Negative temperature coefficient thermistor chip and preparation method thereof

Abstract

The invention relates to the technical field of thermistors, and particularly discloses a negative temperature coefficient thermistor chip and a preparation method thereof. The negative temperature coefficient thermistor chip is prepared from the following raw materials in parts by weight: 771.24-771.34 parts of Mn3O4; 215.82-215. 92 parts of NiO; 12.79-12.89 parts of Al2O3; the preparation methodcomprises the following steps: S1, weighing materials; s2, mixing; s3, calcining; s4, carrying out micro-crushing; s5, carrying out spray granulation; s6, tabletting and forming; s7, pre-sintering; s8, sintering; s9, polishing; s10, brushing silver. The negative temperature coefficient thermistor chip has the advantages that the consistency of the resistance value and the B value is good, the resistance drift rate is smaller than 1% after the thermistor chip is used in a high-temperature environment for a long time, the service life is long, and the stability is high; in addition, the preparation method has the advantages of being high in particle dispersion degree, not prone to agglomeration and high in chip breaking strength.

Description

technical field [0001] This application relates to the technical field of thermistors, more specifically, it relates to a negative temperature coefficient thermistor chip and a preparation method thereof. Background technique [0002] Thermistor is a sensitive element, according to the temperature coefficient is divided into positive temperature coefficient thermistor (PTC) and negative temperature coefficient thermistor (NTC), the typical characteristic of thermistor is that it is sensitive to different temperature , Different resistance values ​​are exhibited at different temperatures. The higher the temperature of the PTC thermistor, the greater the resistance value. The higher the temperature of the NTC thermistor, the lower the resistance value. They both belong to semiconductor devices. [0003] Negative temperature coefficient thermistor is a semiconductor ceramic made of two or more metal oxides such as manganese, cobalt, nickel, copper, silicon, zinc, etc., which ar...

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Problems solved by technology

[0004] With the extensive and in-depth application research, it is found that NTC thermistors have serious aging problems during use, and the specific performance is: as time goes by, the room temperature resistance of NTC thermistors is unstable, that is, the thermal sensitivity index (B value ) and resistance value (R value) increase with the increase of use time, when the negative temperature coefficient thermistor is applied to high temperature equipment (such as large water dispenser, large water heater), it needs to work in a high temperature environment for a long time, generally in In a high temperature environment for 1000h, the resistance deviation of this type of resistor on the market reaches about 5%, which cannot meet the needs of long-term use of high-temperature equipment, and because the chip thickness and density are not enough, the chip is prone to breakdown and failure when current is passed repeatedly

[0005] In view of the above-mentioned related technologies, the inventor believes that when the negative temperature coefficient thermistor is used in high-temperature equipment for a long time, it is prone to drift in R value and B value, and when the current is passed repeatedly, the chip is easily broken down and fails.

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