CN101928139B - Bismuth calcium titanate-based luminous piezoelectric ceramic material and preparation method - Google Patents

Abstract

The invention relates to the field of electronic functional materials, in particular to a bismuth calcium titanate-based luminescent piezoelectric ceramic material and a preparation method thereof. The chemical composition of the calcium bismuth titanate-based luminescent piezoelectric ceramic material conforms to the general chemical formula Ca _x Bi _4-y R _y Ti _3+x O _12+3x , wherein 1≤x≤2, 0.0001≤y≤0.5, The R is selected from one or more of Pr, Gd, Er, Dy, Tm, Ho, Eu, Yb and Tb. The ceramic material not only has ferroelectric, piezoelectric and dielectric properties, but also has photoluminescent properties, and belongs to a new type of multifunctional material. The calcium bismuth titanate-based luminescent piezoelectric ceramic material has excellent photoelectric performance, and has broad application prospects in the fields of photoelectric integration, micro-electromechanical, photoelectric sensing, LED technology and the like.

Description

Bismuth calcium titanate-based luminescent piezoelectric ceramic material and preparation method thereof

technical field

The invention relates to the field of electronic functional materials, in particular to a bismuth calcium titanate-based luminescent piezoelectric ceramic material and a preparation method thereof.

Background technique

With the continuous development of high technology, new material technology has become a hot field of exploration and research by scholars from all over the world. Piezoelectric materials are an important class of electronic functional materials, which are widely used in high-tech fields such as information, laser, navigation and biology. In order to adapt to the development of today's high-tech and meet the requirements of functionalization, miniaturization and intelligence of piezoelectric materials, scholars at home and abroad have actively explored and expanded their original properties while conducting in-depth research and continuously improving the original properties of piezoelectric materials. new features. Studies have shown that piezoelectric materials can be multifunctional through the selection of raw material formulations and the control of experimental processes. For example, the team of the applicant of this patent has realized the multifunctionalization of optical-mechanical-electrical conversion in the barium calcium titanate-based lead-free piezoelectric ceramic system with a perovskite structure. After doping a small amount of rare earth element praseodymium into the crystal lattice of barium calcium titanate two-phase composite ceramics, not only the ferroelectricity of the ceramic material is improved, but also the material has various photoluminescence, electroluminescence and stress luminescence. Characteristics, see magazine "Advanced Materials", 2005, No. 17, pp. 1254-1258. The rare earth praseodymium-doped barium calcium titanate multifunctional piezoelectric material has excellent photoelectric properties and has broad application prospects in optoelectronics, micro-electromechanical and artificial intelligence. The applicant's group is also carrying out related performance research on devices made of the barium calcium titanate two-phase composite ceramic material system, see the magazine "Applied Physics Express", 2010, No. 3, article number: 022601. At present, the research on the luminescence characteristics of rare earth doped multifunctional piezoelectric ceramic materials at home and abroad mainly focuses on the barium calcium titanate system.

As an important class of lead-free piezoelectric ceramic materials, the "bismuth-layered" bismuth-calcium titanate-based ceramic materials with a layered perovskite structure have high Curie temperature, high dielectric breakdown strength, low electrical conductivity, and low dielectric strength. Electrical loss and excellent anti-fatigue characteristics. Due to these characteristics, calcium bismuth titanate-based ceramics have broad application prospects in the fields of high temperature, high frequency, piezoelectric detectors and non-volatile random access memory. At present, reports on the optical properties of bismuth-calcium titanate-based piezoelectric materials are limited to thin-film materials. See the journal "Journal of Physics D: Applied Physics", 2009, No. 42, article number: 105411. In order to meet the requirements of the development of high-tech material technology, the present invention mixes a certain amount of rare earth elements into the "bismuth layered" bismuth calcium titanate single-phase lead-free piezoelectric ceramic matrix material, and realizes its photoluminescence characteristics through process control. The material has excellent optoelectronic properties, and has broad application prospects in the fields of optoelectronic integration, micro-electromechanical and optoelectronic sensing, and LED lighting technology.

