A silicon carbide-based ntc thermistor material and a method for manufacturing the same

Abstract

The application relates to the technical field of thermistor materials, in particular to a silicon carbide-based NTC thermistor material and a preparation method thereof. The silicon carbide-based NTC thermistor material is prepared from the following raw materials in mass percentage: 0.1-0.5 wt% of fluxing agent nano-zinc oxide, 0.05-0.2 wt% of fluxing agent nano-yttrium trioxide, 0.4-2.0 wt% of toughening agent nano-zirconium oxide, 0.1-0.5 wt% of toughening agent nano-titanium nitride, 0.4-2.0% of tempering agent nano-strontium titanate, 0.5-4.0% of nano-metal carbide, and the balance of silicon carbide. The NTC thermistor material has excellent high-temperature resistance and high-low temperature impact resistance, and the resistance deviation is less than 0.5% after 1500 cycles of high-low temperature impact, so that the use requirements of highly integrated circuits, IGBT modules and the like can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermistor materials, in particular to a silicon carbide-based NTC thermistor material and a preparation method thereof. BACKGROUND

[0002] NTC thermistor materials are opposite to PTC thermistor materials in performance, and are a kind of negative temperature coefficient thermistors, that is, different temperatures exhibit different resistance values, and the higher the temperature, the lower the resistivity of the NTC thermistor material. NTC thermistor materials are usually solid solution materials composed of transition metal oxides, and play an important role in temperature measurement, temperature control, temperature compensation, surge suppression, etc., and have the advantages of high sensitivity, fast response speed, small size, and easy to realize remote control. The thermal sensitivity constant, i.e. B value, of the commonly used NTC thermistor material is generally B 25 / 85 , B 25 / 85 is generally 2000-6000K, and the resistivity is generally 5-8*10 5 Ω·cm, which can be applied to low temperature, high frequency, large power and large temperature attenuation compensation, and is widely used in daily life and industrial production, such as refrigerators, air conditioners, electric water heaters, microwave ovens, electric rice cookers, mobile phone batteries, induction cookers, temperature control instruments, medical instruments, fire alarm, integrated circuits, IGBT modules, etc.

[0003] The existing NTC thermoceramic element mainly contains metal oxides with manganese (Mn) and nickel (Ni) as main components, and the resistance deviation is about 2-3% after 1000-1500 times of high and low temperature impact. Although it can meet the use requirements of household appliances, with the development of the third generation semiconductor technology, highly integrated circuits, IGBT modules and the like have higher requirements for NTC thermistor materials, and require better high temperature resistance and high and low temperature impact resistance. Therefore, the present application provides a silicon carbide-based NTC thermistor material and a preparation method thereof. SUMMARY

[0004] In order to solve the better high temperature resistance and high and low temperature impact resistance requirements of highly integrated circuit modules, IGBT modules and the like for NTC thermistor materials, the present application provides a silicon carbide-based NTC thermistor material and a preparation method thereof.

[0005] The silicon carbide-based NTC thermistor material provided by the present application is realized by the following technical scheme:

[0006] The silicon carbide-based NTC thermistor material is made of raw materials with the following mass percentages: 0.1-0.5wt% of fluxing agent nano-zinc oxide, 0.05-0.2wt% of fluxing agent nano-yttrium trioxide, 0.4-2.0wt% of toughening agent nano-zirconium oxide, 0.1-0.5wt% of toughening agent nano-titanium nitride, 0.4-2.0% of tempering agent nano-strontium titanate, 0.5-4.0% of nano-metal carbide, and the balance of silicon carbide; the nano-metal carbide is at least one of MXene multi-layer nanosheet niobium carbide, MXene multi-layer nanosheet tantalum carbide, MAX phase niobium aluminum carbide, and MAX phase tantalum aluminum carbide.

[0007] The NTC thermistor material in the application has excellent high-temperature resistance, high-low temperature impact resistance, and a resistance deviation of less than 0.5% after 1500 cycles of high-low temperature impact, which can meet the use requirements of highly integrated circuits, IGBT modules, and the like.

[0008] Preferably, the silicon carbide-based NTC thermistor material is made of raw materials with the following mass percentages: 0.3-0.4wt% of fluxing agent nano-zinc oxide, 0.05-0.10wt% of fluxing agent nano-yttrium trioxide, 0.8-1.0wt% of toughening agent nano-zirconium oxide, 0.2-0.4wt% of toughening agent nano-titanium nitride, 0.6-1.0% of tempering agent nano-strontium titanate, 2.4-3.2% of nano-metal carbide, and the balance of silicon carbide.

[0009] By adopting the above technical solution, the high-temperature resistance and high-low temperature impact resistance of the NTC thermistor material as a whole can be improved.

[0010] Preferably, the nano-metal carbide is composed of at least one of MXene multi-layer nanosheet niobium carbide and MXene multi-layer nanosheet tantalum carbide, and at least one of MAX phase niobium aluminum carbide and MAX phase tantalum aluminum carbide.

[0011] Preferably, the nano-metal carbide is composed of MXene multi-layer nanosheet tantalum carbide and MAX phase niobium aluminum carbide at a mass ratio of 3:2.

[0012] Preferably, the nano-metal carbide is composed of MXene multi-layer nanosheet niobium carbide, MXene multi-layer nanosheet tantalum carbide, and MAX phase tantalum aluminum carbide at a mass ratio of 4:3:3.

[0013] By optimizing the component ratio of the nano-metal carbide, the high-temperature resistance and high-low temperature impact resistance of the NTC thermistor material as a whole can be effectively improved, and the impact toughness of the NTC thermistor material can be effectively improved without affecting the overall temperature compensation and surge suppression performance.

[0014] Preferably, the silicon carbide is composed of 5-20wt% of surface monatomic modified silicon carbide 6H-SiC, 5-40wt% of surface graphene doped modified silicon carbide 6H-SiC, 5-20wt% of cubic silicon carbide 3C-SiC, and the rest of hexagonal silicon carbide 6H-SiC; the surface monatomic modified silicon carbide 6H-SiC comprises a silicon carbide 6H-SiC carrier and an active metal fixed on the surface of the silicon carbide 6H-SiC carrier in the form of a monatomic atom, and the active metal is at least one of Mn, Co, Ni, Cu, Zn and Bi; the content of the doped monatomic active metal in the surface of the surface monatomic modified silicon carbide 6H-SiC is 0.5-5wt%; the surface graphene doped modified silicon carbide 6H-SiC comprises a silicon carbide 6H-SiC carrier and graphene sintered on the surface of the silicon carbide 6H-SiC carrier by nano-silver, and the content of the graphene in the surface graphene doped modified silicon carbide 6H-SiC is 0.2-2wt%.

