Carbon composite ceramic linear resistor

Abstract

The application discloses a carbon composite ceramic linear resistor and relates to the technical field of carbon ceramic resistors; the carbon composite ceramic linear resistor comprises a ceramic base body and a conductive phase dispersed in the ceramic base body, and the conductive phase is composed of flaky graphite and carbon black; the flaky graphite and the carbon black are adopted as the conductive phase of the carbon ceramic resistor, the carbon black has fine particles and can be filled into the gaps of the ceramic aggregate, the carbon black particles not only compensate for the anisotropy of the flaky graphite, but also have a larger specific surface area compared with the graphite, which is beneficial to forming more conductive paths, so that the resistivity of the carbon ceramic linear resistor is effectively reduced, the resistivity of the carbon ceramic linear resistor can be regulated by designing the proportion of the conductive carbon material, and the energy tolerance level of the carbon ceramic resistor is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of carbon ceramic resistor technology, and more particularly to a carbon composite ceramic linear resistor. Background Technology

[0002] Carbon ceramic linear resistors combine the high mechanical strength, high thermal stability, and corrosion resistance of ceramic matrices with the excellent conductivity of carbon materials, making them core functional materials in fields such as power overvoltage protection, pulse energy absorption, and current limiting in high-voltage electrical equipment. These resistors use alumina, clay, or other materials as the ceramic phase and carbon-based materials as the conductive phase. The ceramic phase ensures the structural strength and thermal insulation performance of the matrix, while the conductive phase constructs the conductive path, achieving stable linear volt-ampere characteristics. They possess irreplaceable application advantages in high-energy impact, high-temperature conditions, and strong electric field environments. Developing high-performance carbon ceramic linear resistors has significant research value and engineering significance for improving the operational safety and reliability of power electronic equipment.

[0003] Currently, carbon ceramic linear resistors generally use flake graphite as the conductive phase. Although flake graphite has excellent electrical and thermal conductivity, providing basic conductivity for the resistor, its inherent layered microstructure is prone to directional alignment during the green body forming and sintering process. The flake morphology is difficult to fully fill the gaps between ceramic aggregates, resulting in limited contact sites for the conductive phase and difficulty in forming a dense and continuous conductive network. This leads to high resistivity and uneven conductivity distribution in carbon ceramic linear resistors, making precise control impossible and limiting the optimization space for the resistor's electrical performance. At the same time, the structural defects of a single flake graphite conductive phase can lead to uneven electric field distribution inside the resistor, insufficient heat conduction and energy dissipation capacity, and drastic resistance changes and performance failure under high-energy pulse impacts. The energy tolerance level is difficult to meet the application requirements of scenarios such as power overvoltage protection and high energy absorption. Summary of the Invention

[0004] This invention provides a carbon composite ceramic linear resistor, which aims to adjust the resistivity of the carbon ceramic linear resistor and enhance its stability.

[0005] The carbon composite ceramic linear resistor provided by this invention comprises a ceramic matrix and a conductive phase dispersed in the ceramic matrix, wherein the conductive phase is composed of flake graphite and carbon black; the carbon composite ceramic linear resistor is prepared by the following steps:

[0006] S1, calcined alumina, clay, conductive carbon material, adhesive, and dispersant are weighed according to a preset ratio and added to a ball mill jar, and a mixed slurry is formed through ball milling; the conductive carbon material is flake graphite and carbon black;

[0007] S2, the mixed slurry is centrifuged by spray granulation to obtain granulated powder; the granulated powder is then sealed and aged before being used to prepare green bodies by pressing molding process;

[0008] S3, the green body is heated to remove the binder, and then the green body after removing the binder is sintered to obtain a ceramic body;

[0009] S4, the ceramic blank is ground into a wafer, and electrodes are prepared on the two end faces of the ground ceramic blank to obtain a carbon ceramic linear resistor.

[0010] Optionally, the preset proportions, by weight, are: 25-35 parts calcined alumina, 45-55 parts clay, 15-25 parts conductive carbon material, 4-6 parts adhesive, and 0.3-0.7 parts dispersant.

[0011] Optionally, by weight, the ratio of flake graphite to carbon black is (60~120): (10~90).

[0012] Optionally, the clay is kaolin.

[0013] Optionally, the average size of the flake graphite is 11~15μm.

[0014] Optionally, the adhesive is polyvinyl alcohol.

