CN1402275A

CN1402275A - Low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain and mfg. method thereof

Info

Publication number: CN1402275A
Application number: CN 02134818
Authority: CN
Inventors: 司留启; 欧明; 刘会冲; 朱松根; 莫方策; 曹英
Original assignee: Guangdong Fenghua High New Science & Technology Group Co Ltd
Priority date: 2002-09-25
Filing date: 2002-09-25
Publication date: 2003-03-12
Anticipated expiration: 2022-09-25
Also published as: CN100418166C

Abstract

A porcelain for low-frequency high-dielectric resistance reduction multi-layer ceramic capacitor (MLCC) has a chemical formula: (Ba1-xCax)m(Ti1-yZry)O3+component A, where A is the additive chosen from MnCo3, MnO2, Nb2O5, etc, x=0.001-0.12, y=0.18-0.22 and m=1.001-1.03. Its preparing process includes synthesizing BaTiO3 and BaZrO3 and adding component A. Its advantage are high performance of MLCC and low cost.

Description

Low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain and preparation method thereof

Technical field

The present invention relates to a kind of low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain that can mate sintering under reducing atmosphere with base metal nickel, copper.

The invention still further relates to the preparation method of this low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain.

Background technology

In recent years, along with miniaturization, the high capacity of chip multilayer ceramic capacitor, MLCC (multilayer ceramic capacitor, down together) inner electrode layer number is on the increase, and interior electrode cost increases severely and causes the MLCC cost to increase severely.Because electrode adopts rare precious metals palladiums (Pd) in the existing MLCC porcelain, the Pd market price rises steadily in the world, causes the interior electrode cost of noble metal sharply to increase to more than the 80-90% by about 60%.Publication number is that 1305193 Chinese patent discloses a kind of multilayer sheet type ceramic capacitor porcelain, and its prescription comprises BaCO ₃, TiO ₂, ZrO ₂, CaCO ₃, Nb ₂O ₃, its percentage by weight is: BaCO ₃65-73%, TiO ₂23-27%, ZrO ₂4-9%, CaCO ₃0.01-2.5%, Nb ₂O ₃0.01-0.75%.Advantages such as the porcelain that makes according to this prescription has the aplitic texture densification, and dielectric is often high, and specific volume is big, and temperature characterisitic and ageing properties are good.But the porcelain that this invention makes can only be made MLCC as electrode with price high precious metals pd or Pd/Ag, causes the rapid increase of cost.Therefore, at present domestic and international manufacturer all utilizes base metal Ni, Cu to make MLCC as electrode.The cost of Ni/Cu electrode MLCC is less than 10% of Pd/Ag electrode MLCC cost, and there is not the Ag migration in metal Ni, and electrode coupling reliability and mechanical strength are higher, and the withstand voltage thermal shock and the wettability of electrode layer are also better.Therefore use the overall performance that Ni, Cu electrode can improve MLCC, also can improve the performance level of complete electronic set simultaneously.Yet, because metallic nickel easily oxidation in high temperature, must be at sintering under the reducing atmosphere, at present, still do not have stable porcelain of performance and nickel electrode and mate and make MLCC.

Summary of the invention

The objective of the invention is to provide a kind of low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain of function admirable for the defective that overcomes the prior art existence.This porcelain satisfies the EIA-Y5V characteristic standard, can make MLCC with base metal Ni, Cu coupling sintering under reducing atmosphere, in the cost of MLCC being dropped to do with Pd/Ag 10% of the cost of the MLCC of electrode, also can improve the overall performance of MLCC simultaneously.

The present invention also aims to provide the preparation method of described low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain.

Low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain of the present invention effectively chemistry is composed as follows:

(Ba _1-xCa _x) _m(Ti _1-yZr _y)O ₃

The described A component of A component is an additive, is MnCO ₃, MnO ₂, Nb ₂O ₅, NiO, Y ₂O ₃, ZnO, Yb ₂O ₃, Er ₂O ₃, Ho ₂O ₃, SiO ₂In one or more mixtures; By weight percentage, content is 0.50%～3.5%, and all the other are (Ba _1-xCa _x) _m(Ti _1-yZr _y) O ₃X=0.001～0.12 wherein, y=0.18～0.22, m=1.001～1.03.

The preparation method of low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain of the present invention is as follows: adopt the synthetic BaTiO of hydro thermal method ₃, solid phase synthesis BaZrO ₃When adding the A component, Ca ²⁺With CaO or CaCO ₃Form add Mn ²⁺With MnO ₂Or MnCO ₃Form add, other then adds with oxide form.

BaTiO ₃Crystal has ABO ₃The type perovskite structure, with molar ratio computing, A/B is greater than the BaTiO of 1.00-1.03 ₃Mix foreign ion in the composition, and manage to make foreign ion to enter the B position and rise and be subjected to main effect, the oxygen vacancy concentration that causes when alms giver effect is during greater than the oxygen vacancy concentration of oxygen volatilization, and the electron concentration on the Ti position is inhibited, thereby makes porcelain sintering under reducing atmosphere have higher insulation resistivity.Because of Ca ²⁺Might replace Ba ²⁺The position, so the resistance to reduction energy and the BaTiO of porcelain ₃Middle Ca ²⁺Concentration is relevant, and is along with Ca ²⁺The increase of concentration, it is poor more that resistance to reduction becomes, and this just need add more Ca ²⁺((Ba+Ca)/Ti) could guarantee that porcelain has the good insulation performance performance under reducing atmosphere to increase A/B.

