CN101337814B - Low temperature sintering lithium antimonite doped quinary system piezoelectric ceramics material and method for preparing same - Google Patents

Abstract

The invention provides low-temperature sintered lithium antimoniate doped quinary system piezoelectric ceramics, which consists of the materials expressed by the following general formula: 0.02Pb(Mg[1/2]W[1/2])O3-yPb(Sb[1/2]Nb[1/2])O3-(0.39-y)Pb(Ni[1/3]Nb[2/3])O3-Pb0.59(Zr0.38Ti0.21)O3+xLiSbO3, wherein 0.00 wt. %<x <= 0.40 wt.%, 0.000<= y<= 0.030mol. A preparation method thereof comprises the processing steps of preparation of lithium antimoniate, synthesis of ingredients, pre-sintering, granulation, tabletting, dumping, sintering, silver sintering and polarization or the like. According to the laboratory investigation result, the prepared quinary system piezoelectric ceramics has high piezoelectric constant, high planar electromechanical coupling factor and good low-temperature sintering performance. Compared with similar piezoelectric ceramics reported in literatures, the mechanical quality factor Qm and the dielectric loss tan Delta are significantly reduced; the piezoelectric constant d33 and the planar electromechanical coupling factor Kp are significantly improved; the sintering temperature is significantly reduced from 1200 DEG C to 900 DEG C; and the preparation process is simple with good repetitiveness, the yield is high and the cost is low.

Description

Low-temperature sintered lithium antimonate-doped five-element piezoelectric ceramic material and preparation method thereof

technical field

The invention belongs to the technical field of materials, and in particular relates to a piezoelectric device or an electrostrictive device.

Background technique

Piezoelectric material is a functional ceramic material that can convert mechanical energy and electrical energy into each other. Because of its high piezoelectric properties, easy processing into complex shapes, low price, and easy mass production, it has been widely used in electronic devices. However, the existing piezoelectric ceramic materials cannot meet the comprehensive requirements of practical applications on material performance. In order to improve the performance of piezoelectric ceramic materials, two ways are often used: one is to achieve the purpose of modification by adding a third or fourth element to the matrix material to form a new material; the other is to modify the material according to different doping ions. The effect of structure and performance is different, and the existing materials are modified by doping. In addition, when lead-based piezoelectric ceramics are sintered at high temperature, due to the volatilization of lead, there are technical problems such as composition deviation, performance degradation, and environmental pollution, especially in order to replace precious metal palladium with low-cost silver as multilayer piezoelectric ceramic devices. It is necessary to study the low-temperature sintering of piezoelectric ceramics.

This unique function of piezoelectric materials makes them have broader application prospects in smart material systems. However, lead volatilization under high temperature sintering can lead to deviation of stoichiometric ratio, performance degradation, and environmental pollution. At present, the commonly used sealing sintering method, atmosphere chip method, buried powder method, and lead excess method cannot fundamentally solve the lead volatilization method. The active and effective method to suppress lead volatilization is to realize low-temperature sintering of piezoelectric ceramics. The development of low-temperature sintered piezoelectric ceramic materials is an important research direction for the development of high-performance, high-reliability, and low-cost multilayer piezoelectric ceramic devices.

At present, the research work is mainly concentrated on piezoelectric ceramic materials of binary system, ternary system and quaternary system, such as: PZT, PMN-PZT, PZN-PMS-PZT, PNW-PMN-PZT. However, it is rare to study the pentad system and obtain high piezoelectric constant, high planar electromechanical coupling coefficient, low sintering temperature, low mechanical quality factor, and low electromechanical loss at the same time. The applicant has applied for a patent with the application number: 200810150177.4 and the title of the invention: five-element piezoelectric ceramic material containing lead niobium antimonate for the driver and its preparation method. It has excellent piezoelectric properties, but the sintering temperature is relatively high ( 1150℃～1200℃). _Therefore , _{this work} aims _to find out _a suitable _additive to reduce _{the 3} Nb _2/3 )O ₃ -PZT (PMWSN-PNN-PZT) ceramic sintering temperature while taking into account high electrical properties. By discussing the influence of LiSbO ₃ content on the sintering temperature and electrical properties of PMWSN-PNN-PZT ceramics, an optimal composition and preparation process can be found to prepare materials with high piezoelectric constant, high planar electromechanical coupling coefficient, and high dielectric constant. It is a piezoelectric ceramic driver material with low mechanical quality factor, low dielectric loss and low sintering temperature.

Contents of the invention

A technical problem to be solved by the present invention is to provide a low-temperature sintered lithium antimonate-doped five-element system with high piezoelectric constant, high electromechanical coupling coefficient, low-temperature sintering, wide temperature range, good performance, strong practicability, and easy production. Piezoelectric ceramic materials.

Another technical problem to be solved by the present invention is to provide a method for preparing a low-temperature sintered lithium antimonate-doped pentad piezoelectric ceramic material.

The solution adopted to solve the above technical problems is a material composition represented by the following general formula: 0.02Pb(Mg _1/2 W _1/2 )O ₃ -yPb(Sb _1/2 Nb _1/2 )]O ₃ -( 0.39-y)Pb(Ni _1/3 Nb _2/3 )O ₃ -Pb _0.59 (Zr _0.38 Ti _0.21 )O ₃ +xLi SbO ₃ , where 0.00wt.%<x≤0.40wt.%, 0.000≤y ≤0.030mol.

