CN100412030C

CN100412030C - Barium strontium titanate base electro-optical composite material and preparation method thereof

Info

Publication number: CN100412030C
Application number: CNB2005100258122A
Authority: CN
Inventors: 陈莹; 董显林
Original assignee: Shanghai Institute of Ceramics of CAS
Current assignee: Shanghai Institute of Ceramics of CAS
Priority date: 2005-05-13
Filing date: 2005-05-13
Publication date: 2008-08-20
Anticipated expiration: 2025-05-13
Also published as: CN1699275A

Abstract

The present invention relates to a method for prepaing barium strontium titanate group electro-optical composite materials. The material comprises (1-y-z)Ba<1-x>Sr<x>TiO3+yMe2SiO4+zMO, wherein x is from 0 to 0.75, y is from 5 to 60 wt%, z is from 0 to 30 wt%, and the sum of y and z is from 5 to 60 wt%. Ba<1-x>Sr<x>TiO3 and Mg2SiO4 are respectively prepared by the present invention according to a stoichiometric proportion, and Ba<1-x>Sr<x>TiO3 powder and Mg2SiO4 powder are respectively obtained by ball milling, discharging, baking and presintering; then Me2SiO4 and MO are doped into BSTO powder according to a component design, and ball milling, baking, granulating, molding and adhesive removing are carried out; the mixture is sintered at 1250 to 1350 DEG C for 2 to 4 hours in a furnace; after natural cooling, the required samples are obtained. The materials have the advantages of low dielectric constant, low loss, high adjustability, high insulation resistance, high breaking resistance, etc., and are especially suitable for phase shifters.

Description

A kind of barium strontium titanate base electro-optical composite material and preparation method thereof

Technical field

The present invention relates to a kind of barium strontium titanate base electro-optical composite material and preparation method thereof, belong to the electrooptical material field.

Background technology

Material as phase shifter mainly is ferrite and PIN diode at present, but all there are some bigger shortcomings in they, and for example, the peak power of ferrite phase shifter is big, and transmission speed is restricted; Temperature-compensation circuit unavoidably causes the error in pointing of phased array antenna; Control circuit, compensating circuit not only make phase changer itself bulky, and cause the phased array antenna reliability to reduce; Complex manufacturing technology, production cost is higher.The PIN diode phase shifter is more cheap than ferrite phase shifter, but high insertion loss has limited its use.Therefore, ferrite phase shifter and PIN diode phase shifter all are difficult to satisfy the requirement of modern military technology to lightweight, miniaturization, high reliability and the high band of phased array antenna proposition of new generation.

The specific inductivity of strontium-barium titanate BSTO material changes with the variation of applying direct current electric field, when voltage from V ₍₀₎Change to V _(opp)The time, specific inductivity will produce an increment Delta ε _r=[ε _{R (0)}-ε _{R (app)}], this increment and ε _{R (0)}The percentage ratio of ratio is called adjustability, promptly uses Tunability=[ε _{R (0)}-ε _{R (app)}]/ε _{R (0)}* 100% expression.And will produce corresponding differential phase shift when applying the light (microwave) of a particular frequencies simultaneously, reach the purpose that changes phase place.Material with this specific character is called electrooptical material.

Twentieth century end of the nineties, people such as US Naval Research Laboratory (NRL) J.L.Rao propose the thought of ferroelectric formula lens phase array system, adopt the monoblock type phase-shifting unit, can effectively reduce the quantity (become m+n by original m * n, wherein m, n are respectively the columns and the line number of phased array) of phase shifter, driving mechanism and controller.The personnel of United States Army research laboratory did a statistics: use ferrite to prepare 1000 unitary radar arrays, about 5,000,000 dollars of required expense, and adopt electrooptical material to replace ferrite only needs 200,000 dollars, and only the material cost is original 1/25.Because but the volume miniaturization improves with integrated level, make phased array radar more be applicable to airborne and On-Board System simultaneously.

