A system for measuring the electrical conductivity of magnesium oxide-based ceramic sheets, a measuring fixture, and its application.

Abstract

The application discloses a magnesium oxide-based ceramic sheet dielectric strength measurement system, a measurement clamp and application, the clamp is connected through a fixing rod respectively, a sliding assembly is sleeved on the fixing rod; a first electrode connector and a second electrode connector are fixed on the end face of the base away from the end disc; a first conductive needle is fixed on the end disc and penetrates the end disc; one end of a first hollow lead pipe penetrates the base and is matched with the first electrode connector, and the other end penetrates the end disc and is matched with the first conductive needle; the first conductive needle is connected with the first electrode connector through a conductive wire penetrating the first hollow lead pipe; a second conductive needle is fixed on the end of the sliding assembly away from the base; one end of a second hollow lead pipe penetrates the base and is matched with the second electrode connector, and the other end penetrates the sliding assembly and is matched with the second conductive needle; the second conductive needle is connected with the second electrode connector through a conductive wire penetrating the second hollow lead pipe. The system can measure the dielectric strength of ceramic sheets under different environmental temperatures at room temperature and high temperature.

Description

Technical Field

[0001] This invention relates to the field of electrical resistance measurement technology for ceramic sheets under high temperature and high pressure, and particularly to a system, measuring fixture, and application for measuring the electrical resistance of magnesium oxide-based ceramic sheets. Background Technology

[0002] Magnesium oxide ceramics possess good electrical conductivity, mechanical strength, and high-temperature resistance, exhibiting a cubic crystal system and a NaCl-type structure. The melting point of pure magnesium oxide ceramics is 2800℃±13℃, with a Mohs hardness of 6. Its tensile strength, compressive strength, and flexural strength are significantly lower than sintered Al₂O₃, and its high-temperature strength is also relatively low. MgO is an excellent insulator, with a resistivity >10¹⁴ Ω·cm at room temperature, which decreases sharply with increasing temperature. Magnesium oxide ceramics are typical alkaline refractory materials, capable of stable operation up to 2400℃ under oxidizing or nitrogen protection. In reducing atmospheres, MgO decomposes and volatilizes as metallic magnesium, with significant volatilization beginning at 1600℃ in a vacuum. Metals such as Fe, Zn, Pb, Cu, and M do not have a reducing effect on it. MgO ceramics can be used as crucibles for smelting metals and are also suitable for smelting high-purity uranium and thorium in the atomic energy industry. They can also be used as thermocouple protective sheaths and, taking advantage of their ability to allow electromagnetic waves to pass through, as radar domes and infrared radiation transmission window materials.

[0003] Currently, most magnesium oxide ceramic products are of low purity or low density, used in refractory materials, ceramic crucibles, and thermocouple protection tubes. High-purity magnesium oxide ceramics either require high-quality raw materials and have relatively complex processes, using more organic matter. High-purity magnesium oxide ceramics have advantages such as high temperature resistance and corrosion resistance, but they are difficult to sinter densely. Using high-purity lightweight magnesium oxide as raw material, due to its low bulk density and high reactivity, makes powder preparation and molding difficult, especially in the preparation of high-density, large-size magnesium oxide tubes and crucibles, which are prone to deformation and cracking.

[0004] The pursuit of electronic materials and devices with high dielectric breakdown strength (DBS) and the elucidation of the high dielectric breakdown mechanism are of great significance to scientific research and industrial applications. Among numerous material systems, MgO ceramics have great potential due to their simple crystal structure, wide band gap, and good physical properties. However, their sintering behavior at high temperatures has become an obstacle to achieving high DBS, and their breakdown mechanism needs further investigation. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a magnesium oxide-based ceramic sheet dielectric strength measurement system, measuring fixture and application that overcomes or at least partially solves the above problems.

