A method for preparing a thermistor coating

Abstract

The present application relates to the technical field of thermistor coating, and discloses a preparation method of thermistor coating, which comprises the following steps: mixing chromium oxide, barium carbonate and titanium dioxide according to a weight ratio of 3:1:2 for standby; then adding 5-10% of the total amount of chromium oxide of nano-silicon dioxide and bentonite adjustment modifier, and stirring uniformly. The thermistor coating is prepared by using chromium oxide, barium carbonate and titanium dioxide, and the nano-silicon dioxide and bentonite adjustment modifier are used for adjustment and modification. The nano-silicon dioxide has a high specific surface agent, and the interlayer spacing of the bentonite is expanded after calcination. The dispersion and preparation liquid is prepared by using silane coupling agent, sodium alginate solution and other raw materials, so that the interface effect between the raw materials of the product is enhanced, the activity of the raw materials of the product is optimized, and the performance of the product is further improved and optimized in subsequent heat treatment and static pressure treatment.

Description

Technical Field

[0001] This invention relates to the field of resistive coating technology, and more specifically to a method for preparing a thermistor coating. Background Technology

[0002] Thermistors are a type of sensitive element, classified into positive temperature coefficient (PTC) thermistors and negative temperature coefficient (NTC) thermistors according to their temperature coefficient. A typical characteristic of thermistors is their sensitivity to temperature, exhibiting different resistance values ​​at different temperatures. PTC thermistors show increased resistance at higher temperatures, while NTC thermistors show decreased resistance at higher temperatures; both belong to the category of semiconductor devices. The main characteristics of thermistors are: high sensitivity, with a resistance temperature coefficient 10 to 100 times greater than that of metals, capable of detecting temperature changes as low as 10⁻⁶℃; wide operating temperature range, with room temperature devices suitable for -55℃ to 315℃, high temperature devices suitable for temperatures above 315℃ (currently reaching up to 2000℃), and low temperature devices suitable for -273℃ to -55℃; small size, enabling the measurement of temperatures in gaps, cavities, and blood vessels within living organisms that other thermometers cannot measure; ease of use, with resistance values ​​selectable arbitrarily between 0.1 and 100kΩ; easy to process into complex shapes, allowing for mass production; and good stability and strong overload capacity.

[0003] To improve breakdown performance, existing thermistor coatings have increased thickness, which leads to increased costs and fails to meet miniaturization requirements. In addition, the coatings have poor weather resistance under high and low temperature and acid corrosion conditions. Therefore, this invention further improves and optimizes them. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the purpose of this invention is to provide a method for preparing a thermistor coating to solve the problems mentioned in the background art.

[0005] The present invention solves the technical problem by adopting the following technical solution:

[0006] This invention provides a method for preparing a thermistor coating, comprising the following steps:

[0007] Step 1: Mix chromium oxide, barium carbonate, and titanium dioxide in a weight ratio of 3:1:2 and set aside.

[0008] Step 2: Then add 5-10% of nano-silica as a co-modifier and bentonite, and stir until homogeneous;

[0009] Step 3: Add the product from Step 2 to a dispersion solution that is 5-10 times the total weight of the product from Step 2 and disperse it thoroughly by ultrasonication.

[0010] Step 4: Wash and dry the product from Step 3, then heat-treat it to obtain the heat-treated body;

[0011] Step 5: Finally, perform static pressure treatment for 5-10 minutes at a static pressure of 20-30 MPa, then reduce the pressure to room temperature at a rate of 5-10℃ / min.

[0012] Preferably, the preparation method of the nano-silica co-modifying bentonite modifier is as follows:

[0013] S01: Bentonite is first placed in a hydrochloric acid solution with a total weight of 2-3 times the bentonite and stirred evenly. Then it is washed with water, dried, and calcined at a temperature of 450-550℃ for 10-20 minutes. After calcination, it is cooled to room temperature at a rate of 2-3℃ / min.

[0014] SO2: Mix nano-silica and SO1 bentonite products at a weight ratio of 2:5 until homogeneous, then add 5-10% of the total amount of nano-silica as a grinding agent and grind thoroughly.

[0015] S03: Add the product of S02 to 4-8 times the amount of chitosan compound treatment agent, stir thoroughly, and finally wash and dry to obtain nano-silica co-co-bentonite conditioning modifier.

[0016] Preferably, the hydrochloric acid solution has a mass fraction of 10-15%.

