High frequency dielectric ceramic material sintered under low temp and its preparation

A technology of low-temperature sintering and dielectric ceramics, which is applied in the direction of ceramics and inorganic insulators, can solve the problems of increasing the production cost of capacitors, complex phase composition of ceramic materials, and insufficient dielectric constant, and achieves large insulation resistance, high dielectric strength, Wide coverage effect

Inactive Publication Date: 2003-07-23
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

The chemical composition of such ceramics currently used is mainly based on TiO 2 Materials as the main body, including titanates of alkaline earth metals and rare earth metals and titanate-based solid solutions, such as TiO with a negative temperature coefficient of dielectric constant for the manufacture of temperature compensation capacitors 2 , CaTiO 3 , BaZrO 3 etc., the temperature coefficient of dielectric constant α ε Distributed between -300ppm / ℃~-1500ppm / ℃, dielectric constant ε is in the range of 30~150; temperature stable high frequency dielectric ceramics such as BaO-TiO 2 Department, TiO 2 -MgO-La 2 o 3 Department, TiO 2 -BaO-Ln 2 o 3 (La, Nd, Sm) series, the dielectric constant is generally not high enough, mostly concentrated in the range of 20~70, and the phase composition of the ceramic material is also relatively complex
Generally speaking, some temperature stable (NP0) ceramic materials commonly used at present have a common disadvantage, that is, when the temperature coefficient of the dielectric constant is close to zero or a small positive or negative value, the dielectric constant is very small
Since the sintering of this type of material basically belongs to solid-phase sintering, the sintering temperature is high, and when manufacturing capacitors, ternary Pt-Pd-Au alloys or high-palladium-low-silver internal electrode pastes are required, which greatly increases the manufacturing cost of capacitors

Method used

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Examples

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preparation example Construction

[0013] The preparation process of the present invention is, the chemical raw material Bi 2 o 3 , ZnO, Nb 2 o 5 , Sb 2 o 5 , SnO 2 , ZrO 2 , Ta 2 o 5 , MoO 3 According to the general formula (Bi 3x Zn 2-3x )(Zn x-y / 3 Nb 2-x-2y / 3 Ma y )O 7 or (Bi 3x Zn 2-3x )(Zn x Nb 2-x-y MB y )O 7 After preparation, fully mix and grind, pass through 80-120 mesh sieve, pre-fire at 700-800°C, and keep warm for 2-3 hours, crush the burnt block and grind it through 200-mesh sieve to obtain the desired ceramic material . After the porcelain material is made into a finished product as required, it is sintered at 840°C to 1060°C to form porcelain.

[0014] The dielectric ceramic composite material of the present invention includes Bi 2 o 3 , ZnO, Nb 2 o 5 Such composition makes it possible to sinter this dielectric ceramic composite material at low temperature.

[0015] According to the chemical principle of pyrochlore crystal and the relevant theory of dielectric, the pres...

Embodiment 1

[0018] The chemical raw material Bi 2 o 3 , ZnO, Nb 2o 5 , Sb 2 o 3 According to the formula: (Bi 3x Zn 2-3x )(Zn x Nb 2-x-y Ma y )O 7 , wherein, x=0.6, y=1.4, fully mixed and ground after preparation, passed through a 80-120 mesh sieve, pre-fired at 700°C-800°C, and kept for 2h-3h, crushed the burnt block and ground it through 200 Mesh sieve, you can get the desired ceramic material. After the porcelain material is made into a finished product as required, it is sintered at 960°C to 1050°C to form porcelain.

[0019] The performance of this group of ceramic materials reaches the following indicators:

[0020] Dielectric constant temperature coefficient α ε =-13.5ppm / ℃, dielectric constant ε=35, dielectric loss tanδ-4 , insulation resistivity ρ v ≥10 14 cm, electric strength E b ≥10KV / mm.

Embodiment 2

[0022] The chemical raw material Bi 2 o 3 , ZnO, Nb 2 o 5 , SnO 2 According to the formula: (Bi 3x Zn 2-3x )(Zn x-y / 3 Nb 2-x-2y / 3 MB y )O 7 , wherein, x=0.5, y=1.5, prepared according to the process of Example 1.

[0023] The performance of this group of ceramic materials reaches the following indicators:

[0024] Dielectric constant temperature coefficient α ε =-120ppm / ℃, dielectric constant ε=65, dielectric loss tanδ-4 , insulation resistivity ρ v ≥10 13 Ω cm, electric strength E b ≥10KV / mm.

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Abstract

A high-frequency dielectric ceramics sintered at low temp has a structure expressing formula: (Bi3xZn2-3x)(Znx-y/3Nb2-x-2y/3May)O7 and (Bi3xZn2-3x)(ZnxNb2-x-yMby)O7, where Ma=Sn or Zn, Mb=Sb, Ta, or Mo, x=0.45-0.67 and y=0-1.5. Its advantages are high dielectric coefficient (25-8), low medium loss, low sintering temp (840-1060 deg.C), high insulating resistance, and wide range of temp coefficients.

Description

1. Technical field [0001] The invention belongs to the field of electronic ceramics and its manufacture, and relates to a Bi-based pyrochlore-structured low-temperature sintered high-frequency dielectric ceramic material and its preparation. 2. Background technology [0002] With the development of surface mount technology (SMT) in the world, chip multilayer capacitors have become one of the components that can best adapt to the rapid development of electronic technology due to their unique advantages such as small size, large specific capacity, high reliability, and low ESR. , the demand for chip multilayer capacitors (MLCC) in the international market is growing at an average annual rate of 15-20%. Chip multilayer ceramic capacitors have developed into the largest and fastest-growing chip component varieties in the world. The annual output of MLC in Japan, the United States and some European countries is more than tens of billions, and a new high-tech industry has been for...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/48C04B35/495C04B35/64H01B3/12
Inventor 姚熹杜慧玲汪宏
Owner XI AN JIAOTONG UNIV
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