CN101792312A - SrTiO3 ceramic dielectric material and preparation method of capacitor thereof - Google Patents

Abstract

The invention relates to a SrTiO3 ceramic dielectric material and a preparation method of a capacitor thereof. The ceramic dielectric material comprises MnCO3, SrTiO3 and (Bi1/2Na1/2) TiO3. The process of preparing the capacitor by using the ceramic dielectric material comprises the steps of: synthesizing (Bi1/2Na1/2) TiO3 by Bi2O3, Na2CO3 and TiO2; preparing a pre-synthetic material SrTiO3 by SrCO3 and TiO2; preparing a dry abrasive by (Bi1/2Na1/2) TiO3, SrTiO3 and MnCO3; adding a polyvinyl alcohol solution to the dry abrasive; granulating, screening, pressing, sintering and preparing a silver electrode to obtain the capacitor. The invention enhances a dielectric constant of SrTiO3 ceramics by regulating the proportion of (Bi1/2Na1/2) TiO3 to SrTiO3, and enables the ceramic material to have fine grain structure by doping MnCO3. The prepared capacitor keeps a high dielectric constant and has low dielectric loss and higher breakdown field strength.

Description

SrTiO 3The preparation method of ceramic dielectric material and electrical condenser thereof

Technical field

The present invention relates to a kind of SrTiO ₃The preparation method of ceramic dielectric material and electrical condenser thereof belongs to the dielectric ceramics technology.

Background technology

For a long time, the research of centering high voltage ceramic capacitor is very active both at home and abroad.These researchs mainly concentrate on by changing material prescription and reach material modification and realize unleaded purpose.In the prior art, the research that has additive to SrTiO ₃Be the rule that influences of high-pressure medium porcelain dielectric properties, find MnO ₂Adding can reduce dielectric loss, the Dy of ceramic dielectric ₂O ₃Adding can improve the specific inductivity of medium, CaTiO ₃, MgTiO ₃, NiO adding can reduce the rate of temperature change of this material dielectric constant, but its Curie temperature is still below 40 ℃, its room temperature dielectric constant lower [Hao person of outstanding talent .[J]. Hebei College of Science and Engineering's journal, 2001,23, (1): 53-58]]; The research that has doped with rare-earth elements La ₂O ₃Y ₂O ₃, CeO ₂Deng to SrTiO ₃ε and the temperature of tg δ and the influence of frequency response characteristic of base pottery find that these rare earth elements make SrTiO ₃The dielectric loss of base pottery reduces, but the rate of temperature change of the specific inductivity of material [Xiao Hong ground, Wang Chengjian, Ma Honglei .[J] bigger than normal. functional materials, 2003,1, (34): 78-82]; The research that has doping Bi ₂O ₃NTiO ₂, Pb ²⁺, Mn ²⁺And Zn ²⁺To SrTiO ₃The modifying function of base high voltage capacitor pottery is found Bi ₂O ₃NTiO ₂And Pb ₃O ₄Add-on in certain scope, can improve the specific inductivity of porcelain, improve its sintering character simultaneously, add an amount of MnCO ₃Can improve the sintering character of porcelain and the rate of temperature change of specific inductivity, unleaded but result of study does not realize, and the specific inductivity under its room temperature less than normal (Zhang Qingqiu, Li Yao continuous heavy rain .[J]. South China Science ﹠ Engineering University's journal, 2000,28, (1): 69-69).

Summary of the invention

The purpose of this invention is to provide a kind of SrTiO ₃The preparation method of ceramic dielectric material and electrical condenser thereof, the high and low loss of this ceramic dielectric material specific inductivity, unleaded; Simple with its preparation electrical condenser process, the capacitor performance that makes is good.

The present invention is realized by following technical proposals, a kind of SrTiO ₃Ceramic dielectric material is characterized in that, this ceramic medium material is made up of following component and content thereof,

SrTiO ₃：(30～90.0)mol％；

(Bi _1/2Na _1/3)TiO ₃：(10.0～70.0)mol％；

And SrTiO ₃(Bi _1/2Na _1/2) TiO ₃The molar content sum be 100%,

MnCO ₃: mass content is SrTiO ₃(Bi _1/2Na _1/2) TiO ₃(0.1～1.3) of quality sum doubly.