The preparation method of the above-mentioned low-temperature sintered lithium antimonate-doped pentad piezoelectric ceramic material includes the following steps:

1. Preparation of lithium antimonate

First mix Li ₂ CO ₃ and Sb ₂ O ₅ at a molar ratio of 1:1, put them into a nylon tank, add absolute ethanol as a dispersant and zirconia balls as a ball milling medium, the weight ratio of absolute ethanol to raw materials 1:1.5～2.5, use a ball mill for 12 hours at a speed of 400 rpm, separate the zirconia balls, put the mixture in a drying oven at 80°C for 10 hours, then put it in a mortar and grind for 30 minutes , through a 80-mesh sieve, the sieved material is placed in an alumina crucible, compacted with agate rods, the bulk density is 1.2-1.5g/cm ³ , covered, and pre-fired in a resistance furnace at 570-730°C to keep warm Synthesize LiSbO ₃ in 2 to 4 hours, cool naturally to room temperature, and take it out of the furnace; crush and grind the pre-fired powder for 1 hour, put it into a nylon tank, and perform ball milling and drying in the same process as above for later use.

2. Ingredients synthesis

Then synthesized LiSbO ₃ , Pb ₃ O ₄ , ZrO ₂ , TiO ₂ , Mg(OH) ₂ MgCO ₃ 6H ₂ O, WO ₃ , Sb ₂ O ₅ , Nb ₂ O ₅ , and NiO according to the general chemical formula Mix according to the metering ratio, put it into a nylon tank, add absolute ethanol as a dispersant and zirconia balls as a ball milling medium, the weight ratio of absolute ethanol to raw materials is 1:2, and use a ball mill to mill for 6 to 12 hours at a speed of 400 RPM, separate the zirconia balls, put the mixture in a drying oven at 80°C for 5-10 hours, put it into a mortar and grind it for 30 minutes, and pass through an 80-mesh sieve.

3. Pre-burning

Put the ground material in an alumina crucible, compact it with an agate rod to make the bulk density reach 1.5g/cm ³ , cover it, and pre-fire it in a resistance furnace at 800-850°C for 2-4 hours. Cool to room temperature and remove from the oven. Grind the calcined powder for 1 hour, put it into a nylon tank, add absolute ethanol as a dispersant and zirconia balls as a ball milling medium, the weight ratio of absolute ethanol to raw materials is 1:2, and use a ball mill to mill for 6~ After 12 hours, perform secondary ball milling at a speed of 300 rpm to separate the zirconia balls, put the mixture in a drying oven at 80°C for 5 to 10 hours, and pass through an 80-mesh sieve.

4. Granulation

Grind the pre-fired agglomerate finely through a 160 mesh sieve with a mortar, add a mass concentration of 5% polyvinyl alcohol solution and glycerin solution, the mass ratio of raw materials to 5% polyvinyl alcohol solution, glycerin 1: 0.068~0.072: 0.0097~0.013, fully stirred, dried naturally, passed through a 120-mesh sieve, and made into spherical powder.

5. Tablet

Put the spherical powder into a stainless steel mold with a diameter of 15mm, and press it into a cylindrical blank of 1.5mm under a pressure of 100Mpa.

6. Glue removal

Put the blank into the electric resistance furnace, keep it warm at 500°C for 1 hour to remove the organic matter.

7. Sintering

Put the debinding blank into the alumina crucible, cover the alumina crucible to seal, heat up at 2-5°C/min, sinter at 880-950°C for 3-5 hours, and cool down to room temperature naturally with the furnace.

8. Burning silver

Grind and polish the sintered ceramic surface to a thickness of 0.8-1.2mm, clean it with an ultrasonic cleaner with a power of 100w and a frequency of 50kHz for 30 minutes, dry it in an oven at 80°C, and coat the upper and lower surfaces with a thickness of 0.01 ~0.03mm silver paste, put it in a resistance furnace at 850°C for 30 minutes, and cool it down to room temperature naturally.

9. Polarization

Heat the burnt silver sample in methyl silicone oil to 120-180°C, apply a DC high voltage of 3kV/mm-5kV/mm for 15-30 minutes, and prepare piezoelectric ceramics.

10. Test piezoelectric performance

After polarizing the test piece, test the piezoelectric performance after standing at room temperature for 24 hours.

In step 1 of the process for preparing lithium antimonate of the present invention, _Li2CO3 and _Sb2O5 mixtures that have been ground and screened are _{pre -} fired in a resistance furnace preferably at 570-700° C. for 2-3 hours to synthesize LiSbO ₃ . In step 3 of the pre-firing process, the ground material is placed in an alumina crucible, compacted with an agate rod until the bulk density is 1.5g/cm ³ , covered, and pre-fired in a resistance furnace preferably at 800-830°C Keep warm for 2-3 hours. In step 7 of the sintering process, put the debinding blank into an alumina crucible, cover the alumina crucible for sealing, and heat up at a rate of 2-5°C/min, preferably sintering at 880-930°C for 3-4.5 hours.

In _{step 1 of the process for preparing lithium antimonate of the present invention, Li2CO3 and Sb2O5} mixtures that have been ground and sieved are pre-fired in an electric resistance furnace at _an optimum temperature of 610°C for 3 hours to synthesize _LiSbO3 . In step 3 of the pre-firing process, the ground material is placed in an alumina crucible, compacted with an agate rod until the bulk density is 1.5g/cm ³ , covered, and pre-fired in a resistance furnace at 800°C for heat preservation 3 hours. In step 7 of the sintering process, put the debinding blank into an alumina crucible, cover the alumina crucible for sealing, and heat up at a rate of 2-5°C/min, preferably sintering at 900°C for 4 hours.