[0015] Preferably, the silicon carbide is composed of 10-12wt% of surface monatomic modified silicon carbide 6H-SiC, 20-24wt% of surface graphene doped modified silicon carbide 6H-SiC, 5-10wt% of cubic silicon carbide 3C-SiC, and the rest of hexagonal silicon carbide 6H-SiC.

[0016] By adopting the technical scheme, the high-temperature resistance and high-low temperature impact resistance of the NTC thermistor material as a whole can be improved.

[0017] Preferably, the active metal in the surface monatomic modified silicon carbide 6H-SiC is Mn, Co and Bi, and the mass ratio of Mn, Co and Bi is 3:1:1; the content of the doped monatomic active metal in the surface of the surface monatomic modified silicon carbide 6H-SiC is 2-3wt%; and the content of the graphene in the surface graphene doped modified silicon carbide 6H-SiC is 0.8-1.2wt%.

[0018] By adopting the technical scheme, the high-temperature resistance and high-low temperature impact resistance of the NTC thermistor as a whole can be further improved.

[0019] The preparation method of the NTC thermistor material based on silicon carbide provided by the application is realized by the following scheme:

[0020] The preparation method of the NTC thermistor material based on silicon carbide comprises the following steps:

[0021] Step one, the accurately metered fluxing agent nano zinc oxide, fluxing agent nano yttrium trioxide, toughening agent nano zirconium oxide, toughening agent nano titanium nitride, tempering agent nano strontium titanate, nano metal carbide are placed in a planetary ball mill, wet ball milling treatment is carried out by adopting tungsten carbide grinding beads, the solid-liquid ratio is 1:(1.0-2.0), the ball milling speed is 120-200 rpm, the ball milling treatment is carried out for 15-30 min, the obtained ball milling mixture is dried and then added into another planetary ball mill, accurately metered silicon carbide is added into the planetary ball mill, dry ball milling treatment is carried out by adopting tungsten carbide grinding beads, the ball milling speed is 60-80 rpm, the ball milling treatment is carried out for 240-300 s, and the uniformly mixed NTC ceramic mixture can be obtained;

[0022] Step two, the NTC ceramic mixture in step one is placed into a forming mold for cold isostatic pressing forming treatment, the forming temperature is 20-50 DEG C, the forming pressure is first pressurized to 200 MPa at 10-20 MPa / s, pressure maintaining is carried out for 30-60 s, then pressurized to 300-400 MPa at 5-10 MPa / s, pressure maintaining is carried out for 120-180 s, then depressurized to 200 MPa at 5-10 MPa / s, pressure maintaining is carried out for 30-40 s, then depressurized to 0 MPa at 20-25 MPa / s, the forming speed is 0.5-2 mm / s, after the cold isostatic pressing forming treatment is completed, the NTC ceramic preform can be prepared;

[0023] Step three, the NTC ceramic preform in step two is subjected to rapid sintering treatment, the temperature is increased to 800-850 DEG C at 100-200 DEG C / min, the temperature is maintained for 0.5-1.0 h, then the temperature is increased to 1650-1680 DEG C at 100-200 DEG C / min, the temperature is maintained for 0.5-1.0 h, then the temperature is increased to 2180-2250 DEG C at 100-200 DEG C / min, the temperature is maintained for 2-4 h, the temperature is decreased to 600-650 DEG C at a cooling rate of 40-80 DEG C / min, and the semi-finished NTC thermistor material is obtained after the furnace is opened and naturally cooled to room temperature;

[0024] Step four, the semi-finished NTC thermistor material obtained in step three is subjected to stress relief treatment, the temperature is increased to 200-240 DEG C at 20-60 DEG C / min in an inert atmosphere, the temperature is maintained for 1-2 h, then the temperature is increased to 400-420 DEG C at 40-80 DEG C / min, the temperature is maintained for 4-8 h, and the finished NTC thermistor material is obtained after the furnace is opened and naturally cooled to room temperature.

[0025] The preparation method provided in the application is simple to operate and easy to realize industrialized production, thereby being favorable for reducing the production cost of the NTC thermistor material, and thereby reducing the market threshold of the NTC thermistor material into the market of highly integrated circuits, IGBT modules and the like, and being favorable for the NTC thermistor material to quickly enter the supply chain market of highly integrated circuits, IGBT modules and the like.

[0026] Preferably, the step three is that the NTC ceramic preform in step two is subjected to rapid sintering treatment, temperature is raised to 820 DEG C at 100 DEG C / min, kept for 0.5h, then raised to 1660 DEG C at 150 DEG C / min, kept for 1.0h, then raised to 2240 DEG C at 200 DEG C / min, kept for 3h, and then reduced to 640 DEG C at a reducing rate of 50-60 DEG C / min, and then naturally cooled to room temperature after opening the furnace to obtain the semi-finished NTC thermistor material.

[0027] Through optimization of the rapid sintering parameters, the high-temperature resistance, high-low temperature impact resistance and impact toughness of the NTC thermistor can be further improved.

[0028] In summary, the present application has the following advantages:

[0029] 1. The NTC thermistor material in the present application has excellent high-temperature resistance and high-low temperature impact resistance, and the resistance deviation is less than 0.5% after 1500 cycles of high-low temperature impact, which can meet the use requirements of highly integrated circuits, IGBT modules and the like.

[0030] 2. The silicon carbide composition obtained by surface modification design of silicon carbide in the present application can further improve the high-temperature resistance, high-low temperature impact resistance and impact toughness of the NTC thermistor.

[0031] 3. The preparation method provided in the present application is simple to operate and easy to realize industrial production, which is conducive to reducing the production cost of the NTC thermistor material, thereby reducing the market threshold of the NTC thermistor material into highly integrated circuits, IGBT modules and the like, and facilitating the rapid entry of the NTC thermistor material into the supply chain market of highly integrated circuits, IGBT modules and the like.

[0032] 4. The optimization of the rapid sintering parameters in the preparation method provided in the present application can further improve the high-temperature resistance, high-low temperature impact resistance and impact toughness of the NTC thermistor. DETAILED DESCRIPTION

[0033] In order to further understand the present application, the preferred embodiments of the present application are described below in combination with examples and comparative examples.

[0034] EXAMPLE

[0035] A silicon carbide-based NTC thermistor material is made from the following raw materials by mass percentage: 0.1-0.5wt% of fluxing agent nano-zinc oxide, 0.05-0.2wt% of fluxing agent nano-yttrium trioxide, 0.4-2.0 wt% of toughening agent nano-zirconium oxide, 0.1-0.5wt% of toughening agent nano-titanium nitride, 0.4-2.0% of tempering agent nano-strontium titanate, 0.5-4.0% of nano-metal carbide, and the balance of silicon carbide.

