阅读说明：本技术 一种高稳定性耐压ntc陶瓷热敏电阻及其制备工艺 (High-stability voltage-resistant NTC ceramic thermistor and preparation process thereof ) 是由 王梅凤 于 2020-12-02 设计创作，主要内容包括：本发明提出了一种高稳定性耐压NTC陶瓷热敏电阻及其制备工艺,该高稳定性耐压NTC陶瓷热敏电阻,包括质量比1:0.1-0.4的组分A、组分B,组分A为复合金属氧化物M_XO_Y,M包括Mn、Cr、Cu、RE,其中,Mn元素摩尔占比大于62%,(Cr+Cu)元素摩尔占比大于26%,RE元素占比为1-6.5%,组分B包括海绵铁、滑石粉、硬脂酸盐、偶联剂、pH调节剂、乙二醇,本申请通过合理的原料选配和针对性的工艺优化,制得的NTC陶瓷热敏电阻具有优异的电学性能稳定性,耐老化性强,对温度变化灵敏度高,B_(25/50)值高达7000K,高效实用。(The invention provides a high-stability voltage-resistant NTC ceramic thermistor and a preparation process thereof, wherein the high-stability voltage-resistant NTC ceramic thermistor comprises a component A and a component B in a mass ratio of 1:0.1-0.4, and the component A is a composite metal oxide M X O Y M comprises Mn, Cr, Cu and RE, wherein the molar ratio of Mn element is more than 62 percent, the molar ratio of (Cr + Cu) element is more than 26 percent, the molar ratio of RE element is 1-6.5 percent, and the component B comprises sponge iron, talcum powder, stearate, coupling agent, pH regulator and ethylene glycol 25/50 The value is as high as 7000K, and the method is efficient and practical.)

1. The utility model provides a withstand voltage NTC ceramic thermistor of high stability which characterized in that: comprises a component A and a component B in a mass ratio of 1:0.1-0.4, wherein the component A is a composite metal oxide M_XO_YM comprises Mn, Cr, Cu and RE, wherein the mol ratio of Mn element is more than 62 percent, the mol ratio of (Cr + Cu) element is more than 26 percent, the mol ratio of RE element is 1-6.5 percent, and the component B comprises sponge iron, talcum powder, stearate, coupling agent, pH regulator and glycol.

2. The high-stability voltage-withstanding NTC ceramic thermistor according to claim 1, wherein: RE is a composition of La and Ce, wherein the mass content of La is not less than 80%.

3. The high-stability voltage-withstanding NTC ceramic thermistor according to claim 1, wherein: the component B comprises 8-15 parts of sponge iron, 3-5 parts of talcum powder, 2-5 parts of stearate, 0.3-1 part of coupling agent, 0.2-2 parts of pH regulator and 8-25 parts of ethylene glycol.

4. The high-stability voltage-withstanding NTC ceramic thermistor according to claim 1, wherein: the stearate is a composition of calcium stearate and barium stearate, the molar ratio of the calcium stearate to the barium stearate is 1:0.5-2, the coupling agent is a silane coupling agent, and the pH regulator is dilute sulfuric acid and ammonia water.

5. The high-stability voltage-withstanding NTC ceramic thermistor according to claim 1, characterized in that the preparation process is as follows:

placing the component A in a ball mill, adding polyethylene glycol and sodium dodecyl sulfate, carrying out ball milling treatment, and then drying in an inert atmosphere to obtain a first material;

blending sponge iron, talcum powder and glycol in the component B, carrying out oscillation treatment in an ultrasonic oscillator for 10-40min, adding stearate and a coupling agent, continuing the oscillation treatment for 3-5min, and finally adjusting to 3.7-4.2 by using a pH regulator to obtain a material II;

adding the material I into the material II under the stirring condition, uniformly stirring at a high speed, sintering at a high temperature under an inert atmosphere, and cooling to room temperature in a staged manner to obtain a sintered material;

and crushing the sintered material into granules, then carrying out compression molding, demolding and drying to obtain the finished product.

6. The high-stability voltage-withstanding NTC ceramic thermistor according to claim 5, wherein: in the step 1), the polyethylene glycol adopts PEG-600 and PEG-1500 with the volume ratio of 1:1, the addition amount is 50-80% of the mass of the component A, the addition amount of the sodium dodecyl sulfate is 1.5-4% of the mass of the component A, the material-water ratio of the ball milling ball is 2:1:0.5, and the particle size of the material after ball milling drying is 0.5-1 mm.

7. The high-stability voltage-withstanding NTC ceramic thermistor according to claim 5, wherein: the inert atmosphere in the step 1) and the step 4) is nitrogen atmosphere, the drying temperature in the step 1) is 80 +/-5 ℃, and the sintering temperature in the step 4) is 850-1000 ℃.