Fig. 1 is BaTiO ₃Middle Ca ²⁺Concentration is to porcelain Effect on Performance graph of a relation, as seen adds percentage by weight and be 0.2%～4.52% CaO (or CaCO ₃), can make A/B greater than 1.While addition and BaTiO ₃Middle Ca ²⁺Concentration is relevant, Ca ²⁺Concentration is high more, need add Ca the more, finally causes A/B to increase, and this may be because Ca ²⁺Existence cause adding the easier A of entering of Ca position, the A position since entering of Ca make Ba ²⁺Residue, and it is generally acknowledged Ba ²⁺Can not enter the B position, only Ca under the situation that adds abundant Ca ²⁺Just enter the B position and play a part to suppress electron concentration, porcelain just has resistance to reduction.

Work as BaTiO ₃In contain low Ca ²⁺During concentration, the adding percentage by weight is 0.05～0.5% MnCO in the porcelain prescription ₃, porcelain can obtain good insulation resistivity equally.

Fig. 2 is MnCO ₃Content is to the graph of a relation that influences of resistivity, as shown in the figure, and MnCO ₃Adding very little to the resistivity effects that adds the Ca sample, but improved the compactness of porcelain body.This illustrates MnCO ₃The following Mn of the lower situation of A/B that is added in (≈ 1) ²⁺Can enter the A position, improve A/B compared with improve the porcelain resistance to reduction can effect, on the other hand, make A/B＞1 or add enough MnCO adding Ca ₃Situation under, Mn ²⁺Enter crystal boundary again, thereby improve the sintering character of porcelain body.MnO ₂Interpolation have identical effect.

The present invention adds Nb ⁵⁺, Nb ⁵⁺Be donor doping, so Nb ⁵⁺Be added with the raising that is beneficial to DIELECTRIC CONSTANT.In molar content, work as Ca ²⁺Content greater than Nb ⁵⁺During the twice of content, Ti ⁴⁺Locational Ca ²⁺Ion has compensated donor ion Nb as acceptor ion ⁵⁺, and prevented Ti ⁴⁺Be reduced to Ti ³⁺

The adding percentage by weight is 0.02%～1.0% NiO, 0.1%～3.0%SiO ₂Or Y ₂O ₃, ZnO, Yb ₂O ₃, Er ₂O ₃, Ho ₂O ₃In one or more, help making porcelain body in the burning temperature scope of broad, to keep thin brilliant.

The prepared porcelain of the present invention, can make electrode sintering under reducing atmosphere with base metal Ni, Cu and make MLCC, in the interior electrode cost of MLCC being dropped to make 10% of the electrode cost of Pd/Ag, and there is not the Ag migration in metal Ni, its electrode coupling reliability and mechanical strength are higher, the withstand voltage thermal shock and the wettability of electrode layer are also better, therefore can improve the overall performance of MLCC.The present invention satisfies the EIA-Y5V characteristic standard, has improved the performance level of complete electronic set.

Description of drawings

Fig. 1 is BaTiO ₃Middle Ca ²⁺Concentration is to porcelain Effect on Performance graph of a relation;

Fig. 2 is MnCO ₃Content is to the figure that influences of resistivity;

Fig. 3 is the concrete porcelain prescription composition diagram in the embodiment;

Fig. 4 is the porcelain prescription electrical property figure behind the sintering under reducing atmosphere among Fig. 3.

Embodiment

By porcelain prescription shown in Figure 3, porcelain production technology with routine is prepared, the termination electrode coupling of the interior electrode of doing with base metal nickel on the MLCC production line, copper work is made into MLCC and gives birth to the embryo chip then, and under reducing atmosphere sintering, test its electrical property, the result as shown in Figure 4, visible porcelain of the present invention satisfies the EIA-Y5V characteristic standard.

Claims

1, a kind of low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain is characterized in that effectively chemistry is composed as follows:

(Ba _1-xCa _x) _m(Ti _1-yZr _y)O ₃

2, low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain according to claim 1 is characterized in that described A component is the MnCO of 05～0.5% weight ₃

3, low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain according to claim 1 is characterized in that described A component is the NiO of 0.02%～1.0% weight.

4, low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain according to claim 1 is characterized in that described A component is the SiO of 0.1%～3.0% weight ₂Or Y ₂O ₃, ZnO, Yb ₂O ₃, Er ₂O ₃, Ho ₂O ₃In one or more.

5, the preparation method of the described low-frequency high dielectric resistance reduced multilayer ceramic capacitor porcelain of claim 1 is characterized in that adopting hydro thermal method to synthesize BaTiO ₃, solid phase synthesis BaZrO ₃When adding the A component, Ca ²⁺With CaO or CaCO ₃Form add Mn ²⁺With MnO ₂Or MnCO ₃Form add, other adds with oxide form.