[0036] A preferred formula of the silicon carbide-based NTC thermistor material is as follows: 0.3-0.4wt% of fluxing agent nano-zinc oxide, 0.05-0.10wt% of fluxing agent nano-yttrium trioxide, 0.8-1.0 wt% of toughening agent nano-zirconium oxide, 0.2-0.4wt% of toughening agent nano-titanium nitride, 0.6-1.0% of tempering agent nano-strontium titanate, 2.4-3.2% of nano-metal carbide, and the balance of silicon carbide.

[0037] The nano-metal carbide is at least one of MXene multi-layer nanosheet niobium carbide, MXene multi-layer nanosheet tantalum carbide, MAX phase niobium aluminum carbide, and MAX phase tantalum aluminum carbide.

[0038] Preferably, the nano-metal carbide is at least one of MXene multi-layer nanosheet niobium carbide and MXene multi-layer nanosheet tantalum carbide, and at least one of MAX phase niobium aluminum carbide and MAX phase tantalum aluminum carbide.

[0039] Further preferably, the nano-metal carbide is composed of MXene multi-layer nanosheet niobium carbide, MXene multi-layer nanosheet tantalum carbide, and MAX phase tantalum aluminum carbide in a mass ratio of 4:3:3.

[0040] Further preferably, the nano-metal carbide is composed of MXene multi-layer nanosheet tantalum carbide and MAX phase niobium aluminum carbide in a mass ratio of 3:2.

[0041] Further preferably, the silicon carbide is composed of 5-20wt% of surface monatomic modification silicon carbide 6H-SiC, 5-40wt% of surface doped graphene modification silicon carbide 6H-SiC, 5-20wt% of cubic silicon carbide 3C-SiC, and the balance of hexagonal silicon carbide 6H-SiC.

[0042] The surface monatomic modification silicon carbide 6H-SiC includes a silicon carbide 6H-SiC carrier and an active metal fixed on the surface of the silicon carbide 6H-SiC carrier in the form of a monatomic atom, and the active metal is at least one of Mn, Co, Ni, Cu, Zn, and Bi. The content of the doped monatomic active metal on the surface of the surface monatomic modification silicon carbide 6H-SiC is 0.5-5wt%.

[0043] The surface-doped graphene modified silicon carbide 6H-SiC comprises a silicon carbide 6H-SiC carrier and graphene sintered on the surface of the silicon carbide 6H-SiC carrier by nano-silver, and the content of the graphene is 0.2-2wt%.

[0044] Further preferably, the silicon carbide is composed of 10-12wt% of the surface-atom modified silicon carbide 6H-SiC, 20-24wt% of the surface-doped graphene modified silicon carbide 6H-SiC, 5-10wt% of cubic silicon carbide 3C-SiC, and the balance of hexagonal silicon carbide 6H-SiC. The active metals in the surface-atom modified silicon carbide 6H-SiC are Mn, Co and Bi, and the mass ratio of Mn, Co and Bi is 3:1:1. The content of the doped single-atom active metals in the surface of the surface-atom modified silicon carbide 6H-SiC is 2-3wt%. The content of the graphene in the surface-doped graphene modified silicon carbide 6H-SiC is 0.8-1.2wt%.

[0045] A preparation method of a silicon carbide-based NTC thermistor material, comprising the following steps:

[0046] Step one, accurately measure the fluxing agent nano-zinc oxide, fluxing agent nano-yttrium trioxide, toughening agent nano-zirconium oxide, toughening agent nano-titanium nitride, tempering agent nano-strontium titanate, and nano-metal carbide, and place them in a planetary ball mill. Wet ball milling treatment is performed using tungsten carbide grinding beads, with a solid-liquid ratio of 1:(1.0-2.0), a ball milling speed of 120-200 rpm, and a ball milling treatment time of 15-30 min. The obtained ball-milled mixture is dried and then added to another planetary ball mill. Accurately measured silicon carbide is added to the planetary ball mill, and dry ball milling treatment is performed using tungsten carbide grinding beads, with a ball milling speed of 60-80 rpm and a ball milling treatment time of 240-300 s. A uniformly mixed NTC ceramic mixture is obtained.

[0047] Step two, the NTC ceramic mixture in step one is placed into a molding mold for cold isostatic pressing molding treatment. The molding temperature is 20-50℃, the molding pressure is first increased to 200MPa at a rate of 10-20 MPa / s, then held for 30-60s, then increased to 300-400MPa at a rate of 5-10 MPa / s, held for 120-180s, then decreased to 200MPa at a rate of 5-10 MPa / s, held for 30-40s, then decreased to 0MPa at a rate of 20-25 MPa / s, and the molding speed is 0.5-2mm / s. After the cold isostatic pressing molding treatment is completed, an NTC ceramic preform is obtained.

[0048] Step three, the NTC ceramic preform in step two is subjected to rapid sintering treatment, heated to 800-850℃ at a rate of 100-200℃ / min, kept for 0.5-1.0h, then heated to 1650-1680℃ at a rate of 100-200℃ / min, kept for 0.5-1.0h, then heated to 2180-2250℃ at a rate of 100-200℃ / min, kept for 2-4h, cooled to 600-650℃ at a rate of 40-80℃ / min, and naturally cooled to room temperature after the furnace is opened to obtain a semi-finished NTC thermistor material;

[0049] Preferably, step three, the NTC ceramic preform in step two is subjected to rapid sintering treatment, heated to 820℃ at a rate of 100℃ / min, kept for 0.5h, then heated to 1660℃ at a rate of 150℃ / min, kept for 1.0h, then heated to 2240℃ at a rate of 200℃ / min, kept for 3h, cooled to 640℃ at a rate of 50-60℃ / min, and naturally cooled to room temperature after the furnace is opened to obtain a semi-finished NTC thermistor material;

[0050] Step four, the semi-finished NTC thermistor material obtained in step three is subjected to stress relief treatment, heated to 200-240℃ at a rate of 20-60℃ / min, kept for 1-2h, then heated to 400-420℃ at a rate of 40-80℃ / min, kept for 4-8h, and naturally cooled to room temperature after the furnace is opened to obtain a finished NTC thermistor material.

