Hydrothermal reaction method for manufacturing negative temperature coefficient heat-sensitive powder

A technology of negative temperature coefficient and hydrothermal reaction, applied in the direction of resistors with negative temperature coefficient, etc., can solve the problems of long synthesis cycle, difficult to control reaction conditions, high temperature, etc., achieve short synthesis cycle, easy control of reaction conditions, and high production efficiency high rate effect

Inactive Publication Date: 2008-12-10
CHINA JILIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] The preparation methods of negative temperature coefficient heat-sensitive powder usually adopt ball milling method, co-precipitation method, sol-g

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0008] Example 1 (content is in moles)

[0009] First, weigh 3.6 mol of manganese acetate and 2.4 mol of nickel acetate and dissolve them in deionized water, stir thoroughly, add an equimolar amount of ammonia solution to the stirred reaction solution, and adjust the pH of the reaction solution to 10.0; then the reaction solution All were transferred into a 5L autoclave for hydrothermal reaction, and the autoclave was set to rotate at 600 revolutions per minute and the reaction temperature was 220° C. and reacted for 10 hours. After the reaction is completed, the product is cooled to room temperature by circulating water, and the reactants are pumped out with a vacuum pump, washed with deionized water and absolute ethanol for 3-4 times, and then centrifuged, washed, and dried at 60℃. Negative temperature coefficient heat Sensitive nano powder.

[0010] Then put the negative temperature coefficient heat-sensitive nano powder into a muffle furnace and thermally decompose it at 700-9...

Example Embodiment

[0011] Example 2 (content in moles)

[0012] First, weigh 3.7 mol manganese sulfate, 2.4 mol nickel sulfate, and 0.6 mol cobalt sulfate and dissolve them in deionized water, stir thoroughly, add an equimolar ammonia solution to the stirred reaction solution, and adjust the pH of the reaction solution to 9.5 ; Then all the reaction solution was transferred into a 5L autoclave for hydrothermal reaction, and the autoclave was set to rotate at 600 revolutions per minute and the reaction temperature was 240° C. and react for 8 hours. After the reaction is completed, the product is cooled to room temperature by circulating water, and the reactants are extracted with a vacuum pump, and washed with deionized water and absolute ethanol for 3-4 times, and then centrifuged, washed, and dried at 80°C. Negative temperature coefficient heat Sensitive nano powder.

[0013] Then put the negative temperature coefficient heat-sensitive nano powder into a muffle furnace and thermally decompose it at...

Example Embodiment

[0014] Example 3 (content in moles)

[0015] First, weigh 3.0 mol of manganese nitrate, 2.0 mol of nickel nitrate, and 1.0 mol of cobalt nitrate and dissolve them in deionized water, stir thoroughly, add an equimolar ammonia solution to the stirred reaction solution, and adjust the pH of the reaction solution to 9.0 ; Then all the reaction solution was moved into a 5L autoclave for hydrothermal reaction, and the autoclave was set to rotate at 600 revolutions per minute and the reaction temperature was 250° C., and react for 8 hours. After the reaction is completed, the product is cooled to room temperature by circulating water, and the reactants are extracted with a vacuum pump, and washed with deionized water and absolute ethanol for 3-4 times, and then centrifuged, washed, and dried at 80°C. Negative temperature coefficient heat Sensitive nano powder.

[0016] Then put the negative temperature coefficient heat-sensitive nano powder into a muffle furnace and thermally decompose i...

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Abstract

The invention relates to a method for preparing negative temperature coefficient heat-variable powder body-the method of hydro-thermal chemical reaction. De-ionized water is added into reaction raw materials of manganous salt, nickelous salt, cobaltous salt and magnesium salt, the mixture is stirred sufficiently; an ammonia solution is added into the stirred reaction solution until the pH value of the reaction solution is between 8.0 and 12.0; the reaction solution is put inside a high pressure reaction kettle to perform the hydro-thermal reaction and then is subject to washing and baking so that the negative temperature coefficient heat-variable nano powder material is produced; the negative temperature coefficient heat-variable nano powder material is put into a blind roaster to be pyrolyzed at a temperature of between 600 and 900 DEG C for 2 to 8 hours, and the negative temperature coefficient heat-variable powder material is produced after sufficient grinding process. Compared with the ball milling method, the coprecipitation method and the sol-gel method, the method has the characteristics that the chemical compositions are even, the reaction temperature is low, the productivity is high, the synthesizing cycle is short, the reaction condition is controlled easily, and the inevitable agglomeration phenomenon in the sintering process is reduced, etc.

Description

technical field [0001] The invention relates to a preparation method of a negative temperature coefficient heat-sensitive powder-a method of hydrothermal chemical reaction. Background technique [0002] The preparation methods of negative temperature coefficient heat-sensitive powder usually adopt ball milling method, co-precipitation method, sol-gel method, etc., but these methods have difficulties such as high reaction temperature, long synthesis period, and difficult control of reaction conditions. Aiming at the existing problems, the present invention develops a hydrothermal chemical reaction method for the preparation of negative temperature coefficient heat-sensitive powder through a large number of experiments. Contents of the invention [0003] The purpose of the present invention is to develop the preparation method of the negative temperature coefficient heat-sensitive powder - the hydrothermal reaction method, adding the reaction raw materials of divalent mangan...

Claims

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Application Information

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IPC IPC(8): C04B35/36C04B35/622H01C7/04
Inventor 王疆瑛
Owner CHINA JILIANG UNIV
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