Thermistor sintered body and thermistor element

Patent metadata

Field	Value
Publication number	US-2019348201-A1
Application number	US-201816475944-A
Country	US
Kind code	A1
Filing date	Apr 27, 2018
Priority date	Jun 20, 2017
Publication date	Nov 14, 2019
Grant date	—

Abstract

A thermistor sintered body that can control a B constant at 1000° C. to the same level as that of a conventional wide range type. The thermistor sintered body according to the present invention has a composite structure that includes a Y 2 O 3 phase and a Y(Cr, Mn)O 3 phase or a YMnO 3 phase. In the thermistor sintered body according to one aspect of the present invention, a chemical composition of Cr, Mn, Ca and Y excluding oxygen is Cr: 3 to 9 mol %, Mn: 5 to 15 mol %, Ca: 1 to 8 mol % (where Cr/Mn<1.0), and the balance being unavoidable impurities and Y. In the thermistor sintered body, the B constant (B(0/1000)) determined by the following Expression (1) is 2400 K or lower; B=(ln Rm−ln Rn)/(1/Tm−1/Tn) . . . (1). Rm: resistance value at 0° C., Rn: resistance value at 1000° C., Tm: 0° C., and Tn: 1000° C.

First claim

1 . A thermistor sintered body comprising a sintered body that comprises a Y 2 O 3 phase and a Y(Cr, Mn)O 3 phase or a YMnO 3 phase, and is rich in Mn relative to Cr, wherein
a B constant (B(0/1000)) determined by the following expression is 2400 K or lower;
B =(ln Rm −ln Rn )/(1/ Tm− 1/ Tn ), wherein

Rm: resistance value at 0° C., Rn: resistance value at 1000° C., Tm: 0° C., and Tn: 1000° C.

2 . The thermistor sintered body according to claim 1 , wherein
the sintered body comprises the Y 2 O 3 phase and the Y(Cr, Mn)O 3 phase; and a chemical composition of Cr, Mn, Ca and Y excluding oxygen is Cr: 3 to 9 mol %, Mn: 5 to 15 mol %, Ca: 1 to 8 mol % (wherein Cr/Mn<1.0), and the balance being unavoidable impurities and Y, wherein Cr/Mn is 0.4 to 0.9.

3 . The thermistor sintered body according to claim 1 , wherein
the sintered body comprises the Y 2 O 3 phase and the Y(Cr, Mn)O 3 phase; and a chemical composition of Cr, Mn, Ca and Y excluding oxygen is Cr: mol % (excluding 0), Mn: 12 to 23 mol %, Ca: 6 to 18 mol %, and the balance being unavoidable impurities and Y, wherein Cr/Mn is 0.5 or smaller (excluding 0).

4 . The thermistor sintered body according to claim 1 , wherein
the sintered body comprises the Y 2 O 3 phase and a YMnO 3 phase; and a chemical composition of Mn, Ca and Y excluding oxygen is Mn: 12 to 18 mol %, Ca: 6 to 18 mol %, and the balance being unavoidable impurities and Y.

5 . The thermistor sintered body according to claim 1 , wherein
Ca dissolves in the Y(Cr, Mn)O 3 phase or in the YMnO 3 phase.

6 . The thermistor sintered body according to claim 1 , comprising a crystal structure of an orthorhombic crystal system.

7 . The thermistor sintered body according to claim 1 , wherein
a B constant (B(−40/25)) determined by the following expression is 2200 K or lower;
B =(ln Rm −ln Rn )/(1/ Tm− 1/ Tn ), wherein

Rm: resistance value at −40° C., Rn: resistance value at 25° C., Tm: −40° C., and Tn: 25° C.

8 . The thermistor sintered body according to claim 1 , wherein
a B constant (B(25/600)) determined by the following expression is 2300 K or lower;
B =(ln Rm −ln Rn )/(1/ Tm− 1/ Tn ), wherein

Rm: resistance value at 25° C., Rn: resistance value at 600° C., Tm: 25° C., and Tn: 600° C.

9 . The thermistor sintered body according to claim 1 , wherein
a B constant (B(600/1000)) determined by the following expression is 2800 K or lower;
B =(ln Rm −ln Rn )/(1/ Tm− 1/ Tn ), wherein

Rm: resistance value at 600° C., Rn: resistance value at 1000° C., Tm: 600° C., and Tn: 1000° C.

10 . The thermistor sintered body according to claim 1 , wherein
a resistance value at 1050° C. is 0.05 kΩ or larger.

11 . The thermistor sintered body according to claim 1 , wherein
a resistance value of 100 kΩ is exhibited at room temperature or lower.

12 . A thermistor element comprising:
a heat sensitive body; a pair of lead wires electrically connected to the heat sensitive body; and a covering layer covering the heat sensitive body, wherein the heat sensitive body comprises the thermistor sintered body according to claim 1 .

13 . A thermistor element comprising:
a heat sensitive body; a pair of lead wires electrically connected to the heat sensitive body; and a covering layer covering the heat sensitive body, wherein the heat sensitive body comprises the thermistor sintered body according to claim 2 .

14 . A thermistor element comprising:
a heat sensitive body; a pair of lead wires electrically connected to the heat sensitive body; and a covering layer covering the heat sensitive body, wherein the heat sensitive body comprises the thermistor sintered body according to claim 3 .

15 . A thermistor element comprising:
a heat sensitive body; a pair of lead wires electrically connected to the heat sensitive body; and a covering layer covering the heat sensitive body, wherein the heat sensitive body comprises the thermistor sintered body according to claim 4 .

16 . A thermistor element comprising:
a heat sensitive body; a pair of lead wires electrically connected to the heat sensitive body; and a covering layer covering the heat sensitive body, wherein the heat sensitive body comprises the thermistor sintered body according to claim 5 .

17 . A thermistor element comprising:
a heat sensitive body; a pair of lead wires electrically connected to the heat sensitive body; and a covering layer covering the heat sensitive body, wherein the heat sensitive body comprises the thermistor sintered body according to claim 6 .

18 . A thermistor element comprising:
a heat sensitive body; a pair of lead wires electrically connected to the heat sensitive body; and a covering layer covering the heat sensitive body, wherein the heat sensitive body comprises the thermistor sintered body according to claim 7 .

19 . A thermistor element comprising:
a heat sensitive body; a pair of lead wires electrically connected to the heat sensitive body; and a covering layer covering the heat sensitive body, wherein the heat sensitive body comprises the thermistor sintered body according to claim 10 .

20 . A thermistor element comprising:
a heat sensitive body; a pair of lead wires electrically connected to the heat sensitive body; and a covering layer covering the heat sensitive body, wherein the heat sensitive body comprises the thermistor sintered body according to claim 11 .

Assignees

• Shibaura Electronics Co Ltd

Inventors

• Takeuchi Akitaka
• Niizeki Naohiro

Classifications

• H01C7/06

  including means to minimise changes in resistance with changes in temperature · CPC title

• H01C17/06533

  composed of oxides · CPC title

• H01C7/008

  Thermistors (H01C7/02 - H01C7/06 take precedence) · CPC title

• C04B2235/5436

  micrometer sized, i.e. from 1 to 100 micron · CPC title

• C04B2235/661

  Multi-step sintering · CPC title