Multi-channel high-precision resistance temperature coefficient testing system and method

Abstract

The invention provides a multi-channel high-precision resistance temperature coefficient test system and method, and the system comprises a vacuum system module which is used for a vacuum test environment, a temperature control heating module which is a heating device with programmable temperature control, and a multi-channel test module which comprises a resistance tester, a multi-channel acquisition card and a connection interface, the multi-channel acquisition card is connected with the resistance tester through an interface, the multi-channel acquisition card is connected with the aviation plug through a test line, the aviation plug is detachably connected with a sample to be tested through the test line, and the temperature monitoring module adopts a thermocouple to test temperature. The data acquisition terminal records and processes multichannel resistance values and corresponding temperature data in real time, the sample table module is used for placing multichannel test samples and is placed in the temperature control heating module, and a sample table adopts an aluminum-based PCB (printed circuit board) or a copper-based PCB subjected to aluminum nitride ceramic or insulation treatment and can bear at least two test samples at the same time.

Description

Technical Field

[0001] This invention belongs to the field of testing technology, and in particular relates to a multi-channel high-precision resistance temperature coefficient testing system and method. Background Technology

[0002] In fields such as energy, power, aerospace, electronics manufacturing, and new energy, the resistivity of metal conductors under high-temperature environments directly affects the safety and operational efficiency of systems. As power transmission evolves towards high voltage and high capacity, cable conductors experience significant temperature rises due to the Joule effect under long-term current-carrying conditions. This resistance change not only increases transmission losses but may also accelerate insulation aging and even induce short circuits and other safety hazards. In the aerospace field, metal conductors in aero-engines and spacecraft thermal protection systems must maintain stable conductivity at extreme temperatures ranging from hundreds to thousands of degrees Celsius. Their temperature coefficient of resistance (TCR) is a key parameter for evaluating the reliability of thermal control systems and the rationality of circuit design. Furthermore, the metal connectors in new energy devices (such as fuel cells and power batteries) experience temperature rises due to current loads during charging and discharging, and the resulting resistance changes directly affect energy conversion efficiency and cycle life. Therefore, accurately measuring the resistance changes of metallic materials over a wide temperature range (especially in high-temperature environments) is crucial for materials research and development (such as high-temperature alloy design and surface modification process optimization), equipment condition monitoring, and safety assessment. It is one of the core technologies driving energy technology upgrades and high-end equipment manufacturing.

[0003] Currently, testing techniques for the resistance-temperature characteristics of metallic materials, both domestically and internationally, still have certain limitations. For example:

[0004] Publication No. CN101021502A (Low-Temperature Resistance Temperature Coefficient Testing Device) proposes a testing scheme applicable to the temperature range of -196℃ to 200℃, but it requires welding to fix the sample, making non-destructive testing impossible, and the upper limit of the temperature range is relatively low, making it difficult to meet the needs of high-temperature applications. Publication No. CN108362743A (Low-Temperature Resistivity Measuring Device) adopts a mechanical clamping sample fixing structure, which can achieve low-temperature resistivity testing, but sample replacement is cumbersome, and it cannot be extended to the temperature range above room temperature, resulting in low testing efficiency. Authorized announcement No. CN219369636U (Variable Temperature Resistivity Testing Device) covers the temperature range of 80K to 700K through the design of a vacuum chamber and a liquid nitrogen chamber, supporting non-destructive testing of thin film samples, but it can only test one sample at a time, making it difficult to meet the needs of batch testing. Authorized announcement No. CN218727627U (High-Temperature Resistivity Tester for Piezoelectric Crystals) uses an electrometer as the measurement core, which solves the problem of weak signal detection at high temperatures, but the high input impedance of the electrometer ( Its characteristics make it only suitable for measuring extremely high resistance values ​​of insulators or semiconductors, while the low resistance characteristics of metallic conductors (typically...) This can lead to measurement failure or even equipment damage. Summary of the Invention

[0005] To address the above technical problems, this invention provides a multi-channel high-precision resistance temperature coefficient testing system and method, the specific technical solution of which is as follows:

[0006] A multi-channel high-precision resistance temperature coefficient testing system includes: a vacuum system module, a temperature control and heating module, a sample stage module, a multi-channel testing module, a temperature monitoring module, and a data acquisition terminal;

[0007] The vacuum system module is connected to the temperature control heating module to provide a vacuum testing environment for the temperature control heating module.

[0008] The temperature-controlled heating module is used to heat the sample to be tested;

[0009] The multi-channel test module is used to measure the resistance and voltage of the sample;

[0010] The temperature monitoring module is located inside the temperature control heating module and is used to measure the temperature;

[0011] The data acquisition terminal is used to record and process multi-channel resistance values ​​and corresponding temperature data in real time;

[0012] The sample stage module is used to place multiple test samples. It is placed in the temperature-controlled heating module and can support no less than two test samples at the same time.

