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Negative temperature coefficient (NTC) material utilized at high temperature and preparation method thereof

A high temperature, raw material technology, applied in the field of NTC materials and its preparation, can solve the problems of low resistivity and low resistance drift rate

Active Publication Date: 2011-10-19
XI AN JIAOTONG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Moreover, the problem of the aging rate of NTC thermistors has not been resolved. The key issue for the development of high-temperature NTCs is to realize the sensitivity of resistance to temperature at high temperature, that is, high B constant, high resistivity and high temperature stability, that is, low resistance. Drift rate

Method used

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  • Negative temperature coefficient (NTC) material utilized at high temperature and preparation method thereof
  • Negative temperature coefficient (NTC) material utilized at high temperature and preparation method thereof
  • Negative temperature coefficient (NTC) material utilized at high temperature and preparation method thereof

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Embodiment 1

[0029] The raw material component of the present embodiment is: 5wt.% La 2 o 3 , 5wt.%ZrO 2 , the rest is Ni 0.6 mn 1.8 al 0.6 o 4 .

[0030] This embodiment includes the following steps:

[0031] Step 1, according to Ni 0.6 mn 1.8 al 0.6 o 4 Weigh the various oxide starting materials, namely MnO, at the stoichiometric molar ratios shown in 2 , NiO, Al2 o 3 , it was mixed evenly by wet ball milling, using absolute ethanol and agate balls as the ball milling medium, the volume ratio of raw materials and absolute ethanol was 1:2, the volume ratio of balls and materials was 2.5:1, and the ball milling time was controlled 8 hours, the power of the ball mill is 0.75KW;

[0032] Step 2. Ni after ball milling 0.6 mn 1.8 Al 0.6 o 4 The powder is dried, and the dried powder is pre-fired at 900°C for 3 hours in an air atmosphere, and the heating rate is 3°C / min;

[0033] Step 3, the pre-burned Ni 0.6 mn 1.8 Al 0.6 o 4 Powder and 5wt.% La 2 o 3 Powder, 5wt.%ZrO 2...

Embodiment 2

[0037] The raw material component of the present embodiment is: 5wt.% La 2 o 3 , 7.5wt.%ZrO 2 , the rest is Ni 0.6 mn 1.8 Al 0.6 o 4 .

[0038] This embodiment includes the following steps:

[0039] Step 1, according to Ni 0.6 mn 1.8 Al 0.6 o 4 Stoichiometric molar ratios shown Weighing various oxide starting materials, i.e. MnO 2 , NiO, Al 2 o 3 , it was mixed evenly by wet ball milling, using absolute ethanol and agate balls as the ball milling medium, the volume ratio of raw materials and absolute ethanol was 1:2, the volume ratio of balls and materials was 2.5:1, and the ball milling time was controlled 10 hours, the power of the ball mill is 0.75KW;

[0040] Step 2. Ni after ball milling 0.6 mn 1.8 Al 0.6 o 4 The powder is dried, and the dried powder is pre-fired at 1000° C. for 1 hour in an air atmosphere, and the heating rate is 5° C. / min.

[0041] Step 3, the pre-burned Ni 0.6 mn 1.8 Al 0.6 o 4 Powder and 5wt.% La 2 o 3 Powder, 7.5wt.%ZrO 2 Ba...

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Abstract

The invention discloses a negative temperature coefficient (NTC) material utilized at a high temperature, and a preparation method thereof. The NTC material comprises 2 to 10 wt% of La2O3, 5 to 20 wt% of ZrO2, and the rest of Ni0.6Mn1.8Al0.6O4. In the invention, oxides which comprise MnO2, NiO and Al2O3 and are traditional materials for preparation of NTC materials are utilized as base materials;a rare earth oxide La2O3 is added into the base materials to improve a stability of the base materials and reduce a ageing rate; and simultaneously, non-conducting ZrO2 is added into the base materials to improve a resistivity of the base materials and an activation energy thereby improving a constant B of the base materials. The NTC material can be utilized at a temperature more than 400 DEG C, and has a room temperature resistivity of 27900 to 64520 omega cm, a constant B of 4529 to 7895 K and a resistance drift rate of 0.6 to 2.3%.

Description

technical field [0001] The invention relates to an NTC material and a synthesis method thereof, in particular to an NTC material with high resistance and high stability at a high temperature of 400-600° C. and a preparation method thereof. Background technique [0002] Negative temperature coefficient (NTC) thermistor is mainly a semiconductor ceramic material formed by mixing and sintering various transition metal oxides (manganese, nickel, copper, aluminum, cobalt, chromium, iron, zinc, etc.). It exhibits a resistance-temperature characteristic in which the resistance decreases exponentially with the increase of temperature, that is, R=R 0 e ΔE / kT Utilizing this characteristic makes NTC materials widely used in temperature measurement, temperature control, overload protection, voltage regulation limiting and other related fields in industry. The main parameters of NTC materials include R 25 (room temperature resistivity), temperature coefficient α, B constant (its unit ...

Claims

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Application Information

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IPC IPC(8): C04B35/01C04B35/626
Inventor 杨建锋伊小红梁森王波杨武柯高潮史忠旗
Owner XI AN JIAOTONG UNIV
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