The laboratory research results of the present invention show that the prepared five-element piezoelectric ceramic material has high piezoelectric constant, high plane electromechanical coupling coefficient, and good low-temperature sintering performance. Compared with similar piezoelectric ceramic materials reported in literature, the mechanical quality The factor Q _m and dielectric loss tanδ are significantly reduced, the piezoelectric constant d ₃₃ and the planar electromechanical coupling coefficient Kp are significantly increased, and the sintering temperature is significantly reduced from 1200°C to 900°C, the preparation process is simple, the repeatability is good, the yield is high, and the cost Low. The piezoelectric ceramics of the present invention can be used to prepare vibration sensors built into automobiles, controller housings, dynamic fuel injection nozzles, high-power ultrasonic devices, high-temperature and high-frequency vibrators, high-temperature flow meters, high-temperature-resistant buzzers and high-temperature sensors, etc. Low-temperature sintered piezoelectric ceramic materials for devices. It is beneficial to use Ag-Pd paste with good conductivity and low price and low palladium content or pure Ag inner paste as the internal electrode in the production process of the multilayer device, which reduces the production cost of the device. The piezoelectric ceramic driver made of this piezoelectric ceramic material has the advantages of large displacement output force, no heat generation, high sensitivity, good stability, high precision, compact structure, and good controllability.

Description of drawings

Figure 1 is the X-ray patterns of different _LiSbO doped 900 °C sintered ceramics.

Figure 2 is the X-ray spectrum of 0.06wt.% LiSbO ₃ doped ceramics sintered at different temperatures.

Fig. 3 is the scanning electron micrographs _of different LiSbO doped ceramics sintered at 900 °C.

Figure 4 is a scanning electron microscope photo of 0.06wt.% LiSbO ₃ doped ceramics sintered at different temperatures.

Fig. 5 is the X-ray patterns of 900°C sintered ceramics with different Pb(Sb _1/2 Nb _1/2 )O ₃ contents.

Fig. 6 is the X-ray patterns of ceramics sintered at different temperatures with 0.10wt.% Pb(Sb _1/2 Nb _1/2 )O ₃ content.

Fig. 7 is a scanning electron micrograph of ceramics sintered at 900°C with different Pb(Sb _1/2 Nb _1/2 )O ₃ contents.

Fig. 8 is a scanning electron micrograph of ceramics sintered at different temperatures with 0.10wt.% Pb(Sb _1/2 Nb _1/2 )O ₃ content.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited to these embodiments.

Example 1

Taking 100g of raw materials used to produce the product of the present invention as an example, when x is 0.2 and y is 0.01, use the general formula 0.02Pb(Mg _1/2 W _1/2 )O ₃ -0.01Pb(Sb _1/2 Nb _1/2 ) ]O ₃ -0.38Pb(Ni _1/3 Nb _2/3 )O ₃ -Pb _0.59 (Zr _0.38 Ti _0.21 )O ₃ +0.2wt% LiSbO ₃ The raw materials and their weight ratios are:

Pb ₃ O ₄ 67.06g

ZrO ₂ 13.75g

TiO ₂ 4.92g

Mg(OH) ₂ MgCO ₃ 6H ₂ O 0.3g

WO ₃ 0.68g

Sb ₂ O ₅ 0.22g

Nb ₂ O ₅ 10.09g

NiO 2.78g

LiSbO ₃ 0.20g

Its preparation method is as follows:

1. Preparation of lithium antimonate

First mix Li ₂ CO ₃ and Sb ₂ O ₅ at a molar ratio of 1:1, put them into a nylon tank, add absolute ethanol as a dispersant and zirconia balls as a ball milling medium, the weight ratio of absolute ethanol to raw materials 1:2, ball milled with a ball mill for 12 hours at a speed of 400 rpm, separated the zirconia balls, put the mixture in a drying oven at 80°C for 10 hours, and then put it into a mortar for grinding for 30 minutes. 80-mesh sieve, the sieved material is placed in an alumina crucible, compacted with agate rods, the bulk density is 1.2-1.5g/cm ³ , covered, and pre-fired in a resistance furnace at 610°C for 3 hours to synthesize Li SbO ₃ , cooled naturally to room temperature, and taken out of the furnace; crush and grind the pre-burned powder for 1 hour, put it into a nylon tank, and carry out ball milling and drying in the same process as above for later use.

2. Ingredients synthesis

Then synthesized LiSbO ₃ , Pb ₃ O ₄ , ZrO ₂ , TiO ₂ , Mg(OH) ₂ MgCO ₃ 6H ₂ O, WO ₃ , Sb ₂ O ₅ , Nb ₂ O ₅ , and NiO according to the general formula Mix at stoichiometric ratio, put into nylon tank, add absolute ethanol as dispersant and zirconia balls as ball milling medium, the weight ratio of absolute ethanol to raw material is 1:2, mill with ball mill for 6-12 hours, the speed is 400 rpm, separate the zirconia balls, put the mixture in a drying oven at 80°C for 5-10 hours to dry, then put it into a mortar and grind for 30 minutes, and pass through an 80-mesh sieve.

3. Pre-burning

Put the ground material in an alumina crucible, compact it with agate rods to make the bulk density reach 1.5g/cm ³ , cover it, pre-fire it in a resistance furnace at 800°C for 3 hours, and cool it down to room temperature naturally. out of the oven. Grind the calcined powder for 1 hour, put it into a nylon tank, add absolute ethanol as a dispersant and zirconia balls as a ball milling medium, the weight ratio of absolute ethanol to raw materials is 1:2, and use a ball mill to mill for 6~ After 12 hours, perform secondary ball milling at a speed of 300 rpm to separate the zirconia balls, put the mixture in a drying oven at 80°C for 5 to 10 hours, and pass through an 80-mesh sieve.

4. Granulation

The calcined block that has been pre-fired is finely passed through a 160 mesh sieve with a mortar, adding weight concentration is 7g of polyvinyl alcohol solution and 1g of glycerin solution, the raw material and 5% polyvinyl alcohol solution, glycerin The weight ratio is 1:0.7:0.01, fully stirred, dried naturally, passed through a 120-mesh sieve, and made into spherical powder.

