Base metal inner electrode multi-layer ceramic wafer type capacitor medium material prepared by chemical coating of water system

A technology of metals and metal salts, applied in the direction of fixed capacitor dielectrics, laminated capacitors, fixed capacitor parts, etc., can solve the problem of dielectric constant reduction and achieve the effects of small dielectric loss, stable performance, and strong reliability

Active Publication Date: 2010-11-10
TSINGHUA UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the reduction of the grain size often leads to the reduction of the dielectric constant. In US-62709906B1, when th

Method used

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  • Base metal inner electrode multi-layer ceramic wafer type capacitor medium material prepared by chemical coating of water system
  • Base metal inner electrode multi-layer ceramic wafer type capacitor medium material prepared by chemical coating of water system
  • Base metal inner electrode multi-layer ceramic wafer type capacitor medium material prepared by chemical coating of water system

Examples

Experimental program
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Effect test

Example Embodiment

[0070] Example 1. Preparation of ceramic powder (i.e. uniformly coated barium titanate powder)

[0071] The barium titanate powder (crystal size of 120nm) was ball milled with water and auxiliary dispersant for 12 hours to obtain a barium titanate suspension; according to the barium titanate (BaTiO 3 ) And the coating layer composite oxide (CL) 96:4 and Y:Ce:Mn:Mg:Si:Ca=4:2:3:12:5:2 (both in molar ratio), weigh the corresponding weight The soluble salt and ethyl orthosilicate are prepared by the chemical coating method provided by the present invention to prepare a suspension of coated barium titanate particles, and the coated barium titanate powder is obtained after drying. After the obtained powder is heat-treated at 550°C for 2 hours, it is sieved to obtain the desired ceramic powder. The ceramic powder is composed of a core and a shell; the core is barium titanate powder, and the shell is made of Y 2 O 3 , Ce 2 O 3 , MnO 2 , MgO, SiO 2 A nano-coating layer formed by a composi...

Example Embodiment

[0072] Example 2. Preparation of ceramic powder (i.e. uniformly coated barium titanate powder) and its dielectric properties test

[0073] The coated barium titanate powder is prepared by the chemical coating method of the present invention (3 groups are prepared, each group is 500g), wherein the selected barium titanate powder has a grain size of 150 nm, and the composite oxide coating layer The molar ratio of each element is Y:Ce:Mn:Mg:Si:Ca=4:3:3:12:4:2. Barium titanate (BaTiO 3 The molar ratio of) to the clad composite oxide (CL) is 95:5.

[0074] After pressing the ceramic powder into a disc, in N 2 / H 2 (30:1, v / v) under reducing atmosphere, sintering at 1200℃ for 2h, and then annealing at 1050℃ for 2h under weak oxidation conditions. The surface of the sample is covered with a silver electrode for electrical performance test. The dielectric performance parameters are shown in Table 1. figure 2 This is the characteristic curve of the dielectric constant of sample 1 in this ...

Example Embodiment

[0077] Example 3 Preparation of ceramic powder (i.e. uniformly coated barium titanate powder) and its dielectric properties test

[0078] The coated barium titanate powder is prepared by the chemical coating method of the present invention, and barium titanate powder with an average initial particle size of 80 nanometers is selected to coat oxide layers of different element types and contents, and various coating layers The ingredients are shown in Table 2. The total content of various oxides accounts for 3-10 mol% of the total material, as shown in Table 3.

[0079] After the porcelain is pressed into a disc, 2 / H 2 (35:1, v / v) under reducing atmosphere, sintering at 1150~1250℃ for 2~3h, and then annealing at 1050℃ for 3h under weak oxidation condition. The surface of the sample is covered with a silver electrode for electrical performance testing. The dielectric performance parameters are shown in Table 3.

[0080] Table 2

[0081] Coating number

[0082] Coating number

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Abstract

The invention discloses a ceramic powder body which can be taken as a base metal inner electrode multi-layer ceramic wafer type capacitor medium material and a preparation method thereof. Doped elements are evenly coated on the surfaces of barium titanate grains by means of chemical coprecipitation; the main material of the barium titanate BaTiO3 is 90-97mol% of the ceramic powder material; and the use amount of the composite oxide of a nanometer coating later is 3-10mol% of the gross amount of the ceramic powder material. The ceramic powder material is sintered in the reducing atmosphere which is controlled by a nitrogen and hydrogen-mixed humidifying gas within the temperature range of 950-1250 DEG C to obtain an X7R/X5R type MLCC material, wherein the room temperature dielectric constant of the material is 2000-3000, the vessel temperature change rate is less than or equal to +/-15%, the vessel temperature dielectric loss is less than or equal to 2%, the crystalline grain of the ceramic is less than 2000nm, the dielectric loss is small, the evenness of the material is good, and the material is applied to manufacturing a multi-layer ceramic capacitor with large capacity and ultrathin dielectric layer (the depth of the dielectric layer is less than 3mu m).

Description

technical field [0001] The invention belongs to the technical field of electronic ceramic capacitor materials, and in particular relates to a base metal inner electrode multilayer ceramic chip capacitor and its special ceramic powder and their preparation method. Background technique [0002] Multilayer Ceramic Capacitors (MLCC) for short. It alternately laminates the ceramic green body and internal electrodes, and co-fires them as a whole. MLCC is especially suitable for chip surface mount, which can greatly increase the circuit assembly density and reduce the volume of the whole machine. This outstanding feature makes MLCC the largest and fastest growing chip component in the world. According to the EIA (Electronic Industries Association) standard, the X7R temperature-stable MLCC refers to the capacity temperature change rate (TCC ) ≤ ± 15%, dielectric loss (DF) ≤ 2.5%; X5R temperature stable MLCC is based on the capacitance value of 25 ℃, within the range of temperature...

Claims

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Application Information

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IPC IPC(8): C04B35/628C04B35/468H01G4/12H01G4/30
Inventor 王晓慧张亦弛金镇龙田之滨李龙土
Owner TSINGHUA UNIV
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