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Lithium-doped potassium-sodium niobate single crystal with high piezoelectric property and preparation method thereof

A technology of potassium sodium niobate and high voltage, applied in the field of lithium-doped potassium sodium niobate single crystal and its preparation, can solve the problem that the performance of single crystal has not been significantly improved, the composition is difficult to control accurately, and the performance of single crystal has not been reported and other problems, to achieve the effect of low cost, short reaction time, and high-voltage performance

Active Publication Date: 2016-01-20
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The preparation of single crystal by high-temperature melting method requires expensive single crystal pulling furnace and precise temperature control device. The obtained single crystal has large component segregation, and the composition is difficult to control accurately, which leads to the fact that the performance of single crystal is not better than that of ceramic materials. Significantly increased
In terms of preparing single crystals by non-melting methods, Jiang Minhong et al. have prepared KNN single crystals with a size of 2 mm, but have not reported the relevant single crystal properties (reference: Chinese invention patent, publication number: CN101913868A)

Method used

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  • Lithium-doped potassium-sodium niobate single crystal with high piezoelectric property and preparation method thereof
  • Lithium-doped potassium-sodium niobate single crystal with high piezoelectric property and preparation method thereof
  • Lithium-doped potassium-sodium niobate single crystal with high piezoelectric property and preparation method thereof

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preparation example Construction

[0024] The preparation method of the present invention comprises the following steps.

[0025] Step 1) According to the chemical formula (K 0.45 Na 0.55 ) 1-x Li x NbO 3 , according to the K:Na:Li:Nb molar ratio of 0.45(1-x):0.55(1-x):x:1 with K 2 CO 3 、Na 2 CO 3 , Li 2 CO 3 and Nb 2 o 5 Raw material; wherein 0.01≤x≤0.1, preferably 0.02≤x≤0.08.

[0026]Step 2) according to step 1) the proportioning of each component, weigh K 2 CO 3 、Na 2 CO 3 , Li 2 CO 3 and Nb 2 o 5 Raw materials, using absolute ethanol as the ball milling medium, planetary ball milling to obtain slurry; the mass ratio of the total mass of raw materials to absolute ethanol is 1: (1-2), preferably 1:1.5; the rotational speed of the planetary ball mill is 200-600 rpm , Ball milling time 4 to 10 hours.

[0027] Step 3) Dry the slurry obtained in step 2) at 90-120°C for 6-12 hours, then pre-fire at 700-950°C for 2-8 hours to synthesize powder raw materials; pre-synthesis optimal conditions: 5...

Embodiment 1

[0034] According to the chemical formula (K 0.45 Na 0.55 ) 0.98 Li 0.02 NbO 3 The K:Na:Li:Nb molar ratio is 0.441:0.539:0.02:1 equipped with K 2 CO 3 、Na 2 CO 3 , Li 2 CO 3 and Nb 2 o 5 Raw materials, using absolute ethanol as a ball milling medium, and planetary ball milling for 6 hours to obtain slurry. After the slurry was dried at 100°C for 8 hours, it was pre-fired at 850°C for 5 hours to synthesize powder raw materials, and 0.25mol% of composite sintering aid Li 2 CO 3 and Bi 2 o 3 (the molar ratio is 1:1), high-energy ball milling was carried out for 2 h with absolute ethanol as the ball milling medium to obtain a slurry. The slurry after high-energy ball milling was dried at 100°C for 12 hours, and uniaxially pressed to make a φ25mm disc, followed by 200MPa cold isostatic pressing to obtain a ceramic green body. Put the ceramic green body into the crucible, and after heat treatment at 1100 °C for 10 h, the (K 0.45 Na 0.55 ) 0.98 Li 0.02 NbO 3 singl...

Embodiment 2

[0036] According to the chemical formula (K 0.45 Na 0.55 ) 0.96 Li 0.04 NbO 3 The K:Na:Li:Nb molar ratio is 0.432:0.528:0.04:1 equipped with K 2 CO 3 、Na 2 CO 3 , Li 2 CO 3 and Nb 2 o 5 Raw materials, using absolute ethanol as a ball milling medium, and planetary ball milling for 6 hours to obtain slurry. After the slurry was dried at 100°C for 8 hours, it was pre-fired at 850°C for 5 hours to synthesize powder raw materials, and 0.25mol% of composite sintering aid Li 2 CO 3 and Bi 2 o 3 (the molar ratio is 1:1), high-energy ball milling was carried out for 2 h with absolute ethanol as the ball milling medium to obtain a slurry. The slurry after high-energy ball milling was dried at 100°C for 12 hours, and uniaxially pressed to make a φ25mm disc, followed by 200MPa cold isostatic pressing to obtain a ceramic green body. Put the ceramic green body into the crucible, and after heat treatment at 1100 °C for 10 h, the (K 0.45 Na 0.55 ) 0.96 Li 0.04 NbO 3 singl...

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Abstract

The invention relates to a lithium-doped potassium-sodium niobate single crystal with the high piezoelectric property and a preparation method thereof. The chemical formula of the lithium-doped potassium-sodium niobate single crystal is (K0.45Na0.55)1-xLixNbO3, wherein x is larger than or equal to 0.01 and is smaller than or equal to 0.1 and preferably x is larger than or equal to 0.02 and is smaller than or equal to 0.08. The preparation method includes the steps that 1, K2CO3, Na2CO3, Li2CO3 and Nb2O5 are weighed according to the stoichiometric ratio, ball-milling and drying are carried out, presintering is conducted for 2-8 hours at the temperature of 700-950 DEG C, and a pre-synthesized lithium-doped potassium-sodium niobate powder is obtained; 2, 0.15-0.35 mol% of composite sintering aid is added into the pre-synthesized powder, ball-milling and drying are carried out, isostatic cool pressing is conducted after single-axis extrusion forming, a ceramic biscuit is obtained, and the composite sintering aid is composed of Li2CO3 and Bi2O3; 3, the ceramic biscuit is annealed for 2-50 hours at the temperature of 1050-1130 DEG C, and accordingly the lithium-doped potassium-sodium niobate single crystal with the high piezoelectric property is prepared.

Description

technical field [0001] The invention relates to a lithium-doped potassium sodium niobate single crystal with high-voltage electrical properties and a preparation method thereof, belonging to the field of lead-free piezoelectric single crystal preparation. Background technique [0002] Because lead will cause harm to the environment and human health, it has become a general trend to use high-performance lead-free piezoelectric materials to replace traditional lead-containing piezoelectric materials. At present, the widely studied lead-free piezoelectric materials mainly include potassium sodium niobate system (KNN), bismuth sodium titanate system (NBT) and bismuth layered piezoelectric materials. Compared with other lead-free piezoelectric materials, KNN has excellent piezoelectric properties and a higher Curie temperature, so it is considered to be one of the lead-free piezoelectric systems most likely to replace lead-based materials. However, there is still a large gap bet...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/495C04B35/622
Inventor 李永祥杨洁杨群保
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI