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Chemical coating prepared base metal internal electrode multi-layer ceramic chip capacitor dielectric material

A technology for capacitor dielectrics and multilayer ceramics, which is applied in the direction of fixed capacitor dielectrics, ceramics, and parts of fixed capacitors. It can solve the problem of dielectric constant reduction and other problems, and achieve low dielectric loss, uniform particle size, and high insulation resistivity. Effect

Active Publication Date: 2008-05-21
TSINGHUA UNIV
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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 the ceramic grain size is reduced to 100-200 nanometers, the dielectric constant is 1600-1800, which are all lower than 2000.

Method used

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  • Chemical coating prepared base metal internal electrode multi-layer ceramic chip capacitor dielectric material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0063] Example 1 Preparation of coated barium titanate powder. The barium titanate (grain size is 120nm) was ball-milled with ethanol as the medium for 12h, according to barium titanate (BaTiO 3 ) and the cladding layer composite oxide (CL) 96:4 and Y:Ce:Mn:Mg:Si:Ca=4:1:3:12:5:2 (both in molar ratio), weigh the corresponding weight of Soluble salts and ethyl orthosilicate. The coated barium titanate particle suspension is prepared by the chemical coating method of the present invention, and the coated barium titanate powder is obtained after drying. The obtained powder was heat-treated at 500°C for 2 hours, and then sieved to obtain the desired medium material. Figure 1 is a transmission electron microscope photograph of coated barium titanate particles.

Embodiment 2

[0064] Embodiment 2 The coated barium titanate powder is prepared by the chemical coating method of the present invention, wherein the barium titanate grain size is respectively 120nm, 135nm, 150nm, and the molar ratio of each element in the composite oxide coating layer is Y: Ce:Mn:Mg:Si:Ca=3:2:3:12:4:2. barium titanate (BaTiO) 3 ) to the cladding complex oxide (CL) in a molar ratio of 95:5. After the ceramic material is pressed into a disc, in N 2 / H 2 (30:1) Under reducing atmosphere, sintered at 1200℃ for 2h, and then annealed at 1050℃ for 2h under weak oxidizing conditions. The surface of the sample was covered with silver electrodes, and the electrical properties were tested. The dielectric properties are shown in Table 1. The curve of FIG. 2 shows the characteristic curve of the dielectric constant of the sample 1 of the present embodiment as a function of temperature, and FIG. 3 shows the curve of the change of the capacitance of the sample 1 as a function of tempe...

Embodiment 3

[0067] Example 3 The chemical coating method of the present invention was adopted, barium titanate powders with different initial particle sizes were selected, and oxide layers with different types and contents of elements were coated. The compositions of various coating layers are shown in Table 2. The total content of various oxides accounts for 3-10 mol% of barium titanate, as shown in Table 3. After the porcelain material is pressed into discs, the 2 / H 2 (35:1) Under reducing atmosphere, sinter at 1150-1250℃ for 2-3h, and then anneal at 1050℃ for 3h under weak oxidizing conditions. The surface of the sample was covered with silver electrodes, and the electrical properties were tested. The dielectric properties are shown in Table 3.

[0068] Table 2

[0069] Cladding Number

Composition (element molar ratio)

CL1

Y:Mn:Mg:Si:Ca=4:3:12:4:1

CL2

Y:Ce:Mn:Mg:Si:Ca=5:1:3:10:5:2

CL3

Dy:Sm:Mn:Mg:Si:Ba=5:1:4:12:5:1 ...

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Abstract

The invention discloses a chemical coating prepared dielectric material of base-metal electrode multilayer ceramic capacitor, belonging to the capacitor material preparing technology, which adopts the technical proposal that a plurality of barium titanate grains are coated by the doped elements through chemical coprecipitation; the main ingredient, barium titanate BaTiO3, accounts for 90mol% to 97mol% of the prescription; the amount of nanometer inhibitory coating composite oxide accounts for 3mol% to 10mol% of the total materials. The ceramic material is sintered at a reducing atmosphere controlled by a humidified gas mixture of nitrogen and hydrogen at a temperature between 950 to 1250 DEG C to get a X7R / X5R type MLCC material; wherein the dielectric constant of the material at room temperature is 2000 to 2700; the temperature coefficient of capacitance is less than or equal to positive and negative 15%; the dielectric loss at room temperature is less than or equal to 2%. The ceramic crystal grain under 200nm has low dielectric loss and good material uniformity; the multilayer ceramic capacitor produced with the ceramic crystal grain has the advantages of large capacity, ultrathin dielectric layer and the thickness less than 2um.

Description

technical field [0001] The invention belongs to the technical field of electronic ceramic capacitor materials, in particular to a dielectric material for preparing base metal inner electrode multilayer ceramic chip capacitors by chemical coating. In particular, the invention relates to the manufacture of a dielectric material for ultra-fine-grained temperature-stabilized base metal internal electrode multilayer ceramic chip capacitors with base metals (eg, nickel) as internal electrodes by a chemical coating method. Background technique [0002] Multilayer Ceramic Capacitors are referred to as MLCCs. It is to alternately stack the ceramic body and the inner electrode, and co-fire as a whole. MLCC is especially suitable for chip surface assembly, which can greatly increase the density of circuit assembly and reduce the size of the whole machine. This outstanding feature makes MLCC the largest and fastest growing chip component in the world. According to the EIA (Electronic ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01G4/12H01B3/12C04B35/468C04B35/622
Inventor 王晓慧田之滨王天李龙土
Owner TSINGHUA UNIV
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