[0015] Optionally, the dispersant is polyacrylate.

[0016] Optionally, in step S3, the sintering temperature is 1260℃~1350℃.

[0017] Optionally, the green blank is in the shape of a disc.

[0018] Optionally, the electrode is an aluminum electrode.

[0019] The present invention has the following beneficial effects:

[0020] This invention uses flake graphite and carbon black as the conductive phases of carbon ceramic resistors. The carbon black particles are small and can fill the gaps in the ceramic aggregate. The carbon black particles not only compensate for the anisotropy of flake graphite, but also have a larger specific surface area than graphite, which is conducive to forming more conductive paths, thereby effectively reducing the resistivity of carbon ceramic linear resistors. The resistivity of carbon ceramic linear resistors can be controlled by designing the ratio of conductive carbon materials. The addition of carbon black particles also significantly improves the energy tolerance level of carbon ceramic resistors. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a flowchart of some embodiments of the method for preparing carbon composite ceramic linear resistors according to the present invention;

[0023] Figure 2 These are actual images of the samples prepared in Comparative Examples 2 and 3 of this invention after aluminum spraying.

[0024] Figure 3 The images are SEM images of samples from Examples 1-3 and Comparative Example 1 of this invention;

[0025] Figure 4 The EDS spectrum of the sample in Example 1 of this invention;

[0026] Figure 5 The XRD patterns are of samples from Examples 1-3 and Comparative Example 1 of this invention;

[0027] Figure 6 The graph shows the temperature coefficient of resistance (TCR) data of samples from Examples 1-3 and Comparative Example 1 of this invention.

[0028] Figure 7 The graph shows the resistance and resistance change rate data of the sample in Example 1 of this invention after being tested alone in an 8 / 20µs lightning impulse withstand test.

[0029] Figure 8 This is a graph showing the resistance and resistance change rate data of the sample in Example 1 of the present invention after undergoing a 500V constant voltage 2ms lightning impulse test. Detailed Implementation

[0030] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0031] Experimental methods in the embodiments of this invention that do not specify specific conditions are generally performed under conventional conditions and conditions described in the manual, or under conditions recommended by the manufacturer; the general equipment, materials, reagents, etc. used are commercially available unless otherwise specified.

[0032] This invention provides a carbon composite ceramic linear resistor, comprising a ceramic matrix and a conductive phase dispersed in the ceramic matrix, wherein the conductive phase is flake graphite and carbon black; see reference. Figure 1 In this embodiment of the invention, the carbon composite ceramic linear resistor is prepared by the following steps:

[0033] S1, calcined alumina, clay, conductive carbon material, adhesive, and dispersant are weighed according to the preset ratio and added to a ball mill jar to form a mixed slurry through ball milling; the conductive carbon material is flake graphite and carbon black.

[0034] In this embodiment of the invention, the preset proportion of raw materials by weight is as follows: 25-35 parts calcined alumina, 45-55 parts clay, 15-25 parts conductive carbon material, 4-6 parts adhesive, and 0.3-0.7 parts dispersant; wherein, by weight, the ratio of flake graphite to carbon black is (60-120):(10-90), for example, the ratio of flake graphite to carbon black can be selected as 120:10, 120:30, 90:60, 60:90 or any ratio within the range; the average size of the flake graphite is 11-15 μm, preferably 13 μm; the carbon black powder is a spherical material that is entangled together and has no fixed size (the general particle size range is defined as several nm to hundreds of nm, with a loose appearance, easy agglomeration, and difficult to measure the specific size).

[0035] In some preferred embodiments, the clay is selected as kaolin, which is a natural hydrous aluminosilicate clay raw material with kaolinite as the main mineral component. Its main chemical composition is Al2O3·2SiO2·2H2O. Kaolin can be gradually transformed into mullite crystal phase during high-temperature sintering, which can significantly improve the mechanical strength, high-temperature resistance and structural density of the ceramic matrix.

[0036] The present invention does not limit the specific substances of the adhesive and dispersant. In some specific embodiments, the adhesive may be polyvinyl alcohol (PVA) and the dispersant may be polyacrylate (sodium polyacrylate, potassium polyacrylate, etc.).

[0037] S2, the mixed slurry is granulated by centrifugal spraying to obtain granulated powder; after the granulated powder is sealed and aged, it is used to prepare green blanks by compression molding process.

