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Preparation Method of NTC Thermistor Materials And Its Application In Electronic Devices-2
2018/10/30 02:10:34

Preparation Method of NTC Thermistor Materials And Its Application In Electronic Devices-2



 The NTC thermistor material obtained from the “Preparation Method of NTC Thermistor Materials And Its Application In Electronic Devices-1” is used to make electronic devices. The operations are as follows:


(1) The NTC thermistor material is cut into the required thickness, then coated the electrode slurry on its surface to make electrodes;

(2) Firing the material coated with the electrode slurry, control the temperature at 500-900, then cut the above-mentioned material into the desired form according to the actual need to be made of electronic devices;

(3) Doing the sensitizing heat treatment for the material obtained by the Step (2), the sensitization temperature is 200-600, the time is 50-100 hours;

(4) Soldered the lead wire to the material obtained by the Step (3), keep warm 100-500 hours to do the sophisticated processing at temperatures higher than electronic devices of actual use 1-10, add the shell and coat finally, made the electronic device.


As described in step (1), the material of the electrode comprises one and a number of combinations or their alloys in Ag, Pt, Pd, Au, the method of coating electrode slurry includes spraying, screen printing, brush printing or spin coating cover.

 

According to the above operations, the following is to introduce a specific example for reference, the operation are as follows:


(1) Use the analytical-reagent-grade Zinc Acetate, Cupric Acetate Monohydrate, Manganous Acetate, Oxalic Acid as raw materials, in accordance with the stoichiometric ratio shown in the CuZnMnO to weight Acetate, in accordance with the total metal ion content and mole ratio of Oxalic Acid 1:1 to weight Oxalic Acid, use Agate Ball as a ball-milling medium, use Ethyl Alcohol Absolute as a dispersant, mix them in the ball-milling machine. The quality ratio of raw material and Ethyl Alcohol Absolute is 1:1, the quality ratio of raw material and Agate Ball is 1:3, the ball-milling time is 0.5 hour, the ball-milling speed is 200 rpm/min.

(2) Dry the mixed Acetate powder after ball milling, the drying temperature is 70 .

(3) Move the dried powder into the muffle furnace, calcine 1 hour at 750 .

(4) Add the aqueous solution of Polyvinyl Alcohol (PVA) into the calcined powder as for granulation, the quality ratio of PVA and powder is 1:99.

(5) Use Isostatic Press makes the powder particle of step (4) into a disk-type NTC thermistor, forming pressure control at 300MPa.

(6) Heat the molded billet from room temperature to 1200 ℃ and sintering for 2 hours, control the heating rate to be 10/min.

(7) Use the inner circle cutting machine to cut the NTC thermistor chips obtained by step (6) into a thin sheet of 0.3mm.

(8) Coated the electrode slurry on the surface of the NTC thermistor chips obtained by step (7) to make electrodes.

(9) Firing the chips, control the temperature at 850 ℃, then use the cutting machine to cut the material obtained above into the chip of 0.6*0.3*0.3mm.

(10) Doing the sensitizing heat treatment for the NTC thermistor chips obtained by the Step (9), the sensitization temperature is 200 , the time is 100 hours.

(11) Soldered the lead wire to the NTC thermistor chips obtained by the Step (10), keep warm 100 hours to do the sophisticated processing at temperatures higher than electronic devices of actual use 1, doing the insulating treatment for the part of chip, add the shell and coat finally, made the electronic device.

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