CN85100513B

CN85100513B - Bi-na-ba-tio3 series piezoelectric ceramic material for ultrasonic devices

Info

Publication number: CN85100513B
Application number: CN 85100513
Authority: CN
Inventors: 王天宝; 高敏
Original assignee: Shanghai Institute of Ceramics of CAS
Current assignee: Shanghai Institute of Ceramics of CAS
Priority date: 1985-04-01
Filing date: 1985-04-01
Publication date: 1987-08-19
Also published as: CN85100513A; JPH0460073B2; JPS62202576A

Abstract

The present invention relates to a binary system piezoceramic material which has high ratio of Kt to Nt and big ratio of Kt to Kp, has low Kp and volume density, and has rather small epsilon 33<T> and Qm<t>. The present invention is good materials for manufacturing ultrasonic flaw detection devices, thickness measuring devices and medicine ultrasonic transducers. The materials have low sintering temperature and small volatility. Ingredients which do not have environmental pollution are needless to seal. The present invention is the piezoelectric materials with low cost, the materials are composed of xNa0.5Bi0.5TiO3-(1-x)BaTiO3, and the x is from 0.80 to 0.99 gram of molecules. Simultaneously, small quantity of modification additives are added or are not added. The optically optimally x value is from 0.89 to 0.99 gram of the molecules.

Description

Bi-Na-Ba-TiO3 series piezoelectric ceramic material for ultrasonic devices

The present invention is a kind of new binary system piezoceramic material.Such material has the Na of ratio _0.5bi _0.5tiO ₃-K _0.5bi _0.5tiO ₃the K that system's pottery is larger _t/ K _pratio (Kt: thickness electromechanical coupling coefficient, K _p: radially electromechanical coupling factor), less dielectric coefficient

there is high thickness vibration frequency constant (N simultaneously _t), lower bulk density and thickness vibration Qm

being particularly suitable for ultrasonic transducer uses; And the manufacturing process of this material is simple, cost is low, not containing the composition that causes public hazards.

1963, sakata is good-and youth studied BaTiO ₃-Na _0.5bi _0.5tiO ₃xi Fubei district, sakata in 1967, the large former Na that studied _0.5bi _0.5tiO ₃-PbTiO ₃the ferroelectric piezoelectric property of system, still, does not all obtain material with practical value.In recent years, the inventor has studied Na _0.5bi _0.5tiO ₃-K _0.5bi _0.5tiO ₃xi Funa district pottery, has obtained K _t: 0.485 K _p: 0.255,

n _t: 2670Hzm,

105 the valuable ultrasonic piezoelectric of using.Because modern ultrasonic technique requires there is more visual, higher resolution, operating frequency also improves day by day, wishes that transducer material has larger K _t/ K _pratio and lower

with

the K of PZT base pottery, potassium-sodium niobate and sodium niobate lithium pottery _t/ K _pratio is all little.PbTiO ₃though meet above-mentioned condition with lead meta-columbute, the former

too large, the latter's K _ton the low side, and agglutinating property is very poor, and in ultrasonic inspection and medical ultrasonic engineering, application is all not satisfied.In addition, at process aspect, PZT pottery volatilizees because of PbO, must use corundum crucible sealed sintering, and this causes that homogeneity of product is poor, and cost is high, and particularly lead causes public hazards, increases protection expense.Niobate ceramics raw material are too expensive.

The object of the invention is to find a kind of completely lead-free Na of ratio that has _0.5bi _0.5tiO ₃-K _0.5bi _0.5tiO ₃be larger K _t/ K _pratio is lower with

cost is low, non-harmful piezoceramic material system.

The invention provides a piezoceramic material system, consist of XNa _0.5bi _0.5tiO ₃-(1-x) BaTiO ₃, wherein X is 0.80～0.99 gram molecule (Fu Na district).In addition, also add or do not add respectively the MnO of 0.1～3% (weight) ₂, Cr ₂o ₂, NiO and Fe ₂o ₃that X is 0.89～0.99 gram molecule Deng the preferential recommended range of modified materials.

