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High-temperature negative temperature coefficient (NTC) material and preparation method thereof

A high-temperature, raw material technology, applied in the field of high-temperature NTC materials and their preparation, can solve problems such as difficult to achieve room temperature resistivity

Active Publication Date: 2013-06-05
XI AN JIAOTONG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The B constant of NTC materials developed by most researchers does not exceed 5000K, and the room temperature resistivity is difficult to reach 1.0E+4Ωcm

Method used

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  • High-temperature negative temperature coefficient (NTC) material and preparation method thereof
  • High-temperature negative temperature coefficient (NTC) material and preparation method thereof
  • High-temperature negative temperature coefficient (NTC) material and preparation method thereof

Examples

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Embodiment 1

[0031] A high-temperature NTC material and a preparation method thereof, comprising the following steps:

[0032] Step 1, follow Ni 0.6 mn 2.0-x Al 0.4 sn x o 4 The chemical analysis formula will require analytically pure MnO 2 , NiO, Al 2 o 3 and SnO 2 Put the powder into a plastic tank, where x=0.1, mix it evenly by wet ball milling, use absolute ethanol and agate balls as the ball milling medium, the volume ratio of raw materials and absolute ethanol is 1:2, and the balls and materials The volume ratio of the mixture is 2.5: 1, and the ball milling time is controlled to be 6 hours; the power of the ball milling is 0.75KW to obtain the mixture;

[0033] Step 2, place the mixture in an oven at 70°C for 12 hours, dry it and pre-fire it in an air furnace at a heating rate of 4°C / min, raise the temperature to 900-1000°C, and keep it warm for 2 hours to obtain NTC prefabricated powder;

[0034] Step 3, put the NTC prefabricated powder in the plastic tank again, use wet b...

Embodiment 2

[0038] A preparation method for an NTC material applied at a high temperature, comprising the following steps:

[0039] Step 1, follow Ni 0.6 mn 2.0-x Al0.4 sn x o 4 The chemical analysis formula will analyze pure MnO 2 , NiO, Al 2 o 3 and SnO 2 Put the powder into a plastic tank, where x=0.2, mix it evenly by wet ball milling, use absolute ethanol and agate balls as the ball milling medium, the volume ratio of raw materials and absolute ethanol is 1:2, and the balls and materials The volume ratio of the mixture is 2.5:1, and the ball milling time is controlled to be 8 hours; the power of the ball milling is 0.75KW to obtain the first mixture;

[0040] Step 2, place the first mixture in an oven at 70°C for 12 hours to dry, then pre-fire it in an air furnace at a heating rate of 3°C / min, raise the temperature to 900-1000°C, and keep it warm for 1.5 hours to obtain NTC prefabricated powder;

[0041] Step 3, put the pre-fired powder in the plastic tank again, use wet ball...

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Abstract

The invention discloses a high-temperature negative temperature coefficient (NTC) material, of which the chemical analytic formula is Ni0.6Mn2.0-xA10.4SnxO4. A preparation method of the high-temperature NTC material comprises the following steps of: putting the needed analytic pure raw material powder into a plastic tank according to the chemical analytic formula, mixing uniformly, and presintering a mixture to obtain the NTC precast powder; putting the NTC precast powder into the plastic tank again, ball milling for the second time to obtain the fine powder; and finally heating the calciningthe fine powder to obtain the NTC powder material. The preparation method may also comprise the following steps of: putting the analytic pure raw material powder into the plastic tank according to the chemical analytic formula, ball milling to obtain a first mixture; presintering to obtain the NTC precast powder; ball milling again to obtain the fine powder; adding polyvinyl alcohol (PVA) to the fine powder to obtain a second mixture; compression molding the second mixture to obtain a compression mixture; and finally disintegrating and sintering the compression mixture in an air furnace to obtain the high-temperature NTC thermistor material. The NTC thermistor material obtained by the method is applied to a high-temperature range of 300-500 DEG C; the room-temperature resistivity ranges from 132590-22685088 ohm.cm, and the B constant ranges from 5464-6148 K.

Description

technical field [0001] The invention relates to an NTC material, in particular to a high-temperature NTC material and a preparation method thereof. Background technique [0002] The negative temperature coefficient (NTC) thermistor is mainly a semiconductor ceramic material formed by mixing and sintering various transition metal oxides such as manganese, nickel, copper, aluminum, cobalt, chromium, iron, zinc, etc. It exhibits a resistance in which the resistance decreases exponentially with increasing temperature - temperature R = R 0 e ΔE / kT Characteristics, that is, the use of 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 room temperature resistivity R 25 , the temperature coefficient α, the B constant, is proportional to the activation energy of the material; it can characterize the sen...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/457C04B35/622
Inventor 杨建锋伊小红梁森王波杨武柯高潮乔冠军
Owner XI AN JIAOTONG UNIV