8. The high-stability voltage-withstanding NTC ceramic thermistor according to claim 5, wherein: in the step 2), the ultrasonic frequency of the ultrasonic oscillator is 35-40KHz, and the power is 450W.

9. The high-stability voltage-withstanding NTC ceramic thermistor according to claim 5, wherein: the high-speed stirring in the step 4) is 1200-1500rpm, and the step-type cooling is specifically to cool the temperature to 650 ℃ at the speed of 10 ℃/min, then cool the temperature to 300 ℃ at the temperature of 20 ℃, and finally naturally cool the temperature to room temperature.

Technical Field

The invention relates to the technical field of sensors, in particular to a high-stability voltage-resistant NTC ceramic thermistor and a preparation process thereof.

Background

NTC thermistors refer to thermistor phenomena and materials with negative temperature coefficients that decrease in resistance exponentially with increasing temperature. The material is a semiconductor ceramic which is prepared by fully mixing, molding, sintering and other processes of two or more than two metal oxides of manganese, copper, silicon, cobalt, iron, nickel, zinc and the like, and can be prepared into a thermistor with a Negative Temperature Coefficient (NTC). The resistivity and material constant of the material vary with the material composition ratio, sintering atmosphere, sintering temperature and structural state. Non-oxide NTC thermistor materials typified by silicon carbide, tin selenide, tantalum nitride, and the like have also been developed. However, the conventional NTC thermal surface resistance material has a serious aging phenomenon due to self-heating when used at a temperature of above 300 ℃, and the conventional NTC thermal sensitive ceramic resistance material loses competitive advantages in the development of various high-end precision instruments due to the problems of nonlinear electrical property characteristics, moisture faults and the like.

Most NTC thermistor materials are produced and researched by still using the traditional solid-phase method production process, and the preparation of the powder material is finished by taking metal oxide or metal carbonate and alkali carbonate as raw materials through a series of processing processes such as ball milling, calcining and the like. In addition, the soft chemical synthesis method has also been widely used in the preparation and research of electronic ceramic powder materials, including coprecipitation method, homogeneous precipitation method, sol-gel method, hydrothermal method, etc. In the preparation of semiconductor ceramic materials by a sol-gel method.

Disclosure of Invention

In view of the above, the present invention aims to provide a high-stability voltage-withstanding NTC ceramic thermistor and a preparation process thereof, wherein the NTC ceramic thermistor prepared through reasonable raw material selection and targeted process optimization has excellent electrical property stability, strong aging resistance, high sensitivity to temperature change, and B_25/50The value is as high as 7000K, and the method is efficient and practical.

In order to achieve the purpose, the invention provides the following technical scheme:

a high-stability voltage-resistant NTC ceramic thermistor comprises a component A and a component B in a mass ratio of 1:0.1-0.4, wherein the component A is a composite metal oxide M_XO_YM comprises Mn, Cr, Cu and RE, wherein the mol ratio of Mn element is more than 62 percent, the mol ratio of (Cr + Cu) element is more than 26 percent, the mol ratio of RE element is 1-6.5 percent, and the component B comprises sponge iron, talcum powder, stearate, coupling agent, pH regulator and glycol.

As the invention further prefers, RE is a composition of La and Ce, wherein the content of La in mass percent is not less than 80%.

The invention is further preferably characterized in that the component B comprises 8-15 parts of sponge iron, 3-5 parts of talcum powder, 2-5 parts of stearate, 0.3-1 part of coupling agent, 0.2-2 parts of pH regulator and 8-25 parts of ethylene glycol.

In a further preferred embodiment of the invention, the stearate is a composition of calcium stearate and barium stearate, the molar ratio of the calcium stearate to the barium stearate is 1:0.5-2, the coupling agent is a silane coupling agent, and the pH regulator is dilute sulfuric acid and ammonia water.

As further optimization of the invention, the preparation process of the high-stability voltage-resistant NTC ceramic thermistor comprises the following steps:

1) placing the component A in a ball mill, adding polyethylene glycol and sodium dodecyl sulfate, carrying out ball milling treatment, and then drying in an inert atmosphere to obtain a first material;

2) blending sponge iron, talcum powder and glycol in the component B, carrying out oscillation treatment in an ultrasonic oscillator for 10-40min, adding stearate and a coupling agent, continuing the oscillation treatment for 3-5min, and finally adjusting to 3.7-4.2 by using a pH regulator to obtain a material II;

3) adding the material I into the material II under the stirring condition, uniformly stirring at a high speed, sintering at a high temperature under an inert atmosphere, and cooling to room temperature in a staged manner to obtain a sintered material;

4) and crushing the sintered material into granules, then carrying out compression molding, demolding and drying to obtain the finished product.