5. Tablet

Put the granulated powder into a stainless steel mold with a diameter of 15mm, and press it into a 1.5mm cylindrical blank under a pressure of 100Mpa.

6. Glue removal

Put the blank into the electric resistance furnace, keep it warm at 500°C for 1 hour to remove the organic matter.

7. Sintering

Put the debinding blank into the alumina crucible, cover the alumina crucible lid to seal, heat up at 4°C/min, sinter at 900°C for 4 hours, and cool to room temperature naturally with the furnace.

8. Burning silver

Grind and polish the sintered ceramic surface to a thickness of 0.8-1.2mm, clean it with an ultrasonic cleaner with a power of 100w and a frequency of 50kHz for 30 minutes, dry it in an oven at 80°C, and coat the upper and lower surfaces with a thickness of 0.01 ~0.03mm silver paste, put it in a resistance furnace at 850°C for 30 minutes, and cool it down to room temperature naturally.

9. Polarization

The burnt silver sample was placed in methyl silicone oil and heated to 150°C, and a DC high voltage of 4kV/mm was applied for 25 minutes to prepare piezoelectric ceramics.

10. Test piezoelectric performance

The piezoelectric performance was tested after standing at room temperature for 24 hours.

Example 2

Taking 100g of raw materials used in the production of the product of the present invention as an example, x is 0.0, y is 0.01, and the general formula 0.02Pb(Mg _1/2 W _1/2 )O ₃ -0.01Pb(Sb _1/2 Nb _1/2 )] O ₃ -0.38Pb(Ni _1/3 Nb _2/3 )O ₃ -Pb _0.59 (Zr _0.3 8Ti _0.21 )O ₃ , the expressed raw materials and their weight ratio are:

Pb ₃ O ₄ 67.22g

ZrO ₂ 13.77g

TiO ₂ 4.93g

Mg(OH) ₂ MgCO ₃ 6H ₂ O 0.3g

WO ₃ 0.68g

Sb ₂ O ₅ 0.22g

Nb ₂ O ₅ 10.10g

NiO 2.78g

LiSbO ₃ 0g

Its preparation method is as follows:

In step 1 of the preparation process of lithium antimonate, Li ₂ CO ₃ and Sb ₂ O ₅ are mixed in a molar ratio of 1:1, put into a nylon tank, add absolute ethanol as a dispersant and zirconia balls as a ball milling medium, The weight ratio of absolute ethanol to raw materials is 1:1.5, milled with a ball mill, dried, regrinded, sieved, and pre-fired in a resistance furnace at 570°C for 4 hours to synthesize LiSbO ₃ , the other steps of the process steps are the same as in Example 1 same. In step 2 of the compounding synthesis process, the raw materials are compounded according to the general formula, 50 g of absolute ethanol is added, and zirconia balls are used as the ball milling medium. The other steps of this process step are the same as in Example 1. In step 3 of the pre-firing process, the ground material is placed in an alumina crucible, compacted with agate rods to make the bulk density reach 1.5g/cm ³ , covered, and pre-fired in a resistance furnace at 800°C for heat preservation After 4 hours, naturally cool to room temperature and take out the furnace. The other steps of this process step are the same as in Example 1. In step 4 of the granulation process, the pre-fired agglomerate is ground and finely passed through a 160 mesh sieve with a mortar, and 6.8 g of a polyvinyl alcohol solution and 0.97 g of a glycerol solution with a weight concentration of 5% are added, and the raw material is mixed with 5% The weight ratio of polyvinyl alcohol solution and glycerol is 1:0.068:0.0097, fully stirred, naturally dried, passed through a 120-mesh sieve, and made into spherical powder. In step 7 of the sintering process, put the debinding blank into the alumina crucible, cover the alumina crucible for sealing, heat up at 2°C/min, sinter at 880°C for 5 hours, and cool to room temperature naturally with the furnace. In step 9 of the polarization process, the burnt silver sample was placed in methyl silicone oil and heated to 120° C., and a DC high voltage of 5 kV/mm was applied for 15 minutes to prepare piezoelectric ceramics. Other processing steps are identical with embodiment 1.

Example 3

Taking 100g of raw materials used in the production of the product of the present invention as an example, when x is 0.40 and y is 0.03, use the general formula 0.02Pb(Mg _1/2 W _1/2 )O ₃ -0.03Pb(Sb _1/2 Nb _1/2 ) ]O ₃ -0.36Pb(Ni _1/3 Nb _2/3 )O ₃ -Pb _0.59 (Zr _0.3 8Ti _0.21 )O ₃ +0.40wt% LiSbO ₃ The raw materials and their weight ratios are:

Pb ₃ O ₄ 66.84g

ZrO ₂ 13.69g

TiO ₂ 4.91g

Mg(OH) ₂ MgCO ₃ 6H ₂ O 0.3g

WO ₃ 0.68g

Sb ₂ O ₅ 0.64g

Nb ₂ O ₅ 9.91g

NiO 2.63g

LiSbO ₃ 0.4g

Its preparation method is as follows:

