Sintered electrically conductive oxide, thermistor element employing the oxide, and temperature sensor employing the thermistor

• US 9,790,098 B2
• Filed: 04/05/2016
• Issued: 10/17/2017
• Est. Priority Date: 04/06/2015
• Status: Active Grant

• Current Assignee: Niterra Co., Ltd.
• Original Assignee: NGK Spark PLUG Company Limited (Niterra Co., Ltd.)
• Inventors: Watanabe, Hiroshi, Ban, Shinji, Yamaguchi, Tomoki, Okimura, Yasuyuki, Nishi, Tomohiro
• Primary Examiner(s): KOPEC, MARK T
• Application Number:
  US15/090,783
• Publication Number:
  US 20160289083A1
• Time in Patent Office: 560 Days
• CPC Class Codes: C01G 37/006 Compounds containing, besides chromium, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: C04B 2235/3205 Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• CPC Class Codes: C04B 2235/3213 Strontium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3225 Yttrium oxide or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3241 Chromium oxides, chromates, or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3262 Manganese oxides, manganates, rhenium oxides or oxide-forming salts thereof, e.g. MnO
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/602 Making the green bodies or pre-forms by moulding
• CPC Class Codes: C04B 2235/604 Pressing at temperatures other than sintering temperatures
• CPC Class Codes: C04B 2235/768 Perovskite structure ABO3
• CPC Class Codes: C04B 35/12 based on chromium oxide C04B35/047 and C04B35/105 take precedence
• CPC Class Codes: G01K 7/22 the element being a non-linear resistance, e.g. thermistor G01K7/26 takes precedence
• CPC Class Codes: G05D 23/24 the sensing element having a resistance varying with temperature, e.g. a thermistor
• CPC Class Codes: H01B 1/08 oxides
• CPC Class Codes: H01C 7/008 : Thermistors H01C7/02 - H01C7/06 take precedence

Abstract

A sintered electroconductive oxide having a perovskite oxide type crystal structure represented by a compositional formula: M1_aM2_bMn_cAl_dCr_eO_f wherein M1 represents at least one element selected from group 3 elements; and M2 represents at least one element selected from among Mg, Ca, Sr and Ba, wherein element M1 predominantly includes at least one element selected from Nd, Pr and Sm, and a, b, c, d, e and f satisfy the following relationships: 0.6005≦a<1.000, 0<b≦0.400, 0≦c<0.150, 0.400≦d<0.950, 0.050<e≦0.600, 0.50<e/(c+e)≦1.00, and 2.80≦f≦3.30. Also disclosed is a thermistor element including a thermistor portion which is formed of the sintered electroconductive oxide as well as a temperature sensor employing the thermistor element.

Claims

1. A sintered electroconductive oxide having a perovskite oxide type crystal structure represented by a compositional formula:

M1_aM2_bMn_cAl_dCr_eO_f wherein M1 represents at least one element selected from group 3 elements; and

M2 represents at least one element selected from the group consisting of Mg, Ca, Sr and Ba, wherein element M1 predominantly includes at least one element selected from the group consisting of Nd, Pr and Sm, and a, b, c, d, e and f satisfy the following relationships;

0.600≦

a<

1.000,

0<

b≦

0.400,

0≦

c<

0.150,

0.400≦

d<

0.950,

0.050<

e≦

0.600,

0.50<

e/(c+e)≦

1.00, and

2.80≦

f≦

3.30.

2. The sintered electroconductive oxide as claimed in claim 1, wherein c and e satisfy 0.65≦

e/(c+e)≦

1.00.

3. The sintered electroconductive oxide as claimed in claim 1, wherein a, b, c d, e and f satisfy the following relationships:

0.700≦

a<

1.000,

0<

b≦

0.300,

0≦

c<

0.140,

0.500<

d<

0.950,

0.050<

e≦

0.500,

0.65<

e/(c+e)≦

1.00, and

2.80≦

f≦

3.30.

4. The sintered electroconductive oxide as claimed in claim 1, wherein M1 is at least one element selected from the group consisting of Nd, Pr and Sm, and M2 is at least one element selected from the group consisting of Ca and Sr.

5. A thermistor element comprising a thermistor portion which is formed of the sintered electroconductive oxide as claimed in claim 1.

6. A temperature sensor comprising the thermistor element as claimed in claim 5.