[0006] In a first aspect, embodiments of the present invention provide a system for measuring the electrical conductivity of magnesium oxide-based ceramic sheets, which may include: a measuring fixture, a high-voltage device, and a tube furnace; wherein, the measuring fixture may include: a base, a fixing rod, a sliding assembly, a first electrode connector, a second electrode connector, a first conductive needle, a second conductive needle, a first hollow lead tube, a second hollow lead tube, and an end plate;

[0007] The base and the end plate are respectively connected by the fixed rod, the sliding component is sleeved on the fixed rod and can slide on the fixed rod; the first electrode connector and the second electrode connector are respectively fixed on the end face of the base away from the end plate;

[0008] The first conductive needle is fixed on the end plate and passes through the end plate; one end of the first hollow lead tube passes through the base and matches the first electrode connector, and the other end passes through the end plate and matches the first conductive needle; the first conductive needle is connected to the first electrode connector through a conductive wire passing through the first hollow lead tube.

[0009] The second conductive needle is fixed at the end of the sliding assembly away from the base; one end of the second hollow lead tube passes through the base and matches the second electrode connector, and the other end passes through the sliding assembly and matches the second conductive needle; the second conductive needle is connected to the second electrode connector through a conductive wire passing through the second hollow lead tube.

[0010] The magnesium oxide-based ceramic sheet to be measured is clamped between the end plate and the sliding assembly, and abuts against the first conductive needle and the second conductive needle respectively; the first electrode connector and the second electrode connector are electrically connected to the high-voltage equipment to form a measurement circuit for measuring the magnesium oxide-based ceramic sheet to be measured; the measuring fixture holds the magnesium oxide-based ceramic sheet to be measured in the tube furnace to heat the magnesium oxide-based ceramic sheet to be measured through the tube furnace.

[0011] In one embodiment, the sliding assembly may include: a sliding plate, a support rod, and a support plate;

[0012] The sliding plate and the support plate are sleeved on the fixed rod, and the sliding plate can slide on the fixed rod; one end of the support rod is fixed to the sliding plate, and the other end passes through the support plate; the second conductive needle is fixed to the end of the support rod away from the sliding plate.

[0013] In another embodiment, the support plate can slide on the fixed rod.

[0014] In another embodiment, the first hollow lead tube and the second hollow lead tube respectively penetrate the slide and the support plate.

[0015] In another embodiment, the surfaces of the fixing rod, the support rod, the support plate, the first hollow lead tube, the second hollow lead tube, and the end plate are coated with a high-temperature resistant ceramic coating.

[0016] In another embodiment, the base and the slide are made of metal.

[0017] In another embodiment, the outer sides of the first electrode connector and the second electrode connector are respectively wrapped with insulating ceramic.

[0018] In another embodiment, the system may further include: a vacuum device having two leads that are connected internally and externally, the magnesium oxide-based ceramic sheet to be tested being located in the vacuum device and connected to the first conductive needle and the second conductive needle respectively through the two leads.

[0019] In a second aspect, embodiments of the present invention provide a measuring fixture, which may include: a base, a fixing rod, a sliding assembly, a first electrode connector, a second electrode connector, a first conductive needle, a second conductive needle, a first hollow lead tube, a second hollow lead tube, and an end plate;

[0020] The base and the end plate are respectively connected by the fixed rod, the sliding component is sleeved on the fixed rod and can slide on the fixed rod; the first electrode connector and the second electrode connector are fixed on the end face of the base away from the end plate;

[0021] The first conductive needle is fixed on the end plate and passes through the end plate; one end of the first hollow lead tube passes through the base and matches the first electrode connector, and the other end passes through the end plate and matches the first conductive needle; the first conductive needle is connected to the first electrode connector through a conductive wire passing through the first hollow lead tube.

[0022] The second conductive needle is fixed at the end of the sliding assembly away from the base; one end of the second hollow lead tube passes through the base and matches the second electrode connector, and the other end passes through the sliding assembly and matches the second conductive needle; the second conductive needle is connected to the second electrode connector through a conductive wire passing through the second hollow lead tube.

[0023] The magnesium oxide-based ceramic sheet to be measured is clamped between the end plate and the sliding assembly, and abuts against the first conductive needle and the second conductive needle respectively; the first electrode connector and the second electrode connector are respectively connected to a high-voltage device to form a measurement circuit for measuring the magnesium oxide-based ceramic sheet to be measured; the measuring fixture clamps the magnesium oxide-based ceramic sheet to be measured for placement in a tube furnace to heat the magnesium oxide-based ceramic sheet to be measured through the tube furnace.