Contents of the invention

The object of the present invention is to provide a bismuth calcium titanate-based luminescent piezoelectric ceramic material with ferroelectric, piezoelectric, dielectric and photoluminescent properties and a preparation method thereof, so as to overcome the deficiencies of the prior art.

A bismuth calcium titanate-based luminescent piezoelectric ceramic material, the chemical composition of which conforms to the general chemical formula Ca _x Bi _4-y R _y Ti _3+x O _12+3x , where 1≤x≤2, 0.0001≤y≤0.5, The R is selected from one or more of rare earth elements Pr, Gd, Er, Dy, Tm, Ho, Eu, Yb and Tb.

Preferably, the value range of y is 0.005≤y≤0.02.

The preparation method of the bismuth calcium titanate-based luminescent piezoelectric ceramic material is a solid phase reaction method, a certain amount of rare earth elements are mixed into the bismuth calcium titanate lead-free piezoelectric ceramic matrix material, and the powder is realized through process control. And the photoluminescent properties of ceramic bulk materials, that is, the performance of emitting red light under the multi-band light excitation of ultraviolet light, blue light and green light.

The preparation method of the calcium bismuth titanate-based luminescent piezoelectric ceramic material specifically includes the following steps:

(1) Weigh raw materials according to the stoichiometric ratio of Ca, Bi, Ti and R in the general chemical formula Ca _x Bi _4-y R _y Ti _3+x O _12+3x : CaCO ₃ , Bi ₂ O ₃ , TiO ₂ , R oxides or nitrates, where 1≤x≤2, 0.0001≤y≤0.5.

(2) Mix the raw materials weighed in step (1), add absolute ethanol or deionized water, grind or ball mill, discharge and dry to obtain powder A.

The mass ratio of the absolute ethanol or deionized water to the raw material is 1-3:1; the mass ratio of the ball mill zirconia ball to the raw material is 1-1.5:1.

(3) Put the powder A in an alumina crucible for pre-calcination to obtain the pre-fired powder B.

The pre-calcination temperature is 750-950° C., and the holding time is 1-6 hours.

Preferably, the pre-calcination temperature is 850-950° C., and the holding time is 2 hours.

(4) After grinding or ball milling the calcined powder B, use a binder with a mass percentage of 8-10% to granulate the powder B, and then press it into a ceramic green sheet under a pressure of 10-100 MPa c.

The binder is polyvinyl alcohol PVA.

The mass percentage of the binder is the mass percentage of the binder relative to the calcined powder.

(5) The ceramic green sheet C is bonded and sintered to obtain the bismuth calcium titanate-based luminescent piezoelectric ceramic material.

The sticking temperature is 550-600°C, and the sticking holding time is 2-4 hours;

The sintering temperature is 1000-1250°C, and the sintering holding time is 2-6 hours;

Preferably, the sintering temperature is 1180-1200° C., and the sintering holding time is 4 hours.

The bismuth calcium titanate-based luminescent piezoelectric ceramic material doped with rare earth elements of the present invention is a "bismuth layered" bismuth calcium titanate single-phase lead-free piezoelectric ceramic material with a layered perovskite structure. Calcium bismuth titanate, which itself does not have luminescent properties, has photoluminescent properties; and the luminescent piezoelectric bismuth calcium titanate-based multifunctional ceramic material of the present invention can be excited by the wavelengths of ultraviolet light, blue light, and green light to emit red light. Light, and the strongest excitation is in the blue light band, which belongs to the environment-friendly luminescent material; while the praseodymium-doped barium calcium titanate composite ceramic material in the prior art has a perovskite structure, and its photoluminescence can only be detected by ultraviolet light. excitation.

The calcium bismuth titanate-based luminescent piezoelectric ceramic material in the invention not only has the original ferroelectric, piezoelectric and dielectric properties, but also has photoluminescent properties, and belongs to a new type of multifunctional material. The ceramic material has excellent optoelectronic properties and has broad application prospects in optoelectronic integration, micro-electromechanical, optoelectronic sensing, LED technology and other fields.

Description of drawings

Fig. 1 XRD patterns of CaBi _4-y R _y Ti ₄ O ₁₅ , x=1, y=0.005, 0.01, 0.015, 0.02 samples.

