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Precursor solution and method for preparing lead-free piezoelectric material

A precursor solution, piezoelectric material technology, applied in chemical instruments and methods, piezoelectric/electrostrictive/magnetostrictive devices, circuits, etc., can solve problems such as difficult to store solutions, unstable sol solutions, high toxicity, etc.

Active Publication Date: 2020-12-04
STMICROELECTRONICS SRL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, 2-methoxyethanol is highly toxic to humans
[0030] Also, systems without 2-MOE lead to the formation of unstable sol solutions that gel in a short time, making it difficult to store the solution and subsequently use it in the deposition of piezoelectric thin films

Method used

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  • Precursor solution and method for preparing lead-free piezoelectric material
  • Precursor solution and method for preparing lead-free piezoelectric material
  • Precursor solution and method for preparing lead-free piezoelectric material

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[0071] It is therefore desirable to minimize the presence of residual water during the preparation of the gel solution.

[0072] It has been noted that the use of the precursor compounds in combination with a solvent selected from polyols, alcohols, carboxylic acids, esters, ketones, ethers and mixtures thereof enables the obtained sol solution to remain transparent and stable over time.

[0073] Other considerations in choosing solvents include their viscosity, availability, stability and toxicity.

[0074] In the following, the term "polyol" refers to a possibly branched alkyl compound comprising at least two carbon atoms and at least two OH groups.

[0075] In particular, the polyol may be a diol. Specific examples of diols include propylene glycol, ethylene glycol, and 1,3-propanediol, particularly propylene glycol and ethylene glycol.

[0076] The use of polyhydric alcohol as a component of the solvent increases the stability of the composition in storage.

[0077] Pol...

Embodiment 1

[0116] BZT-BCT in EG-HAc – preparation and characterization

[0117] All starting materials (barium acetate [Ba(CH 3 COO) 2 ], calcium acetate monohydrate [Ca(CH 3 COO) 2 ·H 2 O], tetrabutyl titanate [Ti(OC 4 h 9 ) 4 ] and zirconium isopropoxide [Zr(OC 3 h 7 ) 4 ] 70% sol in 1-propanol) was of analytical grade and used without further purification.

[0118] Ethylene glycol and ethanol were used as solvents, while glacial acetic acid was used as a chelating agent.

[0119] In the synthesis of precursor solutions, Ba-Ca and Ti-Zr solutions were produced separately.

[0120] Solution A was prepared by separately dissolving BaAc and CaAc in ethylene glycol at 70°C and then by stirring for 30 minutes.

[0121] The solutions were then mixed together and stirred at 100°C for 1 hour to form a Ba-Ca solution.

[0122] For solution B, in order to inhibit the hydrolysis of TiBut due to ambient humidity, first add an appropriate amount of glacial acetic acid to an accuratel...

Embodiment 2

[0134] BZT-BCT in EG-AcAc – Preparation and Characterization

[0135] All starting materials (barium acetate [Ba(CH 3 COO) 2 ], calcium acetate monohydrate [Ca(CH 3 COO) 2 ·H 2 O], titanium isopropoxide and zirconium isopropoxide [Zr(OC 3 h 7 ) 4 ] 70% sol in 1-propanol) was of analytical grade and used without further purification.

[0136] TiBut and ZrIP were preserved and handled precisely in a glove box, but in a nitrogen atmosphere with low moisture content.

[0137] Ethylene glycol was used as a solvent, and acetylacetone was used as a chelating agent in a molar ratio of AcAc:[Ti+Zr]=1.

[0138] In the synthesis of the precursors, Ba-Ca and Ti-Zr solutions were prepared separately.

[0139] Solution A was prepared by dissolving BaAc and CaAc separately in ethylene glycol at 70°C and then stirring for 30 minutes.

[0140] The solutions were then mixed together and stirred at 100°C for 1 hour to form a Ba-Ca solution.

[0141] For solution B, TiIP and ZrIP wer...

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Abstract

The present invention relates to a precursor solution for the preparation of ceramics of the BZT-αBXT type, wherein X is selected from Ca, Sn, Mn and Nb, and α is a mole fraction selected in the range between 0.10 and 0.90, said solution comprising: 1) at least one barium precursor compound; 2) a precursor compound selected from at least one calcium compound, at least one tin compound, at least one manganese compound and at least one niobium compound; 3) at least one zirconium-free 4) at least one anhydrous titanium precursor compound; 5) a solvent selected from polyols and polyol mixtures, and an auxiliary solvent selected from alcohols, carboxylic acids, esters, ketones, ethers, and mixtures thereof and 6) chelating agents. The invention also relates to a method for preparing the precursor solution, a piezoelectric material obtained from the precursor solution, a method for preparing a film of the piezoelectric material, a device comprising the piezoelectric material and the use of the piezoelectric material.

Description

technical field [0001] The present invention relates to precursor solutions and methods for the preparation of piezoelectric materials that are lead-free and free of compounds that are mutagenic and carcinogenic to humans and toxic to the environment. Background technique [0002] Piezoelectric materials are materials that can expand or contract when a voltage is applied (electrical strain effect) and conversely can generate a voltage if they are subjected to pressure (piezoelectric effect). [0003] They thus constitute a very important class of materials capable of converting mechanical energy into electrical energy and vice versa. They have actually been widely used in products in the field of energy conversion, such as actuators and sensors, and are common in general applications as well as advanced technologies, thus playing a fundamental role in today's society. [0004] Piezoelectric materials have a perovskite crystal structure. The mineral perovskite is a chemical...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/49C04B35/622H10N30/078H10N30/853
CPCC04B35/49C04B35/62218C04B2235/3208C04B2235/3215C04B2235/3232C04B2235/3244C04B2235/3251C04B2235/3262C04B2235/3284C04B35/465C04B35/4682C04B2235/3236C01G23/006C04B35/624C04B35/632C04B35/6325C04B35/634C04B2235/3293C04B2235/44C04B2235/441C04B2235/449C04B2235/765C04B2235/81C01G25/006C01P2004/82C01G45/125H10N30/8536H10N30/078
Inventor A·西米诺G·萨尔奇洛V·卡萨塞利A·迪马特奥
Owner STMICROELECTRONICS SRL