[0024] In one embodiment, the sliding assembly may include: a sliding plate, a support rod, and a support plate;

[0025] The sliding plate and the support plate are sleeved on the fixed rod, and the sliding plate can slide on the fixed rod; one end of the support rod is fixed to the sliding plate, and the other end passes through the support plate; the second conductive needle is fixed to the end of the support rod away from the sliding plate.

[0026] In another embodiment, the support plate can slide on the fixed rod.

[0027] In another embodiment, the first hollow lead tube and the second hollow lead tube respectively penetrate the slide and the support plate.

[0028] In another embodiment, the surfaces of the fixing rod, the support rod, the support plate, the first hollow lead tube, the second hollow lead tube, and the end plate are coated with a high-temperature resistant ceramic coating.

[0029] In another embodiment, the base and the slide are made of metal.

[0030] In another embodiment, the outer sides of the first electrode connector and the second electrode connector are respectively wrapped with insulating ceramic.

[0031] Thirdly, embodiments of the present invention provide an application of the measuring fixture described in the second aspect in a system for measuring the electrical conductivity of magnesium oxide-based ceramic sheets.

[0032] The beneficial effects of the above-mentioned technical solutions provided in the embodiments of the present invention include at least the following:

[0033] This invention provides a system for measuring the dielectric strength of magnesium oxide-based ceramic sheets, a measuring fixture, and its application. In this system, the ceramic sheet is fixed by the measuring fixture, and an electrode connector (positive and negative terminals) at one end of the fixture is connected to a high-voltage device. The measuring fixture holds the magnesium oxide-based ceramic sheet to be tested and places it into a tube furnace. The voltage across the ceramic sheet and the current flowing through it are then manually adjusted by the high-voltage device. Simultaneously, the ambient temperature of the measuring fixture within the tube furnace can be controlled by adjusting the temperature, allowing for the measurement of the dielectric strength of the ceramic sheet under high temperature and high pressure. The system provided in this invention has low requirements for the specifications of the ceramic sheet, has a wide size range, and can measure the dielectric strength of ceramic sheets at different ambient temperatures, including room temperature and high temperature, through adjustment. The system is simple and safe to operate.

[0034] The magnesium oxide-based ceramic sheet dielectric strength measurement system provided in this embodiment of the invention can determine the breakdown voltage of pure magnesium oxide-based ceramic sheets at different temperatures, especially high temperatures. The test results can provide reference for key testing process parameters such as those for high-voltage cables, which is more in line with the actual needs of ceramic applications. The testing device has a simple structure and is convenient to use. In addition, during the test, the clamping jaws of the measuring fixture can be adjusted to accommodate ceramic sheets of different sizes. This facilitates the placement and removal of ceramic sheets and other samples before and after the test, making operation convenient. Furthermore, it maintains the relative stability of the positions of the first and second conductive pins during the test, improving the stability and safety of the test.

[0035] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0036] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0037] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0038] Figure 1 This is a framework diagram of the magnesium oxide-based ceramic sheet electrical resistance measurement system provided in the embodiments of the present invention;

[0039] Figure 2 This is one of the structural diagrams of the measuring fixture provided in the embodiments of the present invention;

[0040] Figure 3 This is the second structural diagram of the measuring fixture provided in the embodiments of the present invention;

[0041] Figure 4 The measurement result diagram provided in the embodiment of the present invention;

[0042] 1-Measuring fixture; 2-High-pressure equipment; 3-Tube furnace; 4-Vacuum equipment; 5-Magnesium oxide-based ceramic sheet to be measured;

[0043] 101-Base; 102-Fixing rod; 103-Sliding assembly; 104-First electrode connector; 105-Second electrode connector; 106-First conductive needle; 107-Second conductive needle; 108-First hollow lead tube; 109-Second hollow lead tube; 110-End plate; 111-Insulating ceramic;

[0044] 1031-Slide plate; 1032-Support rod; 1033-Support plate. Detailed Implementation

[0045] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0046] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "far," "near," "front," and "rear," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0048] Example 1