Fig. 2 Excitation spectra of samples of CaBi _4-y R _y Ti ₄ O ₁₅ , x=1, y=0.005, 0.01, 0.015, 0.02.

Fig. 3 CaBi _4-y R _y Ti ₄ O ₁₅ , x=1, y=0.005, 0.01, 0.015, 0.02 samples emission spectra.

Detailed ways

The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the protection scope of the present invention.

Example 1

Taking the preparation of CaBi _4-0.005 Pr _0.005 Ti ₄ O ₁₅ , CaBi _4-0.01 Pr _0.01 Ti ₄ O ₁₅ , CaBi _4-0.015 Pr _0.015 Ti ₄ O ₁₅ , and CaBi _4-0.02 Pr _0.02 Ti ₄ O ₁₅ as an example, the raw material selection CaCO ₃ , Bi ₂ O ₃ , TiO ₂ , Pr ₆ O ₁₁ , according to the general chemical formula CaBi _4-0.005 Pr _0.005 Ti ₄ O ₁₅ , CaBi _4-0.01 Pr _0.01 Ti ₄ O ₁₅ , CaBi _4-0.015 Pr _0.015 Ti ₄ Stoichiometric ratio of Ca, Bi, Ti and R in O ₁₅ , CaBi _4-0.02 Pr _0.02 Ti ₄ O ₁₅ Weigh the raw material, add absolute ethanol or deionized water after weighing the raw material, grind in a mortar and mix well The obtained powders A ₁ , A ₂ , A ₃ , A ₄ , wherein the mass ratio of the absolute ethanol or deionized water to the raw material mixture is 1-3:1; The mass ratio is 1-1.5:1. The powders A ₁ , A ₂ , A ₃ , and A ₄ were pre-fired in alumina crucibles respectively. The pre-fire temperature was 850°C, and the heating rate was 3°C/min. Burn powder B ₁ , B ₂ , B ₃ , B ₄ . Grind the calcined powders B ₁ , B ₂ , B ₃ , and B ₄ separately, then use 10% polyvinyl alcohol PVA as a binder to granulate the calcined powder B, and press it into ceramics under a pressure of 100 MPa Green sheets C ₁ , C ₂ , C ₃ , C ₄ . The ceramic green sheets C ₁ , C ₂ , C ₃ , and C ₄ were respectively held at 550°C for 2 hours for debonding treatment, and then sintered at 1180°C for 4 hours to obtain the luminescent piezoelectric ceramic material CaBi _{4- 0.005} Pr _0.005 Ti ₄ O ₁₅ , CaBi _4-0.01 Pr _0.01 Ti 4 _O 15 , CaBi _{4-0.015 Pr 0.015} Ti ₄ O ₁₅ , and CaBi _4-0.02 Pr _0.02 Ti ₄ O ₁₅ .

The luminescent piezoelectric ceramic materials obtained in Example 1 were CaBi _4-0.005 Pr _0.005 Ti ₄ O ₁₅ , CaBi _4-0.01 Pr _0.01 Ti ₄ O ₁₅ , CaBi _4-0.015 Pr _0.015 Ti ₄ O ₁₅ and CaBi _4-0.02 Pr _0.02 Ti ₄ O ₁₅ was detected, and the following Figure 1, Figure 2 and Figure 3 were obtained:

Fig. 1 is the XRD patterns of CaBi _4-y R _y Ti ₄ O ₁₅ , x=1, y=0.005, 0.01, 0.015, 0.02 samples.

Fig. 2 is the excitation spectrum of samples of CaBi _4-y R _y Ti ₄ O ₁₅ , x=1, y=0.005, 0.01, 0.015, 0.02.

Fig. 3 is the emission spectrum of samples of CaBi _4-y R _y Ti ₄ O ₁₅ , x=1, y=0.005, 0.01, 0.015, 0.02.

It can be seen from the XRD spectrum of Figure 1 that the luminescent piezoelectric ceramic materials in Example 1 are all single-phase "bismuth layered" calcium bismuth titanate structures, and there are no other impurity phases in the XRD spectrum; the excitation light spectrum of the sample in Figure 2 It can be seen that the luminescent piezoelectric ceramic material in this embodiment can be excited by waves in three bands of ultraviolet light (300nm-430nm), blue light (440nm-510nm) or green light (550nm-570nm); It can be seen from the emission spectrum that the luminescent piezoelectric ceramic materials in this embodiment all emit red light, and the position of the main emission peak is 614 nm.

