EP0694930A1 - Thermistor mit positiver charakteristik - Google Patents

Thermistor mit positiver charakteristik Download PDF

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Publication number
EP0694930A1
EP0694930A1 EP94912679A EP94912679A EP0694930A1 EP 0694930 A1 EP0694930 A1 EP 0694930A1 EP 94912679 A EP94912679 A EP 94912679A EP 94912679 A EP94912679 A EP 94912679A EP 0694930 A1 EP0694930 A1 EP 0694930A1
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EP
European Patent Office
Prior art keywords
thermistor
temperature coefficient
composition
positive temperature
main body
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP94912679A
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English (en)
French (fr)
Other versions
EP0694930A4 (de
Inventor
Hiroshi Kabushiki Kaisha Komatsu Sasaki
Hiroshi Kabushiki Kaisha Komatsu Inagaki
Takuji Kabushiki Kaisha Komatsu Okumura
Masatoshi Kabushiki Kaisha Komatsu Tamura
Katsuhiko Kabushiki Kaisha Komatsu Sugisawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Komatsu Ltd
Original Assignee
Komatsu Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP8754993A external-priority patent/JPH06302402A/ja
Priority claimed from JP5281352A external-priority patent/JPH06349604A/ja
Application filed by Komatsu Ltd filed Critical Komatsu Ltd
Publication of EP0694930A1 publication Critical patent/EP0694930A1/de
Publication of EP0694930A4 publication Critical patent/EP0694930A4/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
    • H01C7/022—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient mainly consisting of non-metallic substances
    • H01C7/023—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient mainly consisting of non-metallic substances containing oxides or oxidic compounds, e.g. ferrites
    • H01C7/025—Perovskites, e.g. titanates

