Semiconductor ceramic composition and PTC thermistor

Patent metadata

Field	Value
Publication number	US-10014097-B2
Application number	US-201615222050-A
Country	US
Kind code	B2
Filing date	Jul 28, 2016
Priority date	Aug 4, 2015
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

A semiconductor ceramic composition including a compound represented by the following general formula (1) as a main component.

(Ba v Bi x A y RE w ) m (Ti u TM z )O 3   (1)

(wherein, A represents both elements of Na and K; RE is at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Gd, Dy and Er; and TM is at least one element selected from the group consisting of V, Nb and Ta.)

0.01≤x≤0.15  (2)

x≤y≤0.3  (3)

0≤( w+z )≤0.01  (4)

v+x+y+w=1   (5)

u+z=1   (6)

0.950≤m≤1.050  (7)

further, 0.001 mol to 0.055 mol of Ca is included and the ratio of Na/(Na+K) is 0.1 or more and less than 1.

First claim

What is claimed is:

1. A semiconductor ceramic composition comprising:
Ca in a proportion of 0.001 mol or more and 0.055 mol or less in terms of element relative to 1 mol of Ti site, and
a sintered compact containing a BaTiO 3 based compound represented by the following general formula (1) as a main component,
(Ba v Bi x A y RE w ) m (Ti u TM z )O 3   (1)

where:
A contains both elements of Na and K;
RE is at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Gd, Dy, and Er;
TM is at least one element selected from the group consisting of V, Nb, and Ta; and
w, x, y, z and m satisfy the following formulas (2) through (7),
0.01≤x≤0.15  (2)

x≤y≤0.3  (3)

0≤( w+z )≤0.01  (4)

v+x+y+w= 1  (5)

u+z= 1  (6)

0.950≤m≤1.050  (7)

wherein
Ti site represents a total number of moles of Ti and TM; and
a ratio of Na/(Na+K) is 0.1 or more and 0.5 or less.

2. The semiconductor ceramic composition according to claim 1 , further comprising Si in a proportion of 0.035 mol or less in terms of element relative to 1 mol of Ti site.

3. The semiconductor ceramic composition according to claim 1 , further comprising Mn in a proportion of 0.0015 mol or less in terms of element relative to 1 mol of Ti site.

4. A PTC thermistor comprising:
a ceramic body formed from the semiconductor ceramic composition according claim 1 ; and
electrodes formed on the surfaces of the ceramic body.

5. The semiconductor ceramic composition according to claim 2 , further comprising Mn in a proportion of 0.0015 mol or less in terms of element relative to 1 mol of Ti site.

6. A PTC thermistor comprising:
a ceramic body formed from the semiconductor ceramic composition according to claim 2 ; and
electrodes formed on the surfaces of the ceramic body.

7. A PTC thermistor comprising:
a ceramic body formed from the semiconductor ceramic composition according to claim 3 ; and
electrodes formed on the surfaces of the ceramic body.

8. A PTC thermistor comprising:
a ceramic body formed from the semiconductor ceramic composition according to claim 5 ; and
electrodes formed on the surfaces of the ceramic body.

Assignees

• Tdk Corp

Inventors

• Fujita Kazutaka
• Itoh Kazuhiko
• Shimura Yoshikazu

Classifications

• H01C7/026

  Vanadium oxides or oxidic compounds, e.g. VOx · CPC title

• H01C7/025 Primary

  Perovskites, e.g. titanates · CPC title

• C04B2235/3251

  Niobium oxides, niobates, tantalum oxides, tantalates, or oxide-forming salts thereof · CPC title

• C04B2235/9607

  Thermal properties, e.g. thermal expansion coefficient · CPC title

• C04B35/468 Primary

  based on barium titanates · CPC title