[0049] This invention provides a system for measuring the electrical conductivity of magnesium oxide-based ceramic sheets, referring to... Figures 1-3As shown, the system may include: a measuring fixture 1, a high-pressure device 2, and a tubular furnace 3; wherein, the measuring fixture 1 may include: a base 101, a fixing rod 102, a sliding assembly 103, a first electrode connector 104, a second electrode connector 105, a first conductive needle 106, a second conductive needle 107, a first hollow lead tube 108, a second hollow lead tube 109, and an end plate 110; the base 101 and the end plate 110 are respectively connected by the fixing rod 102, and the sliding assembly 103 is sleeved on the fixing rod 102 and can slide on the fixing rod 102; the first electrode connector 104 and the second electrode connector 105 are respectively fixed on the end face of the base 101 away from the end plate 110; the first conductive needle 106 is fixed on the end plate 110 and penetrates the end plate 110; one end of the first hollow lead tube 108 penetrates the base 101 and matches the first electrode connector 104, and the other end penetrates the end plate 110 and matches the first conductive needle 106; the first conductive needle 106... A needle 106 is connected to a first electrode connector 104 via a conductive wire passing through a first hollow lead tube 108; a second conductive needle 107 is fixed to the end of a sliding assembly 103 away from the base 101; one end of a second hollow lead tube 109 passes through the base 101 and matches with a second electrode connector 105, and the other end passes through the sliding assembly 103 and matches with a second conductive needle 107; the second conductive needle 107 is connected to a second electrode connector 105 via a conductive wire passing through the second hollow lead tube 109; the magnesium oxide-based ceramic sheet 5 to be measured is clamped between the end plate 110 and the sliding assembly 103, and abuts against the first conductive needle 106 and the second conductive needle 107 respectively; the first electrode connector 104 and the second electrode connector 105 are electrically connected to the high-voltage equipment 2 respectively to form a measurement circuit for measuring the magnesium oxide-based ceramic sheet 5; the measuring fixture 1 clamps the magnesium oxide-based ceramic sheet 5 to be measured and places it in a tube furnace 3 to heat the magnesium oxide-based ceramic sheet 5 through the tube furnace 3.

[0050] It should be noted that the magnesium oxide-based ceramic sheet being measured in this embodiment of the invention is a ceramic sheet of a certain size obtained through processes such as ball milling, drying, granulation, pressing, and sintering. The diameter of the ceramic sheet in this embodiment is 6mm to 60mm, and the thickness is no more than 40mm, so that the tested ceramic sheet can be fitted with the measuring fixture in this embodiment. During measurement, silver paste is applied to the ceramic sheet to allow current to pass smoothly. It should also be noted that the temperature regulation range of the tubular furnace in this embodiment is 25℃ to 800℃, the furnace opening diameter is 150mm, and the base size in this embodiment matches the furnace opening. Furthermore, in this embodiment, when the tubular furnace is in use, the furnace opening section is open, and the other end is sealed by a heat insulation pad to maintain the internal temperature. Real-time monitoring by the thermocouple of the tubular furnace can directly test and display the temperature, and the tester can record the test temperature conditions. The high-voltage equipment in this embodiment consists of indicating instruments, a main control circuit, a time control circuit, and a high-voltage transformer.

[0051] The magnesium oxide-based ceramic sheet dielectric strength measurement system provided in this embodiment of the invention uses a measuring fixture to fix the ceramic sheet. One end of the measuring fixture has an electrode connector (positive and negative terminals) connected to a high-voltage device. The measuring fixture holds the magnesium oxide-based ceramic sheet to be tested and places it into a tube furnace. The voltage across the ceramic sheet and the current flowing through it are then manually adjusted by the high-voltage device. Simultaneously, the ambient temperature of the measuring fixture within the tube furnace can be controlled by adjusting the temperature, allowing for the measurement of the dielectric strength of the ceramic sheet under high temperature and high pressure. The system provided in this embodiment of the invention has low requirements for the specifications of the ceramic sheet, offering a wide size range. Furthermore, through adjustment, it can measure the dielectric strength of ceramic sheets at different ambient temperatures, including room temperature and high temperature. The system is simple and safe to operate.

[0052] The measurement process of the system in this embodiment of the invention is as follows: The vertical support rod is slid to a suitable position, and then the ceramic sheet coated with silver electrodes is placed in the fixture opening and fixed. The fixture is then fixed to the furnace opening of the tube furnace, the ambient temperature is adjusted, the special high-voltage device is turned on to adjust the voltage across the sample to be tested, and the voltage passing through the ceramic sample is recorded in real time. The test results are as follows: Figure 4 And as shown in Table 1 below:

[0053] Table 1. Sample voltage test results at different temperatures.