Example 2

Taking the preparation of Ca _1.5 Bi _4-0.01 Pr _0.01 Ti _4.5 O _16.5 as an example, the raw materials are CaCO ₃ , Bi ₂ O ₃ , TiO ₂ , Pr ₆ O ₁₁ , according to the formula Ca _1.5 Bi _4-0.01 Pr _0.01 Ti ₄ O _16.5 element Proportioning The selected raw materials were weighed, the pre-firing temperature was 900°C, the heat preservation temperature of the ceramic green sheet after debonding treatment was 1200°C, and the rest of the experimental conditions were the same as in Example 1.

It can be seen from the test that the final sample obtained in this example is the luminescent piezoelectric ceramic material Ca _1.5 Bi _4-0.01 Pr _0.01 Ti _4.5 O _16.5 in the present invention;

All the luminescent piezoelectric ceramic materials in this embodiment can be excited by waves in three bands of ultraviolet light (300nm-430nm), blue light (440nm-510nm) or green light (550nm-570nm).

Example 3

Take the preparation of Ca ₂ Bi _4-0.02 Pr _0.02 Ti ₅ O ₁₈ as an example, the raw materials are CaCO ₃ , Bi ₂ O ₃ , TiO ₂ , Pr ₆ O ₁₁ , according to the formula Ca ₂ Bi _4-0.02 Pr _0.02 Ti ₅ O ₁₈ element Proportioning The selected raw materials were weighed, the pre-firing temperature was 950°C, the holding temperature of the ceramic green sheet after the debonding treatment was 1200°C, and the rest of the experimental conditions were the same as in Example 1.

It can be seen from the test that the final sample obtained in this example is the luminescent piezoelectric ceramic material Ca ₂ Bi _4-0.02 Pr _0.02 Ti ₅ O ₁₈ in the present invention;

All the luminescent piezoelectric ceramic materials in this embodiment can be excited by waves in three bands of ultraviolet light (300nm-430nm), blue light (440nm-510nm) or green light (550nm-570nm).

Example 4

Taking the preparation of CaBi _4-0.01 Eu _0.01 Ti ₄ O ₁₅ as an example, the raw materials are CaCO ₃ , Bi ₂ O ₃ , TiO ₂ , Eu ₂ O ₃ , according to the formula Ca ₂ Bi _4-0.01 Eu _0.01 Ti ₅ O ₁₈ element ratio The selected raw materials were weighed, the pre-fired temperature was 850°C, and the holding time was 2 hours. The holding temperature of the ceramic green sheet after debonding treatment was 1150°C, and the holding time was 6 hours. The rest of the experimental conditions were the same as in Example 1.

It can be seen from the test that the final sample obtained in this example is the luminescent piezoelectric ceramic material CaBi _4-0.01 Eu _0.01 Ti ₄ O ₁₅ in the present invention;

All the luminescent piezoelectric ceramic materials in this embodiment can be excited by waves in three bands of ultraviolet light (300nm-430nm), blue light (440nm-510nm) or green light (550nm-570nm).

Example 5

Taking the preparation of Ca ₂ Bi _4-0.02 Eu _0.02 Ti ₅ O ₁₈ as an example, the raw materials are CaCO ₃ , Bi ₂ O ₃ , TiO ₂ , Eu ₂ O ₃ , according to the formula Ca ₂ Bi _4-0.02 Pr _0.02 Ti ₅ O ₁₈ element Proportioning The selected raw materials were weighed, the pre-firing temperature was 950°C, the holding temperature of the ceramic green sheet after the debonding treatment was 1200°C, and the rest of the experimental conditions were the same as in Example 1.

It can be seen from the test that the final sample obtained in this example is the luminescent piezoelectric ceramic material Ca ₂ Bi _4-0.02 Eu _0.02 Ti ₅ O ₁₈ in the present invention;

All the luminescent piezoelectric ceramic materials in this embodiment can be excited by waves in three bands of ultraviolet light (300nm-430nm), blue light (440nm-510nm) or green light (550nm-570nm).

