阅读说明：本技术 一种热敏电阻器、芯片材料及其制备方法 (Thermistor, chip material and preparation method thereof ) 是由 杨幼斌 郑传发 郑海法 李鄂胜 张先锋 于 2021-08-06 设计创作，主要内容包括：本发明公开一种热敏电阻器、芯片材料及其制备方法,属于电子元器件技术领域。该芯片材料,按照质量百分比,包括：四氧化三锰40％-50％；四氧化三钴30％-40％；氧化铝10％-20％；氧化铬2％-8％,共计100％。该制备方法,包括：按照配比将各组分混合并球磨得到第一混合物；将第一混合物烘干,之后升温至500-600℃进行煅烧,之后继续升温至900-1000℃进行煅烧,之后降温至500-600℃保温得到第二混合物；将第二混合物采用湿法流延工艺制成中间体；将中间体升温至500-600℃并保温,之后继续升温,之后降温得到所述芯片材料。该芯片材料的年漂移率小于0.1％,而且精度高。(The invention discloses a thermistor, a chip material and a preparation method thereof, and belongs to the technical field of electronic components. The chip material comprises the following components in percentage by mass: 40% -50% of manganous manganic oxide; 30-40% of cobaltosic oxide; 10 to 20 percent of alumina; 2 to 8 percent of chromium oxide, accounting for 100 percent. The preparation method comprises the following steps: mixing the components according to the proportion and performing ball milling to obtain a first mixture; drying the first mixture, heating to 500-600 ℃ for calcination, continuing heating to 900-1000 ℃ for calcination, cooling to 500-600 ℃ for heat preservation to obtain a second mixture; preparing the second mixture into an intermediate by adopting a wet tape casting process; and heating the intermediate to 500-600 ℃, preserving the heat, continuing heating, and cooling to obtain the chip material. The annual drift rate of the chip material is less than 0.1%, and the accuracy is high.)

1. The chip material is characterized by comprising the following components in percentage by mass: 40% -50% of manganous manganic oxide; 30-40% of cobaltosic oxide; 10 to 20 percent of alumina; 2 to 8 percent of chromium oxide, accounting for 100 percent.

2. A method for preparing the chip material of claim 1, comprising the steps of:

s1, mixing the components according to the proportion and performing ball milling to obtain a first mixture;

s2, drying the first mixture, heating to 500-600 ℃ for the first calcination, continuing to heat to 900-1000 ℃ for the second calcination, and then cooling to 500-600 ℃ for heat preservation to obtain a second mixture;

s3, preparing an intermediate from the second mixture by adopting a wet casting process;

s4, heating the intermediate to 500-600 ℃ and preserving heat, then continuing heating to 1100-1200 ℃ and preserving heat, and then cooling to 500-600 ℃ and preserving heat to obtain the chip material.

3. The method for preparing a chip material according to claim 2, wherein in step S2, the time of the first calcination is 2-3 hours, and the time of the second calcination is 1-1.5 hours.

4. The method for preparing a chip material according to claim 2, wherein the holding time in step S2 is 2 to 3 hours.

5. The method as claimed in claim 2, wherein in step S4, the temperature is raised to 500-600 ℃ for 2-3 hours, the temperature is raised to 1100-1200 ℃ for 5-6 hours, and the temperature is lowered to 500-600 ℃ for 2-3 hours.

6. The method for preparing a chip material according to claim 2, wherein in step S2 or S4, the rate of the temperature increase or decrease is 5-10 ℃/min.

7. The method for preparing a chip material according to claim 2, wherein in step S3, the wet casting process specifically comprises: adding PVA glue into the second mixture, stirring to form slurry, casting with a casting machine to obtain a glue block, cutting the prepared glue block, and then performing heat preservation and glue removal at the temperature of 300-400 ℃ to obtain the intermediate.

8. The method as claimed in claim 2, wherein the first mixture is dried at 120 ℃ and 100 ℃ in step S2.

9. A thermistor is characterized in that metal materials are coated on two surfaces of a chip material to form metal electrodes, then one ends of leads are welded on the metal electrodes, and then the thermistor is obtained by packaging with epoxy resin; the chip material is the chip material of claim 1 or the chip material prepared by the preparation method of any one of claims 2 to 8.

10. A thermistor according to claim 9, characterized in that the metal material is silver or a composite metal material of silver.

Technical Field

The invention relates to the technical field of electronic components, in particular to a thermistor, a chip material and a preparation method thereof.