As further preferred in the invention, in the step 1), PEG-600 and PEG-1500 are adopted in a volume ratio of 1:1, the addition amount is 50-80% of the mass of the component A, the addition amount of sodium dodecyl sulfate is 1.5-4% of the mass of the component A, the water-to-powder ratio of the ball grinding balls is 2:1:0.5, and the particle size of the ball-milled and dried material is 0.5-1 mm.

Further preferably, the inert atmosphere in the step 1) and the step 4) is nitrogen atmosphere, the drying temperature in the step 1) is 80 +/-5 ℃, and the sintering temperature in the step 4) is 850-1000 ℃.

As a further preferred mode of the invention, the ultrasonic frequency of the ultrasonic oscillator in the step 2) is 35-40KHz and the power is 450W.

As a further preferred aspect of the invention, the high-speed stirring in step 4) is 1200-1500rpm, and the step-wise cooling is specifically to cool the temperature to 650 ℃ at 10 ℃/min, then cool the temperature to 300 ℃ at 20 ℃, and finally naturally cool the temperature to room temperature.

The invention has the beneficial effects that: through reasonable raw material selection and targeted process optimization, the prepared NTC ceramic thermistor has excellent electrical property stability, strong aging resistance and temperature change resistanceHigh sensitivity, B_25/50The value can reach 7000K, and is efficient and practical.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

Example 1:

a high-stability voltage-resistant NTC ceramic thermistor comprises a component A and a component B in a mass ratio of 1:0.3, wherein the component A is a composite metal oxide M_XO_YM comprises Mn, Cr, Cu and RE, wherein the molar ratio of (Cr + Cu) elements is 30 percent, the molar ratio of RE elements is 3.5 percent, and the balance of Mn elements is the molar ratio; the component B comprises 15 parts of sponge iron, 4 parts of talcum powder, 5 parts of stearate, 1.2 parts of coupling agent, 1.4 parts of pH regulator and 25 parts of glycol.

Specifically, RE is a composition of La and Ce, wherein the mass content of La accounts for 85%.

In the component B, the stearate is a composition of calcium stearate and barium stearate, the molar ratio of the calcium stearate to the barium stearate is 1:1, the coupling agent is a silane coupling agent, and the pH regulator is dilute sulfuric acid and ammonia water.

Based on the raw material components, the preparation process of the high-stability pressure-resistant NTC ceramic thermistor comprises the following steps:

1) placing the component A in a ball mill, adding polyethylene glycol and sodium dodecyl sulfate, carrying out ball milling treatment, and then drying in an inert atmosphere to obtain a first material;

2) blending sponge iron, talcum powder and glycol in the component B, carrying out oscillation treatment in an ultrasonic oscillator for 10-40min, adding stearate and a coupling agent, continuing the oscillation treatment for 3-5min, and finally adjusting to 3.7-4.2 by using a pH regulator to obtain a material II;

3) adding the material I into the material II under the stirring condition, uniformly stirring at a high speed, sintering at a high temperature under an inert atmosphere, and cooling to room temperature in a staged manner to obtain a sintered material;

4) and crushing the sintered material into granules, then carrying out compression molding, demolding and drying to obtain the finished product.

Further, in the step 1), PEG-600 and PEG-1500 are adopted in a volume ratio of 1:1 in the polyethylene glycol, the addition amount is 75% of the mass of the component A, the addition amount of sodium dodecyl sulfate is 2.2% of the mass of the component A, the water-to-powder ratio of the ball-milling ball material is 2:1:0.5, and the particle size of the ball-milled and dried material is 0.5-1 mm.

In the step 1) and the step 4), the inert atmosphere is nitrogen atmosphere, the drying temperature in the step 1) is 80 +/-5 ℃, and the sintering temperature in the step 4) is 950 ℃.

In the step 2), the ultrasonic frequency of the ultrasonic oscillator is 36KHz, and the power is 450W.

And 4) stirring at a high speed of 1500rpm in the step 4), and cooling to 650 ℃ at a speed of 10 ℃/min in a staged manner, then cooling to 300 ℃ at a temperature of 20 ℃, and finally naturally cooling to room temperature.