Use TiO ₂, Bi ₂o ₃, natrium carbonicum calcinatum, brium carbonate and above-mentioned additive are made raw material (except TiO ₂brium carbonate is outside industrial one-level, all the other raw materials are all CP levels), batching, adds absolute alcohol ball milling and mixes 6 hours, after dry, within 1～4 hour, synthesize 800～1150 ℃ of insulations, grog is levigate with ball milling or comminution by gas stream, adds the dry-pressing formed base sample of adhesive, open wide and burn till in atmosphere at 1080～1220 ℃, be incubated 1～4 hour.Then wear into the sample of φ 17 × 1mm, by silver, polarization, by the piezoelectric parameter of IRE canonical measure sample.Table 1 is listed Na ₀₅bi _0.5tiO ₃-BaTiO ₃series piezoelectric ceramic part formula and performance thereof.Table 2 is listed mainly ferroelectric, the piezoelectric parameter of optimum formula.

As can be seen from Table 1, Na _0.5bi _0.5tiO ₃-BaTiO ₃the feature of Xi Funa district piezoceramic material is K _thigher, K _pquite low, K _t/ K _pthan large, higher Nt and Curie temperature are lower

and bulk density.

As can be seen from Table 2, this piezoelectric ceramic has high K _t, large K _t/ K _pratio, high g ₃₃and frequency constant, quite low

with

it is goodish material for ultrasonic transducer.Be expected in ultrasonic inspection, in thickness measuring and medical ultrasonic engineering, be widely used.These performances of this material are not only better than PZT or K _0.5na _0.5nbO ₂deng material, and compare Na _0.5bi _0.5tiO ₂-K _0.5bi _0.5tiO ₃the piezoelectric ceramic of system's (being called for short NKBT) is better, for example K _t/ K _pthan larger, approach 3, and NKBT pottery is less than 2,

be less than 300, and NKBT is greater than 400, particularly this kind ceramic

quite low, except lead meta-columbute, there is large K simultaneously ₁/ K _pratio and little

piezoelectric ceramic, all do not have low like this

value.And the K of lead meta-columbute _tvalue (0.4 left and right) insufficient sensitivity on the low side is high, so this pottery has very important value in ultrasonic reception.

Na _0.5bi _0.5tiO ₂-BaTiO ₃system's pottery is same in technologic advantage and NKBT ceramic phase, and its cost of material is low, there is no public hazards.The sintering temperature of this system pottery is low, and component volatilization is little does not need sealed sintering, thus be that a kind of technique is simple, the lower and non-harmful piezoceramic material of cost.

Implementation example of the present invention:

Formula: 0.85Na _0.5bi _0.1tiO ₂-0.15BaTiO ₃(X=0.85)

Technical process as previously mentioned.Synthesis condition be 1000 ℃ 2 hours.Firing condition is 1150～1190 ℃ of insulations 3 hours.Base sample is worn into the disk of φ 17 × 1mm, by silver, in the silicone oil of 150 ℃, adds the electric field polarization half an hour of 4KV/mm, maintains voltage and is chilled to 100 ℃ of taking-ups.Its main performance is K _t: 0.46, K _p: 0.13,

475, N _t: 2600Hzm, Te:235 ℃, bulk density: 5.60g/cm ³.

Table 1Na _0.5bi _0.5tiO ₃-BaTiO ₃series piezoelectric ceramic formula and main performance

Mainly ferroelectric, the piezoelectric parameter of table 2 optimum formula

Claims

1. a binary system piezoceramic material, contains Na _0.5bi _0.5tiO ₃and BaTiO ₃, consist of XNa _0.5bi _0.5tiO ₃-(1-x) BaTiO ₃, it is characterized in that X is 0.80～0.99 gram molecule (Fu Na district), in addition, also add or do not add respectively the oxide of 0.1～3% (weight).

2. piezoceramic material according to claim 1, is characterized in that the oxide adding is MnO ₂, Fe ₂o ₃, Cr ₂o ₃or NiO.

3. piezoceramic material according to claim 1, is characterized in that X value is 0.89～0.99 gram molecule (Fu Na district).