Dielectric composition, dielectric element, electronic component and laminated electronic component

Patent metadata

Field	Value
Publication number	US-10475576-B2
Application number	US-201615745664-A
Country	US
Kind code	B2
Filing date	Jun 16, 2016
Priority date	Jul 17, 2015
Publication date	Nov 12, 2019
Grant date	Nov 12, 2019

Abstract

A dielectric composition, a dielectric element, an electronic component and a laminated electronic component are disclosed. In an embodiment the dielectric composition includes particles having a perovskite crystal structure including at least Bi, Na, Sr and Ti, wherein the content of the at least one element selected from La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Ba, Ca, Mg or Zn is between 0.5 molar parts and 11.1 molar parts, taking the Ti content of the dielectric composition as 100 molar parts, wherein 0.17≤α≤2.83, where α is the molar ratio of Bi with respect to Sr in the dielectric composition, and wherein at least some of the particles include a high-Bi phase having a Bi concentration of at least 1.2 times the mean Bi concentration of the dielectric composition as a whole.

First claim

The invention claimed is:

1. A dielectric composition comprising:
particles having a perovskite crystal structure including at least Bi, Na, Sr and Ti; and
at least one element selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Ba, Ca, Mg and Zn,
wherein a content of the at least one element selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Ba, Ca, Mg and Zn is between 0.5 molar parts and 11.1 molar parts, taking a Ti content of the dielectric composition as 100 molar parts,
wherein 0.17≤α≤2.83, where α is a molar ratio of Bi with respect to Sr in the dielectric composition,
wherein at least some of the particles include a high-Bi phase having a Bi concentration of at least 1.2 times a mean Bi concentration of the dielectric composition as a whole, and
wherein a total surface area of a high-Bi phase within the particles in a cross section of the dielectric composition is between 0.1% and 15% of a total surface area of the particles.

2. The dielectric composition according to claim 1 , wherein a total content of Bi included in the high-Bi phase within the particles is, as an atomic ratio, between 1.15 and 2.15 times a total content of Bi included in a portion within the particles outside the high-Bi phase.

3. A dielectric element comprising the dielectric composition according to claim 1 .

4. An electronic component comprising a dielectric layer including the dielectric composition according to claim 1 .

5. A laminated electronic component comprising:
a laminated portion formed by alternately laminating an internal electrode layer and a dielectric layer comprising the dielectric composition according to claim 1 .

6. A single-layer ceramic capacitor comprising:
a disc-shaped dielectric body comprising the dielectric composition according to claim 1 ; and
a pair of electrodes arranged on both surfaces of the dielectric body.

7. The single-layer ceramic capacitor according to claim 6 , wherein a material of the electrodes comprises Cu.

8. A laminated ceramic capacitor comprising the laminated electronic component according to claim 5 , wherein the internal electrode layers are stacked such that end surfaces thereof are alternately exposed at surfaces of two opposing ends of the laminated electronic component.

9. The laminated ceramic capacitor according to claim 8 , wherein the internal electrode layers comprise Cu or Cu alloy.

10. The laminated ceramic capacitor according to claim 8 , wherein a pair of external electrodes is arranged at both ends of the laminated electronic component, and wherein the pair of external electrodes is connected to exposed end surfaces of the internal electrode layers.

11. The laminated ceramic capacitor according to claim 10 , wherein the external electrodes comprise Cu.

12. A method for providing a laminated ceramic capacitor, the method comprising:
providing a dielectric starting material form powders of bismuth oxide (Bi 2 O 3 ), sodium carbonate (Na 2 CO 3 ), strontium carbonate (SrCO 3 ) and titanium oxide (TiO 2 );
preparing a green chip using a sheet method or a printing method employing a paste for dielectric layers and a paste for internal electrodes, wherein the paste for the dielectric layers is an organic paint comprising a mixture of the dielectric starting material and an organic vehicle or wherein the paste for the dielectric layers is an aqueous paint comprising a mixture of the dielectric starting material and an aqueous vehicle;
performing a debinding treatment of the green chip;
baking the green chip thereby forming a dielectric composition;
printing or transcribing external electrodes on the dielectric composition; and
baking the dielectric composition comprising a dielectric composition,
wherein the dielectric starting material is weighed out such that the dielectric composition comprises particles having a perovskite crystal structure including at least Bi, Na, Sr and Ti,
wherein the dielectric composition includes at least one element selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Ba, Ca, Mg and Zn,
wherein a content of the at least one element selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Ba, Ca, Mg and Zn is between 0.5 molar parts and 11.1 molar parts, taking a Ti content of the dielectric composition as 100 molar parts,
wherein 0.17≤α≤2.83, where α is a molar ratio of Bi with respect to Sr in the dielectric composition,
wherein at least some of the particles include a high-Bi phase having a Bi concentration of at least 1.2 times a mean Bi concentration of the dielectric composition as a whole, and
wherein a total surface area of the high-Bi phase within the particles in a cross section of the dielectric composition is between 0.1% and 15% of the total surface area of the particles.

13. The method according to claim 12 , further comprising:
preparing the paste for the internal electrodes by mixing a conductive material comprising metals such as Au, Pt, Ag, Ag—Pd alloy, Cu or Ni, or various types of oxide which form the conductive material after baking, organometallic compounds, or resinates with the organic vehicle; and
preparing a paste for the external electrodes in the same way as the paste for the internal electrodes.

14. The method according to claim 12 , wherein the dielectric starting material further comprises a powder from barium carbonate (BaCO 3 ), calcium carbonate (CaCO 3 ), magnesium carbonate (MgCO 3 ), zinc oxide (ZnO), lanthanum hydroxide (La(OH) 3 ), neodymium oxide (Nd 2 O 3 ), samarium oxide (Sm 2 O 3 ) or gadolinium oxide (Gd 2 O 3 ).

Assignees

• Tdk Electronics Ag

Inventors

• Hirose Masakazu
• Imura Tomoya
• Terada Tomohiro
• Tauchi Goushi

Classifications

• H01G4/1218 Primary

  based on titanium oxides or titanates (H01G4/1245 takes precedence) · CPC title

• H01G4/12

  Ceramic dielectrics {(H01G4/085 takes precedence)} · CPC title

• H01G4/30

  Stacked capacitors (H01G4/33 takes precedence) · CPC title

• C04B2235/3298

  Bismuth oxides, bismuthates or oxide forming salts thereof, e.g. zinc bismuthate · CPC title

• C04B2235/3213

  Strontium oxides or oxide-forming salts thereof · CPC title