Definitions

  • Ceramics consisting of a BaTiO3 based perovskite type of compound generally has characteristics that are useful for electrical purposes, such as dielectric characteristics, piezoelectric characteristics, pyroelectric characteristics, and abnormal resistivity, and is widely used in a variety of electronic devices.
  • oxide semiconductors in which 0.1 to 0.3 at% Y, Nd, or the like has been added to BaTiO3 have a high positive temperature coefficient and are thus referred to as positive temperature coefficient thermistors.
  • Such positive temperature coefficient thermistors allow temperature regions having a high positive temperature coefficient to be adjusted with the addition of Sr, Pb, or the like, they have come to be regarded as essential in a wide variety of fields, such as low temperature heaters and circuit elements for degaussing color televisions, starting motors, preventing excess current, and measuring temperatures.
  • composition and manufacturing method must be adjusted so that, as shown in Figure 3, the specific resistance at room temperature (hereinafter ⁇ 25), the resistance-temperature coefficient (hereinafter ⁇ ), and the resistance variation (hereinafter J) are compatible with the intended purpose during actual use.
  • a low specific resistance ⁇ 25 at room temperature, a high resistance-temperature coefficient ⁇ , and a high resistance variation J are required, however, when BaTiO3 based positive temperature coefficient thermistors are actually used, but there is a positive correlation between the ⁇ 25 and ⁇ , and despite efforts to obtain a thermistor with a low ⁇ 25 and high ⁇ , the value ( ⁇ /log ⁇ 25) has been limited to around 10.
  • the aforementioned conventional positive temperature coefficient thermistors suffer from drawbacks in that the material must contain Pb, which has a high vapor pressure, so that when sintered at 1000°C or higher, large amounts of Pb vapor are produced, which is extremely harmful to the environment.
  • a first object of the present invention is to provide a thermistor having the stable characteristics of a low specific resistance ⁇ 25 at room temperature and a substantial resistance-temperature coefficient ⁇ .
  • a second object of the present invention is to provide a positive temperature coefficient thermistor that consumes low levels of electrical power, that does not produce Pb vapor, and that is highly reliable.
  • the present invention is characterized in that the amount of Ti is lower than the stoichiometric ratio in the composition of the semiconductor constituting the main body of the thermistor, which is a BaTiO3 based perovskite type of compound, a composition in which an excess amount of Ti has been preferred.
  • thermistor main body consisting of a barium titanate-based semiconductor formed in such a way that the following formula is satisfied, and electrodes for providing electricity, which are attached to the thermistor main body.
  • S at least one element selected from Sr, Sn, Zr, Ca
  • Pb M at least one element selected from Nb, Ta, Bi, Sb, Y, La, Nd, W, Th, Ce, Sm, Gd
  • Dy A at least one element selected from Mn, Fe, Cu, Cr, F, Cl, Br, K, and V
  • the element S in the composition primarily functions to control the Curie temperature
  • the element M primarily functions in fashioning a semiconductor of the composition
  • the element A is believed to control the surface level of the grain boundary.
  • the present invention is characterized in that the composition of the semiconductor constituting the thermistor main body is composed of the following barium titanate-calcium titanate-based semiconductor.
  • the mixed solution was added in the form of drops over 4 hours to 1440 g of a 16.7 wt% H2C2O4 (oxalic acid) aqueous solution (H2C2O4:1.902 mol) maintained at 75°C ⁇ 0.5°C to obtain an oxalate comprising (BaSrY) TiO (C2O4)2 ⁇ 4H2O in the form of a coprecipitate.
  • composition for a thermistor main body 1 was prepared as shown by the following formula. (Ba 0.7744 Sr 0.2217 Y 0.0039 )Ti 0.9961 O3 + 0.001 Mn (formula) A process for manufacturing this positive temperature coefficient thermistor is described below.
  • composition for a thermistor main body 1 was prepared as shown by the following formula. (Ba 0.7731 Sr 0.2228 Y 0.0041 )Ti 0.9964 O3 + 0.001 Mn (formula)
  • a thermistor element of this composition was manufactured by the same method as in Practical Example 2, and the characteristics were measured, the results of which are shown in Table 1.