[0054]

[0055] from Figure 4 As shown in Table 1, the breakdown voltage of the ceramic sheet decreases to some extent with increasing test temperature. The breakdown voltage test result is lower at higher temperatures, but the breakdown voltage test result has a good linear relationship with temperature. At the same time, the process type and thickness of the ceramic sheet will also have a significant impact on the breakdown voltage test value. It is necessary to monitor the breakdown voltage test results according to the actual temperature parameters used in the production line. This system can effectively test the breakdown voltage of different types of ceramic sheets at different temperatures and can guide the reasonable setting of process parameters in relevant processes in actual production. Figure 4 Sample 3 was broken down at 600℃, and the voltage value could not be measured.

[0056] The system's fixtures, through insulated withstand voltage connectors, ensure no external current connection during breakdown voltage testing. This also ensures that the wires connecting the test ceramic sheet are effectively insulated and looped back to the high-voltage insulation testing equipment. With no current shunt, a controllable voltage is applied across the ceramic sheet. The tube furnace, by adjusting the furnace temperature, exposes the ceramic sheet to different ambient temperatures, thus testing the breakdown resistance of pure magnesium oxide-based ceramic sheets under high temperature and high pressure. Simultaneously, the flatness of the tested pure magnesium oxide-based ceramic sheet is ensured to guarantee the accuracy of the test results. Real-time monitoring via the tube furnace thermocouples allows for direct temperature display, and testers can record the test temperature conditions.

[0057] Furthermore, the magnesium oxide-based ceramic sheet dielectric strength measurement system provided in this embodiment of the invention can determine the breakdown voltage of pure magnesium oxide-based ceramic sheets at different temperatures, especially high temperatures. The test results can provide reference for key testing process parameters such as those for high-voltage cables, which is more in line with the actual needs of ceramic applications. The testing device has a simple structure and is convenient to use. In addition, during the test, the clamping jaws of the measuring fixture can be adjusted to accommodate ceramic sheets of different sizes. This facilitates the placement and removal of ceramic sheets and other samples before and after the test, making operation convenient. On the other hand, it can maintain the relative stability of the positions of the first and second conductive pins during the test, improving the stability and safety of the test.

[0058] In one embodiment, refer to Figure 2 and Figure 3 As shown, the sliding assembly 103 may include: a sliding plate 1031, a support rod 1032, and a support plate 1033; wherein, the sliding plate 1031 and the support plate 1033 are sleeved on the fixed rod 102, and the sliding plate 1031 can slide on the fixed rod 102; one end of the support rod 1032 is fixed to the sliding plate 1031, and the other end passes through the support plate 1033, and the second conductive needle 107 is fixed to the end of the support rod 1032 away from the sliding plate 1031. The sliding assembly described in this embodiment can facilitate the operator to adjust the clamping distance of the fixture, and thus can be adapted to multi-size magnesium oxide-based ceramic sheets being measured.

[0059] In another embodiment, refer to Figure 2 and Figure 3 As shown, the support disk 1033 can slide on the fixed rod 102. In this embodiment, the position of the support disk can also be adjusted, which facilitates clamping larger magnesium oxide-based ceramic sheets to be measured.

[0060] In another embodiment, refer to Figure 2 and Figure 3As shown, the first hollow lead tube 108 and the second hollow lead tube 109 pass through the slide plate 1031 and the support plate 1033, respectively. In this embodiment, the first hollow lead tube and the second hollow lead tube pass through the slide plate and the support plate, thus saving the entire space of the measuring fixture and making it easier to put into the tube furnace.

[0061] In another embodiment, refer to Figure 2 and Figure 3 As shown, the surfaces of the fixing rod 102, support rod 1032, support plate 1033, first hollow lead tube 108, second hollow lead tube 109, and end plate 110 are coated with a high-temperature resistant ceramic coating. In this embodiment, the high-temperature resistant ceramic coating is applied to the above-mentioned components to protect them from high temperatures, thereby improving the service life of the entire measuring fixture.

[0062] In another embodiment, refer to Figure 2 and Figure 3 As shown, the base 101 and the slide 1031 are made of metal. In this embodiment, the base and slide are made of metal to facilitate heat dissipation and improve the service life of the entire measuring fixture.

