A high-power NTC thermistor chip, its formula and production process

Abstract

The invention discloses a high-power NTC thermistor chip, its formula and production process, and relates to the technical field of NTC thermistor production. The powder base material and molar ratio of the NTC thermistor are: Mn3O4: Ni2O3: CuO: Fe2O3: ZnO: BiO: B2O3: Sb2O3: Co3O4: SiO2 = 0.65: 0.1: 0.1: 0.05: 0.02: 0.02: 0.03: 0.01: 0.015: 0.005; the production process comprises the following steps: firstly, the accurate amount of the material is calculated according to the mass percentage ratio and the ingredients are mixed, and then the powder base material and the molar ratio of the NTC thermistor are mixed. The invention discloses a method for preparing a high-power NTC thermistor chip by grinding the granules with sand in a grinding machine; then spray granulation is performed; after granulation, the granules are added into a tablet press to compress green sheets, the pressed green sheets are placed into a tongs pot, high-temperature isolation powder is added, and the green sheets are placed into a high-temperature sintering furnace for sintering to obtain a high-power NTC thermistor chip; the obtained high-power NTC thermistor chip is subjected to chip testing, resistance and current are tested respectively, and chips are sorted to obtain a high-power NTC thermistor chip that meets the standards; in the present invention, the NTCR ceramic element can be fired at a firing temperature of 800° C., which not only has a significant effect of energy saving and consumption reduction, but also greatly reduces the cost, and the product reaches a higher quality standard.

Description

Technical Field

[0001] The invention relates to the technical field of NTC thermistor production, in particular to a high-power NTC thermistor chip and a formula and production process thereof. Background Art

[0002] NTCR thermistors have been widely used because of their functions of controlling surge current / overtemperature protection in electronic circuits. In the manufacturing process of traditional NTCR thermistor elements, the firing temperature of ceramic materials is between 1100 and 1400°C, so there are defects such as high energy consumption and high cost, poor consistency of high-temperature firing, and difficult process control. The processed NTCR thermistor characteristic ceramic resistance temperature coefficient is low. The NTCR thermistor made with this NTCR formula and firing process has unstable performance, large resistance value accuracy error, large energy consumption, and high cost. At present, the electronic sensitive ceramic industry needs to adopt low-temperature firing with superior electrical properties, mechanical properties, thermal properties and high mechanical strength, high temperature resistance, high humidity, excellent radiation resistance, component consistency, and higher reliability. The low-temperature firing material formula and processing method of MnNiCu-based NTCR functional ceramic thermistors are more needed. Therefore, a high-power NTC thermistor chip, its formula and production process are proposed. Summary of the invention

[0003] The purpose of the present invention is to provide a high-power NTC thermistor chip, its formula and its production process. The material formula and production process can be used to sinter NTCR ceramic components at 800°C, and the processed NTCR ceramic sheets can obtain higher quality standards; its processing technology not only greatly reduces energy consumption, but also reduces production costs.

[0004] To achieve the above object, the present invention provides the following technical solutions: a high-power NTC thermistor chip, its formula and production process, the powder base material and molar ratio of the NTC thermistor are:

[0005] Mn3O4:Ni2O3:CuO:Fe2O3:ZnO:BiO:B2O3:Sb2O3:Co3O4:SiO2=0.65:0.1:0.1:0.05:0.02:0.02:0.03:0.01:0.015:0.005.

[0007] Preferably, the production process comprises the following steps:

[0008] S1, batching and powdering;

[0009] S2, granulation;

[0010] S3, tableting and firing;

[0011] S4. Chip testing.

[0012] Preferably, the primary batching and powdering comprises the following steps:

[0013] S11. Calculate the exact amount of materials according to the mass percentage ratio and weigh the materials;

[0014] S12. Use a sand grinder to grind, and the particle size D50 is required to be ≤0.4um.

[0015] Preferably, the granulation comprises the following steps:

[0016] S21, adding 15% PVA aqueous solution according to the weight percentage (wt%) of the powder and stirring evenly to obtain a soft material;

[0017] S22, granulating in a spray granulating tower, and passing the granulated granules through a 40-mesh sieve to obtain granular materials.

[0018] Preferably, the tabletting process comprises the following steps:

[0019] S31. Add the granules into the tablet press to compress the green tablets. The tablet specifications are: 4.8*1.5mm, and the density of the tablets is 3.2g / cm. 3 ;

[0020] S32, putting the pressed green sheet into a tongs bowl, adding high temperature isolation powder, and loading into a high temperature sintering furnace for sintering; the sintering curve is: 50 minutes to heat from room temperature 25°C to 150°C; 240 minutes to heat from 150°C to 400°C; 115 minutes to heat from 400°C to 800°C; keeping at 800°C for 60 minutes, and cooling to room temperature with the furnace;

[0021] S33, the fired ceramic piece is cleaned, dried and copper-electroded to obtain a ceramic NTC thermistor with a negative temperature coefficient.

[0022] Preferably, the chip test comprises the following steps:

[0023] S41. Test the chip. The product specifications after porcelainization are: 4*1.2㎜, B value ≥2850, R25=5Ω±5%, maximum steady-state current (Imax) ≥3A, dissipation factor (mW / ℃)=5, thermal time constant (S)=18.

