo, and the ratio remains unchanged.

[0101] The test results show that the resistivity of the finished alloy foil is 132μΩ·cm, the temperature coefficient of resistance is 3.2ppm, and the annual change rate of resistance value is 2.3ppm.

[0102] Comparative Example 3

[0103] The difference between Comparative Example 3 and Example 2 is that only the transition metals Ti and Zr are replaced by Co and Mo respectively, and the ratio remains unchanged.

[0104] The test results show that the resistivity of the finished alloy foil is 126μΩ·cm, the temperature coefficient of resistance is 5.7ppm, and the annual change rate of resistance value is 2.7ppm.

[0105] Comparative Example 4

[0106] The difference between Comparative Example 4 and Example 2 is that when preparing the alloy foil, the 6 hot rolling passes are all constant temperature hot rolling, and the hot rolling temperature is controlled at 950°C.

[0107] The test results show that the resistivity of the finished alloy foil is 133μΩ·cm, the temperature coefficient of resistance is 7.2ppm, and the annual change rate of resistance value is 2.8ppm.

[0108] Comparative Example 5

[0109] The difference between Comparative Example 5 and Example 2 is that: when preparing the alloy foil, the three cold rolling passes are all constant temperature cold rolling, and the cold rolling temperature is controlled at 350°C.

[0110] The test results show that the resistivity of the finished alloy foil is 130μΩ·cm, the temperature coefficient of resistance is 6.4ppm, and the annual change rate of resistance value is 2.6ppm.

[0111] Comparative Example 6

[0112] The difference between Comparative Example 6 and Example 2 is that when preparing the alloy foil, constant temperature hot rolling and constant temperature cold rolling are adopted, the hot rolling temperature is controlled at 950°C, and the cold rolling temperature is controlled at 350°C.

[0113] The test results show that the resistivity of the finished alloy foil is 122μΩ·cm, the temperature coefficient of resistance is 11.0ppm, and the annual change rate of resistance value is 3.1ppm.

[0114] Comparative Example 7

[0115] The difference between Comparative Example 7 and Example 2 is that after the penultimate hot rolling, no solution treatment and aging treatment are performed, and annealing treatment is performed directly.

[0116] The test results show that the resistivity of the finished alloy foil is 127μΩ·cm, the temperature coefficient of resistance is 5.3ppm, and the annual change rate of resistance value is 2.4ppm.

[0117] Comparative Example 8

[0118] The difference between Comparative Example 8 and Example 2 is that after hot rolling and cold rolling, no solution treatment and aging treatment are performed, only annealing treatment is performed, and the solution aging treatment after the penultimate hot rolling is retained.

[0119] The test results show that the resistivity of the finished alloy foil is 124μΩ·cm, the temperature coefficient of resistance is 10.8ppm, and the annual change rate of resistance value is 3.0ppm.

[0120] Comparative Example 9

[0121] The difference between Comparative Example 9 and Example 2 is that after the penultimate hot rolling, no solution treatment and aging treatment are performed, and annealing treatment is performed directly; after hot rolling and cold rolling are completed, no solution treatment and aging treatment are performed, and only annealing treatment is performed.

[0122] The test results show that the resistivity of the finished alloy foil is 120μΩ·cm, the temperature coefficient of resistance is 12.6ppm, and the annual change rate of resistance value is 3.5ppm.

[0123] In summary, compared with the prior art, the first, second and third embodiments of the present invention all have the following beneficial effects:

[0124] 1. Through the reasonable design of alloy composition and ratio, the conductivity (resistance temperature coefficient, resistivity, annual change rate of resistance value) and processing performance of the alloy are improved:

[0125] Precision resistor alloy foil is made of Ni, Cr, Al, Fe, Ti, W, Zr, and Ce through a reasonable ratio design. Ni, Cr, Fe, Ti, W, and Zr are transition metal elements. The second outer orbit is not filled. When forming an alloy, the outer electrons of heterogeneous atoms can enter the unfilled second outer orbit to form an ordered structure, which makes the interaction energy between heterogeneous atoms stronger than the interaction energy between similar atoms, which is more conducive to the outer electrons entering the inner orbit, reducing the number of free electrons and increasing the resistivity.