Example 2:

a high-stability voltage-resistant NTC ceramic thermistor comprises a component A and a component B in a mass ratio of 1:0.4, wherein the component A is a composite metal oxide M_XO_YM comprises Mn, Cr, Cu and RE, wherein the molar ratio of (Cr + Cu) elements is 30 percent, the molar ratio of RE elements is 1.5 percent, and the balance of Mn elements is the molar ratio; the component B comprises 12 parts of sponge iron, 5 parts of talcum powder, 2 parts of stearate, 0.5 part of coupling agent, 1 part of pH regulator and 15 parts of ethylene glycol.

Specifically, RE is a composition of La and Ce, wherein the mass content of La accounts for 85%.

In the component B, the stearate is a composition of calcium stearate and barium stearate, the molar ratio of the calcium stearate to the barium stearate is 1:1.5, the coupling agent is a silane coupling agent, and the pH regulator is dilute sulfuric acid and ammonia water.

Based on the raw material components, the preparation process of the high-stability pressure-resistant NTC ceramic thermistor comprises the following steps:

1) placing the component A in a ball mill, adding polyethylene glycol and sodium dodecyl sulfate, carrying out ball milling treatment, and then drying in an inert atmosphere to obtain a first material;

2) blending sponge iron, talcum powder and glycol in the component B, carrying out oscillation treatment in an ultrasonic oscillator for 10-40min, adding stearate and a coupling agent, continuing the oscillation treatment for 3-5min, and finally adjusting to 3.7-4.2 by using a pH regulator to obtain a material II;

3) adding the material I into the material II under the stirring condition, uniformly stirring at a high speed, sintering at a high temperature under an inert atmosphere, and cooling to room temperature in a staged manner to obtain a sintered material;

4) and crushing the sintered material into granules, then carrying out compression molding, demolding and drying to obtain the finished product.

Further, in the step 1), PEG-600 and PEG-1500 are adopted in a volume ratio of 1:1 in the polyethylene glycol, the addition amount is 70% of the mass of the component A, the addition amount of sodium dodecyl sulfate is 2.5% of the mass of the component A, the water-to-material ratio of the ball-milling ball is 2:1:0.5, and the particle size of the ball-milled and dried material is 0.5-1 mm.

In the step 1) and the step 4), the inert atmosphere is nitrogen atmosphere, the drying temperature in the step 1) is 80 +/-5 ℃, and the sintering temperature in the step 4) is 900 ℃.

In the step 2), the ultrasonic frequency of the ultrasonic oscillator is 40KHz, and the power is 450W.

And 4) stirring at a high speed of 1200rpm in the step 4), and cooling in a staged manner, namely cooling to 650 ℃ at a speed of 10 ℃/min, then cooling to 300 ℃ at a temperature of 20 ℃, and finally naturally cooling to room temperature.

Example 3:

a high-stability voltage-resistant NTC ceramic thermistor comprises a component A and a component B in a mass ratio of 1:0.2, wherein the component A is a composite metal oxide M_XO_YM comprises Mn, Cr, Cu and RE, wherein the molar ratio of (Cr + Cu) element is 28%, the molar ratio of RE element is 6.5%, and the rest is the molar ratio of Mn element; the component B comprises 15 parts of sponge iron, 3 parts of talcum powder, 5 parts of stearate, 0.8 part of coupling agent, 2 parts of pH regulator, and ethylene glycol,20 parts of ethylene glycol.

Specifically, RE is a composition of La and Ce, wherein the mass content of La accounts for 85%.

In the component B, the stearate is a composition of calcium stearate and barium stearate, the molar ratio of the calcium stearate to the barium stearate is 1:1, the coupling agent is a silane coupling agent, and the pH regulator is dilute sulfuric acid and ammonia water.

Based on the raw material components, the preparation process of the high-stability pressure-resistant NTC ceramic thermistor comprises the following steps:

1) placing the component A in a ball mill, adding polyethylene glycol and sodium dodecyl sulfate, carrying out ball milling treatment, and then drying in an inert atmosphere to obtain a first material;

2) blending sponge iron, talcum powder and glycol in the component B, carrying out oscillation treatment in an ultrasonic oscillator for 10-40min, adding stearate and a coupling agent, continuing the oscillation treatment for 3-5min, and finally adjusting to 3.7-4.2 by using a pH regulator to obtain a material II;

3) adding the material I into the material II under the stirring condition, uniformly stirring at a high speed, sintering at a high temperature under an inert atmosphere, and cooling to room temperature in a staged manner to obtain a sintered material;

4) and crushing the sintered material into granules, then carrying out compression molding, demolding and drying to obtain the finished product.

Further, in the step 1), PEG-600 and PEG-1500 are adopted in a volume ratio of 1:1 in the polyethylene glycol, the addition amount is 70% of the mass of the component A, the addition amount of sodium dodecyl sulfate is 1.5% of the mass of the component A, the water-to-material ratio of the ball-milling ball is 2:1:0.5, and the particle size of the ball-milled and dried material is 0.5-1 mm.