With above-mentioned SrTiO ₃Ceramic dielectric material prepares the method for electrical condenser, it is characterized in that comprising following process:

1) with Bi ₂O ₃With Na ₂CO ₃And TiO ₂According to mol ratio is to prepare burden at 1: 1: 4, is to mix at 1: 1: 2 to carry out wet ball grinding 4～24 hours with this batching and abrading-ball and deionized water by mass ratio, slip behind the mix grinding places baking oven in 110～140 ℃ of oven dry of temperature, oven dry material 760～820 ℃ of temperature down insulation carried out synthetic in advance pre-synthetic material (Bi in 2 hours _1/2Na _1/2) TiO ₃

2) with SrCO ₃With TiO ₂Be to prepare burden at 1: 1 in molar ratio, is to mix at 1: 1: 2 to carry out wet ball grinding 4～24 hours with this batching and abrading-ball and deionized water by mass ratio, slip behind the mix grinding places baking oven in 110～140 ℃ of oven dry of temperature, dry and expect that being incubated 2 hours down for 1050～1180 ℃ through temperature carries out synthesizing in advance, gets pre-synthetic material SrTiO ₃

3) the pre-synthetic material (Bi that step 1) is made _1/2Na _1/2) TiO ₃With step 2) the pre-synthetic material SrTiO that makes ₃And MnCO ₃Be 1 in molar ratio: (0.1～0.7): prepare burden (0.01～0.13), be to mix at 1: 1: 1.5 to carry out ball milling 4～24 hours by this batching and abrading-ball and deionized water by mass ratio again, then the ball milling material is placed baking oven at 110～140 ℃ of oven dry of temperature, the material of must dry grinding;

4) by 5～8% of dry grinding material quality, the adding mass concentration is 5% polyvinyl alcohol aqueous adhesive in the dry bulb abrasive material, carry out granulation after mixing, the granulation material is by 40 mesh sieve branches, get particulate material and on shaper, suppress type in blocks with pressure 100～500MPa, matrix band is placed on the aluminum oxide backing plate that the titanium dioxide zirconium powder is bedding and padding, separate with the titanium dioxide zirconium powder between two matrix bands, put into high temperature box type resistance furnace then and be incubated 20 minutes for 200～350 ℃ in 120～150 ℃ of temperature and temperature respectively, control heat-up rate again at 300～400 ℃/h, be warming up to 1230～1270 ℃ of following sintering 1～4h, furnace cooling is to room temperature then, after the zirconium dioxide bedding and padding removing of burning till on the ceramics of back, with the ceramics preheating, the even silver coating electrode slurry in two sides is incubated burning infiltration in 10 minutes down 530 ℃ of temperature then and makes silver electrode, obtains lead-free ceramic capacitance device of the present invention.

Advantage of the present invention is: by regulating (Bi _1/2Na _1/2) TiO and SrTiO ₃Ratio make SrTiO ₃The specific inductivity of system's pottery is significantly improved; By doped with Mn CO ₃, make stupalith have fine crystalline structure, when keeping high-k, still have very low dielectric loss and higher disruptive field intensity; Raw material and working condition that the present invention adopts realize easily, material repeated fine.

Embodiment

Embodiment 1:

1: 1: 4 in molar ratio difference weighing Bi ₂O ₃, Na ₂CO ₃, TiO ₂1: 1 in molar ratio difference weighing TiO ₂, SrCO ₃: above-mentioned batching is respectively charged into planetary ball mill carries out ball milling 4h (material: ball: water=1: 1: 2).The ball milling material is after 120 ℃ of dryings, respectively at 780 ℃ of temperature and 1100 ℃ of synthetic (Bi of temperature _1/2Na _1/2) TiO ₃And SrTiO ₃Then according to 45mol% (Na _0.5Bi _0.5) TiO ₃+ 55mol%SrTiO ₃+ 0.2wt%MnCO ₃Prepare burden.