[0017] Preferably, the grinding agent is prepared by adding 2-5 parts of sodium carboxymethyl cellulose to 10-15 parts of deionized water, then adding 1-3 parts of yttrium nitrate and 2-5 parts of ammonia water, stirring evenly to obtain the grinding agent.

[0018] Preferably, the chitosan compound treatment agent comprises the following raw materials in parts by weight:

[0019] 10-15 parts chitosan, 20-30 parts sodium dodecyl sulfate solution, 1-3 parts silica sol, and 1-4 parts stearic acid.

[0020] Preferably, the sodium dodecyl sulfate solution has a mass fraction of 10-15%.

[0021] Preferably, the ultrasonic dispersion power in step three is 450-550W, and the ultrasonic time is 20-30min.

[0022] Preferably, the method for preparing the dispersion preparation solution is as follows:

[0023] Add 5-10 parts of coupling agent KH560 to 10-20 parts of deionized water, then add 1-3 parts of citric acid and 2-4 parts of sodium alginate solution, stir well to obtain a dispersion preparation solution.

[0024] Preferably, the sodium alginate solution has a mass fraction of 10-20%.

[0025] Preferably, the heating heat treatment involves raising the temperature from room temperature to 700-750°C at a rate of 6-10°C / s, holding the temperature for 10-15 minutes, and then continuing to raise the temperature to 1050-1100°C at a rate of 1-3°C / s, and holding the temperature thereafter.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The resistive coating of this invention uses chromium oxide, barium carbonate, and titanium dioxide in combination, and is modified by a bentonite modifier in conjunction with nano-silica. Nano-silica has a high specific surface area, and the interlayer spacing of bentonite expands after calcination. A grinding agent composed of sodium carboxymethyl cellulose, yttrium nitrate, and ammonia further modifies the raw materials, enhancing their activity and dispersibility. A chitosan compound treatment agent, combining chitosan, sodium dodecyl sulfate solution, silica sol, and stearic acid, enhances the synergistic modification effect of bentonite and nano-silica, thereby improving the breakdown resistance and weather resistance of the resistive product raw materials. The dispersion preparation liquid uses silane coupling agents, sodium alginate solution, and other raw materials to enhance the interfacial effect between the product raw materials and optimize their activity, thus further improving and optimizing the product's performance in subsequent heat treatment and hydrostatic pressing. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] This embodiment describes a method for preparing a thermistor coating, comprising the following steps:

[0030] Step 1: Mix chromium oxide, barium carbonate, and titanium dioxide in a weight ratio of 3:1:2 and set aside.

[0031] Step 2: Then add 5-10% of nano-silica as a co-modifier and bentonite, and stir until homogeneous;

[0032] Step 3: Add the product from Step 2 to 5-10 times its volume of dispersion solution and disperse it thoroughly by ultrasonication;

[0033] Step 4: Wash and dry the product from Step 3, then heat-treat it to obtain the heat-treated body;

[0034] Step 5: Finally, perform static pressure treatment for 5-10 minutes at a static pressure of 20-30 MPa, then reduce the pressure to room temperature at a rate of 5-10℃ / min.

[0035] The preparation method of the nano-silica co-modifying bentonite modifier in this embodiment is as follows:

[0036] S01: Bentonite is first placed in 2-3 times the amount of hydrochloric acid solution and stirred evenly, then washed with water and dried, and then calcined at 450-550℃ for 10-20 minutes. After calcination, it is cooled to room temperature at a rate of 2-3℃ / min.

[0037] SO2: Mix nano-silica and SO1 bentonite products at a weight ratio of 2:5 until homogeneous, then add 5-10% of the total amount of nano-silica as a grinding agent and grind thoroughly.

[0038] S03: Add the product of S02 to 4-8 times the amount of chitosan compound treatment agent, stir thoroughly, and finally wash and dry to obtain nano-silica co-co-bentonite conditioning modifier.

[0039] The hydrochloric acid solution in this embodiment has a mass fraction of 10-15%.

[0040] The preparation method of the abrasive in this embodiment is as follows: 2-5 parts of sodium carboxymethyl cellulose are added to 10-15 parts of deionized water, then 1-3 parts of yttrium nitrate and 2-5 parts of ammonia are added, and the mixture is stirred evenly to obtain the abrasive.