[0038] In the aging process, based on the preset final moisture content of the granulated material, it can be calculated whether deionized water needs to be added and the amount of deionized water to be added. After the deionized water and the release agent (accounting for 0.7~0.9% of the total mass of the granulated material) are mixed evenly, the mixture is sprayed onto the granulated material, and then the granulated material powder is sealed for aging.

[0039] In some preferred embodiments, the green body is pressed into a disc shape, and when the disc is disc-shaped, the stress on the green body is more uniform.

[0040] S3 involves heating the green body to remove the binder, followed by sintering the green body to obtain a ceramic body.

[0041] In some specific embodiments, the debinding temperature is 410~450℃, the holding time is 1.5~2.5h, the sintering temperature is 1260℃~1350℃, and the sintering time is 1.5~2h.

[0042] S4. The ceramic blank is ground into a wafer, and electrodes are prepared on the two end faces of the ground ceramic blank to obtain a carbon ceramic linear resistor. The preferred electrode material is aluminum electrode, but other metals, alloys or other conductive materials suitable for preparing electrodes can also be selected.

[0043] In this embodiment of the invention, flake graphite and carbon black are used as the conductive phases of carbon ceramic resistors. The carbon black particles are small and can fill the gaps in the ceramic aggregate. The carbon black particles not only compensate for the anisotropy of flake graphite, but also have a larger specific surface area than graphite, which is conducive to forming more conductive paths. This effectively reduces the resistivity of the carbon ceramic linear resistor. The resistivity of the carbon ceramic linear resistor can be controlled by designing the ratio of conductive carbon materials, and the energy tolerance level of the carbon ceramic resistor is significantly improved.

[0044] Based on the above embodiments, in order to illustrate the technical solution and beneficial effects of the present invention in more detail, the present invention also proposes the following specific embodiments. It should be noted that the following specific embodiments are merely exemplary and are not intended to limit the scope of protection of the present invention in any way.

[0045] Example 1

[0046] Process flow reference Figure 1 .

[0047] Raw material ratio: by weight, 30 parts calcined alumina, 50 parts kaolin, 20 parts conductive carbon material, 5 parts polyvinyl alcohol, and 0.5 parts potassium polyacrylate; of which, the conductive carbon material totals 150g, including 120g flake graphite (average size 13μm) and 30g carbon black.

[0048] First, calcined alumina, kaolin, flake graphite, carbon black, and agate balls are poured into a ball mill jar in a certain proportion using an electronic balance. Polyvinyl alcohol and potassium polyacrylate are then added. Finally, a GMJ-8-5 ball mill is used at 450 r / min. -1 The mixture was ball-milled at a certain speed for 24 hours, and then the ball-milled slurry was taken out and sieved to obtain the total slurry.

[0049] The total slurry was spray-granulated using an LZG-5 high-speed centrifugal spray dryer to obtain granulated material. The inlet temperature of the spray dryer was 220℃ and the outlet temperature was 110℃.

[0050] Take a portion of the granulated material and use an HB43-S Halogen moisture analyzer to determine the moisture content of the granulated material. Using a final moisture content of 1.5% as the standard, calculate whether deionized water needs to be added and the amount of deionized water to be added. Mix the mixture evenly with 0.7% of the mass of the granulated material powder as a release agent and spray it onto the granulated material. Then seal the granulated material powder and age it for 20 hours to allow the moisture to be evenly dispersed between the granulated material powder particles. The release agent is HDA-80 ceramic lubricant.

[0051] The aged, water-containing granulated material was pressed into shape using a Y79-25 bidirectional counter-pressure powder hydraulic press to obtain a size of [missing value]. The prepared carbon ceramic linear resistance green body was placed in an ECF1-6-13 high-temperature electric furnace for debinding treatment at a maximum temperature of 430℃ for 2 hours. The debinded green body was then embedded in graphite and placed in an OFS-12-17 high-temperature experimental atmosphere furnace for sintering at a temperature of 1260℃ for 2 hours, with nitrogen as the protective atmosphere.

[0052] The sintered blank was placed on a UPINOL-802 precision grinding and polishing machine to grind the two end faces of the cylindrical blank. After the blank was dried, aluminum electrodes were sprayed onto the two end faces of the ceramic blank using a DPL-IZ aluminum spraying machine to obtain a sample of carbon composite ceramic linear resistor.

