# US 2017/0288129 A1 · Piezoelectric element

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- Number: US 2017/0288129 A1
- Document ID: US20170288129A1
- Status: Published application
- Kind: A1
- Application number: 15/472,615
- Filed: 2017-03-29
- Published: 2017-10-05
- Earliest claimed: 2016-03-30
- Assignees: NGK Insulators, Ltd.
- Applicants: Ngk Insulators, Ltd.
- Inventors: Masayuki UETANI; Tomohiko HIBINO; Akifumi MORISHITA
- Web page: https://patentgrep.com/patent/US20170288129A1

## CPC

- H10N 30/8554: {Lead-zirconium titanate [PZT] based}
- B32B 18/00: Layered products essentially comprising ceramics, e.g. refractory products
- C04B 35/491: based on lead zirconates and lead titanates {, e.g. PZT}
- H10N 30/871: {Single-layered electrodes of multilayer piezoelectric or electrostrictive devices, e.g. internal electrodes}
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3234: Titanates, not containing zirconia
- C04B 2235/3244: Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
- C04B 2235/3249: containing also titanium oxide or titanates, e.g. lead zirconate titanate (PZT)
- C04B 2235/3251: Niobium oxides, niobates, tantalum oxides, tantalates, or oxide-forming salts thereof
- C04B 2235/3262: Manganese oxides, manganates, rhenium oxides or oxide-forming salts thereof, e.g. MnO
- 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 2235/3296: Lead oxides, plumbates or oxide forming salts thereof, e.g. silver plumbate
- C04B 2235/3418: Silicon oxide, silicic acids or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
- C04B 2235/5445: submicron sized, i.e. from 0,1 to 1 micron
- C04B 2235/6025: Tape casting, e.g. with a doctor blade
- C04B 2235/75: Products with a concentration gradient
- C04B 2235/80: Phases present in the sintered or melt-cast ceramic products other than the main phase
- C04B 2235/85: Intergranular or grain boundary phases
- C04B 2235/96: Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
- C04B 2237/346: Titania or titanates
- C04B 2237/68: Forming laminates or joining articles wherein at least one substrate contains at least two different parts of macro-size, e.g. one ceramic substrate layer containing an embedded conductor or electrode
- H10N 30/20: with electrical input and mechanical output, e.g. functioning as actuators or vibrators
- H10N 30/30: with mechanical input and electrical output, e.g. functioning as generators or sensors
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- 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

## Abstract

A piezoelectric element includes a piezoelectric body having a main phase configured by lead zirconate titanate and a heterogenous phase configured by a different component to lead zirconate titanate, and a pair of electrodes provided on the piezoelectric body. The piezoelectric body has a surface region within 10 μm of a surface, and an inner region more than 10 μm from the surface. A surface area coverage of the heterogenous phase in a cross section of the surface region is at least 0.75% greater than a surface area coverage of the heterogenous phase in a cross section of the inner region.

## Claims

### Claim 1

A piezoelectric element comprising;
a piezoelectric body having a main phase configured by lead zirconate titanate and a heterogenous phase configured by a different component to lead zirconate titanate, and
a pair of electrodes provided on the piezoelectric body,
the piezoelectric body having a surface region within 10 μm of a surface, and an inner region more than 10 μm from the surface,
a surface area coverage of the heterogenous phase in a cross section of the surface region being at least 0.75% greater than a surface area coverage of the heterogenous phase in a cross section of the inner region.

### Claim 2 (depends on 1)

The piezoelectric element according to claim 1, wherein
the surface coverage of the heterogenous phase in a cross section of the surface region is greater than or equal to 1.6%, and
the surface coverage of the heterogenous phase in a cross section of the inner region is less than or equal to 1.3%.

### Claim 3 (depends on 1)

The piezoelectric element according to claim 1, wherein
an average particle diameter of lead zirconate titanate particles of the surface region is smaller than an average particle diameter of lead zirconate titanate particles of the inner region.

### Claim 4 (depends on 3)

The piezoelectric element according to claim 3, wherein
the average particle diameter of lead zirconate titanate particles of the surface region is less than or equal to 0.90 μm, and
the average particle diameter of lead zirconate titanate particles of the inner region is greater than or equal to 0.95 μm.

### Claim 5 (depends on 1)

The piezoelectric element according to claim 1, wherein
an average equivalent circle diameter of the heterogenous phase in a cross section of the surface region is greater than an average equivalent circle diameter of the heterogenous phase in a cross section of the inner region.

### Claim 6 (depends on 1)

The piezoelectric element according to claim 1, wherein
a number of the heterogenous phases in a cross section of the surface region is greater than a number of the heterogenous phases in a cross section of the inner region.