Current, the BSTO ferroelectric material is generally believed it is the most promising phase shifter material, from earlier 1990s the ferroelectric ceramic(s) phase shifter since the U.S. enters the applicable feasibility Journal of Sex Research stage, states such as Britain, France, Japan, Sweden and Russia are also in the research of this respect of throwing oneself into, they have carried out doping vario-property to the BSTO material, discovery is mixed multiple metal oxide and is had similar modifying function in the BSTO material system, as the difference doped with Al ₂O ₃, ZrO ₂, MgO the BSTO matrix material, their Curie temperature all decreases, and is in paraelectric phase during room temperature, and follows the increase of oxide compound add-on, the room temperature dielectric constant of material all shows downward trend, adjustability also obviously descends.

Compare with the material of other doping vario-property, BSTO/MgO, BSTO/MgO/ rare earth composite material have more excellent dielectric properties, according to U.S. Pat-5427988 and US-6074971Ba _0.6Sr _0.4TiO ₃The DIELECTRIC CONSTANT of/60wt.%MgO _{R (0)}Be 89.35 o'clock, under the direct-current biasing of 2.63kV/mm, its adjustability is 11.09%, DIELECTRIC CONSTANT _{R (0)}Be 116.86 o'clock, under the direct-current biasing of 2kV/mm, its adjustability is 9.99%; Ba _0.55Sr _0.45TiO ₃/ 60wt.%MgO/La ₂O ₃DIELECTRIC CONSTANT _{R (0)}Be 79 o'clock, under the direct-current biasing of 2kV/mm, its adjustability is 7.85%.But these two kinds of matrix materials exist two big weak points: (1) along with the increase of oxide compound add-on, when specific inductivity reduced, its adjustability suppression ratio was more serious; (2) sintering temperature is higher, and usually between 1350 ℃-1450 ℃, and sintering temperature raises with the increase of oxide compound add-on.

Summary of the invention

The purpose of this invention is to provide a kind of barium strontium titanate base electro-optical composite material and preparation method thereof.This preparation method is simple, but densified sintering product at low temperatures, and material has low-k, low-loss, high adjustability, high insulation resistance, high breakdown characteristics simultaneously.Be suitable for and make phased array phase shifter electrooptical material.

Described material is by (1-y-z) Ba _1-xSr _xTiO ₃+ y Me ₂SiO ₄+ zMO forms, x=0～0.75 wherein, y=5～60wt.%; Z=0～30wt.%, y+z=5～60wt.%.

Wherein, Me ₂SiO ₄Be CaSiO ₃, BaSiO ₃And/or SrSiO ₃Described MO is MgTiO ₃, MgZrO ₃, MgAl ₂O ₄, Al ₂O ₃And/or ZrO ₂

Preparation (1-y-z) Ba _1-xSr _xTiO ₃+ y Me ₂SiO ₄The concrete processing step of+zMO is as follows:

(1) prepares Ba respectively by stoichiometric ratio _1-xSr _xTiO ₃, and Me ₂SiO ₄, raw material adopts pulverous BaCO ₃, SrCO ₃, TiO ₂, Mg ₂Si ₃O ₈And MgO, be medium then with water, agate ball is situated between for mill, behind ball milling 12h～24h, discharging, oven dry, powder pre-burning 2h～4h in 1100 ℃～1200 ℃ scopes obtains Ba respectively _1-xSr _xTiO ₃, and Mg ₂SiO ₄Powder;

(2) according to forming design, in the BSTO powder, mix the Me of different amounts ₂SiO ₄And MO, be medium with water, agate ball is situated between ball milling 24-36h hour for mill;

(3) with the said mixture of oven dry, add the PVA granulation of 3～8wt.%, under the pressure of 50～200Mpa with the pressed by powder moulding;

(4) 800 ℃ below the temperature, be incubated 2 hours, get rid of the organic substance in the green compact, the heat-up rate of binder removal process is not higher than 30 ℃/min;

(5) green compact sintering in 1250 ℃～1350 ℃ scopes, insulation 2h～4h.Behind the naturally cooling, promptly obtain the body material of required excellent property.

The invention has the advantages that by material prescription of the present invention, can be in 1250 ℃～1350 ℃ scopes sintering, and this material to have a specific inductivity low, loss is low, adjustability height, insulation resistance height, excellent properties such as breakdown characteristics height.Successfully obtained the result that high-performance and low fever have both simultaneously.