[0051] Example 1: A silicon carbide-based NTC thermistor material is made from the following mass percentages of raw materials: 0.4wt% of nano-zinc oxide (model CW-ZnO-002, particle size 200nm, Shanghai Superwei Nanotechnology), 0.06wt% of nano-yttrium trioxide (model HN-Y203, particle size 150-200nm, monoclinic crystal type, Hangzhou Hengna New Materials Co., Ltd.), 0.94wt% of nano-zirconium dioxide (model CW-ZrO2-002, particle size 50nm, 3Y tetragonal crystal type, Shanghai Superwei Nanotechnology), 0.4wt% of nano-titanium nitride (model CW-TiN-002, particle size 700nm, cubic crystal type, Shanghai Superwei Nanotechnology), 0.8% of nano-strontium titanate (CAS No. 12060-59-2, Ningbo Luofei Nanotechnology Co., Ltd., LF-SrTiO3-N100, average particle size 100nm), 1.8% of MXene multi-layer nanosheet tantalum carbide, 1.2% of MAX phase niobium aluminum carbide (MAX phase niobium aluminum carbide Nb4AlC3, average particle size 3μm, Zhongke Leiming (Beijing) Technology), and the balance is hexagonal crystal type silicon carbide 6H-SiC (customized by Xi'an Qiyue Biological Technology Co., Ltd., average particle size 0.5-1μm).

[0052] A preparation method of a silicon carbide-based NTC thermistor material, comprising the following steps:

[0053] Step one, accurately measure the nano zinc oxide, nano yttrium trioxide, nano zirconium oxide, nano titanium nitride, nano strontium titanate, MXene multi-layer nanosheet carbon tantalum, MAX phase niobium aluminum carbide, and place them in a planetary ball mill. Wet ball milling treatment is carried out using tungsten carbide grinding beads, the solid-liquid ratio is 1:1.5, the ball milling speed is 120 rpm, and the ball milling treatment time is 20 min. The obtained ball milling mixture is dried and then added to another planetary ball mill. Accurately measure the hexagonal silicon carbide 6H-SiC and add it to the planetary ball mill. Dry ball milling treatment is carried out using tungsten carbide grinding beads, the ball milling speed is 60 rpm, and the ball milling treatment time is 300 s. Thus, a uniformly mixed NTC ceramic mixture is obtained.

[0054] Step two, place the NTC ceramic mixture in step one into a forming mold for cold isostatic pressing forming treatment. The forming temperature is 20℃, the forming pressure is first increased to 200MPa at a rate of 20MPa / s, then kept for 60s, then increased to 320MPa at a rate of 10MPa / s, then kept for 150s, then decreased to 200MPa at a rate of 5MPa / s, then kept for 40s, then decreased to 0MPa at a rate of 20MPa / s, and the forming speed is 0.5mm / s. After the cold isostatic pressing forming treatment is completed, an NTC ceramic preform is obtained.

[0055] Step three, the NTC ceramic preform in step two is subjected to rapid sintering treatment. The temperature is increased to 820℃ at a rate of 100℃ / min, kept for 0.5h, then increased to 1660℃ at a rate of 150℃ / min, kept for 1.0h, then increased to 2240℃ at a rate of 200℃ / min, kept for 3h, then decreased to 640℃ at a rate of 60℃ / min, and then naturally cooled to room temperature after the furnace is opened. A semi-finished NTC thermistor material is obtained.

[0056] Step four, the semi-finished NTC thermistor material obtained in step three is subjected to stress relief treatment. The temperature is increased to 220℃ at a rate of 25℃ / min, kept for 2h, then increased to 420℃ at a rate of 50℃ / min, kept for 6h, and then naturally cooled to room temperature after the furnace is opened. A finished NTC thermistor material is obtained.

[0057] Example 2 differs from Example 1 in that a silicon carbide-based NTC thermistor material is made from the following mass percentages of raw materials: 0.1wt% of nano zinc oxide, 0.05wt% of nano yttrium trioxide, 0.4wt% of nano zirconium dioxide, 0.1wt% of nano titanium nitride, 0.4% of nano strontium titanate, 0.3% of MXene multi-layer nanosheet carbon tantalum, 0.2% of MAX phase niobium aluminum carbide, and the balance is hexagonal silicon carbide 6H-SiC.

[0058] Example 3 differs from Example 1 in that a silicon carbide-based NTC thermistor material is made from the following mass percentages of raw materials: 0.5wt% of nano-zinc oxide, 0.2wt% of nano-yttrium trioxide, 2wt% of nano-zirconium dioxide, 0.5wt% of nano-titanium nitride, 2% of nano-strontium titanate, 2.4% of MXene multi-layer nanosheet tantalum carbide, 1.6% of MAX phase niobium aluminum carbide, and the balance of hexagonal silicon carbide 6H-SiC.

[0059] Example 4 differs from Example 1 in that a silicon carbide-based NTC thermistor material is made from the following mass percentages of raw materials: 0.4wt% of nano-zinc oxide, 0.06wt% of nano-yttrium trioxide, 0.94wt% of nano-zirconium dioxide, 0.4wt% of nano-titanium nitride, 0.8% of nano-strontium titanate, 3% of MXene multi-layer nanosheet tantalum carbide, and the balance of hexagonal silicon carbide 6H-SiC.

[0060] Example 5 differs from Example 1 in that a silicon carbide-based NTC thermistor material is made from the following mass percentages of raw materials: 0.4wt% of nano-zinc oxide, 0.06wt% of nano-yttrium trioxide, 0.94wt% of nano-zirconium dioxide, 0.4wt% of nano-titanium nitride, 0.8% of nano-strontium titanate, 3% of MAX phase niobium aluminum carbide, and the balance of hexagonal silicon carbide 6H-SiC.

[0061] Example 6 differs from Example 1 in that a silicon carbide-based NTC thermistor material is made from the following mass percentages of raw materials: 0.4wt% of nano-zinc oxide, 0.06wt% of nano-yttrium trioxide, 0.94wt% of nano-zirconium dioxide, 0.4wt% of nano-titanium nitride, 0.8% of nano-strontium titanate, 1.2% of MXene multi-layer nanosheet niobium carbide, 0.9% of MXene multi-layer nanosheet tantalum carbide, 0.9% of MAX phase tantalum aluminum carbide, and the balance of hexagonal silicon carbide 6H-SiC.

[0062] Example 7 differs from Example 1 in that the hexagonal silicon carbide 6H-SiC is replaced by a silicon carbide composition composed of 5wt% of surface monatomic modification silicon carbide 6H-SiC, 20wt% of surface doped graphene modification silicon carbide 6H-SiC, 10wt% of cubic silicon carbide 3C-SiC, and the balance of hexagonal silicon carbide 6H-SiC.

[0063] The surface monatomic modification silicon carbide 6H-SiC includes a silicon carbide 6H-SiC carrier and an active metal fixed on the surface of the silicon carbide 6H-SiC carrier in the form of a monatomic, and the active metal is Mn, Ni, and the mass ratio of Mn, Ni is 3:2.