[0126] The atomic radius of Fe (0.127nm), Ni (0.124nm), and Cr (0.127nm) is similar, and the lattice distortion caused by their solid solution in the lattice is small, so they are more easily evenly distributed in the crystal and will not have a dragging effect on the grain boundary; the atomic radius of Al (0.143nm), Ti (0.147nm), W (0.137nm), and Zr (0.160nm) is quite different from that of Fe, Ni, and Cr. In order to reduce distortion and reduce energy, the solid-solution Al, Ti, W, and Zr tend to be concentrated at the grain boundary, thereby inhibiting the grain boundary migration during the recrystallization process and producing the effect of grain refinement. The size of the grain is proportional to the temperature coefficient of resistance. After the grain is refined, the temperature coefficient of resistance decreases;

[0127] As a rare earth element, Ce has a greater affinity with impurity elements such as S, and preferentially combines with impurity elements to form refractory compounds, which can eliminate the brittle phase on the alloy grain boundary and refine the size of inclusions, thereby improving the hot working properties of the alloy.

[0128] 2. The preparation method of the present invention adopts a treatment method of first hot rolling and then cold rolling to roll the alloy into a metal foil that meets the thickness standard requirements. After the penultimate pass and the last pass of hot rolling, solid solution and aging treatment are respectively performed. Solid solution treatment is beneficial to improving the processing performance of the alloy and during the solid solution process, the vacancy concentration of the alloy increases, which is beneficial to improving the resistivity. However, due to the increase in vacancy concentration, excess vacancies are generated. The excess vacancies themselves are highly unstable, resulting in an increase in vacancy mobility. Vacancies are annihilated due to diffusion during the migration process, and the annihilation of excess vacancies will cause the resistivity to decrease. Therefore, aging treatment is performed immediately after solid solution. During the rapid cooling process of the solid solution, the vacancies are eliminated before they have time to diffuse and annihilate, which is beneficial to retaining the high resistivity performance of the alloy and improving the resistance stability. After the last cold rolling, the temperature is immediately raised for solid solution treatment and then aging and annealing, which also utilizes the alloy characteristics and the above-mentioned principles to stabilize the high resistivity and low resistivity coefficient performance of the alloy.

[0129] Those skilled in the art will understand that the grain boundary movement accompanying the solution treatment will cause the grain size to gradually increase, and the increase in grain size will lead to an increase in the temperature coefficient of resistance. Therefore, the embodiment of the present invention finely proportions the alloy components and utilizes the interaction between the metals themselves to weaken or even eliminate the defects associated with the solution treatment, so that the metal foil prepared by the embodiment of the present invention retains a low temperature coefficient of resistance and has a high resistivity.

[0130] Those skilled in the art will understand that the preparation of foil is more difficult than that of strip, wire, and filament, and has higher requirements on process parameters and process conditions. The preparation method of the embodiment of the present invention has easy-to-operate preparation steps, is suitable for industrial production, and can stably produce foils of excellent quality.

[0131] The above is only a specific implementation of the invention, but the protection scope of the invention is not limited thereto. Those skilled in the art should understand that the invention includes but is not limited to the contents described in the above specific implementation. Any modification that does not deviate from the functional and structural principles of the invention will be included in the scope of the claims.

Claims

1. Precision resistance alloy foil, characterized by: It is composed of Cr, Al, Fe, W, Ti, Zr, Ce and Ni, wherein the mass percentage of each element is: 20.4-20.8% Cr, 2.4-2.8% Al, 1-2% Fe, 6.5-7.0% W, 4.2-4.7% Ti, 3.5-3.9% Zr, 0.2-0.6% Ce, and the balance is Ni.

2. The precision resistance alloy foil according to claim 1, characterized in that: The mass percentage of each element is: 20.6% Cr, 2.5% Al, 1.5-1.8% Fe, 6.6% W, 4.4-4.5% Ti, 3.6-3.7% Zr, 0.3-0.5% Ce, and the balance is Ni.

