Precursor solution and method for the preparation of a lead-free piezoelectric material

Patent metadata

Field	Value
Publication number	US-10696597-B2
Application number	US-201615192648-A
Country	US
Kind code	B2
Filing date	Jun 24, 2016
Priority date	Dec 1, 2015
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

The present disclosure relates to a precursor solution for the preparation of a ceramic of the BZT-αBXT type, where X is selected from Ca, Sn, Mn, and Nb, and α is a molar 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 the group consisting of 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 anhydrous precursor compound of zirconium; 4) at least one anhydrous precursor compound of titanium; 5) a solvent selected from the group consisting of a polyol and mixtures of a polyol and a secondary solvent selected from the group consisting of alcohols, carboxylic acids, esters, ketones, ethers, and mixtures thereof; and 6) a chelating agent, as well as method of using the same.

First claim

The invention claimed is:

1. A lead-free precursor solution for preparing a BZT-αBXT type ceramic having a piezoelectric coefficient of 200 to 710 pC/N, wherein, B is barium, Z is zirconium, X is selected from calcium, tin, manganese, and niobium, T is titanium, and α is a molar fraction selected in the range between 0.10 and 0.90, said precursor solution consisting of:
1) at least one barium precursor compound;
2) at least one metal precursor compound selected from the group consisting of a calcium precursor compound, a tin precursor compound, a manganese precursor compound, and a niobium precursor compound;
3) at least one anhydrous zirconium precursor compound;
4) at least one anhydrous titanium precursor compound;
5) a solvent consisting of ethylene glycol and a secondary solvent selected from 3-methylpentanoic acid, 4-methylpentanoic acid, 2-ethylpentanoic acid, 3-ethylpentanoic acid, 2,2-dimethylpentanoic acid, 3,3-dimethylpentanoic acid, 2,3-dimethylpentanoic acid and 3-ethylhexanoic acid adapted to dissolve the at least one barium precursor compound and at least one of the calcium precursor compound, the tin precursor compound, the manganese precursor compound, and the niobium precursor compound;
6) a chelating agent,
and 7) a viscosizing agent selected from the group consisting of polyvinlypyrrolidone and polyethylene glycol wherein said precursor compounds of calcium, barium, zirconium, titanium, tin, niobium, and manganese are selected from the group consisting of metal alkoxides, metal-diol complexes, metal-thiol complexes, metal carboxylates, metal-3-diketonate complexes, metal-3-diketoester complexes, metal-3-iminoketo complexes, and metal-amine complexes.

2. The precursor solution of claim 1 wherein the at least one barium precursor compound and the at least one metal precursor compound are anhydrous or dehydrated.

3. The precursor solution according to claim 1 , wherein said barium precursor compound is barium diisopropoxide.

4. The precursor solution according to claim 1 , wherein said calcium precursor compound is calcium diisopropoxide.

5. The precursor solution according to claim 1 , wherein said titanium precursor compound is selected from the group consisting of titanium tetraethoxide, titanium tetraisopropoxide, titanium tetra-n-butoxide, titanium tetraisobutoxide, titanium tetra-t-butoxide, and titanium dimethoxy diisopropoxide.

6. The precursor solution according to claim 1 , wherein said zirconium precursor compound is selected from the group consisting of zirconium n-propoxide, zirconium tetraethoxide, zirconium tetraisopropoxide, zirconium tetra-n-butoxide, zirconium tetraisobutoxide, zirconium tetra-t-butoxide, and zirconium dimethoxy diisopropoxide.

7. The precursor solution according to claim 1 , wherein said chelating agent is selected from the group consisting of acetylacetone (2,2-pentanedione, or AcAc), acetic acid (HAc), glycerol, propylene glycol, diethanolamine, EDTA (ethylenediaminetetraacetic acid), and triethanolamine.

8. A method of preparing the precursor solution of claim 1 comprising:
1) providing a first solution by dissolving at least one barium precursor compound and at least one metal precursor compound selected from the group consisting of a calcium precursor compound, a tin precursor compound, a manganese precursor compound, and a niobium precursor compound, in a solvent comprising ethylene glycol;
2) providing a second solution by dissolving at least one anhydrous titanium precursor compound and at least one anhydrous zirconium precursor compound in a chelating agent; and
3) providing a precursor solution by mixing said first and second solutions, wherein said precursor compounds of calcium, barium, zirconium, titanium, tin, niobium, and manganese are selected from the group consisting of metal alkoxides, metal-diol complexes, metal-thiol complexes, metal carboxylates, metal-3-diketonate complexes, metal-3-diketoester complexes, metal-3-iminoketo complexes, and metal-amine complexes.

9. The method of claim 8 wherein at least one barium precursor compound and the at least one metal precursor compound are anhydrous or dehydrated.

10. A method comprising:
depositing on a substrate the precursor solution of claim 1 that includes:
calcining the precursor solution to provide a thin film on the substrate; and
providing a piezoelectric material film by sintering the thin film, wherein the piezoelectric material film includes a BZT-αBXT type ceramic, wherein B is barium, Z is zirconium, X is selected from calcium, tin, manganese, and niobium, T is titanium, and α is a molar fraction selected in the range between 0.10 and 0.90.

11. The method of claim 10 wherein at least one barium precursor compound and the at least one metal precursor compound are anhydrous or dehydrated.

Assignees

• St Microelectronics Srl

Inventors

• Cimmino Angela
• Salzillo Giovanna
• Casuscelli Valeria
• Di Matteo Andrea

Classifications

• C04B35/49

  containing also titanium oxides or titanates · CPC title

• C04B35/624

  Sol-gel processing · CPC title

• C04B35/63444

  Nitrogen-containing polymers, e.g. polyacrylamides, polyacrylonitriles, polyvinylpyrrolidone [PVP], polyethylenimine [PEI] · CPC title

• C09D5/03

  Powdery paints · CPC title

• C04B35/62685

  characterised by the order of addition of constituents or additives · CPC title