Method for preparing NTC (negative temperature coefficient) thermosensitive ceramic material through two-step solid-phase chemical reaction

A solid-phase chemical reaction and negative temperature coefficient technology, which is applied in the field of two-step solid-phase chemical reaction to prepare negative temperature coefficient heat-sensitive ceramic materials, can solve the problems of step-by-step precipitation powder element ratio differences and difficulty in obtaining accurate stoichiometric ratios, etc. , to achieve the effects of easy scale-up production, high yield, high consistency of resistance value and B value

Inactive Publication Date: 2015-05-27
XINJIANG ZHONGKE SENSING CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the different pH values ​​of the precipitation of each element, it is easy to cause step-by-step precipitation and the proportion of elements in the precipitated powder is different from the original formula, so it is difficult to obtain a powder with an accurate stoichiometric ratio

Method used

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  • Method for preparing NTC (negative temperature coefficient) thermosensitive ceramic material through two-step solid-phase chemical reaction
  • Method for preparing NTC (negative temperature coefficient) thermosensitive ceramic material through two-step solid-phase chemical reaction
  • Method for preparing NTC (negative temperature coefficient) thermosensitive ceramic material through two-step solid-phase chemical reaction

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Experimental program
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Effect test

Embodiment 1

[0016] Weigh manganese acetate tetrahydrate, nickel nitrate hexahydrate, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate according to the molar ratio of manganese: nickel: magnesium: aluminum = 2:2.5:1.4:0.1, mix and grind in planetary ball mill 2 Hour;

[0017] Add ammonium citrate and surfactant polyethylene glycol-800 (PEG-800) into the resulting mixture at a molar ratio of 5:0.2 and continue grinding for 8 hours to make it undergo a solid-phase chemical reaction and become green and viscous with uniform color and luster thing;

[0018] Put the obtained viscous material in an oven at 100°C for dehydration, crush it, and then place it in a bell furnace at 500°C for 3 hours for decomposition. After the decomposition is completed, put the powder material in a bell furnace at 850°C for pre-calcination 2 hours;

[0019] Then perform pre-press molding, isostatic pressing, and sinter at a temperature of 1100°C for 5 hours to obtain a negative temperature coefficie...

Embodiment 2

[0022] Weigh manganese acetate tetrahydrate, nickel nitrate hexahydrate, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate according to the molar ratio of manganese: nickel: magnesium: aluminum = 3.1:1.4:1.4:0.1, mix and grind in a planetary ball mill for 2 Hour;

[0023] Add ammonium citrate and surfactant polyethylene glycol-800 (PEG-800) into the resulting mixture at a molar ratio of 5:0.2, and continue to grind for 4 hours to make it undergo a solid-phase chemical reaction and become a uniform color green viscous thick matter;

[0024] Put the obtained viscous material in an oven at 100°C for dehydration, crush it, and then place it in a bell furnace at 400°C for 6 hours. After the decomposition is completed, put the powder material in a bell furnace at 700°C for pre-calcination 4 hours;

[0025] Then perform pre-press molding, isostatic pressing, and sinter at a temperature of 1220°C for 2 hours to obtain a negative temperature coefficient thermistor cerami...

Embodiment 3

[0028] Weigh manganese acetate tetrahydrate, nickel nitrate hexahydrate, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate according to the molar ratio of manganese: nickel: magnesium: aluminum = 2.5:1.4:2:0.1, mix and grind in a planetary ball mill for 2 Hour;

[0029] Add ammonium citrate and surfactant polyethylene glycol-800 (PEG-800) into the resulting mixture at a molar ratio of 5:0.2, and continue grinding for 6 hours to make it undergo a solid-phase chemical reaction and become a green viscous gel with uniform color. thick matter;

[0030] Put the obtained viscous material in an oven at 100°C for dehydration, crush it, and then place it in a bell furnace at 450°C for 5 hours. After the decomposition is complete, put the powder material in a bell furnace at 750°C for pre-calcination 3 hours;

[0031] Then perform pre-press molding, isostatic pressing, and sinter at a temperature of 1150°C for 4 hours to obtain a negative temperature coefficient thermistor...

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Abstract

The invention relates to a method for preparing an NTC (negative temperature coefficient) thermosensitive ceramic material through two-step solid-phase chemical reaction. The method comprises the following steps: by taking manganese acetate tetrahydrate, nickel nitrate hexahydrate, magnesium nitrate hexahydrate, aluminium nitratenonahydrate and ammonium citrate as raw materials, carrying out solid-phase chemical reaction at room temperature, calcining the reaction product at a high temperature to obtain composite oxide powder with uniform size and good dispersibility, prepressing the composite oxide powder, pressing isostatically, and calcining to obtain the NTC thermosensitive ceramic material. The NTC thermosensitive ceramic material can be made into an NTC thermosensitive resistor by adopting a conventional method according to the procedures of slicing, coating with electrodes, scribing, welding and encapsulating. The NTC thermosensitive resistor has good consistent resistance value and B value, interchangeability, stability and repeatability and can be widely used for controlling and detecting the temperature of induction cookers, electric pressure cookers, electric rice cookers, electric ovens, disinfection cabinets, water dispensers, microwave ovens, electric heaters and other household appliances.

Description

technical field [0001] The invention relates to a method for preparing a negative temperature coefficient heat-sensitive ceramic material by a two-step solid-phase chemical reaction, belonging to the field of semiconductor functional material products. Background technique [0002] Negative temperature coefficient thermistor (NTC) is an electronic ceramic component whose resistance value decreases with the increase of temperature. It is widely used in air conditioning equipment, heating equipment, medical equipment, temperature control instruments, electronic gifts, electronic temperature and humidity meters, automobiles Temperature measurement, electronic perpetual calendar, temperature measurement and control of rechargeable battery pack and charger. With the development of technology, the market has put forward higher requirements for the accuracy, reliability and yield of negative temperature coefficient thermistor components. [0003] The performance of the negative te...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/622
Inventor 王军华姚金城常爱民
Owner XINJIANG ZHONGKE SENSING CO LTD
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