[0041] The chitosan compound treatment agent in this embodiment includes the following raw materials in parts by weight:

[0042] 10-15 parts chitosan, 20-30 parts sodium dodecyl sulfate solution, 1-3 parts silica sol, and 1-4 parts stearic acid.

[0043] The sodium dodecyl sulfate solution in this embodiment has a mass fraction of 10-15%.

[0044] In this embodiment, the ultrasonic power for sufficient dispersion in step three is 450-550W, and the ultrasonic time is 20-30min.

[0045] The preparation method of the dispersion preparation solution in this embodiment is as follows:

[0046] Add 5-10 parts of coupling agent KH560 to 10-20 parts of deionized water, then add 1-3 parts of citric acid and 2-4 parts of sodium alginate solution, stir well to obtain a dispersion preparation solution.

[0047] The sodium alginate solution in this embodiment has a mass fraction of 10-20%.

[0048] In this embodiment, the heat treatment involves raising the temperature from room temperature to 700-750°C at a rate of 6-10°C / s, holding it at that temperature for 10-15 minutes, and then continuing to raise the temperature to 1050-1100°C at a rate of 1-3°C / s, holding it at that temperature.

[0049] Example 1. A method for preparing a thermistor coating according to this example includes the following steps:

[0050] Step 1: Mix chromium oxide, barium carbonate, and titanium dioxide in a weight ratio of 3:1:2 and set aside.

[0051] Step 2: Then add 5% of the total chromium oxide content of nano-silica and bentonite as a modifier, and stir until homogeneous;

[0052] Step 3: Add the product from Step 2 to 5 times the volume of the dispersion solution and disperse it thoroughly by ultrasonication;

[0053] Step 4: Wash and dry the product from Step 3, then heat-treat it to obtain the heat-treated body;

[0054] Step 5: Finally, perform static pressure treatment for 5 minutes at a static pressure of 20 MPa, then reduce the pressure to room temperature at a rate of 5℃ / min.

[0055] The preparation method of the nano-silica co-modifying bentonite modifier in this embodiment is as follows:

[0056] S01: Bentonite is first placed in 2 times the amount of hydrochloric acid solution and stirred evenly, then washed with water and dried, and then calcined at 450℃ for 10 minutes. After calcination, it is cooled to room temperature at a rate of 2℃ / min.

[0057] SO2: Mix nano-silica and SO1 bentonite products at a weight ratio of 2:5 until homogeneous, then add 5-10% of the total amount of nano-silica as a grinding agent and grind thoroughly.

[0058] S03: Add the product of S02 to 4-8 times the amount of chitosan compound treatment agent, stir thoroughly, and finally wash and dry to obtain nano-silica co-co-bentonite conditioning modifier.

[0059] The hydrochloric acid solution in this embodiment has a mass fraction of 10%.

[0060] The preparation method of the abrasive in this embodiment is as follows: 2 parts of sodium carboxymethyl cellulose are added to 10 parts of deionized water, then 1 part of yttrium nitrate and 2 parts of ammonia are added, and the mixture is stirred evenly to obtain the abrasive.

[0061] The chitosan compound treatment agent in this embodiment includes the following raw materials in parts by weight:

[0062] 10 parts chitosan, 20 parts sodium dodecyl sulfate solution, 1 part silica sol, and 1 part stearic acid.

[0063] The sodium dodecyl sulfate solution in this embodiment has a mass fraction of 10%.

[0064] In this embodiment, the ultrasonic power for sufficient dispersion in step three is 450W, and the ultrasonic time is 20min.

[0065] The preparation method of the dispersion preparation solution in this embodiment is as follows:

[0066] Add 5 parts of coupling agent KH560 to 10 parts of deionized water, then add 1 part of citric acid and 2 parts of sodium alginate solution, stir well to obtain a dispersion preparation solution.

[0067] The sodium alginate solution in this embodiment has a mass fraction of 10%.

[0068] In this embodiment, the heat treatment involves raising the temperature from room temperature to 700°C at a rate of 6°C / s, holding it at that temperature for 10 minutes, and then continuing to raise the temperature to 1050°C at a rate of 1°C / s and holding it thereafter.

[0069] Example 2. A method for preparing a thermistor coating according to this example includes the following steps:

[0070] Step 1: Mix chromium oxide, barium carbonate, and titanium dioxide in a weight ratio of 3:1:2 and set aside.