[0063] In another embodiment, refer to Figure 2 and Figure 3 As shown, the first electrode connector 104 and the second electrode connector 105 are respectively wrapped with insulating ceramic 111. In this embodiment, the insulating ceramic can protect the power supply equipment and prevent operators from being electrocuted.

[0064] In another embodiment, refer to Figure 1 As shown, the system may further include a vacuum device 4, which has two leads that are connected internally and externally. The magnesium oxide-based ceramic sheet 5 to be tested is located in the vacuum device 4 and is connected to the first conductive needle 106 and the second conductive needle 107 respectively through the two leads. In this embodiment, the vacuum device can prevent the magnesium oxide-based ceramic sheet to be tested from breaking down the air and forming an ionization layer during measurement, thereby adversely affecting the measurement process.

[0065] Example 2

[0066] Embodiment 2 of the present invention provides a measuring fixture, referring to... Figure 2 and Figure 3As shown, the measuring fixture 1 may include: a base 101, a fixed rod 102, a sliding assembly 103, a first electrode connector 104, a second electrode connector 105, a first conductive needle 106, a second conductive needle 107, a first hollow lead tube 108, a second hollow lead tube 109, and an end plate 110; the base 101 and the end plate 110 are respectively connected by the fixed rod 102, and the sliding assembly 103 is sleeved on the fixed rod 102 and can slide on the fixed rod 102; the first electrode connector 104 and the second electrode connector 105 are respectively fixed on the end face of the base 101 away from the end plate 110; the first conductive needle 106 is fixed on the end plate 110 and passes through the end plate 110; one end of the first hollow lead tube 108 passes through the base 101 and matches with the first electrode connector 104, and the other end passes through the end plate 110 and matches with the first conductive needle 106; the first conductive needle 106 passes through the first hollow lead tube 109 via a conductive wire. The hollow lead tube 108 is connected to the first electrode connector 104; the second conductive needle 107 is fixed to the end of the sliding assembly 103 away from the base 101; one end of the second hollow lead tube 109 passes through the base 101 and matches the second electrode connector 105, and the other end passes through the sliding assembly 103 and matches the second conductive needle 107; the second conductive needle 107 passes through the second hollow lead tube 109 and connects to the second electrode connector 105 via a conductive wire; the magnesium oxide-based ceramic sheet 5 to be measured is clamped between the end plate 110 and the sliding assembly 103, and abuts against the first conductive needle 106 and the second conductive needle 107 respectively; the first electrode connector 104 and the second electrode connector 105 are respectively connected to the high voltage equipment 2 to form a measurement circuit for measuring the magnesium oxide-based ceramic sheet 5 to be measured; the measuring fixture 1 clamps the magnesium oxide-based ceramic sheet 5 to be measured and places it in the tube furnace 3 so as to heat the magnesium oxide-based ceramic sheet 5 to be measured through the tube furnace 3.

[0067] The measuring fixture provided in this embodiment of the invention can determine the breakdown voltage of pure magnesium oxide-based ceramic sheets at different temperatures, especially high temperatures. The test results can provide reference for key testing process parameters such as those for high-voltage cables, which is more in line with the actual needs of ceramic applications. The testing device has a simple structure and is convenient to use. In addition, during the test, the clamping jaws of the measuring fixture can be adjusted to accommodate ceramic sheets of different sizes. This facilitates the placement and removal of ceramic sheets and other samples before and after the test, making operation convenient. Furthermore, it maintains the relative stability of the positions of the first and second conductive pins during the test, improving the stability and safety of the test.

[0068] In one embodiment, refer to Figure 2 and Figure 3As shown, the sliding assembly 103 may include: a sliding plate 1031, a support rod 1032, and a support plate 1033; wherein, the sliding plate 1031 and the support plate 1033 are sleeved on the fixed rod 102, and the sliding plate 1031 can slide on the fixed rod 102; one end of the support rod 1032 is fixed to the sliding plate 1031, and the other end passes through the support plate 1033, and the second conductive needle 107 is fixed to the end of the support rod 1032 away from the sliding plate 1031. The sliding assembly described in this embodiment can facilitate the operator to adjust the clamping distance of the fixture, and thus can be adapted to multi-size magnesium oxide-based ceramic sheets being measured.

