A manganese-copper alloy material with stable resistance and preparation method thereof

Abstract

The invention discloses a manganese-copper alloy material with stable resistance and a preparation method thereof. The manganese-copper alloy comprises, by mass percentage, 11%-13% manganese, a copper balance, 0.5%-1.5% gallium, 0.3%-1% indium, and 0.05%-0.15% trace rare earth elements; a preparation method of a manganese-copper alloy material with stable resistance comprises the following steps: S1: premixing; S2: preforming; S3: smelting. The invention has the following advantages: refined and uniform mixing is achieved by using microchannels and the like to avoid component segregation; pulse current preforming is efficient and fast, and a boron nitride coating mold ensures the quality and density uniformity of the preformed block; an adaptive gas pressure control smelting system accurately controls the temperature, gas pressure and rate of each stage, monitors and adjusts in real time, promotes atomic diffusion and alloying, improves product quality and qualified rate, reduces scrap rate, and has both efficient and stable production characteristics and broad application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of alloy preparation, in particular to a manganese-copper alloy material with stable resistance and a preparation method thereof. Background Art

[0002] Manganese copper alloy has a low temperature coefficient of resistance and is widely used in electronic components such as precision resistors, standard resistors, strain gauges, etc.

[0003] However, the traditional preparation method of manganese-copper alloy still has certain limitations in improving resistance stability and reducing costs. For example, it is difficult to accurately control the uniform distribution of alloy elements in conventional smelting processes, resulting in fluctuations in alloy properties; although some special processes can improve performance, the cost is too high and is not conducive to large-scale production.

[0004] Therefore, it is necessary to propose a manganese-copper alloy material with stable resistance and a preparation method thereof to improve the resistance stability performance of the manganese-copper alloy. Summary of the invention

[0005] The present invention provides a manganese-copper alloy material with stable resistance and a preparation method thereof, which solves the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A manganese-copper alloy material with stable resistance, the manganese-copper alloy comprising, by mass percentage: 11%-13% manganese, the remainder copper, 0.5%-1.5% gallium, 0.3%-1% indium, and 0.05%-0.15% trace rare earth elements;

[0008] As a preferred technical solution of the present invention, the trace rare earth elements include cerium, lanthanum, neodymium and praseodymium.

[0009] A method for preparing a manganese-copper alloy material with stable resistance comprises the following steps:

[0010] S1: premixed;

[0011] Manganese powder, copper powder and at least one additional element powder selected from gallium powder, indium powder and rare earth element powder are respectively made into suspensions, the solvent of the suspension is an organic solvent, and the mass concentration of the metal powder in the suspension is 10-50%; mixing is performed through a microfluidic chip system, the microfluidic chip comprises a plurality of microchannels with a diameter of 10-100 microns, different suspensions are injected into the microchannels through a micropump at a flow rate of 0.1-1 ml / min, the hydrophilic coating on the wall of the microchannel and a micro-vortex generator are used to enhance the collision and dispersion of the powders, and the organic solvent is removed after mixing to obtain a preliminary mixed powder;

[0012] S2: preforming;

[0013] The preliminary mixed powder is placed in a special conductive mold, and a pulse current is applied to both ends of the mold, wherein the peak current of the pulse current is between 100-1000 amperes, the pulse width is 1-10 milliseconds, and the pulse frequency is 1-100 Hz, so that the surface of the powder particles is partially melted and rearranged and compacted under the action of electromagnetic force to form a preformed block;

[0014] S3: smelting;

[0015] First, the melting furnace is preheated and filled with argon gas. Then the preformed block is slowly added into the melting furnace and heated by induction heating. During the heating process, the air pressure in the melting furnace is gradually reduced by the adaptive air pressure control melting system until a vacuum state is formed in the melting furnace. The atomic diffusion between the powder particles is intensified, and a metallurgical bond is gradually formed to finally obtain a manganese-copper alloy.

[0016] As a preferred technical solution of the present invention, in step S1, the organic solvent is ethanol, and the metal powder is made into a suspension and then ultrasonically dispersed using an ultrasonic disperser, the ultrasonic power is 100-300 watts, and the ultrasonic time is 10-30 minutes.

[0017] As a preferred technical solution of the present invention, the inner wall of the specially made conductive mold is coated with a boron nitride coating with a thickness of 5-15 microns. The coating can reduce the adhesion of the powder to the mold when the pulse current is applied, improve the surface quality of the preformed block, and control the density uniformity deviation of the preformed block within 3%, which is beneficial to the uniform diffusion and alloying of elements in the subsequent smelting process.