Description of drawings

Fig. 1 is the change curve of the dielectric constant with temperature of embodiment 1 sample 1

Fig. 2 is the change curve of the specific inductivity of embodiment 1 sample 1 with bias voltage

Fig. 3 is the change curve of the dielectric constant with temperature of embodiment 2 samples 2

Fig. 4 is the change curve of the specific inductivity of embodiment 2 samples 2 with bias voltage

Fig. 5 is the change curve of the dielectric constant with temperature of embodiment 3 samples 3

Fig. 6 is the change curve of the specific inductivity of embodiment 3 samples 3 with bias voltage

Fig. 7 is the change curve of the dielectric constant with temperature of embodiment 4 samples 4

Fig. 8 is the change curve of the specific inductivity of embodiment 4 samples 4 with bias voltage

Embodiment

Further illustrate substantial characteristics of the present invention and obvious improvement below by embodiment, yet the present invention absolutely not only is confined to described embodiment.

Embodiment 1, with pulverous BaCO ₃, SrCO ₃, TiO ₂, Me ₂Si ₃O ₈With MO be raw material, prepare Ba respectively by stoichiometric ratio _1-xSr _xTiO ₃(x=0.4) and Me ₂SiO ₄, behind the wet ball grinding 24h, discharging, oven dry, powder obtains Ba respectively at 1150 ℃ of following pre-burning 2h _0.6Sr _0.4TiO ₃And Me ₂SiO ₄Powder; According to (1-y-z) Ba _1-xSr _xTiO ₃+ yMe ₂SiO ₄+ zMO (x=0.4 wherein, y=14wt.%, z=6wt.%) proportioning, wet ball grinding 24h; Discharging, oven dry add the PVA granulation of 6wt.%, under the pressure of 100Mpa with the pressed by powder moulding; Through 800 ℃/2h binder removal, 1320 ℃/2h sintering.Sample after burning till is processed through fine grinding, after the ultrasonic cleaning, goes up silver electrode again, can be used for the dielectric properties test.The electric property of sample 1 sees Table 1.Fig. 1 has provided the change curve of the dielectric constant with temperature of sample 1, and Fig. 2 has provided the change curve of the specific inductivity of sample 1 at bias voltage.

Embodiment 1 sample 1 electric property

Moiety	Specific inductivity (25 ℃)	tgδ	Adjustability (at 2kV/mm)	Curie temperature	Insulation resistivity (at 100V/mm)	Voltage breakdown (kV/mm)
Moiety	Specific inductivity (25 ℃)	tgδ	Adjustability (at 2kV/mm)	Curie temperature	Insulation resistivity (at 100V/mm)	Voltage breakdown (kV/mm)	Ba _0.6Sr _0.4TiO ₃ +14wt.％Mg ₂SiO ₄+6wt.％MgO	806.06	0.002	12.77	-31.6℃	8.24×10 ¹⁴ Ω·cm	9.1

Embodiment 2, according to (1-y-z) Ba _1-xSr _xTiO ₃+ y Me ₂SiO ₄+ zMO (x=0.4 wherein, y=25wt.%, z=10wt.%) proportioning preparation, concrete technology is same with embodiment 1.Sample 2 electric properties see Table 2.Fig. 3 has provided the change curve of the dielectric constant with temperature of sample 2, and Fig. 4 has provided the change curve of the specific inductivity of sample 2 with bias voltage.

Embodiment 2 samples 2 electric properties

Moiety	Specific inductivity (25 ℃)	tgδ	Adjustability (at 2kV/mm)	Curie temperature	Insulation resistivity (at 100V/mm)	Voltage breakdown (kV/mm)
Moiety	Specific inductivity (25 ℃)	tgδ	Adjustability (at 2kV/mm)	Curie temperature	Insulation resistivity (at 100V/mm)	Voltage breakdown (kV/mm)	Ba _0.6Sr _0.4TiO ₃ +25wt.％Mg ₂SiO ₄+10wt.％MgO	346	0.0006	12.79	-29.1℃	8.45×10 ¹⁴ Ω·cm	12

Embodiment 3, according to (1-y-z) Ba _1-xSr _xTiO ₃+ yMe ₂SiO ₄+ zMO (x=0.4 wherein, y=35wt.%, z=15wt.%) proportioning preparation, concrete technology is same with embodiment 1.Sample 3 electric properties see Table 3.Fig. 5 has provided the change curve of the dielectric constant with temperature of sample 3, and Fig. 6 has provided the change curve of the specific inductivity of sample 3 with bias voltage.

