Preparation method of 1.28% large-electrostrictive-strain lead-free potassium sodium niobate-based piezoelectric ceramic

A technology of lead potassium niobate and piezoelectric ceramics, applied in the field of functional materials and piezoelectric ceramics, can solve problems such as switching difficulties, and achieve the effects of rich phase transitions, large piezoelectric activity, and large application prospects

Pending Publication Date: 2021-06-01
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Ferroelectric materials with large spontaneous lattice strains theoretically have large electrical strains, but polycrystalline piezoelectric ceramics are inevitably in a multi-domain state, and as the magnitude of spontaneous lattice strain increases, the switching of domains becomes more and more difficult

Method used

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  • Preparation method of 1.28% large-electrostrictive-strain lead-free potassium sodium niobate-based piezoelectric ceramic
  • Preparation method of 1.28% large-electrostrictive-strain lead-free potassium sodium niobate-based piezoelectric ceramic
  • Preparation method of 1.28% large-electrostrictive-strain lead-free potassium sodium niobate-based piezoelectric ceramic

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Weigh 3.433g K according to the raw material ratio of 0.5% mol of lanthanum 2 CO 3 , 2.637g Na 2 CO 3 , 13.234gNb 2 o 5 , 0.163g La 2 o 3 .

[0026] Put the weighed raw material powder into a polytetrafluoroethylene ball mill jar equipped with zirconia balls, and use ethanol as a ball milling aid for ball milling at a rotational speed of 350r / min and a ball milling time of 12-18h.

[0027] The dried powder is sieved and pressed into large pieces with a diameter of 15mm and a height of 28-32mm, placed on a corundum ceramic plate, and calcined at 800-900°C for 2-4h. Secondary ball milling is performed on the once calcined sample, and the ball milling time is 12-18h. After drying and sieving, it is calcined at 800-900°C for 2-4 hours, and then ball milled three times and dried and sieved. The ball milling time is 12-18 hours.

[0028] The powder is pre-pressed into small discs with a diameter of 10mm and a thickness of 0.9-1.1mm, and then formed by a cold isostati...

Embodiment 2

[0034] Weigh 3.45g K2CO3, 2.65g Na2CO3, 13.3g Nb2O5 according to the ratio of raw materials not doped with lanthanum.

[0035] Put the weighed raw material powder into a polytetrafluoroethylene ball mill jar equipped with zirconia balls, and use ethanol as a ball milling aid for ball milling at a rotational speed of 350r / min and a ball milling time of 12-18h.

[0036] The dried powder is sieved and pressed into large pieces with a diameter of 15mm and a height of 28-32mm, placed on a corundum ceramic plate, and calcined at 800-900°C for 2-4h. Secondary ball milling is performed on the once calcined sample, and the ball milling time is 12-18h. After drying and sieving, it is calcined at 800-900°C for 2-4 hours, and then ball milled three times and dried and sieved. The ball milling time is 12-18 hours.

[0037] The powder is pre-pressed into small discs with a diameter of 10mm and a thickness of 0.9-1.1mm, and then formed by a cold isostatic press with a forming pressure of 20...

Embodiment 3

[0041]Weigh 3.416g K2CO3, 2.624g Na2CO3, 13.167g Nb2O5, 0.326g La2O3 according to the raw material ratio of lanthanum doping amount 1%mol.

[0042] Put the weighed raw material powder into a polytetrafluoroethylene ball mill jar equipped with zirconia balls, and use ethanol as a ball milling aid for ball milling at a rotational speed of 350r / min and a ball milling time of 12-18h.

[0043] The dried powder is sieved and pressed into large pieces with a diameter of 15mm and a height of 28-32mm, placed on a corundum ceramic plate, and calcined at 800-900°C for 2-4h. Secondary ball milling is performed on the once calcined sample, and the ball milling time is 12-18h. After drying and sieving, it is calcined at 800-900°C for 2-4 hours, and then ball milled three times and dried and sieved. The ball milling time is 12-18 hours. The powder is pre-pressed into small discs with a diameter of 10mm and a thickness of 0.9-1.1mm, and then formed by a cold isostatic press with a forming pr...

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Abstract

The invention relates to a preparation method of 1.28% large-electrostrictive-strain lead-free potassium sodium niobate-based piezoelectric ceramic, used potassium sodium niobate ceramics have submicron crystal grains, rich phase change and large piezoelectric activity, and lanthanum doping can miniaturize domains and influence the piezoelectric response of the potassium sodium niobate ceramics. Various parameters of the preparation process are optimized to refine crystal grains; the performance table of the lead-free piezoelectric ceramic obtained after sintering is as follows: the maximum polarization intensity under the electric field of 40kV / cm is 19 [mu] C / cm < 2 >, the remanent polarization intensity is 10 [mu] C / cm < 2 >, and the coercive field is 12kV / cm; the bipolar electrostrictive strain under a 40 kV / cm electric field can reach 0.98%, and the inverse piezoelectric coefficient is 2363 pm / V; and the monopole electrostrictive strain under the electric field of 110 kV / cm can reach 1.28%, and the inverse piezoelectric coefficient is 1167 pm / V. The lead-free potassium-sodium niobate-based ceramic obtained by sintering has 1.28% of giant electrostrictive strain, which is the maximum value of the polycrystalline lead-free piezoelectric ceramic researched at present, and has a very great application prospect.

Description

technical field [0001] The invention belongs to the field of functional materials and piezoelectric ceramics, and relates to a preparation method of 1.28% large electric strain lead-free potassium sodium niobate-based piezoelectric ceramics. Background technique [0002] High-performance piezoelectric materials are widely used in various applications due to their simplicity, short response time, and precision, such as ultrasound transducers for medical imaging, high-precision actuation, guidance systems, automotive industry, etc. The most important parameter of the piezoelectric material is the electric strain. At present, lead-containing piezoelectric ceramics and single crystal materials with large electric strain are widely used. The use of lead-containing piezoelectric materials will pollute the environment, and the growth conditions of high-quality single crystals are also very harsh and have low repeatability. [0003] In recent years, polycrystalline lead-free piezoe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/495
CPCC04B35/495C04B2235/442C04B2235/3227C04B2235/6562C04B2235/6567C04B2235/96
Inventor 樊慧庆全琪峰王维佳
Owner NORTHWESTERN POLYTECHNICAL UNIV
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