Background

The negative temperature coefficient thermistor is a semiconductor ceramic element made of high-purity transition metal oxide as main material, and is made up by using metal oxides of manganese, cobalt, nickel and copper as main material and adopting ceramic process. These metal oxide materials all have semiconductor properties because they are completely similar in conduction to semiconductor materials such as germanium, silicon, etc. At low temperatures, these oxide materials have a low number of carriers (electrons and holes) and therefore have a high resistance; as the temperature increases, the number of carriers increases, so the resistance value decreases. Therefore, the resistance value of the sensor has the characteristic that the resistance value changes correspondingly with the change of the temperature, namely, the resistance value decreases with the rise of the temperature under certain measuring power. The variation range of the negative temperature coefficient thermistor at room temperature is 100-1000000 ohms, and the temperature coefficient is-6.5% -2%. By utilizing the characteristic, the negative temperature coefficient thermistor can be widely applied to the occasions of temperature measurement, temperature compensation, surge current suppression and the like.

But the annual drift rate of the resistance value of the domestic similar products is more than or equal to 1 percent. In some fields (such as medical equipment) with higher requirements on temperature control precision, the requirements are far from being met.

Disclosure of Invention

The invention aims to overcome the technical defects, provides a thermistor, a chip material and a preparation method thereof, and solves the technical problem that the annual drift rate of the thermistor is more than or equal to 1% in the prior art.

In order to achieve the technical purpose, the technical scheme of the invention provides a chip material which comprises the following components in percentage by mass: 40% -50% of manganous manganic oxide; 30-40% of cobaltosic oxide; 10 to 20 percent of alumina; 2 to 8 percent of chromium oxide, accounting for 100 percent.

The invention also provides a preparation method of the chip material, which comprises the following steps:

s1, mixing the components according to the proportion and performing ball milling to obtain a first mixture;

s2, drying the first mixture, heating to 500-600 ℃ for the first calcination, continuing to heat to 900-1000 ℃ for the second calcination, and then cooling to 500-600 ℃ for heat preservation to obtain a second mixture;

s3, preparing an intermediate from the second mixture by adopting a wet casting process;

s4, heating the intermediate to 500-600 ℃ and preserving heat, then continuing heating to 1100-1200 ℃ and preserving heat, and then cooling to 500-600 ℃ and preserving heat to obtain the chip material.

Further, in step S2, the time of the first calcination is 2 to 3 hours, and the time of the second calcination is 1 to 1.5 hours.

Further, in step S2, the heat preservation time is 2 to 3 hours.

Further, in step S4, the time for raising the temperature to 500-600 ℃ for heat preservation is 2-3 hours, the time for raising the temperature to 1100-1200 ℃ for heat preservation is 5-6 hours, and the time for lowering the temperature to 500-600 ℃ for heat preservation is 2-3 hours.

Further, in step S2 or S4, the rate of temperature increase or decrease is 5 to 10 ℃/min.

Further, in step S3, the wet casting process specifically includes: adding PVA glue into the second mixture, stirring to form slurry, casting with a casting machine to obtain a glue block, cutting the prepared glue block, and then performing heat preservation and glue removal at the temperature of 300-400 ℃ to obtain the intermediate.

Further, in step S2, the first mixture is dried at 100-120 ℃.

Furthermore, the invention also provides a thermistor, wherein metal materials are coated on two surfaces of a chip material to form metal electrodes, then one end of a lead is welded on the metal electrodes, and then the thermistor is obtained by packaging epoxy resin; the chip material is the chip material or the chip material prepared by the preparation method; further, the metal material is silver or a silver composite metal material.

Compared with the prior art, the invention has the beneficial effects that: the invention provides a chip material which takes manganous manganic oxide as a main material and cobaltous trioxide, aluminum oxide and chromium oxide as auxiliary materials, particularly, the addition of the chromium oxide ensures that the annual drift rate of the chip material is less than 0.1 percent, the precision is high, the annual drift rate of the resistance value at 25 ℃ is less than 0.1 percent, and the resistance value range of R25 +/-1 percent is more than or equal to 90 percent.

According to the preparation method of the chip material, the components are mixed according to the proportion and ball-milled to obtain a first mixture, then the first mixture is dried, first calcination is carried out at a lower temperature, then second calcination is carried out at a higher temperature, third calcination is carried out at a lower temperature continuously to obtain a second mixture, the second mixture is prepared into an intermediate by adopting a wet tape casting process, the intermediate is processed at a lower temperature continuously, then the intermediate is processed at a high temperature and finally the intermediate is processed at a lower temperature, the compactness of the chip material is improved by carrying out successive processing at two different temperatures, the annual drift rate of the chip material is less than 0.1%, the annual drift rate of the resistance value at 25 ℃ is less than 0.1%, and the resistance value range of R25 +/-1% is more than or equal to 90%.