[0013] A multi-channel, high-precision method for measuring the temperature coefficient of resistance includes the following steps:

[0014] S1. Sample mounting: Fix multiple test samples at equal intervals on the sample stage to ensure that each sample forms ohmic contact with the test electrode;

[0015] S2. System vacuuming: Start the vacuum pump to bring the test chamber to the set vacuum level;

[0016] S3. Programmed heating: Heats up at a set rate, holds at the set temperature for a certain time, and simultaneously collects the resistance value and corresponding temperature of each channel;

[0017] S4. Data Processing: Calculate the resistivity of the sample under test based on the resistance values ​​R obtained from tests at different stable temperatures. , S is the cross-sectional area of ​​the sample to be tested. The length of the sample to be tested is then used to plot the RT curve or Curves were generated, and the temperature coefficient of resistance for each sample was calculated.

[0018] or ;

[0019] in, The resistance is obtained from the temperature T2 test. The resistivity is obtained from the temperature T2 test. The resistance is obtained from the test at temperature T1. The resistivity is obtained from the test at temperature T1.

[0020] The present invention has the following beneficial effects:

[0021] This invention enables parallel, non-destructive testing of the resistance of multiple metal samples as a function of temperature over a wide temperature range, filling the technical gap in the accurate characterization of the resistance characteristics of metal wires under high-temperature conditions and providing reliable data support for materials research and engineering applications. Attached Figure Description

[0022] Figure 1 This is a structural diagram of a multi-channel high-precision resistance temperature coefficient testing system according to the present invention;

[0023] Figure 2 This is a schematic diagram of the aluminum nitride sample stage structure used in Example 1;

[0024] Figure 3 This is a schematic diagram of the structure of the alumina dispersion-strengthened copper fixture used in Example 1;

[0025] Figure 4(a) is a top view of the sample stage, sample, and test fixture assembly used in Example 1;

[0026] Figure 4(b) is a bottom view of the sample stage, sample, and test fixture assembly used in Example 1;

[0027] Figure 5 This is a schematic diagram of the test fixture and sample assembly used in Example 1;

[0028] Figure 6 The resistivity of pure copper (Cu) and copper / graphene (Cu / Gr) samples obtained in Example 1 changes with temperature.

[0029] Figure 7 This is a schematic diagram of the aluminum-based PCB board used in Example 2;

[0030] Figure 8 This is a schematic diagram of the stainless steel plate used in Example 2;

[0031] Figure 9 The graph shows the resistivity of pure copper (Cu) and copper / graphene (Cu / Gr) samples obtained in Example 2 as a function of temperature. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other. To achieve the above objectives, this invention adopts the following technical solution.

[0033] Example 1:

[0034] like Figure 1 As shown, this invention provides a multi-channel high-precision resistance temperature coefficient testing system, including a vacuum system module, a temperature control and heating module, a sample stage module, a multi-channel testing module, a temperature monitoring module, and a data acquisition terminal. The temperature control and heating module uses a tubular heat treatment furnace for heating and placing the sample to be tested. The vacuum system module is a molecular pump unit, including a mechanical pump and a molecular pump, connected to the furnace tubes of the tubular heat treatment furnace via flanges and bellows, providing a high vacuum environment for the furnace. The multi-channel testing module includes a high-precision resistance meter, a multi-channel acquisition card, and connection ports. One end of the multi-channel acquisition card is inserted into the corresponding connection interface on the back of the high-precision resistance meter, and the other end is connected to one end of an external connection cable via soldering. The other end of the external connection cable is connected to one end of an aviation connector via soldering. Internal test leads are soldered to the corresponding position on the other end of the aviation connector. The internal test leads are made of copper wire with an outer PTFE insulation layer. The other end of the internal test leads is fixed to a dispersion-strengthened copper alloy clamp with screws. The aviation-grade connector is connected and fixed to the furnace tube of the tubular heat treatment furnace via a custom-shaped vacuum flange. The internal test leads, fixtures, and sample stage module are housed inside the furnace tube. The sample stage module is made of aluminum nitride ceramic plate, such as... Figure 2 As shown, the aluminum nitride ceramic plate has four sets of slots on its surface that match the size of the sample to be tested. These slots are used to place the sample, ensuring it remains straight and preventing inaccurate test data due to measurement length errors. The bottom of the aluminum nitride ceramic plate has holes from the edge to the center for placing thermocouples. The thermocouple test leads are inserted into these holes, forming a thermal coupling connection between the thermocouple test leads and the sample stage module. The thermocouple terminals are soldered to one end of an aviation connector, and the other end of the corresponding aviation connector is connected to the data acquisition terminal. The shape of the test fixture is as follows... Figure 3 As shown in Figure 4, the assembly diagram of the aluminum nitride ceramic plate, sample, test fixture, and internal test lines is as follows: Figure 5 As shown. Each sample corresponds to a set of voltage test terminals in the test fixture (e.g., ...). Figure 3 (as shown in (a)) and a set of current test terminals (as shown in (a)) Figure 3As shown in (b), the current test terminal is located on the outside, and the voltage test terminal is located on the inside. The test sample is pressed against the test terminal by screws. The other end of the clamp is connected to the internal test lead by screws. The contact area between the voltage test terminal and the test sample is designed in a knife-edge shape (e.g., ...). Figure 3 As shown in (a), the purpose is to ensure that the length of the sample under test can be accurately measured. During the test, the resistance tester obtains the resistance value by measuring the voltage and current corresponding to each sample, and the thermocouple measures the corresponding real-time temperature; both are output as resistance values ​​and corresponding temperatures through a connected data acquisition terminal. After each test, there is no need to disassemble the internal test leads and test fixtures; simply loosen the screws fixing the sample on the test fixture to remove the sample. The specific test steps are as follows:

