Potassium sodium niobate-based leadless piezoelectric ceramic and preparation method thereof

A technology based on lead-free piezoelectric and sodium potassium niobate, applied in the field of piezoelectric ceramic devices, can solve the problems of sintered ceramic components deviating from the design stoichiometric ratio, difficulty in obtaining high voltage, electromechanical properties, and difficulty in preparing KNN ceramics , to achieve the effect of removing damage to human health and social environment, decreasing porosity and increasing density

Active Publication Date: 2022-01-28
XI AN JIAOTONG UNIV
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  • Abstract
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Problems solved by technology

Although KNN ceramics have excellent performance, it is difficult to prepare KNN ceramics. The structure of ceramic samples prepared by conventional sintering methods has high porosity and low density; in addition, K and Na are severely volatilized at high temperatures, which leads to serious deviation of the sintered ceramic components from the design. Stoichiometric ratio, difficult to obtain high voltage electrical, electromechanical properties

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  • Potassium sodium niobate-based leadless piezoelectric ceramic and preparation method thereof
  • Potassium sodium niobate-based leadless piezoelectric ceramic and preparation method thereof

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preparation example Construction

[0029] A kind of high-performance sodium potassium niobate base lead-free piezoelectric ceramics of the present invention, chemical formula is (1-x) (K 0.5 Na 0.5 )NbO 3 -xBi(Li 0.5 Sb 0.5 )O 3 , x represents the mole fraction, 0.01≤x≤0.20. Its preparation method comprises the following steps:

[0030] Step 1, pre-drying raw materials of analytically pure sodium carbonate, potassium carbonate, niobium pentoxide, bismuth oxide, lithium carbonate and antimony trioxide;

[0031] Step 2, according to (1-x)(K 0.5 Na 0.5 )NbO 3 -xBi(Li 0.5 Sb 0.5 )O 3 Stoichiometric ratio weighing of each drying raw material, mixing and ball milling and drying to obtain the mixed material A;

[0032] Step 3, pre-calcining the mixed material A to obtain the pre-calcined powder B;

[0033] Step 4, the powder synthesized after pre-calcination is ball-milled for the second time and dried to obtain the second ball-milled powder C;

[0034]Step 5, adding a binder to the secondary ball millin...

Embodiment 1

[0049] Step 1, pre-dry raw materials such as sodium carbonate, potassium carbonate, niobium pentoxide, bismuth oxide, lithium carbonate, antimony trioxide and the like in an oven at 120°C for 24 hours.

[0050] Step 2, with the material obtained in step 1 according to the chemical formula 0.96 (K 0.5 Na 0.5 )NbO 3 -0.04Bi(Li 0.5 Sb 0.5 )O 3 Stoichiometric weighing, mixing and ball milling, and drying after ball milling to obtain the mixed material A. Among them, the mass ratio of raw materials to grinding balls is 1:1.5; the mass ratio of raw materials to absolute ethanol is 1:1.0, the ball milling time is 36 hours, and the drying temperature is 120°C.

[0051] In step 3, the dried mixed material A is put into a crucible, and pre-fired in a muffle furnace to obtain a pre-fired powder B. The pre-firing temperature is 800°C, and the holding time is 4h.

[0052] Step 4: The pre-burned material is ball milled for 48 hours a second time, and a binder PVA with a mass ratio of...

Embodiment 2

[0058] In step 1, raw materials such as sodium carbonate, potassium carbonate, niobium pentoxide, bismuth oxide, lithium carbonate, and antimony trioxide are pre-dried in an oven at 100° C. for 5 hours.

[0059] Step 2, with the material obtained in step 1 according to the chemical formula 0.99 (K 0.5 Na 0.5 )NbO 3 -0.01Bi(Li 0.5 Sb 0.5 )O 3 Stoichiometric weighing, mixing and ball milling, and drying after ball milling to obtain the mixed material A. Among them, the mass ratio of raw materials to grinding balls is 1:2.0; the mass ratio of raw materials to absolute ethanol is 1:0.5, the ball milling time is 24 hours, and the drying temperature is 100°C.

[0060] In step 3, the dried mixed material A is put into a crucible, and pre-fired in a muffle furnace to obtain a pre-fired powder B. The pre-firing temperature is 850°C, and the holding time is 3h.

[0061] Step 4: The pre-burned material is ball milled for 36 hours a second time, and a binder PVA with a mass ratio o...

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Abstract

The invention discloses potassium sodium niobate-based leadless piezoelectric ceramic and a preparation method thereof, the chemical formula of the potassium sodium niobate-based piezoelectric ceramic is (1-x) (K0. 5Na0. 5) NbO3-xBi (Li0. 5Sb0. 5) O3, and x is more than or equal to 0.01 and less than or equal to 0.20. The preparation method comprises the following steps: weighing dry raw materials according to a stoichiometric ratio of (1-x) (K0. 5Na0. 5) NbO3-xBi (Li0. 5Sb0. 5) O3, mixing, carrying out ball milling, and drying to obtain a mixed material; pre-sintering the mixed material obtained in the step 1 at a high temperature to obtain pre-sintered powder, and performing secondary ball-milling and drying to obtain secondary ball-milled powder; adding an adhesive into the secondary ball-milled powder, granulating, sieving, and carrying out compression molding, so as to obtain a ceramic blank; removing the organic adhesive, and sintering at high temperature to obtain sintered ceramic; coating the surfaces of the two sides of the sintered ceramic with silver and carrying out high-voltage polarization, and preparing the potassium sodium niobate-based leadless piezoelectric ceramic. Through component design and process optimization, the sintering characteristic of the potassium sodium niobate-based ceramic is effectively improved, volatilization of sodium and potassium elements is inhibited, the porosity is reduced, the density of the ceramic is improved, the dielectric constant is further improved, the loss is reduced, and the comprehensive performance of the KNN-based ceramic is improved.

Description

technical field [0001] The invention belongs to the technical field of piezoelectric ceramic devices. In particular, a sodium potassium niobate-based lead-free piezoelectric ceramic and a preparation method thereof. Background technique [0002] With the rapid development of electronic information technology, people have higher and higher requirements for the performance, appearance and convenience of electronic products such as mobile phones and personal computers. High-performance capacitors are important electronic components to meet market demand. For this reason, it is urgent to develop new ceramic capacitors with high dielectric constant, low loss and wide temperature range. [0003] At present, lead-based electronic ceramic materials represented by lead zirconate titanate (PZT for short) occupy the vast majority of the application market, and are widely used in piezoelectric devices such as capacitors, sensors, brakes, transformers and ultrasonic transducers. Howeve...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/495C04B35/622C04B35/638C04B35/64
CPCC04B35/495C04B35/622C04B35/638C04B35/64C04B2235/3201C04B2235/3203C04B2235/3298C04B2235/3294C04B2235/6562C04B2235/6567
Inventor 李景雷罗力晨王明文杨帅吴杰李飞
Owner XI AN JIAOTONG UNIV
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