[0064] The preparation method of the surface monatomic modified silicon carbide 6H-SiC is as follows: first, 1L of a 20wt% citric acid aqueous solution is prepared, 100g of silicon carbide 6H-SiC is soaked in the 20wt% citric acid aqueous solution for 6h, and then taken out and dried for standby; then, 0.032mol of manganese dichloride tetrahydrate and 0.02mol of nickel dichloride hexahydrate are dissolved in 500mL of deionized water to obtain a metal impregnation solution, 100g of the silicon carbide 6H-SiC carrier subjected to citric acid acidification treatment is soaked in the metal impregnation solution, ultrasonic dispersion treatment is performed at an ultrasonic frequency of 44kHz and an ultrasonic power of 1200W for 8h, mechanical stirring is performed at 320rpm for 24h, then the supernatant is removed, the obtained solid material is separated by centrifugation and placed in a 120℃ air-drying oven for drying for 12h, after drying is completed, the obtained solid material is placed in a planetary ball mill for ball milling treatment at 120rpm for 30min to obtain a solid powder, the obtained solid powder is heated to 540℃ at a rate of 5℃ / min under an argon atmosphere, the calcination time is 4h, the obtained solid material is placed in a planetary ball mill for ball milling treatment at 80rpm for 60min to obtain surface monatomic modified silicon carbide 6H-SiC with a particle size of 0.5-1μm, and the doping rate is 2.65wt%.

[0065] The surface doped graphene modified silicon carbide 6H-SiC includes a silicon carbide 6H-SiC carrier and graphene sintered on the surface of the silicon carbide 6H-SiC carrier by nano-silver.

[0066] The preparation method of the surface doped graphene modified silicon carbide 6H-SiC is as follows: 4.4g of 2-ethyl-4-methylimidazole 2E4MI and 3.35g of silver acetate AgAc are added to 1kg of dichloromethane at room temperature, magnetic stirring is performed at 200rpm for 2h to obtain a clear and transparent Ag(2E4MI)2Ac complex solution, 5g of graphene (CAS No. 1034343-98-0, thickness 0.55~1.2nm, diameter 0.5-3μm, specific surface area 554.36m 2 / g, brand Jikelongming) and 5g of polyvinylpyrrolidone are added, ultrasonic dispersion is performed at an ultrasonic frequency of 44kHz and an ultrasonic power of 1200W for 4h, then 50g of silicon carbide 6H-SiC is added and ultrasonic dispersion is continued for 60min to obtain a dispersion liquid; dichloromethane in the Ag(2E4MI)2Ac complex solution is removed by vacuum distillation to obtain a solid, the obtained solid is sintered at 215℃ for 5h to obtain a blocky solid, and airflow crushing treatment is performed on the blocky solid to obtain surface doped graphene modified silicon carbide 6H-SiC with an average particle size of 1-3μm, and the graphene loading rate is 0.84%.

[0067] Example 8 differs from Example 1 in that the hexagonal silicon carbide 6H-SiC is replaced by a silicon carbide composition consisting of 10 wt% of surface-atomically modified silicon carbide 6H-SiC, 20 wt% of surface-doped graphene-modified silicon carbide 6H-SiC, 10 wt% of cubic silicon carbide 3C-SiC, and the balance of hexagonal silicon carbide 6H-SiC.

[0068] Example 9 differs from Example 1 in that the hexagonal silicon carbide 6H-SiC is replaced by a silicon carbide composition consisting of 20 wt% of surface-atomically modified silicon carbide 6H-SiC, 40 wt% of surface-doped graphene-modified silicon carbide 6H-SiC, 20 wt% of cubic silicon carbide 3C-SiC, and the balance of hexagonal silicon carbide 6H-SiC.

[0069] Example 10 differs from Example 1 in that the hexagonal silicon carbide 6H-SiC is replaced by a silicon carbide composition consisting of 20 wt% of surface-doped graphene-modified silicon carbide 6H-SiC, 10 wt% of cubic silicon carbide 3C-SiC, and the balance of hexagonal silicon carbide 6H-SiC.

[0070] Example 11 differs from Example 1 in that the hexagonal silicon carbide 6H-SiC is replaced by a silicon carbide composition consisting of 10 wt% of surface-atomically modified silicon carbide 6H-SiC, 10 wt% of cubic silicon carbide 3C-SiC, and the balance of hexagonal silicon carbide 6H-SiC.

[0071] Example 12 differs from Example 7 in that the surface-atomically modified silicon carbide 6H-SiC comprises a silicon carbide 6H-SiC carrier and an active metal fixed in the form of a single atom on the surface of the silicon carbide 6H-SiC carrier, the active metal being Mn, Co, Bi, and the mass ratio of Mn, Co, Bi being 3:1:1.

[0072] The preparation method of the surface single atom modified silicon carbide 6H-SiC is as follows: first, prepare 1L of 20wt% citric acid aqueous solution, weigh 200g of silicon carbide 6H-SiC and soak it in the 20wt% citric acid aqueous solution for 6h, then take it out and dry it for standby; then, 0.05mol of manganese dichloride pentahydrate, 0.0156mol of cobalt dichloride hexahydrate and 0.0044mol of bismuth nitrate pentahydrate are dissolved in 500mL of deionized water to obtain a metal impregnation solution, 200g of the silicon carbide 6H-SiC carrier treated by citric acid acidification is soaked in the metal impregnation solution, ultrasonic dispersion treatment is carried out at an ultrasonic frequency of 44kHz and an ultrasonic power of 1200W for 12h, mechanical stirring is carried out at 320rpm for 24h, then the supernatant is removed, the obtained solid material is separated by centrifugation and dried in a 120℃ air drying oven for 12h, after drying, the obtained solid material is placed in a planetary ball mill and ball milled at 120rpm for 30min to obtain a solid powder, the obtained solid powder is heated to 540℃ at a rate of 5℃ / min under an argon atmosphere, the calcination time is 4h, the obtained solid material is placed in a planetary ball mill and ball milled at 80rpm for 60min to obtain surface single atom modified silicon carbide 6H-SiC with a particle size of 0.5-1μm, and the doping rate is 2.21wt%.

[0073] The difference between Comparative Example 1 and Example 7 is that in step one, accurately metered nano-zinc oxide, nano-yttrium trioxide, nano-zirconium oxide, nano-titanium nitride, nano-strontium titanate, MXene multi-layer nanosheet carbon tantalum, MAX phase carbon niobium aluminum and hexagonal silicon carbide 6H-SiC are placed in a planetary ball mill, wet ball milling is carried out using tungsten carbide grinding beads, the solid-liquid ratio is 1:15, and the ball milling speed is 120rpm for 20min, and the mixture is dried to obtain a uniformly mixed NTC ceramic mixture.