[0053] Example 2

[0054] A carbon ceramic linear resistor was prepared. The raw material ratio and process flow were the same as in Example 1, except that the conductive carbon material in the raw materials was 90g of flake graphite and 60g of carbon black.

[0055] Example 3

[0056] A carbon ceramic linear resistor was prepared. The raw material ratio and process flow were the same as in Example 1, except that the conductive carbon material in the raw materials was 60g of flake graphite and 90g of carbon black.

[0057] Comparative Example 1

[0058] A carbon ceramic linear resistor was prepared. The raw material ratio and process flow were the same as in Example 1, except that the conductive carbon material in the raw material was 150g of flake graphite, and no carbon black was added.

[0059] Comparative Example 2

[0060] A carbon ceramic linear resistor was prepared. The raw material ratio and process flow were the same as in Example 1, except that the conductive carbon material in the raw materials was 30g of flake graphite and 120g of carbon black.

[0061] Comparative Example 3

[0062] A carbon ceramic linear resistor was prepared. The raw material ratio and process flow were the same as in Example 1, except that the conductive carbon material in the raw material was 150g of carbon black and no flake graphite was added.

[0063] After preparing the above samples, the morphology of the samples was characterized and the performance of the samples was tested.

[0064] During the aluminum spraying process, such as Figure 2 As shown, the powder on the surface of the samples in Comparative Examples 2 and 3 was easy to fall off and showed varying degrees of delamination and cracking. The delaminated parts were manually ground off before aluminum spraying. However, the powder falling off the surface of the sample in Comparative Example 2 caused uneven aluminum powder spraying and unstable resistance test results. Only one sample in Comparative Example 3 was successfully sprayed with aluminum. Therefore, the electrical performance test of the samples was only conducted on the samples of Examples 1, 2, 3 and Comparative Example 1.

[0065] The delamination and cracking phenomenon in carbon ceramic resistors is closely related to the increase in carbon black content: as the amount of carbon black increases, the high porosity and easy agglomeration of carbon black itself lead to an increase in the porosity of the carbon ceramic resistor sheet. Due to the short duration of the resistor sheet pressing process, a large amount of gas in the blank cannot be discharged in time, and a large amount of gas remains in the blank, resulting in uneven density of the blank and thus causing delamination of the blank.

[0066] See Figure 3 , 4 , Figure 3 The images show SEM images of samples from Examples 1-3 and Comparative Example 1. Figure 3 (a) in the figure is the sample of Comparative Example 1. Figure 3 In the figures, (b), (c), and (d) are samples from Examples 1, 2, and 3, respectively; Figure 4 The image shows the EDS spectrum of the sample from Example 1. Figure 4 (a) in the diagram is the total elemental distribution spectrum. Figure 4 (b) in the diagram is the carbon element distribution spectrum; by Figure 3 , 4 The interaction between the layered structure of flake graphite and the agglomerated structure of carbon black particles can be observed: agglomerated carbon black particles can be distributed within the layered structure of graphite, and this distribution becomes more pronounced with increasing carbon black content. Due to the high structure and porosity of carbon black, the number of pores on the surface of the carbon ceramic increases with increasing carbon black content; from Figure 4It can be seen that carbon black and flake graphite have good dispersion and the size of ceramic grains is also moderate, which helps to maintain the stability and consistency of carbon ceramic resistors.

[0067] See Figure 5 , Figure 5 The XRD patterns of samples from Examples 1-3 and Comparative Example 1 show that the main components of the carbon ceramic resistor are: corundum (PDF#10-0173), mullite (PDF#15-0776), graphite (PDF#41-1487), carbon (PDF#26-1080), and cristobalite (PDF#27-0605). No new characteristic peaks were formed with increasing carbon black content, indicating that the carbon material did not participate in the chemical reaction to generate new crystalline phases. Furthermore, due to the large porosity of carbon black, the diffraction peak intensities of corundum, mullite, and cristobalite increased with increasing carbon black content. The diffraction peak intensity is proportional to the content of the crystalline phases, indicating that the content of these crystalline phases also increased. This may be because the addition of carbon black promoted the formation or stabilization of these crystalline phases, or because carbon black itself provided more growth space or reaction sites for these crystalline phases.