In step 1 of the preparation process of lithium antimonate, Li ₂ CO ₃ and Sb ₂ O ₅ are mixed in a molar ratio of 1:1, put into a nylon tank, add absolute ethanol as a dispersant and zirconia balls as a ball milling medium, The weight ratio of absolute ethanol to raw materials is 1:2.5, milled with a ball mill, dried, regrinded, sieved, pre-fired in a resistance furnace at 730°C for 2 hours to synthesize LiSbO ₃ , other steps of the process steps are the same as in Example 1 . In step 2 of the compounding synthesis process, the raw materials are loaded into a nylon tank, and 50 g of absolute ethanol is added as a dispersant, which is used as a ball milling medium. The other steps of this process step are the same as in Example 1. In step 3 of the pre-firing process, the ground material is placed in an alumina crucible, compacted with agate rods to make the bulk density reach 1.5g/cm ³ , covered, and pre-fired in a resistance furnace at 850°C for heat preservation After 2 hours, naturally cool to room temperature and take out the furnace. The other steps of this process step are the same as in Example 1. In step 4 of the granulation process, the pre-fired agglomerate is ground and finely passed through a 160 mesh sieve with a mortar, and 7.2 g of polyvinyl alcohol solution and 1.3 g of glycerol solution with a weight concentration of 5% are added, and the raw material is mixed with 5% The weight ratio of polyvinyl alcohol solution and glycerin is 1:0.072:0.013, fully stirred, naturally dried, passed through a 120-mesh sieve, and made into spherical powder. In step 7 of the sintering process, put the debinding blank into the alumina crucible, cover the alumina crucible for sealing, heat up at 5°C/min, sinter at 950°C for 3 hours, and cool to room temperature naturally with the furnace. In step 8 of the polarization process, the burnt silver sample was placed in methyl silicone oil and heated to 180°C, and a DC high voltage of 3kV/mm was applied for 30 minutes to prepare piezoelectric ceramics. Other processing steps are identical with embodiment 1.

Example 4

Taking 100g of the raw materials used to produce the product of the present invention as an example, when x is 0.06 and y is 0.006, use the general formula 0.02Pb(Mg _1/2 W _1/2 )O ₃ -0.006Pb(Sb _1/2 Nb _1/2 ) ]O ₃ -0.384Pb(Ni _1/3 Nb _2/3 )O ₃ -Pb _0.59 (Zr _0.3 8Ti _0.21 )O ₃ +0.06wt% LiSbO ₃ The raw materials and their weight ratios are:

Pb ₃ O ₄ 67.20g

ZrO ₂ 13.76g

TiO ₂ 4.93g

Mg(OH) ₂ MgCO ₃ 6H ₂ O 0.30g

WO ₃ 0.68g

Sb ₂ O ₅ 0.13g

Nb ₂ O ₅ 10.13g

NiO 2.81g

LiSbO ₃ 0.06g

Its preparation method is identical with embodiment 1.

In order to determine the best proportioning of the present invention and the best process steps, the inventor has carried out a large amount of laboratory research experiments, and various experimental situations are as follows:

Test instruments: precision LCR bridge tester, model HP4294A, produced by Agilent Technologies Co., Ltd.; quasi-static d ₃₃ tester, produced by Institute of Acoustics, Chinese Academy of Sciences; precision impedance analyzer, model HP4294A, produced by Agilent Technologies Co., Ltd. Production; X-ray diffractometer, model D/max-2200, produced by Japan Rigaku; scanning electron microscope model, Quanta200, produced by Philips FEI Company of the Netherlands.

1. The effect of LiSbO ₃ content on the electrical properties of ceramics

First mix Li ₂ CO ₃ and Sb ₂ O ₅ at a molar ratio of 1:1, put them into a nylon tank, add absolute ethanol as a dispersant and zirconia balls as a ball milling medium, the weight ratio of absolute ethanol to raw materials 1:2, ball milled with a ball mill for 12 hours at a speed of 400 rpm, separated the zirconia balls, put the mixture in a drying oven at 80°C for 10 hours, and then put it into a mortar for grinding for 30 minutes. 80-mesh sieve, the sieved material is placed in an alumina crucible, compacted with agate rods, the bulk density is 1.2-1.5g/cm ³ , covered, and pre-fired in a resistance furnace at 610°C for 3 hours to synthesize LiSbO _3. Naturally cool to room temperature and take it out of the oven; crush and grind the pre-fired powder for 1 hour, put it into a nylon tank, and perform ball milling and drying in the same manner as above for later use.

The raw materials were then dried in a drying oven at 120°C for 5 hours, according to the general formula 0.02Pb(Mg _1/2 W _1/2 )O ₃ -0.01Pb(Sb _1/2 Nb _1/2 )O ₃ -0.38Pb( Ni _1/3 Nb _2/3 )O ₃ -Pb _0.59 (Zr _0.38 Ti _0.21 )O ₃ +x LiSbO ₃ for batching, where y is 0.010, x is 0.00wt.%, 0.03wt.%, 0.06wt .%, 0.10wt.%, 0.15wt.%, 0.20wt.%, 0.30wt.%, 0.40wt.%, wet ball milling for 12 hours, discharge, wet material drying, pre-calcination at 800 ℃ for 3 hours . The pre-calcined powder was ball milled twice under the same conditions for 10 hours, discharged, dried at 80°C for 8 hours, passed through a 160-mesh sieve with a mortar for 1 hour, and added polyvinyl alcohol with a weight concentration of 5%. Granules, the addition amount is 7% of the weight of the pre-fired powder, and the granulated material is pressed into a disc with a diameter of 15±0.05mm and a thickness of 1.5±0.02mm, and is uniaxially pressed under a pressure of 100Mpa. Heat at 500°C for 1 hour for debinding, the heating rate is 1.5°C/min, sinter at 880-950°C for 4 hours in a lead protective atmosphere, and cool down to room temperature naturally with the furnace. Grind and polish the sintered ceramic disc to a diameter of 13.5mm and a thickness of 1.2mm, clean it with ultrasonic waves, dry it at 80°C, coat silver paste on both sides, and burn in silver electrodes at 850°C for 30 minutes. Then put the sample with the burned electrodes in the silicone oil at 150°C and polarize with a DC high voltage of 4kV/mm for 25 minutes to obtain a finished piezoelectric ceramic. The piezoelectric performance was tested after standing at room temperature for 24 hours. The capacitance C and the dielectric loss tanδ of the sample with the electrodes burned were measured. Calculate the dielectric constant using the following formula:

ε _r ＝4Ct/(πε ₀ d ² ) (1)

In the formula, t is the thickness of the ceramic sheet, ε ₀ is the vacuum dielectric constant (8.85×10 ^-12 F/m), and d is the diameter of the ceramic sheet.