[0074] The difference between Comparative Example 2 and Example 7 is that in step two, the NTC ceramic mixture in step one is placed in a forming mold for cold isostatic pressing forming treatment, the forming temperature is 20℃, the forming pressure is first increased to 320MPa at a rate of 20MPa / s, the pressure is maintained for 240s, then the pressure is reduced to 0MPa at a rate of 20MPa / s, the forming speed is 0.5mm / s, and the NTC ceramic preform is obtained after the cold isostatic pressing forming treatment is completed.

[0075] The difference between Comparative Example 3 and Example 7 is that in step three, the NTC ceramic preform in step two is subjected to rapid sintering treatment, the temperature is increased to 2240℃ at a rate of 200℃ / min and maintained for 3h, the temperature is decreased to 640℃ at a rate of 60℃ / min, and the semi-finished NTC thermistor material is obtained after the furnace is opened and naturally cooled to room temperature.

[0076] The difference between Comparative Example 4 and Example 7 is that the preparation method of the silicon carbide-based NTC thermistor material is as follows:

[0077] Step one, accurately measure the nano zinc oxide, nano yttrium trioxide, nano zirconium oxide, nano titanium nitride, nano strontium titanate, MXene multi-layer nanosheet tantalum carbide, MAX phase niobium aluminum carbide and put them into a planetary ball mill, wet ball milling treatment with tungsten carbide grinding beads, solid-liquid ratio is 1:15, ball milling speed is 120 rpm, ball milling treatment time is 20 min, the obtained ball milling mixture is dried and then added into another planetary ball mill, accurately measure the hexagonal silicon carbide 6H-SiC and add it into the planetary ball mill, dry ball milling treatment with tungsten carbide grinding beads, ball milling speed is 60 rpm, ball milling treatment time is 300 s, and then a uniformly mixed NTC ceramic mixture is obtained.

[0078] Step two, put the NTC ceramic mixture in step one into a forming mold for cold isostatic pressing forming treatment, forming temperature is 20℃, forming pressure: first pressurize to 200 MPa at 20 MPa / s, hold for 60 s, then pressurize to 320 MPa at 10 MPa / s, hold for 150 s, then reduce the pressure to 200 MPa at 5 MPa / s, hold for 40 s, and then reduce the pressure to 0 MPa at 20 MPa / s, the forming speed is 0.5 mm / s, after the cold isostatic pressing forming treatment is completed, the NTC ceramic preform is obtained.

[0079] Step three, rapid sintering treatment is carried out on the NTC ceramic preform in step two, the temperature is raised to 820℃ at 100℃ / min, held for 0.5h, then the temperature is raised to 1660℃ at 150℃ / min, held for 1.0h, then the temperature is raised to 2240℃ at 200℃ / min, held for 3h, then the temperature is reduced to 640℃ at 60℃ / min, and the furnace is opened for natural cooling to room temperature to obtain the finished product NTC thermistor material.

[0080] The difference between Comparative Example 5 and Example 1 is that a silicon carbide-based NTC thermistor material is made from the following mass percentage of raw materials: 0.4wt% of nano zinc oxide, 0.06wt% of nano yttrium trioxide, 0.94wt% of nano zirconium dioxide, 0.4wt% of nano titanium nitride, 0.8wt% of nano strontium titanate, and the balance is hexagonal silicon carbide 6H-SiC.

[0081] The difference between Comparative Example 6 and Example 1 is that a silicon carbide-based NTC thermistor material is made from the following mass percentage of raw materials: 0.4wt% of nano zinc oxide, 0.06wt% of nano yttrium trioxide, 0.94wt% of nano zirconium dioxide, 0.4wt% of nano titanium nitride, 1.8wt% of MXene multi-layer nanosheet tantalum carbide, 1.2wt% of MAX phase niobium aluminum carbide, and the balance is hexagonal silicon carbide 6H-SiC.

[0082] Performance test: NTC thermistor discs with a diameter of 10 mm and a thickness of 2 mm were prepared using the formulations and processes of Examples 1-12 and Comparative Examples 1-6, and after coating silver paste electrodes on both ends, they were placed in a muffle furnace at 750°C for 30 min to obtain the NTC thermistors to be tested. The prepared NTC thermistors to be tested were heated to 85°C, 250°C, and 400°C in a muffle furnace, and the electrical properties were tested by a Keithley 2600B multi-channel test system, and the B value was calculated. 25 / 85 , B 85 / 250 , B 250 / 400 . The B value (thermistor constant) calculation formula is: B T1 / T2 = [(T1*T2) / (T2-T1)]*ln(R T1 / R T2 ), wherein T1 and T2 are both in Kelvin, T1 is the initial test temperature, T2 is the terminal test temperature, R T1 is the resistance at the initial test temperature, and R T2 is the resistance at the terminal test temperature.

[0083] High and low temperature impact resistance test: the NTC thermistors to be tested were cycled from 25°C to 400°C for 1500 times, and R 0次 / 25℃ , R 0次 / 400℃ , R 1500次 / 25℃ , R 1500次 / 400℃ , R 0次 / 25℃ was tested at 25°C, R 0次 / 400℃ was tested at 400°C after the first temperature rise, R 1500次 / 25℃ was tested at 25°C after 1500 cycles, and R 1500次 / 400℃ was tested at 400°C after 1500 cycles, and the ∆ R 25℃ (abs) = |(R 0次 / 25℃ - R 1500次 / 25℃ ) / R 0次 / 25℃| , ∆ R 25℃ is the resistance change rate at 25°C after 1500 cycles; ∆ R 400℃ (abs) = |(R 0次 / 400℃ - R 1500次 / 400℃ ) / R 0次 / 25℃ |, ∆ R 400℃ is the resistance change rate at 400°C after 1500 cycles.

[0084] Table 1: Test parameter table of NTC thermistor materials in Examples 1-12 and Comparative Examples 1-6

[0085] Flexural strength MPa Thermal conductivity at room temperature W / m*K B 25 / 85 / B 85 / 250 / B 250 / 400 ]]> Δ R 25℃ / %]]> Δ R 400℃ / %]]> Example 1 514.2 158.2 7217 / 4327 / 11375 0.24 0.39 Example 2 473.6 156.7 6439 / 4032 / 1237 0.35 0.46 Example 3 523.1 160.1 7438 / 4438 / 11039 0.21 0.35 Example 4 503.6 158.5 7138 / 4287 / 11689 0.29 0.43 Example 5 502.1 157.2 7154 / 4358 / 12039 0.31 0.45 Example 6 519.5 160.5 7635 / 3957 / 12438 0.19 0.35 Example 7 532.9 182.5 6324 / 3623 / 10325 0.20 0.31 Example 8 547.5 186.7 6115 / 3569 / 9735 0.19 0.29 Example 9 553.6 191.2 6032 / 3507 / 9532 0.17 0.26 Example 10 527.2 183.5 6735 / 4159 / 10574 0.22 0.32 Example 11 523.4 178.1 7125 / 4168 / 10219 0.23 0.35 Example 12 536.2 184.2 6401 / 3675 / 10895 0.20 0.28 Comparative Example 1 515.5 168.5 6532 / 4236 / 10863 0.23 0.36 Comparative Example 2 521.5 175.6 6535 / 3812 / 10712 0.22 0.34 Comparative Example 3 498.3 163.5 7032 / 5198 / 8352 0.45 0.54 Comparative Example 4 488.5 173.4 7035 / 4873 / 9468 0.48 0.63 Comparative Example 5 498.1 158.7 5985 / 5132 / 8325 0.65 0.87 Comparative Example 6 505.4 157.8 6538 / 4735 / 9125 0.34 0.48