[0071] Step 2: Then add 10% of the total chromium oxide content of nano-silica and bentonite as a modifier, and stir until homogeneous;

[0072] Step 3: Add the product from Step 2 to a 10-fold dilution of dispersion solution and ultrasonically disperse thoroughly.

[0073] Step 4: Wash and dry the product from Step 3, then heat-treat it to obtain the heat-treated body;

[0074] Step 5: Finally, perform static pressure treatment for 10 minutes at a static pressure of 30 MPa, and then reduce the temperature to room temperature at a rate of 10℃ / min.

[0075] The preparation method of the nano-silica co-modifying bentonite modifier in this embodiment is as follows:

[0076] S01: Bentonite is first placed in 3 times the amount of hydrochloric acid solution and stirred evenly, then washed with water and dried, and then calcined at 550℃ for 20 minutes. After calcination, it is cooled to room temperature at a rate of 3℃ / min.

[0077] S02: Mix nano-silica and bentonite products of SO1 at a weight ratio of 2:5 until uniform, then add 10% of the total amount of nano-silica as a grinding agent and grind thoroughly.

[0078] S03: Add the product of S02 to 8 times the amount of chitosan compound treatment agent, stir thoroughly, and finally wash and dry to obtain nano-silica co-co-bentonite conditioning modifier.

[0079] The hydrochloric acid solution in this embodiment has a mass fraction of 15%.

[0080] The preparation method of the abrasive in this embodiment is as follows: 5 parts of sodium carboxymethyl cellulose are added to 15 parts of deionized water, then 3 parts of yttrium nitrate and 5 parts of ammonia are added, and the mixture is stirred evenly to obtain the abrasive.

[0081] The chitosan compound treatment agent in this embodiment includes the following raw materials in parts by weight:

[0082] 15 parts chitosan, 30 parts sodium dodecyl sulfate solution, 3 parts silica sol, and 4 parts stearic acid.

[0083] The sodium dodecyl sulfate solution in this embodiment has a mass fraction of 15%.

[0084] In this embodiment, the ultrasonic power for sufficient dispersion in step three is 550W, and the ultrasonic time is 30min.

[0085] The preparation method of the dispersion preparation solution in this embodiment is as follows:

[0086] Add 10 parts of coupling agent KH560 to 20 parts of deionized water, then add 3 parts of citric acid and 4 parts of sodium alginate solution, stir well to obtain a dispersion preparation solution.

[0087] The sodium alginate solution in this embodiment has a mass fraction of 20%.

[0088] In this embodiment, the heat treatment involves raising the temperature from room temperature to 750°C at a rate of 10°C / s, holding it at that temperature for 15 minutes, and then continuing to raise the temperature to 1100°C at a rate of 3°C / s and holding it thereafter.

[0089] Example 3. A method for preparing a thermistor coating according to this example includes the following steps:

[0090] Step 1: Mix chromium oxide, barium carbonate, and titanium dioxide in a weight ratio of 3:1:2 and set aside.

[0091] Step 2: Then add 7.5% of nano-silica as a modifier and bentonite, and stir until homogeneous;

[0092] Step 3: Add the product from Step 2 to a 7.5-fold dilution of dispersion solution and ultrasonically disperse thoroughly.

[0093] Step 4: Wash and dry the product from Step 3, then heat-treat it to obtain the heat-treated body;

[0094] Step 5: Finally, perform static pressure treatment for 7.5 minutes at a static pressure of 25 MPa, and then reduce the temperature to room temperature at a rate of 7.5℃ / min.

[0095] The preparation method of the nano-silica co-modifying bentonite modifier in this embodiment is as follows:

[0096] S01: Bentonite is first placed in 2.5 times the amount of hydrochloric acid solution and stirred evenly, then washed with water and dried, and then calcined at 500℃ for 15 minutes. After calcination, it is cooled to room temperature at a rate of 2.5℃ / min.

[0097] SO2: Mix nano-silica and SO1 bentonite products evenly at a weight ratio of 2:5, then add 7.5% of the total amount of nano-silica grinding agent and grind thoroughly.

[0098] S03: Add the product of S02 to 6 times the amount of chitosan compound treatment agent, stir thoroughly, and finally wash and dry to obtain nano-silica co-co-bentonite conditioning modifier.

[0099] The hydrochloric acid solution in this embodiment has a mass fraction of 12.5%.

