EXSENSE Electronics Technology Co., Ltd. has been focusing on the research, development and production of NTC thermistor for automobile for more than 14 years. Thermistor for automobile sold by EXSENSE Electronic has the characteristics of high precision, high sensitivity and fast response, etc., which are widely used in automotive electronics and automotive oil temperature sensors.
NTC thermistor has the technical advantages of small fluctuation of resistance value and temperature characteristic, fast response time and high sensitivity, etc., but it has the technical problem of low detection temperature. Specific value of material constant B value is 25℃ and 50℃, 25℃and 85℃, the highest is only 25℃ and 100℃, due to highest temperature point is low, which can only be used for protection of electronic products of low temperature detection, for the motor over-temperature protection, temperature is determined according to the class of insulation protection, general motor insulation class is F, the limits of its temperature is 155℃, The protection temperature is set at 140℃, therefore, conventional NTC thermistor cannot become over-temperature protection induction motor components.
In order to solve the above technical problems, EXSENSE Electronics recommends a type of NTC thermistor for automobile, which improves the parameter range and precision requirements of the thermistor through the selection, dosage, ball milling medium ball of basic components, and the optimization of process method, makes the NTC thermistor suitable for the motor over-temperature protection device. The specific preparation method of this NTC thermistor for automobile is as follows:
First, preparation: 48 parts of Manganese Dioxide, 20 parts of Carbon Trioxide, 19 parts of Nickel Oxide, 6 parts of Copper Oxide, 2 parts of Iron Trioxide, 1 part of Cobalt Trioxide, 90 parts of Ethanol, 120 parts of Zirconium Dioxide ball, 8 parts of Silicon Dioxide;
Second, Manganese dioxide, Carbon Trioxide, Nickel Oxide, Copper Oxide, Iron Trioxide, Cobalt Trioxide, Ethanol, Zirconium Dioxide ball, Silicon Dioxide are uniformly mixed and ball milling. The revolving time of ball milling is 280r/min, and the ball milling time is 6.5 hours;
Third, the mixture is dried and heated to 750℃ for 3 hours to obtain powder;
Fourth, the obtained powder is ball-milled for the second time, the revolving time of ball milling is 280r/min, and the ball milled time is 6.5 hours;
Fifth, polyvinyl alcohol is added for granulation, pressed and sintered into ceramic wafers in a high temperature furnace at 1350℃;
Sixth, metal layer electrodes are printed and then cut to the desired NTC chip size according to the conventional process;
Seventh, after the welding leads are sealed with thermal insulation, the NTC thermistor for automobile is made.