[0086] It can be seen from the combination of Example 7 and Comparative Example 1 and Table 1 that, in Step 1, the accurately metered fluxing agent nano-zinc oxide, fluxing agent nano-yttrium trioxide, toughening agent nano-zirconium oxide, toughening agent nano-titanium nitride, tempering agent nano-strontium titanate, and nano-metal carbide are placed in a planetary ball mill, wet ball milling is performed using tungsten carbide beads, the solid-liquid ratio is 1:(1.0-2.0), the ball milling speed is 120-200 rpm, and the ball milling time is 15-30 min. After the obtained ball-milled mixture is dried, it is added to another planetary ball mill, accurately metered silicon carbide is added to the planetary ball mill, dry ball milling is performed using tungsten carbide beads, the ball milling speed is 60-80 rpm, and the ball milling time is 240-300 s to obtain a uniformly mixed NTC ceramic mixture. The morphology of the silicon carbide combination can be largely maintained, and the comprehensive performance of the NTC thermistor material can be effectively improved.

[0087] It can be seen from the combination of Example 7 and Comparative Example 2 and Table 1 that, compared with the conventional cold isostatic pressing forming treatment method, the cold isostatic pressing forming treatment method provided in Step 2 can improve the comprehensive performance of the NTC thermistor material.

[0088] It can be seen from the combination of Example 7 and Comparative Example 3 and Table 1 that, compared with the conventional sintering forming treatment method, the rapid sintering treatment method provided in the present application can improve the comprehensive performance of the NTC thermistor material.

[0089] It can be seen from the combination of Example 7 and Comparative Example 4 and Table 1 that, the stress relief treatment method in Step 4 can effectively eliminate stress, and thus improve the comprehensive performance of the NTC thermistor material.

[0090] It can be seen from the combination of Example 1 and Comparative Examples 5-6 and Table 1 that, the addition of nano-strontium titanate and nano-metal carbide can improve the mechanical strength, thermal conductivity, and high-low temperature impact resistance of the NTC thermistor material.

[0091] It can be seen from the combination of Examples 1-12 and Comparative Examples 1-6 and Table 1 that, the NTC thermistor material provided in the present application has excellent high-temperature resistance and high-low temperature impact resistance, and the resistance deviation is less than 0.5% after 1500 cycles of high-low temperature impact, which can meet the use requirements of highly integrated circuits, IGBT modules, and the like.

[0092] It can be seen from the combination of Examples 1-12 and Comparative Examples 1-4 and Table 1 that, the preparation method provided in the present application is simple to operate and easy to realize industrial production, which is conducive to reducing the production cost of the NTC thermistor material, and thus reduces the market threshold of the NTC thermistor material entering highly integrated circuits, IGBT modules, and the like, and facilitates the rapid entry of the NTC thermistor material into the supply chain market of highly integrated circuits, IGBT modules, and the like.

[0093] The specific embodiments are only illustrative of the present application, and are not intended to limit the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, and the modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A silicon carbide-based NTC thermistor material, characterized by: The silicon carbide-based NTC thermistor material is made of the following mass percentages of raw materials: 0.1-0.5wt% of fluxing agent nano-zinc oxide, 0.05-0.2wt% of fluxing agent nano-yttrium trioxide, 0.4-2.0wt% of toughening agent nano-zirconium oxide, 0.1-0.5wt% of toughening agent nano-titanium nitride, 0.4-2.0% of tempering agent nano-strontium titanate, 0.5-4.0% of nano-metal carbide, and the balance of silicon carbide; the silicon carbide-based NTC thermistor material is prepared by the following steps: step one, accurately measuring the fluxing agent nano-zinc oxide, fluxing agent nano-yttrium trioxide, toughening agent nano-zirconium oxide, toughening agent nano-titanium nitride, tempering agent nano-strontium titanate, and nano-metal carbide, and placing them in a planetary ball mill, wet ball milling treatment is carried out with tungsten carbide grinding beads, the solid-liquid ratio is 1:(1.0-2.0), the ball milling speed is 120-200rpm, the ball milling treatment time is 15-30min, the obtained ball milling mixture is dried and then added to another planetary ball mill, accurately measured silicon carbide is added to the planetary ball mill, dry ball milling treatment is carried out with tungsten carbide grinding beads, the ball milling speed is 60-80rpm, the ball milling treatment time is 240-300s, and a uniformly mixed NTC ceramic mixture is obtained; step two, the NTC ceramic mixture in step one is placed in a forming mold for cold isostatic pressing forming treatment, the forming temperature is 20-50℃, the forming pressure is first increased to 200MPa at 10-20MPa / s, the pressure is maintained for 30-60s, then increased to 300-400MPa at 5-10MPa / s, the pressure is maintained for 120-180s, then decreased to 200MPa at 5-10MPa / s, the pressure is maintained for 30-40s, then decreased to 0MPa at 20-25MPa / s, the forming speed is 0.5-2mm / s, and the NTC ceramic preform is prepared after the cold isostatic pressing forming treatment; step three, the NTC ceramic preform in step two is subjected to rapid sintering treatment, the temperature is increased to 800-850℃ at 100-200℃ / min, the temperature is maintained for 0.5-1.0h, then the temperature is increased to 1650-1680℃ at 100-200℃ / min, and the temperature is maintained for 0.5-1.0h, and then heated to 2180-2250 DEG C at a rate of 100-200 DEG C / min, and held for 2-4h, and then cooled to 600-650 DEG C at a rate of 40-80 DEG C / min, and then naturally cooled to room temperature to obtain a semi-finished NTC thermistor material; and then the semi-finished NTC thermistor material is subjected to stress relief treatment, heated to 200-240 DEG C at a rate of 20-60 DEG C / min in an inert atmosphere, and held for 1-2h, and then heated to 400-420 DEG C at a rate of 40-80 DEG C / min, and held for 4-8h, and then naturally cooled to room temperature to obtain a finished NTC thermistor material.