[0100] The preparation method of the abrasive in this embodiment is as follows: 3.5 parts of sodium carboxymethyl cellulose are added to 12.5 parts of deionized water, then 2 parts of yttrium nitrate and 3.5 parts of ammonia are added and stirred evenly to obtain the abrasive.

[0101] The chitosan compound treatment agent in this embodiment includes the following raw materials in parts by weight:

[0102] 12.5 parts chitosan, 25 parts sodium dodecyl sulfate solution, 2 parts silica sol, and 2.5 parts stearic acid.

[0103] The sodium dodecyl sulfate solution in this embodiment has a mass fraction of 12.5%.

[0104] In this embodiment, the ultrasonic power for sufficient dispersion in step three is 500W, and the ultrasonic time is 25min.

[0105] The preparation method of the dispersion preparation solution in this embodiment is as follows:

[0106] Add 7.5 parts of coupling agent KH560 to 15 parts of deionized water, then add 2 parts of citric acid and 3 parts of sodium alginate solution, stir well to obtain a dispersion preparation solution.

[0107] The sodium alginate solution in this embodiment has a mass fraction of 15%.

[0108] In this embodiment, the heat treatment involves raising the temperature from room temperature to 725°C at a rate of 8°C / s, holding it at that temperature for 12.5 minutes, and then continuing to raise the temperature to 1060°C at a rate of 2°C / s, followed by holding the temperature.

[0109] Example 4. A method for preparing a thermistor coating according to this example includes the following steps:

[0110] Step 1: Mix chromium oxide, barium carbonate, and titanium dioxide in a weight ratio of 3:1:2 and set aside.

[0111] Step 2: Then add 6% of nano-silica as a co-modifier and bentonite, and stir until homogeneous;

[0112] Step 3: Add the product from Step 2 to a 6-fold dilution of dispersion solution and ultrasonically disperse thoroughly.

[0113] Step 4: Wash and dry the product from Step 3, then heat-treat it to obtain the heat-treated body;

[0114] Step 5: Finally, perform static pressure treatment for 6 minutes at a static pressure of 22 MPa, then reduce the pressure to room temperature at a rate of 6℃ / min.

[0115] The preparation method of the nano-silica co-modifying bentonite modifier in this embodiment is as follows:

[0116] S01: Bentonite is first placed in 2.2 times the amount of hydrochloric acid solution and stirred evenly, then washed with water and dried, and then calcined at 460℃ for 12 minutes. After calcination, it is cooled to room temperature at a rate of 2.2℃ / min.

[0117] S02: Mix nano-silica and bentonite products of SO1 at a weight ratio of 2:5 until uniform, then add 6% of the total amount of nano-silica grinding agent and grind thoroughly.

[0118] S03: Add the product of S02 to 5 times the amount of chitosan compound treatment agent, stir thoroughly, and finally wash and dry to obtain nano-silica co-co-bentonite conditioning modifier.

[0119] The hydrochloric acid solution in this embodiment has a mass fraction of 11%.

[0120] The preparation method of the abrasive in this embodiment is as follows: 3 parts of sodium carboxymethyl cellulose are added to 2 parts of deionized water, then 2 parts of yttrium nitrate and 3 parts of ammonia are added, and the mixture is stirred evenly to obtain the abrasive.

[0121] The chitosan compound treatment agent in this embodiment includes the following raw materials in parts by weight:

[0122] 11 parts chitosan, 22 parts sodium dodecyl sulfate solution, 1.2 parts silica sol, and 2 parts stearic acid.

[0123] The sodium dodecyl sulfate solution in this embodiment has a mass fraction of 12%.

[0124] In this embodiment, the ultrasonic power for sufficient dispersion in step three is 460W, and the ultrasonic time is 22min.

[0125] The preparation method of the dispersion preparation solution in this embodiment is as follows:

[0126] Add 6 parts of coupling agent KH560 to 12 parts of deionized water, then add 2 parts of citric acid and 3 parts of sodium alginate solution, stir well to obtain a dispersion preparation solution.

[0127] The sodium alginate solution in this embodiment has a mass fraction of 12%.

[0128] In this embodiment, the heat treatment involves raising the temperature from room temperature to 710°C at a rate of 7°C / s, holding it at that temperature for 12 minutes, and then continuing to raise the temperature to 1060°C at a rate of 2°C / s and holding it thereafter.

