US2862891A - Sintered electrical resistor - Google Patents

Sintered electrical resistor Download PDF

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Publication number
US2862891A
US2862891A US518388A US51838855A US2862891A US 2862891 A US2862891 A US 2862891A US 518388 A US518388 A US 518388A US 51838855 A US51838855 A US 51838855A US 2862891 A US2862891 A US 2862891A
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Prior art keywords
trivalent
metal ion
group
tetravalent
ion selected
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US518388A
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Jonker Gerard Heinrich
Gerard Willem Van Oosterhout
Jan Heinrik Van Santen
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US Philips Corp
North American Philips Co Inc
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US Philips Corp
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/26—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on ferrites
    • C04B35/2608—Compositions containing one or more ferrites of the group comprising manganese, zinc, nickel, copper or cobalt and one or more ferrites of the group comprising rare earth metals, alkali metals, alkaline earth metals or lead
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/26—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on ferrites
    • C04B35/2608—Compositions containing one or more ferrites of the group comprising manganese, zinc, nickel, copper or cobalt and one or more ferrites of the group comprising rare earth metals, alkali metals, alkaline earth metals or lead
    • C04B35/2616—Compositions containing one or more ferrites of the group comprising manganese, zinc, nickel, copper or cobalt and one or more ferrites of the group comprising rare earth metals, alkali metals, alkaline earth metals or lead containing lithium
    • 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
    • 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
    • H01C7/001—Mass resistors
    • 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
    • H01C7/04—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 negative temperature coefficient
    • H01C7/042—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 negative temperature coefficient mainly consisting of inorganic non-metallic substances
    • H01C7/043—Oxides or oxidic compounds
    • H01C7/045—Perovskites, e.g. titanates

Definitions

  • the invention relates to a sintered, electrical resistor substantially consisting of a phase of oxidic compounds with perovskite structure, containing Fe and/or Cr or else Co and Fe and/or Cr, in which at least one of the metals Fe, Cr and Co occurs in the trivalent and the tetravalent form.
  • a sintered, electrical resistor substantially consisting of a phase of oxidic compounds with perovskite structure, containing Fe and/or Cr or else Co and Fe and/or Cr, in which at least one of the metals Fe, Cr and Co occurs in the trivalent and the tetravalent form.
  • manganese in the tetravalent form may be included.
  • it is desirable to restrict the Co content in the conductive phase to not more than 90 atom percent, calculated on the total content of Fe, Cr, Co and Mn.
  • Part of the said metal ions may furthermore be replaced by other small trivalent or tetravalent metal ions, for example of Al, Ti and Ni.
  • other small trivalent or tetravalent metal ions for example of Al, Ti and Ni.
  • ABO The general formula for the chemical composition of perovskites is ABO wherein A designates a large metal ion, having an ion radius according to Goldschmidt of more than 1.0 A. and B a small metal ion having an ion radius between 0.5 and 1.0 A., the sum of the valencies of A and B being 6. Both A and B may designate a mixture of metal ions which fulfil the afore said conditions.
  • a mixed crystal of LaFe +O with SrFe +O inay for example, be formed by sintering in air La O SrO (if desired in the form of carbonate) and Fe O at temperatures lying between 1250" C. and 1400 C.
  • La O SrO if desired in the form of carbonate
  • Fe O at temperatures lying between 1250" C. and 1400 C.
  • the desired concentrations of Fe and Fe are obtained by a choice of the ratio between La and Sr.
  • the ratio between the concentrations of the trivalent and the tetravalent small metal ions may be adjusted fairly accurately in accordance with the formula ABO; by means of the concentrations of the trivalent and the bivalent large metal ions, if the latter ratio exceeds about 1.5.
  • oxygen content may be acted upon to some extent by means of the partial 'oxygen pressure of the gaseous atmosphere in which the sintering takes place.
  • the deviation from the 1 formula ABO may be considerable.
  • strontium ferrite sintered in air at 1320 C. the composition SrFeO has been found. Since the effect of the partial oxygen pressure is comparatively slight, stable resisters are also obtained with the perovskites having an oxygen deficiency.
  • perovskite compositions containing Fe or Cr exhibit a high temperature coefficient at a comparatively low specific resistance.
  • a greater variety in resistance properties may be obtained by combining the Feand Cr-containing perovskites with one another or with the other aforesaid metals.
  • the sintered products according to the invention should be constituted mainly by the aforesaid conductive phases. Moreover, other conductive or nonconductive phases may be contained in the sintered products to a content of about 15% by volume. If desired, fluxes, for example copper oxide, zinc oxide, clay and glass may be added to a quantity of about 10% by weight.
  • the products according to the invention may be obtained from the composing oxides, if desired in the form of double oxides or compounds, for example carbonates, changing into oxides during sintering.
  • the said constituents are ground, mixed, worked up to obtain a paste, for example with an organic binder, and then, subsequent to shaping, sintered in an oxygen containing atmosphere.
  • the constituents may, as an alternative, be caused to react, subsequent to mixing, at a higher temperature: they may then be ground again and sintered subsequent to shaping.
  • a sintered electrical resistor having a conductive phase consisting of crystals having a perovskite structure and a composition corresponding approximately to the formula AB D ,,O wherein A represents a mixture of at least one trivalent metal ion selected from the group consisting of La+++, Nd and Pr+++ and at least one bivalent metal ion selected from the group consisting of Ca++, Sr++, Ba++ and Pb++; B represents at least one trivalent metal ion selected from the group consisting of Fe+++, Cr+++, and Co+++, D represents at least one tetravalent metal ion selected from the group consisting of Fe++++ cr++++ Co++++ and Mn++++; Mn++++ Co+++ and Co++++ being present only when at least one of the other metal ions other than the metal ions represented by A in said formula is present, the elements Co, Fe and Cr being present in both the trivalent and tetravalent states, and wherein n represents a numeral having a value greater than
  • the resistor of claim 1 in which the conductive phase contains Co in an amount up to atom percent of the total content of Fe, Cr, Co and Mn.