[0018] As a preferred technical solution of the present invention, the adaptive gas pressure control smelting system comprises the following steps:

[0019] Step 1: Data collection and initialization;

[0020] A temperature sensor and a pressure sensor are installed in the melting furnace to collect data of the temperature T and the air pressure P in the furnace in real time and transmit the data to the control system; the initial temperature T0, the initial air pressure P0, the target final air pressure Pf and the melting point Tm of the alloy are set when the preformed block is placed in the melting furnace;

[0021] Step 2: low temperature and low pressure preheating;

[0022] Set the target temperature T1 and target air pressure P1 for the first stage; calculate the temperature rise rate r1=(T1-T0) / t1, where t1 is the estimated time for the first stage; calculate the air pressure drop rate s1=(P0-P1) / t1; the control system controls the induction heating power and the vacuum pump exhaust rate according to r1 and s1, monitors T and P in real time, ensures that the temperature rises at a rate close to r1, and the air pressure drops at a rate close to s1, and enters the next stage when T reaches T1 and P reaches P1;

[0023] Step 3: Medium temperature and pressure reduction stage;

[0024] Set the target temperature T2 and target air pressure P2 for the second stage; calculate the temperature rise rate r2=(T2-T1) / t2, where t2 is the estimated time for the second stage; calculate the air pressure drop rate s2=(P1-P2) / t2; the control system adjusts the heating and exhaust parameters according to r2 and s2, and continuously monitors T and P until T reaches T2 and P reaches P2;

[0025] Step 4: High temperature vacuum stage;

[0026] Set the target temperature T3 and target gas pressure P3 of the third stage; calculate the temperature rise rate r3=(T3-T2) / t3, where t3 is the estimated time of the third stage; calculate the gas pressure drop rate s3=(P2-P3) / t3; the control system strongly increases the heating power and speeds up the exhaust speed according to r3 and s3, closely monitors T and P, and when T reaches T3 and P reaches P3, the smelting process is completed and this high-temperature vacuum state is maintained for a period of time.

[0027] As a preferred technical solution of the present invention, if the temperature rise rate deviates from the set value by more than ±1°C / min, the control system adjusts the induction heating power accordingly; if the air pressure drop rate is abnormal, the control system adjusts the vacuum pump operating parameters.

[0028] As a preferred technical solution of the present invention, in the first stage, the value range of t1 is 50-70 minutes, the value range of T1 is 300-400°C, and the value range of P1 is 60-90 kPa.

[0029] As a preferred technical solution of the present invention, in the second stage, t2 is in the range of 30-50 minutes, T2 is in the range of 600-700°C, and P2 is in the range of 20-40 kPa.

[0030] As a preferred technical solution of the present invention, in the third stage, the value range of t3 is 20-40 minutes, the value range of T3 is Tm+50-100°C, and the value range of P3 is - kPa.

[0031] The present invention has the following advantages: in terms of alloy performance, precise composition design (manganese 11%-13%, copper balance, gallium 0.5%-1.5%, indium 0.3%-1%, trace rare earth elements 0.05%-0.15% and containing cerium, lanthanum, neodymium, praseodymium) makes each element work together to ensure excellent resistance stability and reduce the influence of external factors on resistance, which is suitable for the field of precision electronics; at the same time, trace rare earth elements refine the grains, gallium and indium optimize the structure, give good comprehensive mechanical properties, and enhance fatigue resistance and wear resistance. In terms of preparation technology, the microfluidic chip system premixes, and uses microchannels to achieve refined and uniform mixing to avoid component segregation; pulse current preforming is efficient and fast, and the boron nitride coating mold ensures the quality and density uniformity of the preformed block; the adaptive air pressure control smelting system accurately controls the temperature, air pressure and rate of each stage, monitors and adjusts in real time, promotes atomic diffusion and alloying, improves product quality and qualified rate, and reduces the scrap rate, which has both efficient and stable production characteristics and broad application prospects. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention are described below. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0033] Example 1

[0034] Alloy composition: manganese 11%, copper 87.4%, gallium 0.5%, indium 0.3%, trace rare earth elements (cerium 0.05%, lanthanum 0.05%, neodymium 0.03%, praseodymium 0.02%).

