High-temperature stable medium material for multilayer ceramic capacitors and preparation method thereof

A technology of capacitor dielectric and multilayer ceramics, which is applied in the direction of fixed capacitor dielectric, laminated capacitor, fixed capacitor parts, etc., can solve the problem of reducing the dielectric properties of dielectric materials, and achieve wide temperature stability range and high dielectric strength Constant, the effect of excellent temperature stability

Inactive Publication Date: 2009-10-21
WUHAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Now it is reported that glass frit is used as a sintering aid, but the glass frit will form a se

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  • High-temperature stable medium material for multilayer ceramic capacitors and preparation method thereof
  • High-temperature stable medium material for multilayer ceramic capacitors and preparation method thereof
  • High-temperature stable medium material for multilayer ceramic capacitors and preparation method thereof

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Embodiment 1

[0027] Ingredients basis: (1-x)BaTiO 3 -xBiScO 3 +a(CaF 2 +4LiF), x=0.05, a is 1 mol% of the molar number of the main component.

[0028] The materials were mixed and ball milled according to the above preparation method, then dried, sieved, granulated into uniform granules with a concentration of 0.25wt% PVA as a binder, and pressed under a pressure of 200MPa to make discs with a diameter of 12mm with a thickness of 1mm. The discs were calcined at 650 °C to remove the PVA binder, and then 2 o 3 In a sealed corundum crucible, sinter at a temperature of 1200°C, the sintering time is 2 hours, and the heating rate is 5°C / min. The fired ceramic discs were surface polished, silver-fired, and their dielectric properties were measured. The dielectric properties of the obtained ceramic samples are shown in Table 1. figure 1Be the characteristic curve that the dielectric constant of embodiment 1 sample changes with temperature; figure 2 It is the curve of the rate of change of...

Embodiment 2

[0032] Ingredients basis: (1-x)BaTiO 3 -xBiScO 3 +a(CaF 2 +4LiF), x=0.10, a is 3 mol% of the molar number of the main component.

[0033] The materials were mixed and ball milled according to the above-mentioned preparation method, then dried, sieved, granulated into uniform particles with a concentration of 0.25wt% PVA as a binder, and pressed under a pressure of 200MPa to make discs with a diameter of 12mm with a thickness of 1mm. The discs were calcined at 650 °C to remove the PVA binder, and then 2 o 3 In a sealed corundum crucible, sinter at a temperature of 1160°C, the sintering time is 2 hours, and the heating rate is 5°C / min. The fired ceramic discs were surface polished, silver-fired, and their dielectric properties were measured. The dielectric properties parameters of the obtained ceramic samples are shown in Table 2. image 3 Be the characteristic curve that the dielectric constant of embodiment 2 sample changes with temperature; Figure 4 It is the curve o...

Embodiment 3

[0036] Ingredients basis: (1-x)BaTiO 3 -xBiScO 3 +a(CaF 2 +4LiF), x=0.10, a is 5 mol% of the molar number of the main component.

[0037] The materials were mixed and ball milled according to the above-mentioned preparation method, then dried, sieved, granulated into uniform particles with a concentration of 0.25wt% PVA as a binder, and pressed under a pressure of 200MPa to make discs with a diameter of 12mm with a thickness of 1mm. The discs were calcined at 650 °C to remove the PVA binder, and then 2 o 3 In a sealed corundum crucible, sinter at a temperature of 1160°C, the sintering time is 2 hours, and the heating rate is 5°C / min. The fired ceramic discs were surface polished, silver-fired, and their dielectric properties were measured. The dielectric performance parameters of the obtained ceramic samples are shown in Table 3. Figure 5 Be the characteristic curve that the dielectric constant of embodiment 3 sample changes with temperature; Figure 6 It is the curve...

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Abstract

The invention discloses a high-temperature stable medium material for multilayer ceramic capacitors and a preparation method thereof. The medium material consists of a main component and a doping component; the chemical constitution of the main component is (1-x) BaTiO3-xBiScO3, wherein x is equal to between 0.5 and 0.15; the doping component is CaF2+4LiF, wherein the purity of the CaF2+4LiF is more than 99 percent and the molar doping quantity of the CaF2+4LiF is 1 to 5 percent of the total mol number of the main component. The preparation method comprises the following steps: firstly, using BaCO3 and TiO2 as raw materials and mixing the materials according to the stoichiometric proportion of the BaTiO3 to synthesize BaTiO3 powder with a tetragonal phase structure; secondly, mixing BaTiO3, Bi2O3 and Sc2O3 according to the stoichiometric proportion of (1-x) BaTiO3-xBiScO3, wherein x is equal to between 0.05 and 0.15; and finally, adding CaF2 and LiF powder which have a purity of more than 99 percent, mixing and ball milling the mixture in absolute ethanol for 48 hours, drying the milled mixture, adding a solution of polyvinylalcohol into the dried mixture for granulation, passing the product obtained after granulation through an 80 mesh sieve, subjecting the product to press forming and sintering and obtaining the medium material. The material has high dielectric constant, low dielectric loss and excellent temperature stability, can be sintered at intermediate temperature and is suitable to be sintered together with cheap base metals. The medium material can be used to produce multilayer ceramic capacitors having X8R and X9R properties.

Description

technical field [0001] The invention relates to a ceramic material applied to electronic components, in particular to a dielectric material for a multilayer ceramic capacitor with high temperature resistance and temperature stability and a preparation method thereof. Background technique [0002] Multilayer ceramic capacitor (MLCC) is an important basic device of electronic information technology. With the rapid development of multilayer ceramic capacitors (MLCC), its application fields are becoming more and more extensive. The research on dielectric materials for MLCCs is proposed on the basis of high withstand voltage strength, high dielectric constant, low loss, and high energy storage. New requirements have been imposed, that is, it is hoped that it has stable dielectric properties at higher temperatures so that it can exert its performance in high-temperature working environments. In applications in high-end fields such as aerospace, automotive industry, and military mo...

Claims

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Application Information

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IPC IPC(8): C04B35/468C04B35/622H01G4/12H01G4/30
Inventor 刘韩星刘洋曹明贺郝华尧中华
Owner WUHAN UNIV OF TECH
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