[0129] Example 5. A method for preparing a thermistor coating according to this example includes the following steps:

[0130] Step 1: Mix chromium oxide, barium carbonate, and titanium dioxide in a weight ratio of 3:1:2 and set aside.

[0131] Step 2: Then add 9% of nano-silica as a co-modifier and bentonite, and stir until homogeneous;

[0132] Step 3: Add the product from Step 2 to a 9-fold dilution of dispersion solution and ultrasonically disperse thoroughly.

[0133] Step 4: Wash and dry the product from Step 3, then heat-treat it to obtain the heat-treated body;

[0134] Step 5: Finally, perform static pressure treatment for 8 minutes at a static pressure of 28 MPa, and then reduce the temperature to room temperature at a rate of 9℃ / min.

[0135] The preparation method of the nano-silica co-modifying bentonite modifier in this embodiment is as follows:

[0136] S01: Bentonite is first placed in 2.8 times the amount of hydrochloric acid solution and stirred evenly, then washed with water and dried, and then calcined at 540℃ for 18 minutes. After calcination, it is cooled to room temperature at a rate of 2.8℃ / min.

[0137] S02: Mix nano-silica and bentonite products of SO1 at a weight ratio of 2:5 until uniform, then add 9% of the total amount of nano-silica grinding agent and grind thoroughly.

[0138] S03: Add the product of S02 to 7 times the amount of chitosan compound treatment agent, stir thoroughly, and finally wash and dry to obtain nano-silica co-co-bentonite conditioning modifier.

[0139] The hydrochloric acid solution in this embodiment has a mass fraction of 14%.

[0140] The preparation method of the abrasive in this embodiment is as follows: 4 parts of sodium carboxymethyl cellulose are added to 14 parts of deionized water, then 2.8 parts of yttrium nitrate and 4 parts of ammonia are added, and the mixture is stirred evenly to obtain the abrasive.

[0141] The chitosan compound treatment agent in this embodiment includes the following raw materials in parts by weight:

[0142] 14 parts chitosan, 28 parts sodium dodecyl sulfate solution, 2 parts silica sol, and 3 parts stearic acid.

[0143] The sodium dodecyl sulfate solution in this embodiment has a mass fraction of 14%.

[0144] In this embodiment, the ultrasonic power for sufficient dispersion in step three is 520W, and the ultrasonic time is 28min.

[0145] The preparation method of the dispersion preparation solution in this embodiment is as follows:

[0146] Add 9 parts of coupling agent KH560 to 18 parts of deionized water, then add 2 parts of citric acid and 3 parts of sodium alginate solution, stir well to obtain a dispersion preparation solution.

[0147] The sodium alginate solution in this embodiment has a mass fraction of 18%.

[0148] In this embodiment, the heat treatment involves raising the temperature from room temperature to 745°C at a rate of 8°C / s, holding it at that temperature for 14 minutes, and then continuing to raise the temperature to 1090°C at a rate of 2°C / s and holding it thereafter.

[0149] Comparative Example 1 differs from Example 3 in that no nano-silica co-modifying bentonite modifier was added.

[0150] Comparative Example 2 differs from Example 3 in that no grinding agent was added during the preparation of the nano-silica co-modified bentonite modifier.

[0151] Comparative Example 3 differs from Example 3 in that yttrium nitrate was not added during the preparation of the abrasive.

[0152] Comparative Example 4 differs from Example 3 in that the nano-silica co-modifier and bentonite modifier are directly mixed at a ratio of 2:5 instead of nano-silica and bentonite.

[0153] Comparative Example 5 differs from Example 3 in that graphene is used instead of bentonite in the preparation of the nano-silica co-modifier.

[0154] Comparative Example 6 differs from Example 3 in that it did not use a dispersion preparation solution.

[0155] Comparative Example 7 differs from Example 3 in that it did not employ static pressure treatment.

[0156] Apply AC voltage and test the maximum voltage that the coating can withstand without breakdown for 1 minute. At the same time, test the coating for cracking under alternating hot and cold temperatures of -40℃ / 30min to 125℃ / 30min.

[0157] The performance measurement results of Examples 1-5 and Comparative Examples 1-6 are as follows:

[0158]

[0159] From Examples 1-5 and Comparative Examples 1-7, it can be seen that the product of Example 3 of the present invention has excellent coating pressure resistance and cycle count performance at a coating thickness of 0.35.