[0035] Preparation method:

[0036] S1: Premixed

[0037] Manganese powder, copper powder, gallium powder, indium powder and mixed rare earth element powder were made into suspensions respectively, the solvent was ethanol, and the mass concentration of metal powder was 10%. Ultrasonic dispersion was performed at 100 watts for 10 minutes. Mixing was performed through a microfluidic chip system, the microchannel diameter was 10 microns, and different suspensions were injected into the microchannel at a flow rate of 0.1 ml / min. After mixing, ethanol was removed to obtain a preliminary mixed powder.

[0038] S2: Preform

[0039] The preliminary mixed powder is placed in a special conductive mold with an inner wall coated with a 5-micron boron nitride coating, and a pulse current is applied to both ends of the mold with a peak current of 100 amperes, a pulse width of 1 millisecond, and a pulse frequency of 1 Hz to form a preformed block.

[0040] S3: Smelting

[0041] Preheat the melting furnace and fill it with argon. Slowly add the preformed block into the melting furnace and use induction heating.

[0042] Low temperature and low pressure preheating: t1=50 minutes, T1=300℃, P1=60kPa, calculate and control the temperature rise rate and pressure drop rate for preheating.

[0043] Medium temperature and pressure reduction stage: t2=30 minutes, T2=600℃, P2=20kPa, adjust the parameters according to the corresponding rate.

[0044] High temperature vacuum stage: t3 = 20 minutes, T3 = Tm + 50 ° C (assuming the alloy melting point Tm is 1000 ° C, then T3 = 1050 ° C), P3 = kPa, complete melting and maintain high temperature vacuum state.

[0045] Example 2

[0046] Alloy composition: manganese 12%, copper 86.1%, gallium 1%, indium 0.6%, trace rare earth elements (cerium 0.06%, lanthanum 0.04%, neodymium 0.03%, praseodymium 0.02%).

[0047] Preparation method:

[0048] S1: Premixed

[0049] The metal powder is made into a suspension, the solvent is ethanol, the mass concentration is 30%, and the ultrasonic dispersion instrument is ultrasonicated at 200 watts for 20 minutes. The microchannel diameter of the microfluidic chip is 50 microns, the flow rate is 0.5 ml / min, and the ethanol is removed after mixing to obtain a preliminary mixed powder.

[0050] S2: Preform

[0051] Conductive mold boron nitride coating 10 microns, pulse current peak 500 amperes, pulse width 5 milliseconds, frequency 50 Hz.

[0052] S3: Smelting

[0053] Low temperature and low pressure preheating: t1=60 minutes, T1=350℃, P1=75kPa.

[0054] Medium temperature and pressure reduction stage: t2=40 minutes, T2=650℃, P2=30kPa.

[0055] High temperature vacuum stage: t3 = 30 minutes, T3 = Tm + 75 °C (assuming Tm = 1000 °C, then T3 = 1075 °C), P3 = 5 × kPa.

[0056] Example 3

[0057] Alloy composition: manganese 13%, copper 85.3%, gallium 1.5%, indium 1%, trace rare earth elements (cerium 0.08%, lanthanum 0.03%, neodymium 0.02%, praseodymium 0.02%).

[0058] Preparation method:

[0059] S1: Premixed

[0060] The suspension solvent was ethanol, the metal powder concentration was 50%, and the ultrasound was performed at 300 W for 30 minutes. The microchannel diameter was 100 μm, the flow rate was 1 ml / min, and the ethanol was removed by mixing.

[0061] S2: Preform

[0062] The die coating was 15 microns, the pulse current parameters were 1000 amperes peak, 10 milliseconds pulse width, and 100 Hz frequency.

[0063] S3: Smelting

[0064] Low temperature and low pressure preheating: t1=70 minutes, T1=400℃, P1=90kPa.

[0065] Medium temperature and pressure reduction stage: t2=50 minutes, T2=700℃, P2=40kPa.

[0066] High temperature vacuum stage: t3 = 40 minutes, T3 = Tm + 100 ° C (assuming Tm = 1000 ° C, then T3 = 1100 ° C), P3 = kPa.

[0067] Example 4

[0068] Alloy composition: manganese 11.5%, copper 87%, gallium 0.8%, indium 0.4%, trace rare earth elements (cerium 0.07%, lanthanum 0.03%, neodymium 0.03%, praseodymium 0.02%).

