# US 8,541,102 B2 · (Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric material and manufacturing method of the same

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- Number: US 8,541,102 B2
- Document ID: US8541102B2
- Status: Granted
- Kind: B2
- Application number: 12/495,830
- Filed: 2009-07-01
- Published: 2010-01-28
- Granted: 2013-09-24
- Earliest claimed: 2008-07-28
- Assignees: NGK Insulators, Ltd.
- Applicants: Kazuyuki Kaigawa; Ritsu Tanaka; Hirofumi Yamaguchi
- Inventors: Kazuyuki Kaigawa; Ritsu Tanaka; Hirofumi Yamaguchi
- Web page: https://patentgrep.com/patent/US8541102B2

## CPC

- H10N 30/8542: {Alkali metal based oxides, e.g. lithium, sodium or potassium niobates}
- C01G 35/006: {Compounds containing tantalum, with or without oxygen or hydrogen, and containing two or more other elements}
- C04B 35/495: based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates
- H10N 30/097: by sintering
- C01P 2004/03: obtained by SEM
- C01P 2006/10: Solid density
- C01P 2006/40: Electric properties
- C04B 2235/3201: Alkali metal oxides or oxide-forming salts thereof
- C04B 2235/3203: Lithium oxide or oxide-forming salts thereof
- C04B 2235/3241: Chromium oxides, chromates, or oxide-forming salts thereof
- C04B 2235/3251: Niobium oxides, niobates, tantalum oxides, tantalates, or oxide-forming salts thereof
- C04B 2235/3267: MnO2
- C04B 2235/3272: Iron oxides or oxide forming salts thereof, e.g. hematite, magnetite
- C04B 2235/3275: Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite
- C04B 2235/3279: Nickel oxides, nickalates, or oxide-forming salts thereof
- C04B 2235/3281: Copper oxides, cuprates or oxide-forming salts thereof, e.g. CuO or Cu2O
- C04B 2235/3284: Zinc oxides, zincates, cadmium oxides, cadmiates, mercury oxides, mercurates or oxide forming salts thereof
- C04B 2235/3298: Bismuth oxides, bismuthates or oxide forming salts thereof, e.g. zinc bismuthate
- C04B 2235/449: Organic acids, e.g. EDTA, citrate, acetate, oxalate
- C04B 2235/5445: submicron sized, i.e. from 0,1 to 1 micron
- C04B 2235/656: characterised by specific heating conditions during heat treatment
- C04B 2235/6562: Heating rate
- C04B 2235/6565: Cooling rate
- C04B 2235/661: Multi-step sintering
- C04B 2235/765: Tetragonal symmetry
- C04B 2235/768: Perovskite structure ABO3
- C04B 2235/77: Density
- C04B 2235/783: Bimodal, multi-modal or multi-fractional
- C04B 2235/786: Micrometer sized grains, i.e. from 1 to 100 micron
- C04B 2235/79: Non-stoichiometric products, e.g. perovskites (ABO3) with an A/B-ratio other than 1
- Y10T 428/268: Monolayer with structurally defined element
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Piezoelectric materials having improved electrical properties, and manufacturing methods of the same, are provided. In (Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric materials, the surface microstructures of sintered bodies include microscopic grains having grain diameters of less than 5 μm, intermediate grains having grain diameters of 5 μm or more and less than 15 μm, and coarse grains having grain diameters of 15 μm or more and 100 μm or less.

## Claims

### Claim 1

An (Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric material containing Mn, wherein a surface microstructure of a sintered body of the (Li, Na, K, Bi) (Nb, Ta)O3 based piezoelectric material is constituted of microscopic grains having grain diameters of less than 5 μm, intermediate grains having grain diameters of 5 μm or more and less than 15 μm, and coarse grains having grain diameters of 15 μm or more and 100 μm or less, and wherein the surface microstructure of the sintered both includes 10 to 60% of the microscopic grains and 1% or more of the coarse grains in share of grains in terms of area.

### Claim 2 (depends on 1)

The (Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric material according to claim 1, which is represented by the following formula:
{Liy(Na1-xKx)1-y}1-tBit]a(Nb1-zTaz)O3,
wherein 1.00≦a≦1.10, 0.20≦x≦0.80, 0.02≦y≦0.20, 0.00≦z≦0.50, and 0.0000<t<0.0100.

### Claim 3 (depends on 1)

The (Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric material according to claim 1, which is represented by the following formula:
{Liy(Na1-xKx)1-y}a(Nb1-zTaz)O3+Bi2O3,
wherein 1.00≦a≦1.10, 0.20≦x≦0.80, 0.02≦y≦0.20, 0.00≦z≦0.50, and
wherein an amount of Bi2O3 added is larger than 0.00 mol % and smaller than 0.5 mol %.

### Claim 4 (depends on 1)

The (Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric material according to claim 1, wherein a ratio c/a obtained by diffraction angles which are middle points of full width at half maximum of diffraction line profiles is larger, and a temperature T(∈max) at which a dielectric constant is maximum shifts to a low temperature side, compared with a sintered body having the same constituent elements and the same composition ratio but which does not include the coarse grains having grain diameters of 15 μm or more and 100 μm or less.

### Claim 5 (depends on 2)

The (Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric material according to claim 2, wherein a ratio c/a obtained by diffraction angles which are middle points of full width at half maximum of diffraction line profiles is larger, and a temperature T(∈max) at which a dielectric constant is maximum shifts to a low temperature side, compared with a sintered body having the same constituent elements and the same composition ratio but which does not include the coarse grains having grain diameters of 15 μm or more and 100 μm or less.

### Claim 6 (depends on 3)

The (Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric material according to claim 3, wherein a ratio c/a obtained by diffraction angles which are middle points of full width at half maximum of diffraction line profiles is larger, and a temperature T(∈max) at which a dielectric constant is maximum shifts to a low temperature side, compared with a sintered body having the same constituent elements and the same composition ratio but which does not include the coarse grains having grain diameters of 15 μm or more and 100 μm or less.

### Claim 7 (depends on 1)

The (Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric material according to claim 1, which further contains at least one metal element selected from the group consisting of Cr, Fe, Co, Ni, Cu and Zn.

### Claim 8 (depends on 2)

The (Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric material according to claim 2, which further contains at least one metal element selected from the group consisting of Cr, Fe, Co, Ni, Cu and Zn.

### Claim 9 (depends on 3)

The (Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric material according to claim 3, which further contains at least one metal element selected from the group consisting of Cr, Fe, Co, Ni, Cu and Zn.

### Claim 10 (depends on 6)

The (Li, Na, K, Bi)(Nb, Ta)O3 based piezoelectric material according to claim 6, which further contains at least one metal element selected from the group consisting of Cr, Fe, Co, Ni, Cu and Zn.