[0024] In the present invention, the NTCR ceramic element can be fired at a firing temperature of 800° C., which not only has a significant effect of energy saving and consumption reduction, but also greatly reduces the cost, and the product reaches a higher quality standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a high-power NTC thermistor chip production process flow chart. DETAILED DESCRIPTION

[0026] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example

[0030] See also Figure 1 As shown, a high-power NTC thermistor chip, its formula and production process, include the following steps:

[0031] 1. Purchase and prepare raw materials;

[0032] Specifically, the raw materials used are:

[0033] The purity of Mn3O4 / Ni2O3 / CuO / Fe2O3 / ZnO / BiO / B2O3 / Sb2O3 / Co3O4 / SiO2 is ≧99.95.

[0034] 2. Ingredient granulation;

[0035] Mn3O4:Ni2O3:CuO:Fe2O3:ZnO:BiO:B2O3:Sb2O3:Co3O4:SiO2=0.65:0.1:0.1:0.05:

[0036] 0.02:0.02:0.03:0.01:0.015:0.005, calculate the exact amount of materials according to the mass percentage ratio, weigh the materials, and use a sand mill to grind them. The particle size D50 is required to be ≦0.4um. Granulate the ground materials: add a 15% PVA aqueous solution according to the weight percentage (wt%) of the powder, stir evenly to obtain a soft material, and granulate it in a spray granulation tower. The granules are sieved through a 40-mesh sieve to obtain granules.

[0037] 3. Tableting and firing;

[0038] Specifically, the pellets are added to a tablet press to obtain pressed green tablets, the tablet specifications are: 4.8*1.5mm, and the density of the tablets is 3.2g / cm 3 , put the pressed green sheet into a tongs bowl, add high-temperature isolation powder, and put it into a high-temperature sintering furnace for sintering. The sintering curve is that the temperature increases by 100℃ for 50 minutes, and when it increases to 800℃, it is kept warm for 80 minutes, and then the temperature is reduced by 100℃ every 30 minutes until it reaches room temperature; the NTC ceramic sheet is obtained, and the specifications of the ceramic sheet after firing are: 4*1.2㎜. Finally, the sintered NTC ceramic sheet is cleaned with clean water, dried at 100℃, and the silver electrode is printed and kept warm at 550℃ for 15 minutes to sinter the chip.

[0039] 4. Chip testing;

[0040] Specifically, according to the product standards, the resistance and current are tested respectively, and the chips are sorted to obtain high-power NTC thermistor chips that meet the standards. 25 =5Ω±5%, maximum steady-state current (Imax) ≥3A, dissipation factor (mW / ℃) ≤5, thermal time constant (S) ≤18.

[0041] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high power NTC thermistor chip and its formula, characterized in that: The powder base material and molar ratio of NTC thermistor are: Mn3O4:Ni2O3:CuO:Fe2O3:ZnO:BiO:B2O3:Sb2O3:Co3O4:SiO2=0.65:0.1:0.1:0.05:0.02:0.02:0.03:0.01:0.015:0.

005.

2. The production process of a high-power NTC thermistor chip according to claim 1, characterized in that: The following steps are involved: S1, batching and powdering; S2, granulation; S3, tableting and firing; S4. Chip testing.

3. The high-power NTC thermistor chip, its formula and production process according to claim 2, characterized in that: In step S1, the primary batching and powdering comprises the following steps: S11. Calculate the exact amount of materials according to the mass percentage ratio and weigh the materials; S12. Use a sand grinder to grind, and the particle size D50 is required to be ≤0.4um.

4. A high-power NTC thermistor chip, its formula and production process according to claim 2, characterized in that: In step S2, the granulation comprises the following steps: S21, adding 15% PVA aqueous solution according to the weight percentage (wt%) of the powder and stirring evenly to obtain a soft material; S22, granulating in a spray granulating tower, and passing the granulated granules through a 40-mesh sieve to obtain granular materials.

5. The high-power NTC thermistor chip, its formula and production process according to claim 2, characterized in that: In step S3, the tableting process includes the following steps: S31. Add the granules into the tablet press to compress the green tablets. The tablet specifications are: 4.8*1.5mm, and the density of the tablets is 3.2g / cm 3 ; S32, putting the pressed green sheet into a tongs bowl, adding high temperature isolation powder, and loading into a high temperature sintering furnace for sintering; the sintering curve is: 50 minutes to heat from room temperature 25°C to 150°C; 240 minutes to heat from 150°C to 400°C; 115 minutes to heat from 400°C to 800°C; keeping at 800°C for 60 minutes, and cooling to room temperature with the furnace; S33, the fired ceramic piece is cleaned, dried and copper-electroded to obtain a ceramic NTC thermistor with a negative temperature coefficient.

6. A high-power NTC thermistor chip, its formula and production process according to claim 2, characterized in that: In step S4, the chip test includes the following steps: S41. Test the chip. The product specifications after porcelainization are: 4*1.2㎜, B value ≥2850, R25=5Ω±5%, maximum steady-state current (Imax) ≥3A, dissipation factor (mW / ℃)=5, thermal time constant (S)=18.

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