[0035] (1) Sample installation: Place the sample in the slot of the aluminum nitride sample stage, fix the test fixture in the corresponding test position, and maintain close contact between the fixture and the sample by adjusting the screws. The connection of a single sample is as follows: Figure 5 As shown in Figure 4(a) and Figure 4(b), connect the four sets of samples to the sample stage, test fixture and test wires, insert the thermocouple into the temperature measuring hole, and finally put the sample stage module, internal test wires and thermocouple into the temperature control heating module, i.e., the tube furnace.

[0036] (2) System vacuuming: Connect the irregular vacuum flange and the vacuum system connection flange to the furnace tube of the tube furnace using vacuum flange bolts. Start the vacuum system, first use the mechanical pump to evacuate to a low vacuum of less than 5 Pa, and then turn on the molecular pump to evacuate to a vacuum level better than 5 Pa. ;

[0037] (3) Programmed heating: Set the heating program to heat from room temperature to the test point at a heating rate of 5K / min, and hold the test point at that temperature for 30min. For example, the test point holding temperatures are: room temperature, 50℃, 75℃, 100℃, 125℃, 150℃, 175℃, 200℃, and 250℃. Simultaneously collect the resistance values ​​and corresponding temperatures of each channel; both temperature and resistance values ​​are set to collect one data point every 1min.

[0038] (4) Data processing: Considering temperature fluctuations, the average value of all data during the heat preservation stage was calculated. Then, the RT curve was plotted based on the resistance value corresponding to the stable temperature, and the temperature coefficient of resistance of each sample was calculated.

[0039] ;

[0040] in, The resistance is obtained from the temperature T2 test. The resistance is obtained from the temperature test at T1. Alternatively, it can be determined using the formula... Calculate the resistivity of the sample to be tested and plot the resistivity as a function of temperature. Figure 6 ), where S is the cross-sectional area of ​​the sample to be tested, The length of the sample to be tested.

[0041] Example 2:

[0042] The sample stage uses an aluminum-based PCB board, such as Figure 7 As shown, the board surface has two sets of test pads, with pad spacing compatible with standard SMD package sizes. To support the internal test leads (Class C enameled copper wire) and the aluminum-based PCB, a stainless steel support plate is welded inside the irregularly shaped vacuum flange. This support plate features enameled wire slots and PCB positioning holes for securing the enameled wires and the PCB. The PCB and internal test leads are located on either side of the support plate, which is made of 304 stainless steel. The structural diagrams of the sample stage PCB and support plate are shown below. Figure 7 and Figure 8 As shown. One end of the internal test lead is securely soldered to the test pads on the PCB board using high-temperature resistant solder, and the other end is securely soldered to the aviation connector. The internal voltage and current test leads for each sample are connected to their corresponding voltage and current test lead pads via soldering. The test sample and test pins are fixed in place with insulating screws and washers to ensure tight contact. The thermocouple is inserted into the temperature sensing hole on the PCB board. The specific test steps are as follows:

[0043] (1) Sample mounting: Place the sample on the PCB board so that the test sample and the test pin have sufficient contact area. Adjust the insulating screws and shims to maintain good contact between the test pin and the sample under test.

[0044] (2) System vacuuming: Connect the irregular vacuum flange and other vacuum flanges to the furnace tube using vacuum flange bolts, start the vacuum system, first use the mechanical pump to evacuate to a low vacuum of less than 5 Pa, and then turn on the molecular pump to evacuate to a vacuum level of 100%. ;

[0045] (3) Programmed heating: Set the heating program to heat from room temperature to the test point at a heating rate of 5K / min, and hold the test point at that temperature for 30min. For example, the test point holding temperatures are: room temperature, 50℃, 75℃, 100℃, 125℃, 150℃, 180℃, and 210℃. Simultaneously collect the resistance values ​​and corresponding temperatures of each channel; both temperature and resistance values ​​are set to collect one data point every 1min.

