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Preparation method of lead-free high-Curie-point BaTiO3-based positive-temperature-coefficient thermal sensitive ceramic

A technology of positive temperature coefficient, heat-sensitive ceramics, applied in high-tech functional ceramics and its application fields, can solve problems such as inaccurate chemical compounding, achieve low room temperature resistivity, ensure consistency and repeatability, and high Curie temperature Effect

Inactive Publication Date: 2017-06-20
CHINA UNIV OF GEOSCIENCES (BEIJING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, in the synthesis (Bi 0.5 Na 0.5 )TiO 3 In the process, due to Bi 2 o 3 The melting point is low (820 ℃), there will still be a part of volatilization, so the chemical composition of the prepared sample will be inaccurate, and (Bi 0.5 Na 0.5 )TiO 3 Doped BaTiO 3 Based on positive temperature coefficient thermosensitive ceramic materials, there are still problems in reducing the room temperature resistivity and further increasing the lift-to-drag ratio

Method used

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  • Preparation method of lead-free high-Curie-point BaTiO3-based positive-temperature-coefficient thermal sensitive ceramic
  • Preparation method of lead-free high-Curie-point BaTiO3-based positive-temperature-coefficient thermal sensitive ceramic
  • Preparation method of lead-free high-Curie-point BaTiO3-based positive-temperature-coefficient thermal sensitive ceramic

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preparation example Construction

[0040] The present invention proposes a lead-free BaTiO with high Curie temperature, high lift-to-drag ratio, and low room temperature resistivity. 3 A thermosensitive ceramic based on a positive temperature coefficient and a preparation method thereof, wherein the ceramic is made of tetragonal perovskite BaTiO 3 phase as matrix, with (Bi 0.5 Na 0.5 )TiO 3 In order to increase the peak shifting agent of the Curie temperature, the rare earth oxide Ta 2 o 5 or Sm 2 o 3 Reduce room temperature resistivity and add transition metal oxide MnO 2 To improve the lift-to-drag ratio; the preparation method uses a one-pot method to prepare this lead-free BaTiO 3 Based on thermosensitive ceramics, the reduction-reoxidation sintering method is used to obtain BaTiO with excellent thermosensitive properties 3 Based on positive temperature coefficient heat-sensitive ceramics; the preparation method includes "weighing → mixing → ball milling → drying → calcining → grinding and sieving →...

Embodiment 1

[0053] Embodiment 1: BaTiO of the embodiment of the present invention 3 The manufacturing method and technological process of the base positive temperature coefficient heat-sensitive ceramics are as follows:

[0054] (1) According to the synthetic mole fraction of 91.2% BaTiO 3 powder, synthetic 8.8% (Bi 0.5 Na 0.5 )TiO 3 powder, plus a mole fraction of 0.3% Ta 2 o 5 Powder, weigh BaCO 3 、TiO 2 、 Bi 2 o 3 、Na 2 CO 3 and Ta 2 o 5 powdered reagents.

[0055] (2) Add all the reagents weighed in proportion to the ball mill tank of the planetary ball mill, and add 10 times the mass of ZrO 2 Grinding balls and 5 times the mass of anhydrous ethanol solvent, ball milling for 6 hours.

[0056] (3) Dry the finely ground and mixed slurry in an atmospheric drying oven at a temperature of 80° C. for 72 hours.

[0057] (4) The mixed powder after ball milling and drying is put into a crucible, and then calcined in a muffle furnace at a temperature of 900° C. for 4 hours.

[...

Embodiment 2

[0065] Embodiment 2: BaTiO of the embodiment of the present invention 3 The manufacturing method and technological process of the base positive temperature coefficient heat-sensitive ceramics are as follows:

[0066] (1) BaTiO with a synthetic mole fraction of 92% 3 powder, synthetic 8% (Bi 0.5 Na 0.5 )TiO 3 powder, plus a mole fraction of 0.3% Ta 2 o 5 powder and 0.04 mol% MnO 2 Powder, weigh BaCO 3 、TiO 2 、 Bi 2 o 3 、Na 2 CO 3 、 Ta 2 o 5 and MnO 2 powdered reagents.

[0067] (2) Add all the reagents weighed in proportion to the ball mill jar of the stirring ball mill, and add 10 times the mass of ZrO 2 Grinding balls and 5 times the mass of anhydrous ethanol solvent, ball milling for 18 hours.

[0068] (3) In an atmospheric pressure drying oven, dry the finely ground and mixed slurry at a temperature of 90° C. for 48 hours.

[0069] (4) Put the mixed powder after ball milling and drying into a crucible, and then calcinate in a muffle furnace at a temperatur...

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Abstract

The invention relates to a lead-free high-Curie-point BaTiO3-based positive-temperature-coefficient thermal sensitive ceramic, and a preparation method thereof, and belongs to the field of ceramic with high technological functions, and applications of the ceramic with high technological functions. According to the preparation method, tetragonal perovskite BaTiO3 phase is taken as a matrix, (Bi0.5Na0.5)TiO3 is taken as a peak moving reagent of Curie point, rare earth oxide Ta2O5 or Sm2O3 is used for reducing room temperature electrical resistivity, and transition metal oxide MnO2 is added to increase resistance increasing ratio; one pot reaction is adopted to prepare the lead-free BaTiO3-based thermal sensitive ceramic; reduction-reoxidation sintering is adopted to obtain the BaTiO3-based positive-temperature-coefficient thermal sensitive ceramic with excellent heat sensitive properties. The preparation method comprises following steps: weighing, material mixing, ball milling, drying, sintering, grinding and sieving, pelletizing, tabletting, hydrocarbon removing, sintering, and coating with electrode. The lead-free high-Curie-point BaTiO3-based positive-temperature-coefficient thermal sensitive ceramic is high in Curie point and resistance increasing ratio, low in room temperature electrical resistivity, contains no lead, and is especially suitable to be used for preparing parts used for heating protection, overtemperature protection, overcurrent protection, and temperature monitoring and sensing.

Description

technical field [0001] The invention relates to a lead-free high Curie temperature BaTiO 3 The invention relates to positive temperature coefficient heat-sensitive ceramics and a preparation method thereof, which belong to the field of high-tech functional ceramics and their applications. Background technique [0002] TiO 3 The positive temperature characteristic of the thermosensitive ceramic material based on positive temperature coefficient was discovered by Heywang et al. by doping a small amount of high-priced rare earth cations in barium titanate (Heywang W, et al.Journal of America Ceramic Society, 1964,47(10): 484-490). Composite positive temperature coefficient thermosensitive material with high expansion ceramic matrix, polymer matrix composite positive temperature coefficient thermosensitive ceramic material and V 2 o 3 , BaPbO 3 Based on positive temperature coefficient thermosensitive ceramic materials compared to BaTiO 3 Based on positive temperature coef...

Claims

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Application Information

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IPC IPC(8): C04B35/468
CPCC04B35/4682C04B2235/3201C04B2235/3224C04B2235/3234C04B2235/3251C04B2235/3267C04B2235/3298C04B2235/785
Inventor 彭志坚杨梦梦王成彪符秀丽
Owner CHINA UNIV OF GEOSCIENCES (BEIJING)
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