Preparation method of continuous silicon carbide ceramic fiber thermistor

A technology of silicon carbide ceramics and silicon carbide fibers, which is applied in the field of continuous silicon carbide ceramic fiber thermistor preparation to achieve fast temperature response and low cost

Inactive Publication Date: 2017-06-09
XIAMEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] So far, there have been no domestic and foreign reports on the modification

Method used

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  • Preparation method of continuous silicon carbide ceramic fiber thermistor
  • Preparation method of continuous silicon carbide ceramic fiber thermistor
  • Preparation method of continuous silicon carbide ceramic fiber thermistor

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Embodiment Construction

[0035] The following embodiments will further describe the present invention in detail in conjunction with the accompanying drawings.

[0036] (1) Using the Yajima route, using dimethyldichlorosilane as a raw material, using sodium metal as a reducing agent, and using toluene or xylene as a solvent, dechlorination at 110 ° C to obtain polydimethylsilane; then, polydimethylsilane Carbosilane is pyrolyzed at 450°C under an inert atmosphere, and the molecular structure is rearranged to prepare polycarbosilane. The number average molecular weight measured by gel permeation chromatography (GPC) is Mn=995, and the melting point measured by the melting point instrument is 181°C .

[0037] (2) Put polycarbosilane into a spinning vessel, heat to 275° C. under the protection of nitrogen to melt the precursor, and then stand still for degassing for 4 hours. Extrude with a φ0.3mm spinneret and wind at a speed of 170m / s to obtain a precursor fiber with a diameter of 18μm, also known as a ...

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Abstract

The invention discloses a preparation method of a continuous silicon carbide ceramic fiber thermistor and relates to thermistors. The preparation method includes: using dimethyl dichlorosilane as the raw material, using metallic sodium as the reducing agent, using toluene or xylene as the solvent, dechlorinating to obtain polydimethylsilane, and pyrolyzing the polydimethylsilane under inert atmosphere to rearrange the molecular structure so as to generate polycarbosilane; loading the generated polycarbosilane into a spinning container, heating under nitrogen protection to melt the polycarbosilane, statically defoaming, and extruding to form fibers so as to obtain polycarbosilane fibers; heating the obtained polycarbosilane fibers to perform oxidation chemical crosslinking reaction to obtain crosslinking filaments which do not dissolve and melt; pyrolyzing the obtained crosslinking filaments to obtain pyrolyzed silicon carbide fibers; performing high-temperature thermal treatment on the obtained pyrolyzed silicon carbide fibers to obtain continuous silicon carbide ceramic fibers low in resistivity.

Description

technical field [0001] The invention relates to a thermistor, in particular to a method for preparing a continuous silicon carbide ceramic fiber thermistor. Background technique [0002] Thermistors are a type of sensitive element whose resistance value changes with temperature, and are mainly divided into positive temperature coefficient thermistors (Positive Temperature Coefficient, PTC) and negative temperature coefficient thermistors (Negative Temperature Coefficient, NTC). PTC refers to a thermistor material with a sharp increase in resistance at a certain temperature and a positive temperature coefficient. Because of its characteristics, it is mainly used as a constant temperature sensor; NTC has a smaller resistance value when the temperature is higher, and the sensitivity of resistance to temperature changes is high. , can be a linear relationship, and the response speed is relatively fast, so it is mainly used for the determination of dynamic temperature. For therm...

Claims

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Application Information

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IPC IPC(8): C04B35/565C04B35/622
CPCC04B35/571C04B2235/94C04B2235/96
Inventor 李思维王淇陈立富李永财涂惠彬汤明
Owner XIAMEN UNIV
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