[0069] In another embodiment, refer to Figure 2 and Figure 3 As shown, the support disk 1033 can slide on the fixed rod 102. In this embodiment, the position of the support disk can also be adjusted, which facilitates clamping larger magnesium oxide-based ceramic sheets to be measured.

[0070] In another embodiment, refer to Figure 2 and Figure 3 As shown, the first hollow lead tube 108 and the second hollow lead tube 109 pass through the slide plate 1031 and the support plate 1033, respectively. In this embodiment, the first hollow lead tube and the second hollow lead tube pass through the slide plate and the support plate, thus saving the entire space of the measuring fixture and making it easier to put into the tube furnace.

[0071] In another embodiment, refer to Figure 2 and Figure 3 As shown, the surfaces of the fixing rod 102, support rod 1032, support plate 1033, first hollow lead tube 108, second hollow lead tube 109, and end plate 110 are coated with a high-temperature resistant ceramic coating. In this embodiment, the high-temperature resistant ceramic coating is applied to the above-mentioned components to protect them from high temperatures, thereby improving the service life of the entire measuring fixture.

[0072] In another embodiment, refer to Figure 2 and Figure 3 As shown, the base 101 and the slide 1031 are made of metal. In this embodiment, the base and slide are made of metal to facilitate heat dissipation and improve the service life of the entire measuring fixture.

[0073] In another embodiment, refer to Figure 2 and Figure 3 As shown, the first electrode connector 104 and the second electrode connector 105 are respectively wrapped with insulating ceramic 111. In this embodiment, the insulating ceramic can protect the power supply equipment and prevent operators from being electrocuted.

[0074] In another embodiment, refer to Figure 1As shown, the system may further include a vacuum device 4, which has two leads that are connected internally and externally. The magnesium oxide-based ceramic sheet 5 to be tested is located in the vacuum device 4 and is connected to the first conductive needle 106 and the second conductive needle 107 respectively through the two leads. In this embodiment, the vacuum device can prevent the magnesium oxide-based ceramic sheet to be tested from breaking down the air and forming an ionization layer during measurement, thereby adversely affecting the measurement process.

[0075] Based on the same inventive concept, this embodiment of the invention also provides an application of the above-mentioned measuring fixture in a magnesium oxide-based ceramic sheet dielectric strength measuring system.

[0076] The specific implementation and beneficial effects of the measuring fixture and its application provided in the embodiments of the present invention can be referred to the relevant description of the magnesium oxide-based ceramic sheet dielectric strength measuring system, and will not be repeated here.

[0077] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. This disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims. Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A magnesium oxide-based ceramic sheet dielectric strength measurement system, characterized by, The system comprises a measuring clamp, a high-voltage device, and a tube furnace; wherein the measuring clamp comprises a base, a fixed rod, a sliding assembly, a first electrode connector, a second electrode connector, a first conductive pin, a second conductive pin, a first hollow lead tube, a second hollow lead tube, and an end disc; the base and the end disc are connected by the fixed rod, the sliding assembly is sleeved on the fixed rod and can slide on the fixed rod, the first electrode connector and the second electrode connector are respectively fixed on the end faces of the base away from the end disc; the first conductive pin is fixed on the end disc and penetrates the end disc, one end of the first hollow lead tube penetrates the base and matches the first electrode connector, the other end penetrates the end disc and matches the first conductive pin, and the first conductive pin is connected with the first electrode connector through a conductive wire penetrating the first hollow lead tube; the second conductive pin is fixed on the end of the sliding assembly away from the base, one end of the second hollow lead tube penetrates the base and matches the second electrode connector, the other end penetrates the sliding assembly and matches the second conductive pin, and the second conductive pin is connected with the second electrode connector through a conductive wire penetrating the second hollow lead tube; the measured magnesium oxide-based ceramic sheet is clamped between the end disc and the sliding assembly and abuts against the first conductive pin and the second conductive pin respectively, the first electrode connector and the second electrode connector are respectively electrically connected with the high-voltage device to form a measuring loop for measuring the measured magnesium oxide-based ceramic sheet, and the measuring clamp clamps the measured magnesium oxide-based ceramic sheet in the tube furnace to heat the measured magnesium oxide-based ceramic sheet by the tube furnace. The sliding assembly comprises a sliding disc, a support rod, and a support disc; 2. The system of claim 1, wherein, wherein the sliding disc and the support disc are sleeved on the fixed rod, and the sliding disc can slide on the fixed rod; one end of the support rod is fixed on the sliding disc, and the other end penetrates the support disc, and the second conductive pin is fixed on the end of the support rod away from the sliding disc. The support disc can slide on the fixed rod.

