Semiconductor ceramic composition and ptc thermistor

Patent metadata

Field	Value
Publication number	US-2017226018-A1
Application number	US-201715422087-A
Country	US
Kind code	A1
Filing date	Feb 1, 2017
Priority date	Feb 8, 2016
Publication date	Aug 10, 2017
Grant date	—

Abstract

A semiconductor ceramic composition represented by formula (1),
(Ba v Bi x A y RE w ) m (Ti u TM z )O 3   (1),

wherein, A represents at least one element selected from Na and K, RE represents at least one element selected from Y, La, Ce, Pr, Nd, Sm, Gd, Dy and Er;
0.750 y≦x ≦1.50 y   (2),

0.007≦ y ≦0.125  (3),

0≦( w+z )≦0.010  (4),

v+x+y+w =1  (5),

u+z =1  (6),

0.950≦ m ≦1.050  (7),

0.001 to 0.055 mol of Ca is contained, and 0.0005 to 0.005 mol of at least one selected from Mg, Al, Fe, Co, Cu and Zn is contained.

First claim

1 . A semiconductor ceramic composition represented by the following formula (1),
(Ba v Bi x A y RE w ) m (Ti u TM z )O 3   (1)
wherein, in the formula (1), A represents at least one element selected from the group consisting of Na and K, RE represents at least one element selected from the group consisting of Y, La, Ce, Pr, Nd, Sm, Gd, Dy and Er, TM represents at least one element selected from the group consisting of V, Nb and Ta,
u, v, w, x, y, z and m satisfy the following formulas (2) to (7),
0.750 y≦x≦ 1.50 y   (2)

0.007≦ y≦ 0.125  (3)

0≦( w+z )≦0.010  (4)

v+x+y+w= 1  (5)

u+z= 1  (6)

0.950≦ m≦ 1.050  (7)

Ca is further contained in a ratio of 0.001 mol or more and 0.055 mol or less relative to 1 mol of Ti site in terms of element; and an additive M is contained in a ratio of 0.0005 mol or more and 0.005 mol or less in terms of element, wherein, the Ti site is the total molar number of Ti and TM, and M is at least one selected from Mg, Al, Fe, Co, Cu and Zn.

2 . The semiconductor ceramic composition of claim 1 , wherein, Si is further contained in the semiconductor ceramic composition in a ratio of 0.035 mol or less relative to 1 mol of Ti site in terms of element, wherein, the Ti site is the total molar number of Ti and TM.

3 . The semiconductor ceramic composition of claim 1 , wherein,
Mn is further contained in the semiconductor ceramic composition in a ratio of 0.0015 mol or less relative to 1 mol of Ti site in terms of element, wherein, the Ti site is the total molar number of Ti and TM.

4 . A PTC thermistor comprising a ceramic body and electrodes formed on two main faces of the ceramic body, wherein,
the ceramic body is formed by using the semiconductor ceramic composition of claim 1 .

5 . The semiconductor ceramic composition of claim 2 , wherein,
Mn is further contained in the semiconductor ceramic composition in a ratio of 0.0015 mol or less relative to 1 mol of Ti site in terms of element, wherein, the Ti site is the total molar number of Ti and TM.

6 . A PTC thermistor comprising a ceramic body and electrodes formed on two main faces of the ceramic body, wherein,
the ceramic body is formed by using the semiconductor ceramic composition of claim 2 .

7 . A PTC thermistor comprising a ceramic body and electrodes formed on two main faces of the ceramic body, wherein,
the ceramic body is formed by using the semiconductor ceramic composition of claim 3 .

8 . A PTC thermistor comprising a ceramic body and electrodes formed on two main faces of the ceramic body, wherein,
the ceramic body is formed by using the semiconductor ceramic composition of claim 5 .

Assignees

• Tdk Corp

Inventors

• Fujita Kazutaka
• Itoh Kazuhiko
• Shimura Yoshikazu
• Morikoshi Hiroki
• Terada Tomohiro

Classifications

• C04B2235/3201

  Alkali metal oxides or oxide-forming salts thereof · CPC title

• C04B2235/3255

  Niobates or tantalates, e.g. silver niobate · CPC title

• C04B2235/3215

  Barium oxides or oxide-forming salts thereof · CPC title

• C04B2235/3225

  Yttrium oxide or oxide-forming salts thereof · CPC title

• C04B2235/3427

  Silicates other than clay, e.g. water glass · CPC title