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Method for preparing barium strontium titanate composite ceramic with low-temperature sintering by adding B2O3-Li2CO3 auxiliary sintering agent

A low-temperature sintering technology of strontium barium calcium titanate, which is applied in the field of preparation of strontium barium calcium titanate composite ceramics, can solve the problems of difficult grain refinement, high BSCT sintering temperature, and increased material preparation costs. Achieve the effects of shortening the holding time, broadening the Curie peak, and improving the dielectric constant-temperature stability

Inactive Publication Date: 2011-08-17
NO 52 INST OF CHINA NORTH IND GRP CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The sintering temperature of BSCT prepared by the traditional process is very high, between 1350-1400°C, and the holding time is long, 6-24 hours, which determines that BSCT can only be co-fired with noble metal Pt or other refractory metals. These metals not only Expensive and often do not have superior electrical properties
On the one hand, the high sintering temperature increases the preparation cost of the material, and on the other hand, it makes it difficult to achieve grain refinement due to grain growth.

Method used

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  • Method for preparing barium strontium titanate composite ceramic with low-temperature sintering by adding B2O3-Li2CO3 auxiliary sintering agent
  • Method for preparing barium strontium titanate composite ceramic with low-temperature sintering by adding B2O3-Li2CO3 auxiliary sintering agent
  • Method for preparing barium strontium titanate composite ceramic with low-temperature sintering by adding B2O3-Li2CO3 auxiliary sintering agent

Examples

Experimental program
Comparison scheme
Effect test

Embodiment example 1

[0026] The formula for choosing the main crystal phase is Ba 0.4 Sr 0.3 Ca 0.3 TiO 3 , prepared by the oxalate co-precipitation method, the sintering aid is 0.5wt% B 2 o 3 -2.5wt% Li 2 CO 3 . Using the traditional electronic ceramic preparation process, the sintering temperatures are 980°C, 1000°C, 1030°C, 1050°C, 1080°C, 1100°C for 2 hours, and the sintering densities are 4.326, 4.978, 5.053, 5.051, 5.026, 5.042g / cm 3 , the theoretical density of this system is 5.149g / cm 3 . After the sample is processed into the required size, it is electroded and encapsulated, and then its electrical properties are measured. This example figure 1 Shown is the relationship curve between ceramic volume density and temperature, indicating that adding this sintering aid can significantly reduce the sintering temperature of strontium barium calcium titanate composite ceramics, and the sintering temperature of this formula is about 1000 °C.

Embodiment example 2

[0028] The formula for choosing the main crystal phase is Ba 0.7Sr 0.2 Ca 0.1 TiO 3 , prepared by the oxalate co-precipitation method, the sintering aid is 0.5wt% B 2 o 3 -2.5wt%Li 2 CO 3 . Using the traditional electronic ceramic preparation process, the sintering temperatures are 980°C, 1000°C, 1030°C, 1050°C, 1080°C, 1100°C for 2 hours, and the sintering densities are 4.566, 5.136, 5.554, 5.561, 5.511, 5.548g / cm 3 , the theoretical density of this system is 5.635g / cm 3 . After the sample is processed into the required size, it is electroded and encapsulated, and then its electrical properties are measured. This example figure 2 As shown, the result is the same as in Example 1, and the sintering temperature of this formulation is about 1030°C.

Embodiment example 3

[0030] The formula for selecting the main crystal phase is Ba 0.6 Sr 0.3 Ca 0.1 TiO 3 , prepared by the oxalate co-precipitation method, the sintering aid is 1.0wt% B 2 o 3 -2.3wt% Li 2 CO 3 . Using the traditional electronic ceramic preparation process, the sintering temperature is 950°C, 970°C, 980°C, 1000°C, 1020°C, 1050°C for 2 hours, and the sintering density is 4.912, 5.236, 5.355, 5.325, 5.328, 5.307g / cm 3 , the theoretical density of this system is 5.545g / cm 3 . After the sample is processed into the required size, it is electroded and encapsulated, and then its electrical properties are measured. This example image 3 Shown is the relationship between dielectric constant and temperature, which shows that after adding this additive, the Curie peak of the ceramic is broadened, and the temperature stability of the dielectric constant becomes better.

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Abstract

The invention relates to a method for preparing barium strontium titanate composite ceramic with low-temperature sintering by adding a B2O3-Li2CO3 auxiliary sintering agent. The method comprises the following steps of: a, selecting chemically-synthesized analytically pure BaxSryCa1-x-yTiO3 serving as raw material, and specifically designing the elements in anatomic ratio, wherein x is more than or equal to 0.4 and less than or equal to 0.8, and y is more than or equal to 0.2 and less than or equal to 0.6; b, adding the B2O3-Li2CO3 auxiliary sintering agent into the raw material, wherein the adding amount of the B2O3 is 0.2 to 1.5 weight percent of the total amount of the raw material, and the adding amount of the Li2CO3 is 0.6 to 2.5 weight percent of the total amount of the raw material; c, performing granulation and dry pressing molding to obtain a ceramic blank by adopting a traditional ceramic preparation process; d, removing glue at the temperature of between 600 and 800 DEG C; and e, performing normal pressure sintering at the temperature of between 950 and 1,100 DEG C, and preserving the heat for 1.5 to 2.5 hours, wherein the temperature rise rate is required for 1 to 2 DEGC per minute when the temperature exceeds 80 DEG C. The method has the advantages that: (1) the sintering temperature is reduced by 300 DEG C, the heat preservation time is shortened, and the energy is greatly saved; (2) the sintering temperature range is about 30 DEG C, and is convenient for process control; and (3) the crystal grains of the materials are thinned by low-temperature sintering, the crystal grain size effect of the material system is exerted, the Curie peak of the materials is broadened, and the dielectric constant and the temperature stability are improved.

Description

technical field [0001] The invention relates to a preparation method of strontium barium calcium titanate composite ceramics, in particular to a method of adding B 2 o 3 -Li 2 CO 3 Method for preparing strontium barium calcium titanate composite ceramics by low temperature sintering with sintering aid Background technique [0002] Calcium strontium barium titanate (Ba x Sr y Ca 1-x-y TiO 3 , referred to as BSCT) solid solution is a typical perovskite ferroelectric oxide material, which has both BaTiO 3 (BT) high dielectric constant and low dielectric loss, and has SrTiO 3 (ST) has a stable structure, while CaTiO 3 The solid solution of (CT) can also bring about the broadening effect of the Curie peak, significantly improving the dielectric constant-temperature stability of the material, and the dielectric properties of the material system can be adjusted by adjusting the Ba / Sr / Ca ratio, reflecting It is easy to adjust the dielectric constant under the DC electric f...

Claims

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Application Information

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IPC IPC(8): C04B35/465C04B35/622C04B35/63
Inventor 李明利纪松钱坤明张延松丁昂
Owner NO 52 INST OF CHINA NORTH IND GRP CORP