[0068] The density, porosity, and resistivity of samples from Examples 1-3 and Comparative Example 1 were tested, and their linearity R was calculated. 2 The data shown in Table 1 is obtained.

[0069] Table 1. Basic properties of carbon ceramic linear resistors

[0070]

[0071] As shown in Table 1, with the increase of carbon black content, the density of the ceramic body of the resistor gradually decreases, while the porosity increases sequentially. This is because carbon black is more porous and has a greater structural density; therefore, the higher the carbon black content in the resistor, the lower the density of the ceramic body. Furthermore, with the increase of carbon black content, the resistivity of the carbon ceramic linear resistor gradually decreases. This is the result of the combined effect of the following two factors:

[0072] Firstly, compared to graphite, carbon black powder is more porous and has a larger specific surface area, increasing the contact area between carbon black particles, shortening the distance for electron migration, and facilitating the formation of more conductive pathways. Carbon black particles are prone to agglomeration and have complex branches, resulting in high structural density, which can form well-developed conductive pathways, and good conductivity can be achieved with a small filling amount. At the same time, the greater the pressure on carbon black, the greater its conductivity. Applying pressure can reduce the porosity in carbon black agglomerates, increase the contact sites between particles, and according to the tunneling effect, electrons can jump over the air gaps between carbon black agglomerates to form conductive pathways.

[0073] Secondly, carbon black forms a blocky resistor sheet with ceramic powder under strong pressure, and then is sintered at high temperature (1260℃) under inert gas. Graphitization rearrangement occurs inside the carbon black, a process also known as high-temperature graphitization treatment. During this process, the basic unit of graphite microcrystals gradually transforms into larger, more ordered graphite layers, and the amorphous structure transforms into an ordered graphite crystal form. In addition, after high-temperature graphitization treatment, some ash, metallic impurities, and oxygen-containing groups that affect the conductivity of carbon black are removed from its surface.

[0074] Table 1 shows the correlation coefficient R after linear fitting of the voltage-current curves. 2 The values ​​indicate that changes in the carbon black addition ratio did not negatively affect the linearity of the carbon ceramic linear resistor. This demonstrates that resistors with different carbon black contents can maintain good linear characteristics, which is crucial for maintaining a stable voltage-current relationship in practical applications of carbon ceramic resistors.

[0075] Since carbon ceramic linear resistors are mainly composed of a ceramic phase, a conductive phase, and pores, their temperature coefficient of resistance (TCR) is primarily determined by the thermal expansion coefficients of the conductive carbon material and the ceramic crystals. Flake graphite and carbon black both exhibit negative temperature coefficients; therefore, carbon ceramic linear resistors generally exhibit a negative temperature coefficient. At the macroscopic level, the high specific surface area, high structure, and high porosity of carbon black result in better conductivity and easier heat dissipation, allowing the linear resistor to maintain good conductivity even as temperature increases. At the microscopic level, the thermal expansion of the carbon crystals, the thermal vibration of particles, and the electron... Thermal migration becomes more intense, resulting in a decrease in the rate of change of linear resistance and a reduction in the absolute value of TCR. Therefore, theoretically, as the carbon black content increases, the absolute value of TCR of carbon ceramic linear resistance will decrease. However, at the same time, the expansion of ceramic crystals intensifies. The high structure and high porosity of carbon black itself negatively increase the conductivity of carbon ceramic linear resistance. That is, as the temperature increases, the thermal expansion of carbon black and ceramic aggregates creates more pores, breaking the original conductive path. This is manifested as an increase in the rate of change of linear resistance and an increase in the absolute value of TCR of carbon ceramic linear resistance.

[0076] See Figure 6 , Figure 6 The graph shows the temperature coefficient of resistance (TCR) data of samples from Examples 1-3 and Comparative Example 1. As the carbon black content increases, the absolute value of the temperature coefficient of resistance of the carbon ceramic linear resistor first decreases and then increases. The sample from Example 1 has the optimal temperature coefficient of resistance.

[0077] The samples from Examples 1-3 and Comparative Example 1 were subjected to a standard lightning wave (1.2 / 50µs) impact resistance test, and the results are shown in Table 2.

