Multi-layer ceramic capacitor material with dielectric constant and temp stability and its preparing process

A temperature-stable, multi-layer ceramic technology, applied in the direction of fixed capacitor dielectric, fixed capacitor parts, ceramics, etc., can solve the problems of complex sintering process, etc., and achieve easy control of sintering process, small dielectric loss, and high insulation resistivity Effect

Inactive Publication Date: 2004-10-20
TSINGHUA UNIV
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

The American Materials Research and Analysis Laboratory reported low-grade BaTiO 3 The base multilayer ceramic capacitor material has a dielectric constant of 4400, but the sintering process is complicated and needs to be strictly controlled. Three times of firing, the sintering temperature is ~1110°C

Method used

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  • Multi-layer ceramic capacitor material with dielectric constant and temp stability and its preparing process
  • Multi-layer ceramic capacitor material with dielectric constant and temp stability and its preparing process
  • Multi-layer ceramic capacitor material with dielectric constant and temp stability and its preparing process

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Embodiment 1

[0028] Embodiment 1, taking Nb, Co, Nd element doping as an example. The amount of fixed additives Nb and Co is 1.0 mol%. Nb:Co=2.5. Barium titanate (BaTiO 3 ) The main material is prepared by chemical synthesis method, and its initial raw material is tetrabutyl titanate (Ti(OC 4 h 9 ) 4 ) 102.1g dissolved in ethanol, barium acetate (Ba(CH 3 COO) 2 ) is 76.64g soluble in water, oxalic acid (H 2 C 2 o 4 2H 2 O) 83.2g was dissolved in ethanol. Firstly add tetrabutyl titanate ethanol solution into oxalate ethanol solution, stir evenly, then slowly add barium acetate aqueous solution to form white precipitate of barium titanyl oxalate. The precipitate is firstly washed several times with deionized water, and then washed several times with ethanol, then dried and calcined to obtain white barium titanate powder material. Add secondary additives to 20g of barium titanate powder according to the formula, the content of niobium oxide and cobalt oxide in the formula is 1.0mo...

Embodiment 2

[0029] Example 2: Fixed formula The main ingredient is barium titanate at 98 mol%, the contents of niobium oxide and cobalt oxide at 1.0 mol%, and neodymium oxide at 1.0 mol%. Barium titanate was prepared by the chemical synthesis method in Example 1. Add secondary additives to 20 g of barium titanate powder according to the formula in Example 1. The ingredients are mixed by ball milling, and after drying, press molding under a pressure of 2 MPa, with a diameter of 10 mm and a thickness of 1 mm. Sinter at 1200°C, 1220°C, 1240°C, 1250°C, 1260°C, 1280°C for 2 hours. The heating rate is 6°C / min. The dielectric properties of the fired tiles were measured after firing silver on the upper and lower surfaces. The dielectric performance parameters of the obtained ceramic samples are shown in Table 2. image 3 The curve shows the dielectric temperature characteristic curve of the sample. Figure 4 Give the volumetric temperature change rate curve of the sample.

Embodiment 3

[0030] Example 3: Use and weigh three groups of 20g barium titanate, add secondary additives according to the formula in Example 1, and then add 0.2g, 1.0g, 2.0g metal silver powder respectively, recorded as 3-1, 3-2, 3- 3. The ingredients are mixed by alcohol ball mill, dried, molded under 2MPa pressure, sintered at 1240℃, and the holding time is 2 hours. The dielectric properties of the obtained ceramic samples were tested after firing silver. Table 3 lists the dielectric performance parameters of ceramic samples with different metal Ag powder additions under 1240°C sintering. Figure 5 with Image 6 are the dielectric temperature characteristic curve and capacity temperature change rate curve of the sample, respectively.

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Abstract

This invention discloses a multi-layer ceramic capacitor material with superhigh dielectric constant and stable temp and its preparation method with the main components of barium titanate, metal powder and secondary additives of Co oxide, Nb oxide and rare earth oxide. Barium titanate is prepared by solid phase synthesis and chemical synthesis mixed with metal powders and secondary additives, formed under pressure and sintered to multi-layer ceramic capacitor materials greatly reducing temp of synthesis and finish without adding combustion adjuvant with the controlled room temp dielectric constant of the material of 4000-42000, tolerant variety of less than and equal to minus or plus 15% and sintered temp under 128 deg.C.

Description

technical field [0001] The invention belongs to the technical field of capacitor material preparation, and in particular relates to a dielectric constant and temperature stable multilayer ceramic capacitor material and a preparation method thereof. technical background [0002] Multilayer ceramic capacitors are laminated with electrode materials and ceramic bodies in parallel in multiple layers, and fired into a whole at the same time. According to the International Electronics Industries Association EIA standard. Its capacitance value refers to the capacitance value at 25°C as the reference, within the temperature range from -55 to +125°C, the capacity temperature change rate is <±15%, and the dielectric loss (DF) is ≤2.5%. Multilayer ceramic capacitors are divided into two categories according to their composition: one is composed of lead-containing ferroelectrics, and the other is composed of BaTiO 3 Based on the non-lead-based ferroelectric composition. The latter ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/468C04B35/622H01B3/12H01G4/12
Inventor 王晓慧陈仁政桂治轮李詜李龙土
Owner TSINGHUA UNIV
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