2. A silicon carbide-based NTC thermistor material according to claim 1, characterized in that: The silicon carbide-based NTC thermistor material is made of raw materials with the following mass percentages: 0.3-0.4wt% of fluxing agent nano-zinc oxide, 0.05-0.10wt% of fluxing agent nano-yttrium trioxide, 0.8-1.0wt% of toughening agent nano-zirconium oxide, 0.2-0.4wt% of toughening agent nano-titanium nitride, 0.6-1.0% of tempering agent nano-strontium titanate, 2.4-3.2% of nano-metal carbide, and the balance of silicon carbide.

3. A silicon carbide based NTC thermistor material according to claim 1 or 2, characterized in that: The nano-metal carbide is composed of at least one of MXene multi-layer nanosheet niobium carbide, MXene multi-layer nanosheet tantalum carbide, at least one of MAX phase niobium aluminum carbide, and MAX phase tantalum aluminum carbide.

4. A silicon carbide-based NTC thermistor material according to claim 3, characterized in that: The nano-metal carbide is composed of MXene multi-layer nanosheet niobium carbide and MAX phase niobium aluminum carbide at a mass ratio of 3:

2.

5. A silicon carbide-based NTC thermistor material according to claim 3, characterized in that: The nano-metal carbide is composed of MXene multi-layer nanosheet niobium carbide, MXene multi-layer nanosheet tantalum carbide, and MAX phase tantalum aluminum carbide at a mass ratio of 4:3:

3.

6. A silicon carbide-based NTC thermistor material according to claim 1, characterized in that: The silicon carbide is composed of 5-20wt% of surface monatomic modified silicon carbide 6H-SiC, 5-40wt% of surface graphene doped modified silicon carbide 6H-SiC, 5-20wt% of cubic silicon carbide 3C-SiC, and the balance of hexagonal silicon carbide 6H-SiC; the surface monatomic modified silicon carbide 6H-SiC includes a silicon carbide 6H-SiC carrier and an active metal fixed on the surface of the silicon carbide 6H-SiC carrier in the form of a monatomic atom, the active metal being at least one of Mn, Co, Ni, Cu, Zn, and Bi; the content of the doped monatomic active metal on the surface of the surface monatomic modified silicon carbide 6H-SiC is 0.5-5wt%; the surface graphene doped modified silicon carbide 6H-SiC includes a silicon carbide 6H-SiC carrier and graphene sintered on the surface of the silicon carbide 6H-SiC carrier by nano-silver, and the content of graphene in the surface graphene doped modified silicon carbide 6H-SiC is 0.2-2wt%.

7. A silicon carbide-based NTC thermistor material according to claim 6, characterized in that: The silicon carbide is composed of 10-12wt% of surface monatomic modified silicon carbide 6H-SiC, 20-24wt% of surface graphene doped modified silicon carbide 6H-SiC, 5-10wt% of cubic silicon carbide 3C-SiC, and the balance of hexagonal silicon carbide 6H-SiC.

8. A silicon carbide based NTC thermistor material according to claim 6 or 7, characterized in that: The active metal in the surface monatomic modified silicon carbide 6H-SiC is Mn, Co, and Bi, and the mass ratio of Mn, Co, and Bi is 3:1:1; the content of the doped monatomic active metal on the surface of the surface monatomic modified silicon carbide 6H-SiC is 2-3wt%; and the content of graphene in the surface graphene doped modified silicon carbide 6H-SiC is 0.8-1.2wt%.

9. A method of producing a silicon carbide-based NTC thermistor material according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: Step one, the accurate fluxing agent nano zinc oxide, fluxing agent nano yttrium trioxide, toughening agent nano zirconium oxide, toughening agent nano titanium nitride, tempering agent nano strontium titanate, nano metal carbide are placed in a planetary ball mill, wet ball milling treatment is carried out with tungsten carbide grinding beads, the solid-liquid ratio is 1:(1.0-2.0), the ball milling speed is 120-200 rpm, the ball milling treatment time is 15-30 min, the obtained ball milling mixture is dried and then added into another planetary ball mill, the accurate silicon carbide is added into the planetary ball mill, dry ball milling treatment is carried out with tungsten carbide grinding beads, the ball milling speed is 60-80 rpm, the ball milling treatment time is 240-300 s, and then the uniformly mixed NTC ceramic mixture is obtained; Step two, the NTC ceramic mixture in step one is put into a forming mold for cold isostatic pressing forming treatment, the forming temperature is 20-50 DEG C, the forming pressure is first pressurized to 200 MPa at 10-20 MPa / s, the pressure is maintained for 30-60 s, then pressurized to 300-400 MPa at 5-10 MPa / s, the pressure is maintained for 120-180 s, then depressurized to 200 MPa at 5-10 MPa / s, the pressure is maintained for 30-40 s, then depressurized to 0 MPa at 20-25 MPa / s, the forming speed is 0.5-2 mm / s, and the NTC ceramic preform is obtained after the cold isostatic pressing forming treatment is completed; Step three, the NTC ceramic preform in step two is subjected to rapid sintering treatment, the temperature is raised to 800-850 DEG C at 100-200 DEG C / min, the temperature is maintained for 0.5-1.0 h, then the temperature is raised to 1650-1680 DEG C at 100-200 DEG C / min, the temperature is maintained for 0.5-1.0 h, then the temperature is raised to 2180-2250 DEG C at 100-200 DEG C / min, the temperature is maintained for 2-4 h, the temperature is lowered to 600-650 DEG C at a rate of 40-80 DEG C / min, and the semi-finished NTC thermistor material is obtained after the furnace is opened and naturally cooled to room temperature; Step four, the semi-finished NTC thermistor material obtained in step three is subjected to stress relief treatment, the temperature is raised to 200-240 DEG C at 20-60 DEG C / min in an inert atmosphere, the temperature is maintained for 1-2 h, then the temperature is raised to 400-420 DEG C at 40-80 DEG C / min, the temperature is maintained for 4-8 h, the furnace is opened and naturally cooled to room temperature, and the finished NTC thermistor material is obtained.

10. The method for preparing a silicon carbide-based NTC thermistor material according to claim 9, characterized in that: In step three, the NTC ceramic preform in step two is subjected to rapid sintering treatment, the temperature is raised to 820 DEG C at 100 DEG C / min, the temperature is maintained for 0.5 h, then the temperature is raised to 1660 DEG C at 150 DEG C / min, the temperature is maintained for 1.0 h, then the temperature is raised to 2240 DEG C at 200 DEG C / min, the temperature is maintained for 3 h, the temperature is lowered to 640 DEG C at a rate of 50-60 DEG C / min, and the semi-finished NTC thermistor material is obtained after the furnace is opened and naturally cooled to room temperature.