[0078] Table 2 Results of 1.2 / 50µs pulse shock test

[0079]

[0080] The results of the standard lightning surge withstand test show that the resistance of Comparative Example 1 sample changed significantly after 2kV and 4kV surges, and after a 6kV surge, Comparative Example 1 sample directly experienced flashover (the component instantly lost its insulation and current-limiting capabilities). In contrast, the resistance change rate of samples in Examples 1-3 after 2kV, 4kV, and 6kV surges did not exceed 10%, indicating that the addition of carbon black material can significantly improve the energy withstand level of carbon composite ceramic linear resistors with flake graphite as the conductive phase.

[0081] Among them, the resistance value of the sample in Example 1 was more suitable, the TCR performance was the best, and the impact resistance result was qualified, showing the best overall performance.

[0082] Furthermore, the sample from Example 1 was subjected to 8 / 20µs and 2ms lightning impulse withstand tests individually to detect its operating withstand voltage level in different circuits. The test results are as follows: Figure 7 , 8 As shown.

[0083] Figure 7 This indicates that during the 8 / 20µs lightning impulse test on the resistor, as the test voltage increased, the resistance change rate of the sample in Example 1 was less than 10% before 10 consecutive impulses. However, after the 11th impulse, with a voltage level of 2019.25V and a current level of 1184.32A, the resistance change rate exceeded 10%, no longer meeting the usage requirements.

[0084] Next, a constant voltage 2ms lightning impulse test was performed on the sample of Example 1, and the results are as follows. Figure 8 As shown, after four consecutive impact tests with a constant voltage of 500V, the resistance change rate of the sample in Example 1 was still less than 10%. However, after five consecutive impact tests with a constant voltage of 500V, the resistance change rate of the resistor exceeded 10%, which no longer met the usage requirements.

[0085] The experimental results above show that the present invention uses flake graphite and carbon black as the conductive phase of carbon ceramic resistor. The carbon black particles are small and can fill the gaps in the ceramic aggregate. The carbon black particles not only compensate for the anisotropy of flake graphite, but also have a larger specific surface area than graphite, which is conducive to forming more conductive paths, thereby effectively reducing the resistivity of carbon ceramic linear resistor. The resistivity of carbon ceramic linear resistor can be controlled by designing the ratio of conductive carbon materials, and the energy tolerance level of carbon ceramic resistor is significantly improved.

[0086] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A carbon composite ceramic linear resistor, characterized in that, The carbon composite ceramic linear resistor comprises a ceramic matrix and a conductive phase dispersed within the ceramic matrix, the conductive phase being composed of flake graphite and carbon black; the carbon composite ceramic linear resistor is prepared through the following steps: S1, calcined alumina, clay, conductive carbon material, adhesive, and dispersant are weighed according to a preset ratio and added to a ball mill jar, and a mixed slurry is formed through ball milling; the conductive carbon material includes flake graphite and carbon black; S2, the mixed slurry is centrifuged by spray granulation to obtain granulated powder; the granulated powder is then sealed and aged before being used to prepare green bodies by pressing molding process; S3, the green body is heated to remove the binder, and then the green body after removing the binder is sintered to obtain a ceramic body; S4, the ceramic blank is ground into a wafer, and electrodes are prepared on the two end faces of the ground ceramic blank to obtain a carbon ceramic linear resistor.

2. The carbon composite ceramic linear resistor according to claim 1, characterized in that, The preset proportions, by weight, are: 25-35 parts calcined alumina, 45-55 parts clay, 15-25 parts conductive carbon material, 4-6 parts adhesive, and 0.3-0.7 parts dispersant.

3. The carbon composite ceramic linear resistor according to claim 1, characterized in that, By weight, flake graphite: carbon black = (60~120): (10~90).

4. The carbon composite ceramic linear resistor according to claim 1, characterized in that, The clay is kaolin.

5. The carbon composite ceramic linear resistor according to claim 1, characterized in that, The average size of the flake graphite is 11~15μm.

6. The carbon composite ceramic linear resistor according to claim 1, characterized in that, The adhesive is polyvinyl alcohol.

7. The carbon composite ceramic linear resistor according to claim 1, characterized in that, The dispersant is polyacrylate.

8. The carbon composite ceramic linear resistor according to claim 1, characterized in that, In step S3, the sintering temperature is 1260℃~1350℃.

9. The carbon composite ceramic linear resistor according to claim 1, characterized in that, The green blank is in the shape of a round sheet.

10. The carbon composite ceramic linear resistor according to claim 1, characterized in that, The electrode is an aluminum electrode.

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