Nano doping dielectric material for preparing base-metal inner-electrode multi-layer ceramic sheet type capacitor

A technology for capacitor dielectrics and multilayer ceramics, which is applied in the direction of fixed capacitor dielectrics, laminated capacitors, and components of fixed capacitors. It can solve problems such as unsuitable for large-scale production, large dielectric temperature coefficient, and unfavorable thinning of the dielectric layer. , to achieve the effects of simple and adjustable formula, small temperature change rate and small dielectric loss

Active Publication Date: 2008-05-21
TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The composition of this material meets the performance requirements of X7R. The dielectric constant at room temperature can be adjusted from 2000 to 4000, but the sintering temperature is too high, greater than 1300°C, and the dielectric temperature coefficient is relatively large, which is close to -15% at -55°C or -125°C. Not suitable for mass production
In US Patent US-20040229746A1, the basic composition of the ceramic material is BaTiO 3 -Mn 3 o 4 -Y 2 o 3 -Ho 2 o 3 -CaCO 3 -SiO 2 -B 2 o 3 -Al 2 o 3 -MgO-CaO, can be sintered at 1200℃~1300℃, but the ceramic grain is larger than 500nm, which is not conducive to the thinning of the dielectric layer

Method used

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  • Nano doping dielectric material for preparing base-metal inner-electrode multi-layer ceramic sheet type capacitor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0062] Embodiment 1 Preparation of nano dopant. According to the molar ratio of Y:Mn:Mg:Si:Ca=5:3:12:7:1, the corresponding weight of soluble salt and ethyl orthosilicate was weighed. According to the sol-gel method nano-dopant preparation process of the present invention, the precursor solution is prepared, firstly dried at 120° C. for 24 hours, and then dried at 140° C. for 6 hours to obtain a xerogel. The obtained xerogel was heat-treated at 800° C. for 3 h, and then ground and sieved to obtain the desired nano-dopant ND1. Figure 1 is a transmission electron micrograph of nano dopants.

Embodiment 2

[0063] Embodiment 2 According to BaTiO 3 : 93mol%; (grain size is respectively 110nm, 125nm, 150nm), nano dopant ND1: 7mol% proportioning. The above materials were mixed, ball milled and then dried. After the ceramic material is pressed into a disc, the N 2 / H 2 (20:1) Under reducing atmosphere, sinter at 1200°C for 2h, and then anneal at 1050°C for 2h under weak oxidation conditions. The surface of the sample was covered with a silver electrode, and the electrical performance test was carried out. The dielectric performance parameters are shown in Table 1. The curve in FIG. 2 shows the characteristic curve of the dielectric constant of sample 1 in Example 2 as a function of temperature, and FIG. 3 shows the curve of the capacitance change rate of sample 1 in Example 2 as a function of temperature. 4 is a scanning electron microscope photo of the surface morphology of sample 1 in Example 2 after sintering. The ceramic grains are spherical and uniform in size, with an avera...

Embodiment 3

[0066] Example 3 Nano-dopants ND2 to ND7 with different components were synthesized according to the sol-gel nano-dopant preparation process provided by the present invention, as shown in Table 2. The doping is performed at 2-10 mol% of the nano dopant relative to the barium titanate, as shown in Table 3. The above materials are mixed, ball milled, and then dried. After the obtained ceramic material is pressed into a disc, the N 2 / H 2 (25:1) Under reducing atmosphere, sinter at 1150-1250°C for 2-3h, then anneal at 1050°C for 3h under weak oxidation conditions. The surface of the sample was covered with a silver electrode, and the electrical performance test was carried out. The dielectric performance parameters are shown in Table 3.

[0067] Table 2

[0068] Dopant No.

Composition (element molar ratio)

ND2

Y: Ce: Mn: Mg: Si: Ca = 4: 1: 3: 12: 5: 2

ND3

Y: Ce: Mn: Mg: Si: Ca = 5: 1: 2.5: 10: 5: 2.5

ND4

Y:Sm:Mn:Mg:Si:Ba=3:1:4.5:10...

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Abstract

The invention discloses a base metal internal electrode multilayer ceramic chip capacitor dielectric material prepared by nano-doping, which belongs to the technical scope of capacitor material preparation. The ceramic material is composed of barium titanate BaTiO3 as the main material with a mole fraction of 90-98 mol% in the formula and nano dopant accounting for 2-10 mol% of the total material. In a reducing atmosphere, "two-stage" sintering or conventional sintering at a temperature range of 950 ° C to 1250 ° C can obtain X7R / X5R type MLCC materials with excellent performance. The room temperature dielectric constant of the material (wafer sample) can be Controlled at 2000-2600, capacity temperature change rate ≤ ± 15%, dielectric loss at room temperature ≤ 1.5%, ceramic grain size can be controlled at 100-200nm, good uniformity, suitable for production of large capacity, dielectric layer thickness less than Multilayer ceramic capacitors with an ultra-thin dielectric layer of 3 μm, high insulation resistivity, and stable performance.

Description

technical field [0001] The invention belongs to the technical field of electronic ceramic capacitor materials, and in particular relates to a base metal internal electrode multilayer ceramic chip capacitor dielectric material prepared by nano-doping. In particular, it relates to the manufacture of ultra-fine-grained, temperature-stable base metal internal electrode multilayer ceramic chip capacitor dielectric material with base metal (such as nickel) as the internal electrode. Background technique [0002] With the development trend of miniaturization and large capacity of electronic equipment and products, the application of surface mount technology is becoming more and more extensive. Electronic components for surface mounting are chip components. Multilayer ceramic capacitors are the most widely used type of chip components. Multilayer Ceramic Capacitors (MLCC) for short. It is prepared by a tape-casting-co-firing process, and the dielectric material and the electrode ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/462C04B35/624H01G4/12H01G4/30
Inventor 王晓慧田之滨王天李龙土
Owner TSINGHUA UNIV
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