Embodiment 3 samples 3 electric properties

Moiety	Specific inductivity (25 ℃)	tg δ	Adjustability (at 2kV/mm)	Curie temperature	Insulation resistivity (at 100V/mm)	Voltage breakdown (kV/mm)
Moiety	Specific inductivity (25 ℃)	tg δ	Adjustability (at 2kV/mm)	Curie temperature	Insulation resistivity (at 100V/mm)	Voltage breakdown (kV/mm)	Ba _0.6Sr _0.4TiO ₃ +35wt.％Mg ₂SiO ₄+15wt.％MgO	118.40	0.001	13.18	-37℃	8.87×10 ¹⁴ Ω·cm	10

Embodiment 4, according to (1-y-z) Ba _1-xSr _xTiO ₃+ yMe ₂SiO ₄+ zMO (x=0.4 wherein, y=40wt.%, z=20wt.%) proportioning preparation, concrete technology is same with embodiment 1.Sample 4 electric properties see Table 4.Fig. 7 has provided the change curve of the dielectric constant with temperature of sample 4, and Fig. 8 has provided the change curve of the specific inductivity of sample 4 with bias voltage.

Embodiment 4 samples 4 electric properties

Moiety	Specific inductivity (25 ℃)	tgδ	Adjustability (at 2kV/mm)	Curie temperature	Insulation resistivity (at 100V/mm)	Voltage breakdown (kV/mm)
Moiety	Specific inductivity (25 ℃)	tgδ	Adjustability (at 2kV/mm)	Curie temperature	Insulation resistivity (at 100V/mm)	Voltage breakdown (kV/mm)	Ba _0.6Sr _0.4TiO ₃ +40wt.％Mg ₂SiO ₄+20wt.％MgO	65.10	0.002	8.9	-33.6℃	1.05×10 ¹⁵ Ω·cm	7.5

Claims

1. a barium strontium titanate base electro-optical composite material is characterized in that material is by Ba _0.6Sr _0.4TiO ₃+ y Mg ₂SiO ₄+ zMgO forms, wherein y=14～40wt.%; Z=6～20wt.%.

2. by the preparation method of the described barium strontium titanate base electro-optical composite material of claim 1, it is characterized in that comprising the steps:

(1) prepares Ba respectively by stoichiometric ratio _0.6Sr _0.4TiO ₃And Mg ₂SiO ₄, be medium then with water, agate ball is situated between for mill, behind ball milling 12h～24h, discharging, oven dry, powder pre-burning 2h～4h in 1100 ℃～1200 ℃ scopes obtains Ba respectively _0.6Sr _0.4TiO ₃And Mg ₂SiO ₄Powder;

(2) according to forming proportioning, at Ba _0.6Sr _0.4TiO ₃Mix Mg in the powder ₂SiO ₄And MgO, be medium with water, agate ball is situated between ball milling 24-36 hour for mill;

(3), add PVA granulation and the compression moulding green compact of 3～8wt.% with the said mixture of oven dry;

(4) 800 ℃ below the temperature, be incubated 2 hours, to get rid of the organic substance in the green compact, the heat-up rate of binder removal process is not higher than 30 ℃/min;

(5) green compact sintering in 1250 ℃～1350 ℃ scopes, behind insulation 2h～4h, naturally cooling.

3. by the preparation method of the described barium strontium titanate base electro-optical composite material of claim 2, it is characterized in that preparing Ba _0.6Sr _0.4TiO ₃And Mg ₂SiO ₄Raw material be pulverous BaCO ₃, SrCO ₃, TiO ₂, Mg ₂Si ₃O ₈And MgO.