[0160] As can be seen from Comparative Examples 1-6, the performance of products without the addition of nano-silica co-modifiers and bentonite modifiers is significantly reduced. Furthermore, in the preparation of nano-silica co-modifiers and bentonite modifiers, the use of graphene instead of nano-silica, and the direct mixing of nano-silica and bentonite in a 2:5 ratio, all resulted in a deterioration in product performance. The selection of nano-silica and bentonite as raw materials significantly improved product performance. In the preparation of nano-silica co-modifiers and bentonite modifiers, the absence of abrasives and the absence of yttrium nitrate in the abrasive preparation both led to performance degradation. The selection and optimization of abrasives improved product performance. Only the nano-silica co-modifier and bentonite modifier prepared using the method of this invention showed the best performance optimization effect.

[0161] The product was placed in a 2-5% hydrochloric acid environment for 24 hours before performance testing.

[0162]

[0163] The product of this invention does not contain nano-silica co-modified bentonite. After being placed in a 2-5% hydrochloric acid environment for 24 hours, the stability of the product is significantly reduced. The nano-silica co-modified bentonite has an important effect on improving the acid corrosion stability of the product. At the same time, the product of this invention has excellent resistance to puncture, acid corrosion and weathering.

[0164] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0165] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a thermistor coating, characterized in that, Includes the following steps: Step 1: Mix chromium oxide, barium carbonate, and titanium dioxide in a weight ratio of 3:1:2 and set aside. Step 2: Then add 5-10% of nano-silica as a co-modifier and bentonite, and stir until homogeneous; Step 3: Add the product from Step 2 to a dispersion solution that is 5-10 times the total weight of the product from Step 2 and disperse it thoroughly by ultrasonication. Step 4: Wash and dry the product from Step 3, then heat-treat it to obtain the heat-treated body; Step 5: Finally, perform static pressure treatment for 5-10 minutes, with a static pressure of 20-30 MPa, and then reduce the pressure to room temperature at a rate of 5-10℃ / min. The preparation method of the nano-silica co-modifying bentonite modifier is as follows: S01: Bentonite is first placed in a hydrochloric acid solution with a total weight of 2-3 times the bentonite and stirred evenly. Then it is washed with water, dried, and calcined at a temperature of 450-550℃ for 10-20 minutes. After calcination, it is cooled to room temperature at a rate of 2-3℃ / min. SO2: Mix nano-silica and SO1 bentonite products at a weight ratio of 2:5 until homogeneous, then add 5-10% of the total amount of nano-silica as a grinding agent and grind thoroughly. S03: Add the product of S02 to 4-8 times the amount of chitosan compound treatment agent, stir thoroughly, and finally wash and dry to obtain nano-silica co-co-bentonite conditioning modifier. The chitosan compound treatment agent comprises the following raw materials in parts by weight: Chitosan 10-15 parts, sodium dodecyl sulfate solution 20-30 parts, silica sol 1-3 parts, stearic acid 1-4 parts; The method for preparing the dispersion solution is as follows: Add 5-10 parts of coupling agent KH560 to 10-20 parts of deionized water, then add 1-3 parts of citric acid and 2-4 parts of sodium alginate solution, stir well to obtain a dispersion preparation solution.

2. The method for preparing a thermistor coating according to claim 1, characterized in that, The hydrochloric acid solution has a mass fraction of 10-15%.

3. The method for preparing a thermistor coating according to claim 2, characterized in that, The grinding agent is prepared by adding 2-5 parts of sodium carboxymethyl cellulose to 10-15 parts of deionized water, then adding 1-3 parts of yttrium nitrate and 2-5 parts of ammonia water, stirring evenly to obtain the grinding agent.

4. The method for preparing a thermistor coating according to claim 3, characterized in that, The sodium dodecyl sulfate solution has a mass fraction of 10-15%.

5. The method for preparing a thermistor coating according to claim 1, characterized in that, In step three, the ultrasonic dispersion power is 450-550W, and the ultrasonic time is 20-30min.

6. The method for preparing a thermistor coating according to claim 5, characterized in that, The sodium alginate solution has a mass fraction of 10-20%.

7. The method for preparing a thermistor coating according to claim 1, characterized in that, The heating process involves raising the temperature from room temperature to 700-750℃ at a rate of 6-10℃ / s, holding the temperature for 10-15 minutes, and then continuing to raise the temperature to 1050-1100℃ at a rate of 1-3℃ / s, followed by holding the temperature.

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