  • composition for a thermistor main body 1 was prepared as shown by the following formula. (Ba 0.7707 Sr 0.2254 Y 0.0039 )Ti 0.9972 O3 + 0.001 Mn (formula)
  • a thermistor element of this composition was manufactured by the same method as in Practical Examples 2 and 3. The results are shown in Table 1.
  • composition for a thermistor main body 1 was prepared as shown by the following formula as a comparative example. (Ba 0.7778 Sr 0.2180 Y 0.0042 )Ti 1.0033 O3 + 0.001 Mn (formula) This composition was outside the upper limits of the compositional range for Ti.
  • the positive temperature coefficient thermistor was then manufactured in the same manner as in Practical Example 1 except for the use of an H2C2O4 (oxalic acid) aqueous solution maintained at 70°C ⁇ 0.5°C.
  • H2C2O4 oxalic acid
  • the present invention thus allows a better positive temperature coefficient thermistor with a low ⁇ 25 and a high ⁇ to be obtained.
  • Figure 4 depicts a practical example of a positive temperature coefficient thermistor in the present invention.
  • This positive temperature coefficient thermistor is characterized by comprising the following barium titanate-calcium titanate-based semiconductor, wherein the composition of the thermistor main body 1S has the compositional ratio shown in the following table. (Ba 1-x-y Ca x Y y ) Ti (1+z) O3+pSiO2 + qM 0.01 ⁇ x ⁇ 0.2, 0.002 ⁇ y ⁇ 0.006, 0.001 ⁇ z ⁇ 0.010, 0.005 ⁇ p ⁇ 0.03, 0.0005 ⁇ q ⁇ 0.0015 (formula) Table 2 Compo sition No.
  • the positive temperature coefficient thermistor comprises a thermistor main body 1S of the composition described above consisting primarily of barium titanate; first electrode layers 2a and 2b consisting of Ni vapor deposited layers formed on the top and bottom of the main body in such a way that the edges are somewhat short of the outer circumferential edge of the main body; and second electrode layers 3a and 3b consisting primarily of silver and formed as the upper layer on the first electrode layers 2a and 2b so that the edges are flush with those of the first electrode layers.
  • a method for manufacturing the positive temperature coefficient thermistor is described below.
  • the power consumption was measured using the measuring circuit shown in Figure 5.
  • the positive temperature coefficient thermistor 10 was connected via load resistance 11 to a power source 12, this connection could be turned on and off by a switch 13, the voltage across the both ends of the positive temperature coefficient thermistor 10 was measured by a voltmeter 14 connected in parallel to the positive temperature coefficient thermistor 10, and the current flowing to the positive temperature coefficient thermistor was measured by an ampere meter 15 connected in series with the positive temperature coefficient thermistor 10. In this way, the voltage across the both ends of the positive temperature coefficient thermistor 10 and the current flowing through the positive temperature coefficient thermistor 10 were measured to calculate the power consumption.
  • the power consumption P (W) was determined by the following equation.
  • P (W) V p (v) ⁇ I (A)
  • Composition Nos. 1 through 5, 8, and 9 indicate the present invention, while Compositions Nos. 6, 7, 10, and 11 indicate comparative examples.
  • a comparison of Composition Nos. 1 through 5 with 6 and 7 reveals that an excess amount of TiO2 between 0.001 to 0.01 mol (total amount of TiO2 100.1 to 101.0 mol) results in a low power consumption equal to or lower than the power consumption of conventional Composition No. 11 containing Pb (3.0 W). An excess amount of Ti of 0.001 mol or less and 0.01 mol or more results in a power consumption of 3.0 W or more.
  • the first of the present inventions allows a positive temperature coefficient thermistor with a low ⁇ 25 and substantial ⁇ to be obtained because the amount of Ti in the composition of the BaTiO3 based perovskite type of compound constituting the main body of the thermistor is lower than the stoichiometric ratio.
  • the second of the present inventions makes it possible to provide a positive temperature coefficient thermistor that has low power consumption during the application of electricity and that does not produce Pb vapor when fired because the composition of the semiconductor constituting the thermistor main body comprises a barium titanate-calcium titanate-based semiconductor containing no Pb.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Ceramic Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Thermistors And Varistors (AREA)
EP94912679A 1993-04-14 1994-04-14 Thermistor mit positiver charakteristik Withdrawn EP0694930A4 (de)