3. A method for preparing a precision resistance alloy foil, characterized in that: The following steps are involved: Step S1, preparing metal raw materials according to the composition and proportion described in claim 1 or 2; Step S2, melting and casting the prepared metal raw materials to obtain a cast alloy; Step S3, performing homogenization annealing treatment on the cast alloy, then performing surface treatment, and then performing three-way free forging to obtain a forged alloy; Step S4, performing surface treatment on the forged alloy to remove oxides on the alloy surface, and then performing multiple hot rolling passes, wherein the temperature of each hot rolling pass is higher than the temperature of the previous pass, and an annealing treatment is performed after each hot rolling pass. After the second-to-last hot rolling pass is completed, the forged alloy is successively subjected to a solution treatment and an aging treatment, and the second-to-last annealing treatment step is performed after the aging treatment; Step S5: After hot rolling is completed, the alloy is subjected to a solid solution treatment and an aging treatment in succession; Step S6: After aging is completed, multiple cold rolling passes are performed, and the temperature of each cold rolling pass is lower than the temperature of the previous pass; Step S7: After the cold rolling is completed, a solution treatment and an aging treatment are performed successively; Step S8: After the aging is completed, annealing treatment is performed to obtain a precision resistor alloy foil.

4. The method for preparing the precision resistance alloy foil according to claim 3, characterized in that: Step S1 also includes pre-treatment of the metal raw material for impurity removal. The specific method of the pre-treatment for impurity removal is: ultrasonic cleaning with deionized water, acid washing, alcohol washing, and finally drying for standby use.

5. The method for preparing the precision resistance alloy foil according to claim 3, characterized in that: In step S2, the specific method of smelting and casting treatment is: controlling the temperature at 1200-1300°C, stirring for a period of time after all the metal raw materials are melted, casting into a mold after standing, and then demolding by rapid cooling by water quenching to obtain a cast resistance alloy.

6. The method for preparing the precision resistance alloy foil according to claim 3, characterized in that: In step S3, the temperature of homogenization annealing is 960-1050° C., and the holding time is 2.5-3 h; and / or, The temperature of three-way free forging is 850-950℃, and the forging temperature is maintained for 2-2.5h after forging as incomplete annealing treatment.

7. The method for preparing the precision resistance alloy foil according to claim 3, characterized in that: In step S4, 5 hot rolling passes are performed, the deformation amount of the first hot rolling pass is 60-65%, and the deformation amount of each subsequent pass is reduced by 4-5%; the thickness of the material after hot rolling is 1.00-2.00 mm; the temperature of the first hot rolling pass is 800°C, and the temperature of each subsequent pass is increased by 50°C compared with the previous pass.

8. The method for preparing the precision resistance alloy foil according to claim 3, characterized in that: The solution treatment temperature in step S4, step S5 and step S7 is 900-950°C and maintained for 7-8h; the aging treatment temperature is 400-450°C and maintained for 0.4-0.6h.

9. The method for preparing the precision resistance alloy foil according to claim 3, characterized in that: In step S4, the annealing temperature is 450-550°C, maintained for 1-1.5 hours, and annealing is performed at the furnace temperature; in step S8, the annealing temperature is 300-350°C, maintained for 1-1.5 hours, and annealing is performed at the furnace temperature.

10. The method for preparing the precision resistance alloy foil according to claim 3, characterized in that: In step S6, three cold rolling passes are performed. The first cold rolling pass adopts an eight-roll rolling mill to roll the material into a sheet of 0.10-0.50 mm; the second cold rolling pass adopts a twenty-roll rolling mill to roll the material into a foil of 0.005-0.01 mm; the third cold rolling pass adopts a thirty-six-roll rolling mill to roll the material into a foil of 0.001-0.005 mm; the temperature of the first cold rolling pass is 400°C, and the temperature of each subsequent pass is reduced by 50°C compared with the previous pass.