Detailed Description

The specific embodiment provides a chip material, which comprises the following components in percentage by mass: 40% -50% of manganous manganic oxide; 30-40% of cobaltosic oxide; 10 to 20 percent of alumina; 2 to 8 percent of chromium oxide, accounting for 100 percent.

The specific embodiment also provides a preparation method of the chip material, which comprises the following steps:

s1, mixing the components according to the proportion and ball-milling the mixture for 8 to 9 hours at the speed of 240-; ball milling to mix the raw materials evenly;

s2, drying the first mixture at the temperature of 100-;

s3, preparing an intermediate from the second mixture by adopting a wet casting process; specifically, the wet casting process includes: adding PVA glue into the second mixture, stirring to form slurry, casting for 2-3 times by using a casting machine to prepare a glue block, cutting the prepared glue block into square blocks of 15cm multiplied by 15cm, and performing heat preservation and glue removal at the temperature of 300-400 ℃ for 2-3 hours to obtain the intermediate;

s4, heating the intermediate to 500-plus 600 ℃ and preserving heat for 2-3 hours, then continuing heating to 1100-plus 1200 ℃ and preserving heat for 5-6 hours, then cooling to 500-plus 600 ℃ and preserving heat for 2-3 hours, then cutting off the power and cooling to obtain the chip material, and further in the step S2 or the step S4, the speed of heating or cooling is 5-10 ℃/min.

The specific embodiment also comprises a thermistor, wherein metal materials are coated on two surfaces of a chip material to form metal electrodes, then one end of a lead is welded on the metal electrodes, and then the thermistor is obtained by packaging epoxy resin; the chip material is the chip material or the chip material prepared by the preparation method; further, the metal material is silver or a silver composite metal material.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

The embodiment provides a chip material, which comprises the following components in percentage by mass: manganic manganous oxide 40%; 37% of cobaltosic oxide; 15% of alumina; 8 percent of chromium oxide, and the total is 100 percent.

The embodiment also provides a preparation method of the chip material, which comprises the following steps:

s1, mixing the components according to the proportion, and performing ball milling for 9 hours at the speed of 240 circles/minute to obtain a first mixture;

s2, drying the first mixture at 100 ℃, then heating to 500 ℃ for carrying out primary calcination for 2 hours, then continuing heating to 900 ℃ for carrying out secondary calcination for 1 hour, then cooling to 500 ℃ for heat preservation for 2 hours, and then powering off and cooling to obtain a second mixture; in the step, the temperature rising speed is 10 ℃/min, and the temperature reducing speed is 5 ℃/min;

s3, preparing an intermediate from the second mixture by adopting a wet casting process; specifically, the wet casting process includes: adding PVA glue into the second mixture, stirring to form slurry, casting for 3 times by using a casting machine to prepare a glue block, cutting the prepared glue block into square blocks of 15cm multiplied by 15cm, and carrying out heat preservation and glue discharge for 3 hours at 300 ℃ to obtain the intermediate;

s4, heating the intermediate to 500 ℃ and preserving heat for 2 hours, then continuing heating to 1100 ℃ and preserving heat for 5 hours, then cooling to 600 ℃ and preserving heat for 3 hours, and then powering off and cooling to obtain the chip material, wherein in the step, the heating or cooling speed is 5 ℃/min.

Example 2

The embodiment provides a chip material, which comprises the following components in percentage by mass: 50% of manganic manganous oxide; 30% of cobaltosic oxide; 18% of aluminum oxide; 2 percent of chromium oxide, and the total is 100 percent.