Example 6

To prepare CaBi _4-0.01 Eu _0.01 Gd _0.01 Ti ₄ O ₁₅ , the raw materials are CaCO ₃ , Bi ₂ O ₃ , TiO ₂ , Eu ₂ O ₃ , Gd ₂ O ₃ , according to the formula CaBi _4-0.01 Eu _0.01 Gd _0.01 Ti ₄ Proportion of O ₁₅ elements The selected raw materials were weighed, the pre-firing temperature was 850°C, the holding temperature of the ceramic green sheet after debonding treatment was 1220°C, and the rest of the experimental conditions were the same as in Example 1.

It can be seen from the test that the final sample obtained in this example is the luminescent piezoelectric ceramic material CaBi _4-0.01 Eu _0.01 Gd _0.01 Ti ₄ O ₁₅ in the present invention;

All the luminescent piezoelectric ceramic materials in this embodiment can be excited by waves in three bands of ultraviolet light (300nm-430nm), blue light (440nm-510nm) or green light (550nm-570nm).

Claims (6)

1. bismuth calcium titanate-based luminous piezoelectric ceramic material, its chemical composition meets chemical general formula Ca _xBi _4-yR _yTi _3+xO _12+3x, 1≤x≤2,0.0001≤y≤0.5 wherein, described R is selected from one or more among Pr, Gd, Er, Dy, Tm, Ho, Eu, Yb and the Tb; Described bismuth calcium titanate-based luminous piezoelectric ceramic material is the single-phase lead-free piezoceramic material of laminated perovskite structure " bismuth stratiform " bismuth calcium titanate, and has photoluminescence performance, can be excited and red-emitting by the wavelength of UV-light, blue light, three wave bands of green glow.

2. bismuth calcium titanate-based luminous piezoelectric ceramic material as claimed in claim 1 is characterized in that, the span of y is 0.005≤y≤0.02.

3. bismuth calcium titanate-based luminous piezoelectric ceramic material as claimed in claim 1 or 2 is characterized in that, described bismuth calcium titanate-based luminous piezoelectric ceramic material is for adopting solid reaction process to make.

4. such as the preparation method of the arbitrary described bismuth calcium titanate-based luminous piezoelectric ceramic material of claim 1-3, it is characterized in that, comprise the steps:

(1), according to chemical general formula Ca _xBi _4-yR _yTi _3+xO _12+3xThe stoichiometric ratio of middle Ca, Bi, Ti and R takes by weighing raw material: CaCO ₃, Bi ₂O ₃And TiO ₂, and the oxide compound of R or nitrate, wherein 1≤x≤2,0.0001≤y≤0.5;

(2), raw material that step (1) is taken by weighing mixes, add dehydrated alcohol or deionized water through grind or ball milling after, the discharging oven dry obtains powder A;

(3), place the alumina crucible pre-burning to obtain preburning powdered material B powder A, wherein, described calcined temperature is 750～950 ℃, and soaking time is 1～6h;

(4), preburning powdered material B ground or ball milling after, adopting the quality percentage composition is that 8～10% binding agent polyvinyl alcohol carries out granulation to preburning powdered material B, then is pressed into ceramic green sheet C under 10～100MPa pressure;

(5), obtain described bismuth calcium titanate-based luminous piezoelectric ceramic material behind ceramic green sheet C row is sticking, the sintering, wherein, the sticking temperature of described row is 550～600 ℃, and the sticking soaking time of row is 2～4h; Described sintering temperature is 1000～1250 ℃, and the sintered heat insulating time is 2～6h.

5. preparation method as claimed in claim 4 is characterized in that, the mass ratio of described dehydrated alcohol or deionized water and raw material is 1～3:1; The mass ratio of ball milling material zirconia ball and raw material is 1～1.5:1 in the described ball milling.

6. the application in, photoelectric sensing integrated, micro electronmechanical at photoelectricity such as the arbitrary described bismuth calcium titanate-based luminous piezoelectric ceramic material of claim 1-3 and the LED field.

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