[0046] (4) Data processing: Considering temperature fluctuations, the average value of all data during the heat preservation stage was calculated. Then, the RT curve was plotted based on the resistance value corresponding to the stable temperature, and the temperature coefficient of resistance of each sample was calculated. :

[0047] ;

[0048] in, R1 is the sample resistance value at temperature T2, where T2 is the sample resistance value at temperature T1. Alternatively, it can be determined using the formula... Calculate the resistivity and temperature coefficient of resistivity of the sample to be tested, where S is the cross-sectional area of ​​the sample and l is the length of the sample. By testing annealed pure copper (Cu) and copper / graphene (Cu / Gr) samples, the temperature coefficients of resistivity are 0.004 / ℃ and 0.0039 / ℃, respectively. The resistivity changes with temperature as shown in the following figures. Figure 9 As shown.

Claims

1. A multi-channel high-precision resistance temperature coefficient testing system, characterized in that, include: Vacuum system module, temperature control and heating module, sample stage module, multi-channel testing module, temperature monitoring module, and data acquisition terminal; The vacuum system module is connected to the temperature control heating module to provide a vacuum testing environment for the temperature control heating module. The temperature-controlled heating module is used to heat the sample to be tested; The multi-channel test module is used to measure the resistance of the sample; The temperature monitoring module is located inside the temperature control heating module and is used to measure the temperature; The data acquisition terminal is connected to the multi-channel test module and the temperature monitoring module to record and process multi-channel resistance values ​​and corresponding temperature data in real time. The sample stage module is used to place multiple test samples. It is placed in the temperature-controlled heating module and can support no less than two test samples at the same time.

2. The system according to claim 1, characterized in that, The vacuum system module includes a vacuum pump, a bellows, and a vacuum flange. The vacuum pump is connected to the temperature-controlled heating device through the bellows and the vacuum flange.

3. The system according to claim 1, characterized in that, The temperature control heating module adopts a programmable temperature control heating device, which is selected from one of a tubular furnace, a muffle furnace, or an oven.

4. The system according to claim 1, characterized in that, The multi-channel test module includes a resistance tester, a multi-channel acquisition card, and a connection interface. The multi-channel acquisition card is connected to the resistance tester through the interface, and the multi-channel acquisition card is connected to an aviation connector via external test leads. The aviation connector is detachably connected to the sample under test via internal test leads.

5. The system according to claim 1, characterized in that, The sample stage shown is made of aluminum nitride ceramic or an insulated aluminum-based PCB or copper-based PCB.

6. The system according to claim 4, characterized in that, The resistance tester has a measurement range of: precision The multi-channel acquisition card supports 1-8 channel parallel measurements. Aviation connectors use gold-plated contacts, resulting in low contact resistance. .

7. The system according to claim 5, characterized in that, When aluminum nitride ceramic is used, equally spaced test positions are set on the surface, and each test position is equipped with a copper alloy test fixture; when aluminum-based PCB board or copper-based PCB board is used, gold-plated test pads and test pins are arranged on the board surface.

8. The system according to claim 4, characterized in that, The test fixture is made of CuCrZr alloy or alumina dispersion-strengthened copper alloy with a softening temperature ≥300℃; the fixture is fixed to the internal test lines with screws.

9. The system according to claim 1, characterized in that, The temperature monitoring module uses a thermocouple, and the thermocouple measuring end is thermally coupled to the sample stage. The thermocouple is located in the middle of the sample stage.

10. A multi-channel high-precision resistance temperature coefficient testing method using the system described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Sample mounting: Fix multiple samples to be tested on the sample stage, ensuring that each sample is in close contact with the test electrode; S2. System vacuuming: Start the vacuum pump to bring the test chamber to the set vacuum level; S3. Programmed heating: Heats up at a set rate, holds at the set temperature for a certain time, and simultaneously collects the resistance value and corresponding temperature of each channel; S4. Data Processing: Calculate the resistivity of the sample under test based on the resistance values ​​R obtained from tests at different stable temperatures. , S is the cross-sectional area of ​​the sample to be tested. The length of the sample to be tested is then used to plot the RT curve or Curves were generated, and the temperature coefficient of resistance for each sample was calculated. or ; in, The resistance is obtained from the temperature T2 test. The resistivity is obtained from the temperature T2 test. The resistance is obtained from the test at temperature T1. The resistivity is obtained from the test at temperature T1.

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