The piezoelectric constant d ₃₃ of the finished piezoelectric ceramics was measured with a quasi-static tester.

The density ρ (g/cm ³ ) of ceramic samples was determined by the Archimedes method. The specific method is: clean the sample, put it in a constant temperature drying box, take it out after drying, weigh the mass A (unit is g) of the sample in the air with a Mettler-Toledo electronic balance, put it into water and boil for 40 minutes, Soak for another 5 to 10 minutes, and weigh the mass B (in g) of the sample in distilled water. Calculate its bulk density according to the following formula:

$\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; A</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&rho;</span>}}_{\mathrm{<span\; class="notranslate">\; L</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

In the formula, A is the mass of the solid to be measured in the air, B is the mass of the solid to be measured in the auxiliary liquid water, _ρ0 is the density of the auxiliary liquid, and _ρL is the air density (0.0012g/cm ³ )

Test with a precision impedance analyzer to obtain the resonance frequency and anti-resonance frequency, and calculate the planar electromechanical coupling coefficient K _p according to formula (3):

${\mathrm{<span\; class="notranslate">\; K</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; 2.51</span>}<span\; class="notranslate">\; \&times;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the formula, f _r is the resonant frequency, f _a is the anti-resonant frequency, and the mechanical quality factor Q _m is calculated according to (4):

Q _m ＝f _a ² [2πrC ^T f _r (f _a ² -f _r ² )] ^-1 (4)

Where f _r is the resonant frequency, f _a is the anti-resonant frequency, r is the resonant resistance, C ^T is the static capacitance of the sample at 1kHz. The test and calculation results are shown in Table 1.

Table 1y is the effect of LiSbO ₃ content on the electrical properties of ceramics after sintering at 0.010mol for 4 hours at different sintering temperatures

It can be seen from Table 1 that in the sintering range of 880-950°C, when x is 0.00-0.40wt.%, the performance indicators of piezoelectric ceramics are good, and when x is 0.06wt.%, the sintering temperature is 900 At ℃, the performance of piezoelectric ceramics is the best.

The X-ray spectrum of the piezoelectric ceramic prepared by y being 0.010 mol, LiSbO ₃ content being 0.00-0.40wt.%, and sintering at 900°C for 4 hours is shown in FIG. 1 . It can be seen from Figure 1 that when x<0.40wt.%, all components are pure perovskite phase structure, and there is no appearance of pyrochlore phase and second phase impurity that deteriorate the performance. Moreover, the single peak (200) _R at 2θ of 43° to 47° indicates that the material system has a rhombohedral phase structure.

The X-ray patterns of piezoelectric ceramics prepared with y being 0.010 mol, LiSbO ₃ content of 0.06 wt.%, and different sintering temperatures are shown in FIG. 2 . It can be seen from Figure 2 that all components are pure perovskite phase structure, the second phase appears at 880°C, and disappears as the temperature increases. Moreover, it can be seen from the single peak (200) _R at 2θ of 43°-47° that the material system has a rhombohedral phase structure.

Figure 3 shows the scanning electron micrograph of the piezoelectric ceramic cross-section prepared by y being 0.010 mol, LiSbO ₃ content of 0.00-0.40wt.%, and sintering at 900°C for 4 hours. In Fig. 3, a is an electron scanning electron micrograph of a ceramic section with a LiSbO content of 0.00wt.% sintered at 900°C, b is an electron scanning electron micrograph of a ceramic section with a LiSbO content of 0.03wt _. % sintered _at 900°C, c is the electron scanning electron micrograph of the ceramic section with LiSbO ₃ content of 0.06wt.% sintered at 900 ℃, d is the electron scanning electron micrograph of the ceramic section of 0.10wt.% LiSbO ₃ sintered at 900 ℃, e is the LiSbO ₃ content of 0.20 The SEM photographs of the ceramic cross-sections sintered at 900 °C by wt.%, f is the SEM micrographs of the ceramic cross-sections sintered at 900 °C with a _LiSbO3 content of 0.40 wt.%. It can be seen from Figure 3 that when the content of LiSbO ₃ in piezoelectric ceramics is 0.03wt.%~0.06wt.%, the grain boundaries of piezoelectric ceramics are clear, the grains are full, and the grains grow and grow uniformly.

The electron scanning electron micrographs of the piezoelectric ceramic cross-sections prepared with y being 0.010 mol, LiSbO ₃ content being 0.06 wt.%, and different sintering temperatures are shown in Fig. 4 . In Figure 4, a is an electron scanning electron micrograph of a ceramic section doped with 0.06wt.% LiSbO ₃ and sintered at 880°C, b is an electron scanning electron micrograph of a ceramic section doped with 0.06wt.% LiSbO ₃ and sintered at 900°C, c is the electron scanning electron micrograph of the ceramic cross-section doped with 0.06wt.% LiSbO ₃ and sintered at 930°C, and d is the electron scanning electron micrograph of the ceramic cross-section doped with 0.06wt.% LiSbO ₃ and sintered at 950°C. It can be seen from Figure 4 that when the sintering temperature is 900 °C, the grain boundaries of piezoelectric ceramics are clear, the grains are full, and the grain growth is uniform.

