NTC thermistor is widely used in household appliances, automobile, medical equipment, etc., especially plays an important role in temperature controlling, temperature monitoring and integrated circuit protection. The production principle of NTC thermistor is to mix nickel, manganese, cobalt and other metal oxides to co-heat and calcine at high temperature, and then carry out deep processing. Due to metal oxides are solid and it is difficult to avoid the problems of uneven mixing and large particle size difference when they are mixed, which will affect the precision and reliability of the produced thermistor, resulting in a narrow temperature measurement range of thermistor, limited linear relationship and low stability.
In view of the defects of the existing technology, EXSENSE Electronics recommends a high sensitive NTC thermistor material, which has great sensitivity, stable performance, good linearity, long service life and a wide range of temperature. At the same time, the NTC thermistor material has a low cost, easy to obtain raw materials, simple preparation method, and has a good application prospect. The high sensitive NTC thermistor is prepared as follows:
First, material preparation: 60 parts of Manganese Oxide, 10 parts of Nickel Oxide, 10 parts of Cobalt Oxide, 5 parts of Alumina Oxide, 0.5 parts of rare-earth chloride, 30 parts of organic solvent, 40 parts of adhesive, 0.5 parts of dispersing agent, 1 part of plasticizer. Among them, the rare-earth chloride is Holmium Chloride; The organic solvent is Ethanol; The adhesive is Acrylic Resin;The dispersing agent is Triton X-100; The plasticizer is Dibutyl Phthalate.
Second, add the above materials to the ball mill, ball mill and mix for 10 hours, and then add the ball mill mixture to the box-type calcining furnace and calcine the mixture for 1 hour at 920℃;
Third, the mixture, organic solvent, adhesive, dispersing agent, plasticizer are put into the blender and stir it for 30 minutes, the stirring speed is 100r/min, and then grind the slurry fully with the ball mill, grinding time is 6 hours, get the mixed slurry;
Fourth, the mixed slurry is placed in a vacuum tank, and the slurry is added to the water-absorbing bearing film by a conduit to obtain a film with a thickness of 30μm. Then the film is annular conveyed and dried by the oven at 30℃, circulating produce to get the designed number of layers, obtain the molded bar;
Fifth, the bar is cut, tape-ranked, sintered, polished and chamfered to obtain NTC thermistor material.
Compared with thermistor material produced by existing technology, this high sensitive NTC thermistor material has the following advantages:
(1) Add trace amounts of rare-earth oxides can greatly improve the stability of the material and prolong the service life of the material;
(2) With Manganese Oxide, Nickel Oxide, Cobalt Oxide and Alumina Oxide as the main components, the obtained thermistor material has good linearity and can be used in a wide temperature range, so as to avoid customers needing series thermistor in high temperature section because of small resistance value and weak signal.