Multilayer ceramic capacitor

Patent metadata

Field	Value
Publication number	US-9570235-B2
Application number	US-201514983859-A
Country	US
Kind code	B2
Filing date	Dec 30, 2015
Priority date	Jul 9, 2013
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

A multilayer ceramic capacitor that is highly resistant to insulation degradation under high-temperature load includes an inner ceramic layer that has a composition mainly composed of a perovskite-type compound containing Ba and Ti, at least one of Nb and Ta, contains Mn and Al, and optionally contains Mg and a rare-earth element that is at least one of Y, Gd, Tb, Dy, Ho, and Er, with a content of Ti being 100 parts by mole, and (a) a total of Nb and Ta is from about 0.2 to about 1.5 part by mole, (b) Mg is not more than about 0.2 part by mole including 0 part by mole, (c) Mn is from about 1.0 to about 3.5 parts by mole, (d) Al is from about 1.0 to about 4.0 parts by mole, and (e) the rare-earth element is not more than about 0.05 part by mole including 0 part by mole. Furthermore, an average number of particles per one layer of the inner ceramic layer is not more than 3.

First claim

What is claimed is:

1. A multilayer ceramic capacitor, comprising:
a multilayer body including a plurality of dielectric ceramic layers and a plurality of internal electrodes along an interface between the dielectric ceramic layers; and
a plurality of external electrodes on an outer surface of the multilayer body and electrically connected to the internal electrodes; wherein
each of the dielectric ceramic layers is mainly composed of a perovskite-type compound containing Ba and Ti, contains at least one of Nb and Ta, contains Mn and Al, and optionally contains Mg and a rare-earth element that is at least one of Y, Gd, Tb, Dy, Ho, and Er, with a content of Ti being 100 parts by mole; and
(a) a total of Nb and Ta is from about 0.2 to about 1.5 part by mole;
(b) Mg is not more than about 0.2 part by mole including 0 part by mole;
(c) Mn is from about 1.0 to about 3.5 parts by mole;
(d) Al is from about 1.0 to about 4.0 parts by mole; and
(e) the rare-earth element is not more than about 0.05 part by mole including 0 part by mole; and
an average number of particles per one layer of the dielectric ceramic layer is not more than 3.

2. The multilayer ceramic capacitor according to claim 1 , wherein the multilayer body has a parallelepiped or substantially parallelepiped shape.

3. The multilayer ceramic capacitor according to claim 1 , wherein the plurality of dielectric layers include a plurality of inner dielectric layers and a plurality of outer dielectric layers disposed at outer portions of the multilayer body and sandwich the plurality of inner dielectric layers.

4. The multilayer ceramic capacitor according to claim 3 , wherein the plurality of outer ceramic layers are composed of a dielectric ceramic composition that is the same as that of the plurality of inner ceramic layers.

5. The multilayer ceramic capacitor according to claim 3 , wherein the plurality of outer ceramic layers are composed of a dielectric ceramic composition that is different from that of the plurality of inner ceramic layers.

Assignees

• Murata Manufacturing Co

Inventors

• Okamoto Takafumi

Classifications

• C04B2235/6582

  Hydrogen containing atmosphere · CPC title

• C04B35/4682

  based on BaTiO3 perovskite phase · CPC title

• C04B2235/3262

  Manganese oxides, manganates, rhenium oxides or oxide-forming salts thereof, e.g. MnO · CPC title

• B32B18/00

  Layered products essentially comprising ceramics, e.g. refractory products · CPC title

• C04B2235/3206

  Magnesium oxides or oxide-forming salts thereof · CPC title