3. The system of claim 2, wherein, The first hollow lead tube and the second hollow lead tube respectively penetrate the sliding disc and the support disc.

4. The system of claim 2, wherein, The surfaces of the fixed rod, the support rod, the support disc, the first hollow lead tube, the second hollow lead tube, and the end disc are coated with a high-temperature-resistant ceramic coating.

5. The system of any one of claims 2-4, wherein, The base and the sliding disc are made of metal.

6. The system of any one of claims 2-4, wherein, The outer sides of the first electrode connector and the second electrode connector are respectively wrapped with insulating ceramic.

7. The system of any one of claims 1-4, wherein, The system further comprises a vacuum device provided with two lead wires in communication with the inside and outside, the measured magnesium oxide-based ceramic sheet is located in the vacuum device, and is connected with the first conductive pin and the second conductive pin through the two lead wires respectively.

8. The system of any one of claims 1-4, wherein, The system comprises a measuring clamp, a high-voltage device, and a tube furnace; wherein the measuring clamp comprises a base, a fixed rod, a sliding assembly, a first electrode connector, a second electrode connector, a first conductive pin, a second conductive pin, a first hollow lead tube, a second hollow lead tube, and an end disc; 9. A measurement jig, characterized by, the base and the end disc are connected by the fixed rod, the sliding assembly is sleeved on the fixed rod and can slide on the fixed rod, the first electrode connector and the second electrode connector are respectively fixed on the end faces of the base away from the end disc; ​ The base and the end disc are connected by the fixed rod respectively, the sliding assembly is sleeved on the fixed rod and can slide on the fixed rod; The first electrode connector and the second electrode connector are fixed on the end face of the base away from the end disc; The first conductive needle is fixed on the end disc and penetrates the end disc; one end of the first hollow lead tube penetrates the base and matches the first electrode connector, and the other end penetrates the end disc and matches the first conductive needle; the first conductive needle is connected with the first electrode connector through the conductive wire penetrating the first hollow lead tube; The second conductive needle is fixed on the end of the sliding assembly away from the base; one end of the second hollow lead tube penetrates the base and matches the second electrode connector, and the other end penetrates the sliding assembly and matches the second conductive needle; the second conductive needle is connected with the second electrode connector through the conductive wire penetrating the second hollow lead tube; The measured magnesium oxide-based ceramic sheet is clamped between the end disc and the sliding assembly and abuts against the first conductive needle and the second conductive needle respectively; the first electrode connector and the second electrode connector are connected with high-voltage equipment respectively to form a measurement loop for measuring the measured magnesium oxide-based ceramic sheet; the measurement clamp clamps the measured magnesium oxide-based ceramic sheet for being placed in a tube furnace to heat the measured magnesium oxide-based ceramic sheet by the tube furnace.

10. The measurement fixture of claim 9, wherein, The sliding assembly comprises a sliding disc, a support rod and a support disc; The sliding disc and the support disc are sleeved on the fixed rod, and the sliding disc can slide on the fixed rod; one end of the support rod is fixed on the sliding disc, and the other end penetrates the support disc, and the second conductive needle is fixed on the end of the support rod away from the sliding disc.

11. The measurement fixture of claim 10, wherein, The support disc can slide on the fixed rod; the first hollow lead tube and the second hollow lead tube penetrate the sliding disc and the support disc respectively; the surfaces of the fixed rod, the support rod, the support disc, the first hollow lead tube, the second hollow lead tube and the end disc are coated with a high-temperature-resistant ceramic coating; the base and the sliding disc are made of metal; the outer sides of the first electrode connector and the second electrode connector are wrapped with insulating ceramic respectively.

12. Application of the measurement clamp in any one of claims 9-11 in a magnesium oxide-based ceramic sheet electric strength measurement system.

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