Take by weighing pre-synthetic material 45mol (Na respectively _0.5Bi _0.5) TiO ₃SrTiO with 55mol ₃, allocate 0.1000g MnCO again into ₃Mix by this batching 50g, abrading-ball 50g and deionized water 100g then and carried out wet ball grinding 6 hours.The ball milling material is after 120 ℃ of dryings of temperature, 7% adding mass concentration by oven dry material quality is that 5% polyvinyl alcohol water solution 3.5ml mixes, cross 40 mesh sieve granulations, under pressure 350MPa pressure, the granulation material is pressed into Φ 10mm * 2mm disk then, sample after the moulding is placed on aluminum oxide or the zirconium dioxide backing plate, between sheet and the sheet zirconium dioxide bedding and padding need be arranged, put into high temperature box type resistance furnace and respectively be incubated 20 minutes for 200 ℃ in 120 ℃ of temperature and temperature, again per hour to heat up 300-400 ℃, 2h burns till under 1250 ℃ of temperature, and the ceramics after burning till is through 530 ℃ of burning infiltration silver electrodes.The ε of sample is 3125, tan δ is 34 * 10 ^-4, T _CIt is 8 ℃.

Claims (2)

1. SrTiO ₃Ceramic dielectric material is characterized in that, this ceramic dielectric material is made up of following component and content thereof,

SrTiO ₃：(30～90.0)mol％；

(Bi _1/2Na _1/2)TiO ₃：(10.0～70.0)mol％；

And SrTiO ₃(Bi _1/2Na _1/2) TiO ₃The molar content sum be 100%,

MnCO ₃: mass content is SrTiO ₃(Bi _1/2Na _1/2) TiO ₃(0.1～1.3) of quality sum doubly.

2. one kind with the described SrTiO of claim 1 ₃Ceramic dielectric material prepares the method for electrical condenser, it is characterized in that comprising following process:

1) with Bi ₂O ₃With Na ₂CO ₃And TiO ₂According to mol ratio is to prepare burden at 1: 1: 4, is to mix at 1: 1: 2 to carry out wet ball grinding 4～24 hours with this batching and abrading-ball and deionized water by mass ratio, slip behind the mix grinding places baking oven in 110～140 ℃ of oven dry of temperature, oven dry material 760～820 ℃ of temperature down insulation carried out synthetic in advance pre-synthetic material (Bi in 2 hours _1/2Na _1/2) TiO ₃

2) with SrCO ₃With TiO ₂Be to prepare burden at 1: 1 in molar ratio, is to mix at 1: 1: 2 to carry out wet ball grinding 4～24 hours with this batching and abrading-ball and deionized water by mass ratio, slip behind the mix grinding places baking oven in 110～140 ℃ of oven dry of temperature, dry and expect that being incubated 2 hours down for 1050～1180 ℃ through temperature carries out synthesizing in advance, gets pre-synthetic material SrTiO ₃

3) the pre-synthetic material (Bi that step 1) is made _1/2Na _1/2) TiO ₃With step 2) the pre-synthetic material SrTiO that makes ₃And MnCO ₃Be 1 in molar ratio: (0.1～0.7): prepare burden (0.01～0.13), be to mix at 1: 1: 1.5 to carry out ball milling 4～24 hours by this batching and abrading-ball and deionized water by mass ratio again, then the ball milling material is placed baking oven at 110～140 ℃ of oven dry of temperature, the material of must dry grinding;

4) by 5～8% of dry grinding material quality, the adding mass concentration is 5% polyvinyl alcohol aqueous adhesive in the dry bulb abrasive material, carry out granulation after mixing, the granulation material is by 40 mesh sieve branches, get particulate material and on shaper, suppress type in blocks with pressure 100～500MPa, matrix band is placed on the aluminum oxide backing plate that the titanium dioxide zirconium powder is bedding and padding, separate with the titanium dioxide zirconium powder between two matrix bands, put into high temperature box type resistance furnace then and be incubated 20 minutes for 200～350 ℃ in 120～150 ℃ of temperature and temperature respectively, control heat-up rate again at 300～400 ℃/h, be warming up to 1230～1270 ℃ of following sintering 1～4h, furnace cooling is to room temperature then, after the zirconium dioxide bedding and padding removing of burning till on the ceramics of back, with the ceramics preheating, the even silver coating electrode slurry in two sides is incubated burning infiltration in 10 minutes down 530 ℃ of temperature then and makes silver electrode, obtains lead-free ceramic capacitance device of the present invention.