[0069] Preparation method:

[0070] S1: Premixed

[0071] Ethanol was used as solvent, metal powder concentration was 20%, ultrasound was performed at 150 watts for 15 minutes, microchannel was 30 microns, flow rate was 0.3 ml / min, and ethanol was removed after mixing.

[0072] S2: Preform

[0073] The conductive mold coating is 8 microns, the pulse current peak is 300 amperes, the pulse width is 3 milliseconds, and the frequency is 30 Hz.

[0074] S3: Smelting

[0075] Low temperature and low pressure preheating: t1=55 minutes, T1=320℃, P1=70kPa.

[0076] Medium temperature and pressure reduction stage: t2=35 minutes, T2=620℃, P2=25kPa.

[0077] High temperature vacuum stage: t3 = 25 minutes, T3 = Tm + 60 ° C (assuming Tm = 1000 ° C, then T3 = 1060 ° C), P3 = 3 × kPa.

[0078] Example 5

[0079] Alloy composition: manganese 12.5%, copper 86%, gallium 1.2%, indium 0.8%, trace rare earth elements (cerium 0.1%, lanthanum 0.02%, neodymium 0.02%, praseodymium 0.01%).

[0080] Preparation method:

[0081] S1: Premixed

[0082] The suspension was prepared with ethanol as solvent, the metal powder mass concentration was 40%, and the ultrasonic dispersion instrument was ultrasonicated at 250 watts for 25 minutes. The microfluidic chip system was used for mixing, the microchannel diameter was 80 microns, and different suspensions were injected into the microchannel at a flow rate of 0.8 ml / min. After mixing, the organic solvent was removed to obtain a preliminary mixed powder.

[0083] S2: Preform

[0084] The preliminary mixed powder is placed in a special conductive mold, the inner wall of which is coated with a 12-micron-thick boron nitride coating. A pulse current is applied to both ends of the mold, with a peak current of 800 amperes, a pulse width of 8 milliseconds, and a pulse frequency of 80 Hz, so that the surface of the powder particles is partially melted and rearranged and compacted under the action of electromagnetic force to form a preformed block.

[0085] S3: Smelting

[0086] First, the melting furnace is preheated, argon gas is filled into the melting furnace, and then the preformed block is slowly added into the melting furnace and heated by induction heating.

[0087] Low temperature and low pressure preheating: t1=65 minutes, T1=380℃, P1=80kPa, accurately control the temperature rise rate and pressure drop rate to ensure that the temperature and pressure change according to the set values.

[0088] Medium temperature depressurization stage: t2=45 minutes, T2=680℃, P2=35kPa, closely monitor and adjust parameters.

[0089] High temperature vacuum stage: t3 = 35 minutes, T3 = Tm + 90 ° C (assuming the alloy melting point Tm is 1000 ° C, then T3 = 1090 ° C), P3 = 8 × kPa, and maintain high temperature vacuum state for a period of time after smelting to promote further improvement of alloy uniformity and stability.

[0090] The following table shows the data of the alloy materials obtained in the above five embodiments:

[0091]

[0092] By comparing the above multiple embodiments, it can be seen that embodiment 5 is the best embodiment. In embodiment 5, the alloy composition ratio is closer to the ideal state, and the synergistic effect of each element is better. In the preparation process, the parameter setting of the premixing step can make the metal powder mix more uniformly, the preforming conditions can effectively improve the quality of the preformed block, and the parameters of each stage of the smelting process are accurately controlled, so that the stability and controllability of the entire preparation process are better, and the manganese-copper alloy finally obtained has better resistance stability and the best comprehensive performance.