2. Effect of Pb(Sb _1/2 Nb _1/2 )O ₃ content on the electrical properties of ceramics

In experiment 1, x is 0.06wt.%, and the content of Pb(Sb _1/2 Nb _1/2 )O ₃ is within 0.000～0.030mol, according to 0.02Pb(Mg _1/2 W _1/2 )O ₃ -yPb(Sb _1/2 Nb _1/2 )]O ₃ -(0.39-y)Pb(Ni _1/3 Nb _2/3 )O ₃ -Pb _0.59 (Zr _0.38 Ti _0.21 )O ₃ +0.06wt.% LiSbO ₃ is used for batching, and the experimental process is the same as that of Experiment 1. The capacitance C and the dielectric loss tanδ of the sample with the electrodes burned were measured. Measure the piezoelectric constant d ₃₃ of the finished piezoelectric ceramic with a quasi-static tester, calculate the dielectric constant ε _r according to the formula (1), calculate the density according to the formula (2), and calculate the planar electromechanical coupling coefficient K _p according to the formula (3), Calculate the mechanical quality factor Q _m according to formula (4). The test and calculation results are shown in Table 2.

Table 2 Electrical properties of ceramics with different Pb(Sb _1/2 Nb _1/2 )O ₃ contents at different sintering temperatures

It can be seen from Table 2 that the sintering temperature is 880-950°C, and the performance indicators of piezoelectric ceramics are good. Among them, the content of Pb(Sb _1/2 Nb _1/2 )O ₃ is 0.010mol, and the sintering temperature is 900°C Piezoelectric ceramics have the best performance.

X is 0.06wt.%, Pb(Sb _1/2 Nb _1/2 )O ₃ content is 0.000-0.030 mol, and the X-ray pattern of ceramics sintered at 900°C for 4 hours is shown in FIG. 5 . It can be seen from Figure 5 that all components are pure perovskite phase structure, and when the content is from 0.000mol to 0.010mol, there is no pyrochlore phase and second phase impurity that deteriorate the performance. Moreover, the single peak (002) R at 2θ of 43° to 47° indicates that the system is a rhombohedral phase.

x is 0.06wt.%, the content of Pb(Sb _1/2 Nb _1/2 )O ₃ is 0.010mol, and the X-ray patterns of ceramics sintered at different temperatures are shown in FIG. 6 . It can be seen from Figure 6 that all the components are in the pure perovskite phase structure, and when the temperature is 880-950°C, there is no pyrochlore phase and second phase impurity that deteriorate the performance. Moreover, the single peak (002) _R at 2θ of 43° to 47° shows that the system is a rhombohedral phase.

x is 0.06wt.%, Pb(Sb _1/2 Nb _1/2 )O ₃ content is 0.000～0.030mol, different Pb(Sb _1/2 Nb _1/2 )O ₃ content is prepared by sintering at 900℃ for 4 hours The scanning electron micrograph of the piezoelectric ceramic section is shown in Fig. 7. In Fig. 7, a is the scanning electron micrograph of the piezoelectric ceramic cross section sintered at 900°C for 4 hours with Pb(Sb _1/2 Nb _1/2 )O ₃ content of 0.000 mol, and b is the Pb content of 0.006 mol (Sb _1/2 Nb _1/2 )O ₃ , the scanning electron micrograph of the piezoelectric ceramic cross section sintered at 900°C for 4 hours, c is Pb(Sb _1/2 Nb _1/2 )O ₃ with a content of 0.010mol, Scanning electron micrograph of the piezoelectric ceramic section sintered at 900°C for 4 hours, d is Pb(Sb _1/2 Nb _1/2 )O ₃ with a content of 0.015 mol, and the electronic scanning of the piezoelectric ceramic section sintered at 900°C for 4 hours Electron micrograph, e is the scanning electron micrograph of the piezoelectric ceramic section with Pb(Sb _1/2 Nb _1/2 )O ₃ content of 0.030mol and sintered at 900°C for 4 hours. It can be seen from Fig. 7 that when the content of Pb(Sb _1/2 Nb _1/2 )O ₃ is 0.006-0.010mol, the crystal grains are relatively uniform, the grain boundaries are clear, and the compactness is good.

x is 0.06wt.%, and the content of Pb(Sb _1/2 Nb _1/2 )O ₃ is 0.010 mol. The scanning electron micrographs of the cross-sections of ceramics sintered at different temperatures are shown in FIG. 8 . In Fig. 8, a is the scanning electron micrograph of the piezoelectric ceramic cross section sintered at 880°C for 4 hours with Pb(Sb _1/2 Nb _1/2 )O ₃ content of 0.010 mol, and b is the Pb content of 0.010 mol (Sb _1/2 Nb _1/2 )O ₃ , the scanning electron micrograph of the piezoelectric ceramic cross section sintered at 900°C for 4 hours, c is Pb(Sb _1/2 Nb _1/2 )O ₃ with a content of 0.010mol, Scanning electron micrograph of the piezoelectric ceramic section sintered at 930°C for 4 hours, d is Pb(Sb _1/2 Nb _1/2 )O ₃ with a content of 0.010 mol, and the electronic scanning electron microscope of the piezoelectric ceramic section sintered at 950°C for 4 hours Electron microscope photo. It can be seen from Figure 8 that when the sintering temperature is 900°C, the ceramic grains are relatively large and uniform, the grain boundaries are clear, and the compactness is good.