The embodiment also provides a preparation method of the chip material, which comprises the following steps:

s1, mixing the components according to the proportion, and performing ball milling for 8.5 hours at the speed of 250 circles/minute to obtain a first mixture;

s2, drying the first mixture at 110 ℃, heating to 600 ℃ for first calcination for 3 hours, continuing heating to 950 ℃ for second calcination for 1.5 hours, cooling to 600 ℃, preserving heat for 3 hours, and then cutting off the power and cooling to obtain a second mixture; in the step, the temperature rising speed is 5 ℃/min, and the temperature reducing speed is 8 ℃/min;

s3, preparing an intermediate from the second mixture by adopting a wet casting process; specifically, the wet casting process includes: adding PVA glue into the second mixture, stirring to form slurry, casting for 2 times by using a casting machine to prepare a glue block, cutting the prepared glue block into square blocks of 15cm multiplied by 15cm, and carrying out heat preservation and glue removal for 2 hours at 400 ℃ to obtain the intermediate;

s4, heating the intermediate to 600 ℃ and preserving heat for 3 hours, then continuing heating to 1150 ℃ and preserving heat for 6 hours, then cooling to 500 ℃ and preserving heat for 2.5 hours, and then powering off and cooling to obtain the chip material, wherein in the step, the heating or cooling speed is 8 ℃/min.

Example 3

The embodiment provides a chip material, which comprises the following components in percentage by mass: 45% of manganic manganous oxide; 40% of cobaltosic oxide; 10% of aluminum oxide; 5 percent of chromium oxide, and the total is 100 percent.

The embodiment also provides a preparation method of the chip material, which comprises the following steps:

s1, mixing the components according to the proportion, and ball-milling for 9 hours at the speed of 245 circles/minute to obtain a first mixture;

s2, drying the first mixture at 120 ℃, heating to 550 ℃ for carrying out primary calcination for 2.5 hours, continuing heating to 1000 ℃ for carrying out secondary calcination for 1 hour, cooling to 550 ℃, preserving heat for 2.5 hours, and then cutting off the power and cooling to obtain a second mixture; further, in the step, the speed of temperature rise or temperature reduction is 8 ℃/min;

s3, preparing an intermediate from the second mixture by adopting a wet casting process; specifically, the wet casting process includes: adding PVA glue into the second mixture, stirring to form slurry, casting for 3 times by using a casting machine to prepare a glue block, cutting the prepared glue block into square blocks of 15cm multiplied by 15cm, and carrying out heat preservation and glue discharge for 2.5 hours at 350 ℃ to obtain the intermediate;

s4, heating the intermediate to 500 ℃ and preserving heat for 2.5 hours, then continuing heating to 1200 ℃ and preserving heat for 5.5 hours, then cooling to 550 ℃ and preserving heat for 2 hours, and then powering off and cooling to obtain the chip material, wherein in the step, the speed of heating or cooling is 10 ℃/min.

Example 4

The embodiment provides a chip material, which comprises the following components in percentage by mass: 42% of manganic manganous oxide; 35% of cobaltosic oxide; 15% of alumina; 8 percent of chromium oxide, and the total is 100 percent.

The embodiment also provides a preparation method of the chip material, which comprises the following steps:

s1, mixing the components according to the proportion, and performing ball milling for 9 hours at the speed of 240 circles/minute to obtain a first mixture;

s2, drying the first mixture at 115 ℃, heating to 600 ℃ for first calcination for 3 hours, continuing heating to 1000 ℃ for second calcination for 1 hour, cooling to 500 ℃ for heat preservation for 3 hours, and then cutting off the power and cooling to obtain a second mixture; the speed of the temperature rise or the temperature reduction is 8 ℃/min;

s3, preparing an intermediate from the second mixture by adopting a wet casting process; specifically, the wet casting process includes: adding PVA glue into the second mixture, stirring to form slurry, casting for 3 times by using a casting machine to prepare a glue block, cutting the prepared glue block into square blocks of 15cm multiplied by 15cm, and carrying out heat preservation and glue discharge for 2 hours at 350 ℃ to obtain the intermediate;

and S4, heating the intermediate to 550 ℃ and preserving heat for 2.5 hours, then continuously heating to 1100 ℃ and preserving heat for 6 hours, then cooling to 550 ℃ and preserving heat for 2.5 hours, and then powering off and cooling to obtain the chip material, wherein the heating or cooling speed is 5 ℃/min.

Example 5

The embodiment provides a chip material, which comprises the following components in percentage by mass: manganic manganous oxide 40%; 36% of cobaltosic oxide; 20% of alumina; 4% of chromium oxide, and the total is 100%.