Applications Claiming Priority (7)

Application Number Priority Date Filing Date Title
JP8755093 1993-04-14
JP87550/93 1993-04-14
JP8754993A JPH06302402A (ja) 1993-04-14 1993-04-14 正特性サーミスタ
JP87549/93 1993-04-14
JP5281352A JPH06349604A (ja) 1993-04-14 1993-11-10 正特性サーミスタ
JP281352/93 1993-11-10
PCT/JP1994/000622 WO1994024680A1 (en) 1993-04-14 1994-04-14 Positive characteristic thermistor

Publications (2)

Publication Number Publication Date
EP0694930A1 true EP0694930A1 (de) 1996-01-31
EP0694930A4 EP0694930A4 (de) 1997-04-09

Family

ID=27305540

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94912679A Withdrawn EP0694930A4 (de) 1993-04-14 1994-04-14 Thermistor mit positiver charakteristik

Country Status (3)

Country Link
EP (1) EP0694930A4 (de)
KR (1) KR960701453A (de)
WO (1) WO1994024680A1 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0937692A1 (de) * 1997-09-05 1999-08-25 TDK Corporation Halbleiterkeramik auf der basis von bariumtitanat
EP0961299A1 (de) * 1997-09-05 1999-12-01 TDK Corporation Verfahren zur herstellung von ptc-halbleiterkeramiken
FR2792933A1 (fr) * 1999-04-28 2000-11-03 Murata Manufacturing Co Ceramique semiconductrice, element en ceramique semiconductrice et element de protection de circuits
EP1058276A2 (de) * 1999-06-03 2000-12-06 Matsushita Electric Industrial Co., Ltd. Dünnschichtthermistor und Herstellungsverfahren
DE10026261A1 (de) * 2000-05-26 2001-12-06 Epcos Ag Keramisches Material, Verfahren zu dessen Herstellung, Bauelement mit dem keramischen Material und Verwendung des Bauelements
DE10061458B4 (de) * 2000-12-09 2005-12-15 Eichenauer Heizelemente Gmbh & Co. Kg Verfahren und Vorrichtung zum Regeln einer Kfz-Zusatzheizung

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4175060A (en) * 1977-11-25 1979-11-20 Bell Telephone Laboratories, Incorporated Composition and processing procedure for making thermistors
EP0454857A1 (de) * 1989-11-13 1991-11-06 Nkk Corporation Kleiner gleichstrommotor

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS525998B2 (de) * 1972-03-28 1977-02-18
JPS5410110B2 (de) * 1974-03-20 1979-05-01
JPH02192456A (ja) * 1989-01-21 1990-07-30 Chichibu Cement Co Ltd 半導体磁器
JPH05251203A (ja) * 1992-03-04 1993-09-28 Chichibu Cement Co Ltd 半導体磁器組成物
JPH0613203A (ja) * 1992-06-25 1994-01-21 Murata Mfg Co Ltd 半導体セラミック素子の製造方法
JPH0684605A (ja) * 1992-08-31 1994-03-25 Shinagawa Refract Co Ltd 正特性サーミスタ及びその製造方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4175060A (en) * 1977-11-25 1979-11-20 Bell Telephone Laboratories, Incorporated Composition and processing procedure for making thermistors
EP0454857A1 (de) * 1989-11-13 1991-11-06 Nkk Corporation Kleiner gleichstrommotor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO9424680A1 *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0937692A1 (de) * 1997-09-05 1999-08-25 TDK Corporation Halbleiterkeramik auf der basis von bariumtitanat
EP0961299A1 (de) * 1997-09-05 1999-12-01 TDK Corporation Verfahren zur herstellung von ptc-halbleiterkeramiken
EP0961299A4 (de) * 1997-09-05 2000-07-05 Tdk Corp Verfahren zur herstellung von ptc-halbleiterkeramiken
US6221800B1 (en) 1997-09-05 2001-04-24 Tdk Corporation Method of producing PTC semiconducting ceramic
EP0937692A4 (de) * 1997-09-05 2003-05-14 Tdk Corp Halbleiterkeramik auf der basis von bariumtitanat
FR2792933A1 (fr) * 1999-04-28 2000-11-03 Murata Manufacturing Co Ceramique semiconductrice, element en ceramique semiconductrice et element de protection de circuits
EP1058276A2 (de) * 1999-06-03 2000-12-06 Matsushita Electric Industrial Co., Ltd. Dünnschichtthermistor und Herstellungsverfahren
EP1058276A3 (de) * 1999-06-03 2004-01-28 Matsushita Electric Industrial Co., Ltd. Dünnschichtthermistor und Herstellungsverfahren
DE10026261A1 (de) * 2000-05-26 2001-12-06 Epcos Ag Keramisches Material, Verfahren zu dessen Herstellung, Bauelement mit dem keramischen Material und Verwendung des Bauelements
DE10061458B4 (de) * 2000-12-09 2005-12-15 Eichenauer Heizelemente Gmbh & Co. Kg Verfahren und Vorrichtung zum Regeln einer Kfz-Zusatzheizung

Also Published As

Publication number Publication date
EP0694930A4 (de) 1997-04-09
WO1994024680A1 (en) 1994-10-27
KR960701453A (ko) 1996-02-24

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