Claims (4)

1. A low-temperature sintered lithium antimonate doped pentad piezoelectric ceramic material, characterized in that: the general formula 0.02Pb(Mg _1/2 W _1/2 )O ₃ -yPb(Sb _1/2 Nb _1/2 )]O ₃ -(0.39-y)Pb(Ni _1/3 Nb _2/3 )O ₃ -Pb _0.59 (Zr _0.38 Ti _0.21 )O ₃ +xLiSbO ₃ represents the material composition, where 0.00wt. %<x≤0.40wt.%, 0.000≤y≤0.030mol. 2. a preparation method of claim 1 low-temperature sintered lithium antimonate doped quinary piezoelectric ceramic material, characterized in that the method may further comprise the steps: (1) Preparation of Lithium Antimonate First mix Li ₂ CO ₃ and Sb ₂ O ₅ at a molar ratio of 1:1, put them into a nylon tank, add absolute ethanol as a dispersant and zirconia balls as a ball milling medium, the weight ratio of absolute ethanol to raw materials 1:1.5～2.5, use a ball mill for 12 hours at a speed of 400 rpm, separate the zirconia balls, put the mixture in a drying oven at 80°C for 10 hours, then put it in a mortar and grind for 30 minutes , through a 80-mesh sieve, the sieved material is placed in an alumina crucible, compacted with agate rods, the bulk density is 1.2-1.5g/cm ³ , covered, and pre-fired in a resistance furnace at 570-730°C to keep warm Synthesize LiSbO ₃ in 2 to 4 hours, cool naturally to room temperature, and take it out of the furnace; crush and grind the pre-burned powder for 1 hour, put it into a nylon tank, and perform ball milling and drying in the same process as above for later use; (2) Ingredients synthesis Then synthesized LiSbO ₃ , Pb ₃ O ₄ , ZrO ₂ , TiO ₂ , Mg(OH) ₂ MgCO ₃ 6H ₂ O, WO ₃ , Sb ₂ O ₅ , Nb ₂ O ₅ , and NiO according to the general chemical formula The metering ratio is mixed, put into a nylon tank, add absolute ethanol as a dispersant and zirconia balls as a ball milling medium, the weight ratio of absolute ethanol to raw materials is 1:2, and use a ball mill to mill for 6 to 12 hours at a speed of 400 RPM, separate the zirconia balls, put the mixture in a drying oven at 80°C and dry for 5-10 hours, then put it in a mortar and grind for 30 minutes, and pass through an 80-mesh sieve; (3) pre-burning Put the ground material in an alumina crucible, compact it with an agate rod to make the bulk density reach 1.5g/cm ³ , cover it, and pre-fire it in a resistance furnace at 800-850°C for 2-4 hours. Cool to room temperature and take it out of the furnace; crush and grind the calcined powder for 1 hour, put it into a nylon tank, add absolute ethanol as a dispersant and zirconia balls as a ball milling medium, and the weight ratio of absolute ethanol to raw materials is 1:2 , use a ball mill to mill for 6 to 12 hours, perform secondary ball milling at a speed of 300 rpm, separate the zirconia balls, put the mixture in a drying oven at 80°C for 5 to 10 hours, and pass through an 80-mesh sieve; (4) Granulation Grind the pre-fired agglomerate finely through a 160 mesh sieve with a mortar, add a mass concentration of 5% polyvinyl alcohol solution and glycerin solution, the mass ratio of raw materials to 5% polyvinyl alcohol solution, glycerin 1:0.068～0.072:0.0097～0.013, fully stirred, naturally dried, passed through a 120-mesh sieve, and made into spherical powder; (5) Tablet Put the spherical powder into a stainless steel mold with a diameter of 15mm, and press it into a cylindrical blank of 1.5mm under a pressure of 100Mpa; (6) Glue removal Put the blank into the resistance furnace, keep it warm at 500°C for 1 hour to remove organic matter; (7) Sintering Put the debinding blank into the alumina crucible, cover the alumina crucible to seal, heat up at 2-5°C/min, sinter at 880-950°C for 3-5 hours, and cool down to room temperature naturally with the furnace; (8) burnt silver Grind and polish the sintered ceramic surface to a thickness of 0.8-1.2mm, clean it with an ultrasonic cleaner with a power of 100w and a frequency of 50kHz for 30 minutes, dry it in an oven at 80°C, and coat the upper and lower surfaces with a thickness of 0.01 ~0.03mm silver paste, put it in a resistance furnace at 850°C for 30 minutes, and cool it down to room temperature naturally; (9) Polarization Heat the burnt silver sample in methyl silicone oil to 120-180°C, apply a DC high voltage of 3kV/mm-5kV/mm for 15-30 minutes, and prepare piezoelectric ceramics. 3. according to the preparation method of the pentad system piezoelectric ceramic material doped by low-temperature sintering lithium antimonate claimed in claim 2, it is characterized in that: in preparing lithium antimonate process step (1), after grinding and sieving Li ₂ CO ₃ , Sb ₂ O ₅ mixture, pre-fired in a resistance furnace at 570-700°C for 2-3 hours to synthesize LiSbO ₃ ; in the pre-fired process step (3), put the ground material in an alumina crucible Inside, compact with agate rods until the bulk density is 1.5g/cm ³ , add a cover, and pre-fire in a resistance furnace at 800-830°C for 2-3 hours; in the sintering process step (7), the debinding blank Put the pieces into the alumina crucible, cover the alumina crucible lid to seal, the heating rate is 2-5°C/min, and sinter at 880-930°C for 3-4.5 hours. 4. according to the preparation method of the pentad system piezoelectric ceramic material doped by low-temperature sintering lithium antimonate claimed in claim 2, it is characterized in that: in preparing lithium antimonate process step (1), after grinding and sieving Li ₂ CO ₃ , Sb2O5 mixture is pre-fired in a resistance furnace at 610°C for 3 hours to synthesize LiSbO ₃ ; in step (3) of the pre-fire process, the ground material is placed in an alumina crucible and compacted with an agate rod When the bulk density is 1.5g/cm ³ , cover it, and pre-fire it in a resistance furnace at 800°C for 3 hours; in the sintering process step (7), put the debinding blank into an alumina crucible, cover The lid of the aluminum crucible is sealed, the heating rate is 2-5°C/min, and sintering is carried out at 900°C for 4 hours.

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