The embodiment also provides a preparation method of the chip material, which comprises the following steps:

s1, mixing the components according to the proportion, and performing ball milling for 8.5 hours at the speed of 245 circles/minute to obtain a first mixture;

s2, drying the first mixture at 100 ℃, then heating to 500 ℃ for carrying out primary calcination for 2 hours, then continuing heating to 900 ℃ for carrying out secondary calcination for 1.5 hours, then cooling to 600 ℃ for heat preservation for 3 hours, and then powering off and cooling to obtain a second mixture; the speed of the temperature rise or the temperature reduction is 10 ℃/min;

s3, preparing an intermediate from the second mixture by adopting a wet casting process; specifically, the wet casting process includes: adding PVA glue into the second mixture, stirring to form slurry, casting for 2 times by using a casting machine to prepare a glue block, cutting the prepared glue block into square blocks of 15cm multiplied by 15cm, and carrying out heat preservation and glue removal for 2.5 hours at 300 ℃ to obtain the intermediate;

and S4, heating the intermediate to 600 ℃ and preserving heat for 2.5 hours, then continuing heating to 1100 ℃ and preserving heat for 5 hours, then cooling to 600 ℃ and preserving heat for 3 hours, and then cutting off power and cooling to obtain the chip material, wherein the heating or cooling speed is 8 ℃/min.

Comparative example 1

The preparation method of the chip material provided by the comparative example is the same as that of the example 1, and the difference is that the components are different, specifically, the comparative example provides a chip material which comprises, by mass, trimanganese tetroxide of 40%; 37% of cobaltosic oxide; 23% of alumina, and the total is 100%.

Comparative example 2

The preparation method of the chip material provided by the comparative example is the same as that of the example 1, and the difference is that the components are different, specifically, the comparative example provides a chip material which comprises, by mass, trimanganese tetroxide of 40%; 37% of cobaltosic oxide; 15% of aluminum oxide and 8% of magnesium oxide, and the total content is 100%.

Comparative example 3

The composition and the compounding ratio of the chip material proposed in this comparative example were the same as those of example 1, except that the preparation method, specifically,

the preparation method of the chip material comprises the following steps:

s1, mixing the components according to the proportion, and performing ball milling for 9 hours at the speed of 240 circles/minute to obtain a first mixture;

s2, drying the first mixture at 100 ℃, then heating to 500 ℃ for carrying out primary calcination for 2 hours, then continuing heating to 900 ℃ for carrying out secondary calcination for 1 hour, and then powering off and cooling to obtain a second mixture; in the step, the temperature rising speed is 10 ℃/min, and the temperature reducing speed is 5 ℃/min;

s3, preparing an intermediate from the second mixture by adopting a wet casting process; specifically, the wet casting process includes: adding PVA glue into the second mixture, stirring to form slurry, casting for 3 times by using a casting machine to prepare a glue block, cutting the prepared glue block into square blocks of 15cm multiplied by 15cm, and carrying out heat preservation and glue discharge for 3 hours at 300 ℃ to obtain the intermediate;

and S4, heating the intermediate to 500 ℃ and preserving heat for 2 hours, then continuing heating to 1100 ℃ and preserving heat for 5 hours, and then powering off and cooling to obtain the chip material, wherein in the step, the heating or cooling speed is 5 ℃/min.

Application example

The thermistor is manufactured by adopting the chip materials of the examples 1-5 and the comparative examples 1-2, specifically, silver paste is coated on two sides of the chip material in the examples 1-5 or the comparative examples 1-2 to form silver electrodes, then a high-precision dicing saw is used for scribing small chips with the length and width of 1.0 multiplied by 1.0cm and the thickness of 0.5cm, then one end of a lead is welded on the silver electrodes, and then the small chips are packaged by epoxy resin. The annual drift rate and the R25 ± 1% resistance value range of the thermistors obtained in examples 1 to 5 and comparative examples 1 to 2 were measured using agilent 34401A and Ningbo day constant high-precision thermostatic bath, and the results are shown in table 1.

TABLE 1 results of performance test of thermistors made from chip materials of examples 1-5 and comparative examples 1-2

As can be seen from Table 1, the thermistor of each of the chip materials of examples 1 to 5 had a annual drift rate of less than 0.1% and as low as 0.03%, and the thermistor of each of the chip materials of comparative examples 1 and 2 had a higher annual drift rate; in addition, it can be seen that the resistance ranges of R25 + -1% of the chip materials of the examples provided by the invention are all higher, up to more than 90%, and up to 96%, while the resistance ranges of R25 + -1% of the thermistors made of the chip materials of the comparative examples 1 and 2 are all lower, as low as 45.9%, which indicates that the thermistors made of the chip materials provided by the invention have high precision. In addition, it can be seen that in addition to the components of the chip material affecting its performance, temperature control in the manufacturing process also has a greater impact on its performance.

The above-described embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.