Claims

1. A manganese-copper alloy material with stable resistance, characterized in that: The manganese-copper alloy contains, by mass percentage: 11%-13% manganese, the remainder copper, 0.5%-1.5% gallium, 0.3%-1% indium, and 0.05%-0.15% trace rare earth elements, wherein the trace rare earth elements are cerium, lanthanum, neodymium, and praseodymium; The preparation of the manganese-copper alloy material with stable resistance comprises the following steps: S1: premixed; Manganese powder, copper powder, gallium powder, indium powder and rare earth element metal powder are respectively made into suspensions, the solvent of the suspensions is an organic solvent, and the mass concentration of the metal powder in the suspensions is 10-50%; mixing is performed through a microfluidic chip system, the microfluidic chip comprises a plurality of microchannels with a diameter of 10-100 microns, different suspensions are injected into the microchannels through a micropump at a flow rate of 0.1-1 ml / min, the hydrophilic coating on the wall of the microchannel and a micro-vortex generator are used to enhance the collision and dispersion of the powders, and the organic solvent is removed after mixing to obtain a preliminary mixed powder; S2: preforming; The preliminary mixed powder is placed in a conductive mold, the inner wall of which is coated with a layer of boron nitride coating, and a pulse current is applied to both ends of the mold, wherein the peak current of the pulse current is between 100-1000 amperes, the pulse width is 1-10 milliseconds, and the pulse frequency is 1-100 Hz, so that the surface of the powder particles is partially melted and rearranged and compacted under the action of electromagnetic force to form a preformed block; S3: smelting; First, the melting furnace is preheated and filled with argon gas. Then the preformed block is slowly added into the melting furnace and heated by induction heating. During the heating process, the air pressure in the melting furnace is gradually reduced by the adaptive air pressure control melting system until a vacuum state is formed in the melting furnace. The atomic diffusion between the powder particles is intensified, and a metallurgical bond is gradually formed to finally obtain a manganese-copper alloy.

2. The manganese-copper alloy material with stable resistance according to claim 1, characterized in that: In step S1, the organic solvent is ethanol, and the metal powder is made into a suspension and then subjected to ultrasonic dispersion treatment using an ultrasonic disperser, with an ultrasonic power of 100-300 watts and an ultrasonic time of 10-30 minutes.

3. The manganese-copper alloy material with stable resistance according to claim 1, characterized in that: The thickness of the boron nitride coating on the inner wall of the conductive mold is 5-15 microns.

4. The manganese-copper alloy material with stable resistance according to claim 1, characterized in that: The adaptive gas pressure control smelting system comprises the following steps: Step 1: Data collection and initialization; A temperature sensor and a pressure sensor are installed in the melting furnace to collect data of the temperature T and the air pressure P in the furnace in real time and transmit the data to the control system; the initial temperature T0, the initial air pressure P0, the target final air pressure Pf and the melting point Tm of the alloy are set when the preformed block is placed in the melting furnace; Step 2: low temperature and low pressure preheating; Set the target temperature T1 and target air pressure P1 for the first stage; calculate the temperature rise rate r1=(T1-T0) / t1, where t1 is the estimated time for the first stage; calculate the air pressure drop rate s1=(P0-P1) / t1; the control system controls the induction heating power and the vacuum pump exhaust rate according to r1 and s1, monitors T and P in real time, ensures that the temperature rises at the rate of r1 and the air pressure drops at the rate of s1, and enters the next stage when T reaches T1 and P reaches P1; Step 3: Medium temperature and pressure reduction stage; Set the target temperature T2 and target air pressure P2 for the second stage; calculate the temperature rise rate r2=(T2-T1) / t2, where t2 is the estimated time for the second stage; calculate the air pressure drop rate s2=(P1-P2) / t2; the control system adjusts the heating and exhaust parameters according to r2 and s2, and continuously monitors T and P until T reaches T2 and P reaches P2; Step 4: High temperature vacuum stage; Set the target temperature T3 and target gas pressure P3 of the third stage; calculate the temperature rise rate r3=(T3-T2) / t3, where t3 is the estimated time of the third stage; calculate the gas pressure drop rate s3=(P2-P3) / t3; the control system strongly increases the heating power and speeds up the exhaust speed according to r3 and s3, closely monitors T and P, and when T reaches T3 and P reaches P3, the smelting process is completed and this high-temperature vacuum state is maintained for a period of time.

5. The manganese-copper alloy material with stable electrical resistance according to claim 4, characterized in that: If the temperature rise rate deviates from the set value by more than ±1℃ / min, the control system will adjust the induction heating power accordingly; if the air pressure drop rate is abnormal, the control system will adjust the vacuum pump working parameters.

6. The manganese-copper alloy material with stable electrical resistance according to claim 4, characterized in that: In the first stage, t1 is in the range of 50-70 minutes, T1 is in the range of 300-400°C, and P1 is in the range of 60-90 kPa.

7. The manganese-copper alloy material with stable electrical resistance according to claim 4, characterized in that: In the second stage, t2 is in the range of 30-50 minutes, T2 is in the range of 600-700°C, and P2 is in the range of 20-40 kPa.

8. The manganese-copper alloy material with stable electrical resistance according to claim 4, characterized in that: In the third stage, the range of t3 is 20-40 minutes, the range of T3 is Tm+50-100°C, and the range of P3 is - kPa.

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