In the step 1) and the step 4), the inert atmosphere is nitrogen atmosphere, the drying temperature in the step 1) is 80 +/-5 ℃, and the sintering temperature in the step 4) is 1000 ℃.

In the step 2), the ultrasonic frequency of the ultrasonic oscillator is 40KHz, and the power is 450W.

And 4) stirring at a high speed of 1400rpm in the step 4), and cooling to 650 ℃ at a speed of 10 ℃/min in a staged manner, then cooling to 300 ℃ at a temperature of 20 ℃, and finally naturally cooling to room temperature.

Example 4:

a high-stability voltage-resistant NTC ceramic thermistor comprises a component A and a component B in a mass ratio of 1:0.1, wherein the component A is a composite metal oxide M_XO_YM comprises Mn, Cr, Cu and RE, wherein the molar ratio of (Cr + Cu) elements is 32%, the molar ratio of RE elements is 4.5%, and the molar ratio of Mn elements is the rest; the component B comprises 12 parts of sponge iron, 4 parts of talcum powder, 4 parts of stearate, 0.6 part of coupling agent, 1.4 parts of pH regulator and 20 parts of glycol.

Specifically, RE is a composition of La and Ce, wherein the mass content of La accounts for 85%.

In the component B, the stearate is a composition of calcium stearate and barium stearate, the molar ratio of the calcium stearate to the barium stearate is 1:2, the coupling agent is a silane coupling agent, and the pH regulator is dilute sulfuric acid and ammonia water.

Based on the raw material components, the preparation process of the high-stability pressure-resistant NTC ceramic thermistor comprises the following steps:

1) placing the component A in a ball mill, adding polyethylene glycol and sodium dodecyl sulfate, carrying out ball milling treatment, and then drying in an inert atmosphere to obtain a first material;

2) blending sponge iron, talcum powder and glycol in the component B, carrying out oscillation treatment in an ultrasonic oscillator for 10-40min, adding stearate and a coupling agent, continuing the oscillation treatment for 3-5min, and finally adjusting to 3.7-4.2 by using a pH regulator to obtain a material II;

3) adding the material I into the material II under the stirring condition, uniformly stirring at a high speed, sintering at a high temperature under an inert atmosphere, and cooling to room temperature in a staged manner to obtain a sintered material;

4) and crushing the sintered material into granules, then carrying out compression molding, demolding and drying to obtain the finished product.

Further, in the step 1), PEG-600 and PEG-1500 are adopted in a volume ratio of 1:1 in the polyethylene glycol, the addition amount is 80% of the mass of the component A, the addition amount of sodium dodecyl sulfate is 3.5% of the mass of the component A, the water-to-material ratio of the ball-milling ball is 2:1:0.5, and the particle size of the ball-milled and dried material is 0.5-1 mm.

In the step 1) and the step 4), the inert atmosphere is nitrogen atmosphere, the drying temperature in the step 1) is 80 +/-5 ℃, and the sintering temperature in the step 4) is 850 ℃.

In the step 2), the ultrasonic frequency of the ultrasonic oscillator is 40KHz, and the power is 450W.

And 4) stirring at a high speed of 1500rpm in the step 4), and cooling to 650 ℃ at a speed of 10 ℃/min in a staged manner, then cooling to 300 ℃ at a temperature of 20 ℃, and finally naturally cooling to room temperature.

Comparative example 1:

based on example 1, sponge iron was removed from component B and replaced by a bentonite supplement.

Comparative example 2:

based on example 1, the component A was directly subjected to ball milling and then sintered and extruded.

The product prepared by the embodiment of the invention is subjected to performance test, and the data is as follows:

	pressure resistance%	B25/50，K	After aging B25/50，K
				Example 1	6.8	6878	6445
Example 2	8.2	6936	6610
				Example 3	7.4	7150	6850
Example 4	8.5	7065	6416
				Comparative example 1	21.4	4550	3833
Comparative example 2	56	2689	1712
				Comparative example	37.5	3440	2036

Wherein, the voltage resistance IS detected by a low-temperature voltage resistance test device (IS-062), and the resistance change rate (25 ℃) when 15A current flows through the NTC thermistor IS tested;

B_25/50a temperature coefficient of resistance in the range of 25 to 50 ℃;

after aging B_25/50The temperature is alternately preserved for 30min at minus 50 ℃ and 150 ℃, and the resistance temperature coefficient is measured after the heat circulation is carried out for 100 times in sequence;

the comparative example is a commercially available NTC ceramic thermistor material.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.