Description

United States Patent SINTERED ELECTRICAL RESISTOR Gerard Heinrich Jonlrer, Gerard Willem van Oosterhout, and Jan Heinrik van Santen, Eindhoven, Netherlands, assignors, by mesne assignments, to North American Philips Company, Inc., New York, N. Y., a corporation of Delaware No Drawing. Application June 27, 1955 Serial No. 518,388
Claims priority, application Netherlands June 26, 1954 4 Claims. (Cl. 252-519) Sintered, electrical resistors on the basis of manganites with perovskite structure containing trivalent and tetravalent manganese are known. These resistors exhibit a comparatively low temperature coefficient of for example 0.6% per degree centigrade and a low specific resistance of 0.10 cm.
There are furthermore described the semi-conductive properties of cobaltites with perovskite structure, containing trivalent and tetravalent cobalt. Also with these materials the specific resistance and the temperature coeflicient are low.
It has been found that on the basis of ferrites and chromites with perovskite structure semi-conductive resistors may be obtained, having a high temperature coeflicient at a comparatively low specific resistance.
The invention relates to a sintered, electrical resistor substantially consisting of a phase of oxidic compounds with perovskite structure, containing Fe and/or Cr or else Co and Fe and/or Cr, in which at least one of the metals Fe, Cr and Co occurs in the trivalent and the tetravalent form. In the conductive phase manganese in the tetravalent form may be included. In order to obtain a high temperature coefficient, it is desirable to restrict the Co content in the conductive phase to not more than 90 atom percent, calculated on the total content of Fe, Cr, Co and Mn.
Part of the said metal ions may furthermore be replaced by other small trivalent or tetravalent metal ions, for example of Al, Ti and Ni. In order to prevent the specific resistance from becoming too high, it is desirable to restrict its content to not more than 20 atom percent.
The general formula for the chemical composition of perovskites is ABO wherein A designates a large metal ion, having an ion radius according to Goldschmidt of more than 1.0 A. and B a small metal ion having an ion radius between 0.5 and 1.0 A., the sum of the valencies of A and B being 6. Both A and B may designate a mixture of metal ions which fulfil the afore said conditions.
It is known that the obtainment of conductivity in heteropolar crystals requires that they should contain one metal ion occurring in different valencies. This is permitted by the metal ions Fe, Cr and Co, which may occur in the perovskites in the trivalent and the tetravalent form, if a mixture of trivalent and bivalent metal ions is chosen for the large metal ions designated by A in the general formula. To this end use may be made of the trivalent metals yttrium and the so-called large lanthanides, for example La, Pr and Nd and the bivalent metals for example Ca, Sr, Ba and also Pb and Cd.
, 2,862,891 Patented Dec. 2, 1958 The latter two are less suitable because of the volatility of their oxides.
A mixed crystal of LaFe +O with SrFe +O inay, for example, be formed by sintering in air La O SrO (if desired in the form of carbonate) and Fe O at temperatures lying between 1250" C. and 1400 C. In this case the desired concentrations of Fe and Fe are obtained by a choice of the ratio between La and Sr.
In general with the sintering in air the ratio between the concentrations of the trivalent and the tetravalent small metal ions, may be adjusted fairly accurately in accordance with the formula ABO; by means of the concentrations of the trivalent and the bivalent large metal ions, if the latter ratio exceeds about 1.5.
At a higher content of large bivalent metal ions not all oxygen positions in the perovskite lattice areoccupied so that the content of tetravalent small ions is smaller. The oxygen content may be acted upon to some extent by means of the partial 'oxygen pressure of the gaseous atmosphere in which the sintering takes place.
If the A-position in the perovskite is completely occupied by large bivalent ions, the deviation from the 1 formula ABO may be considerable. For strontium ferrite, sintered in air at 1320 C. the composition SrFeO has been found. Since the effect of the partial oxygen pressure is comparatively slight, stable resisters are also obtained with the perovskites having an oxygen deficiency.
It has been found that perovskite compositions containing Fe or Cr exhibit a high temperature coefficient at a comparatively low specific resistance. A greater variety in resistance properties may be obtained by combining the Feand Cr-containing perovskites with one another or with the other aforesaid metals.
In order to obtain a favourable temperature coefiicient it is necessary that the sintered products according to the invention should be constituted mainly by the aforesaid conductive phases. Moreover, other conductive or nonconductive phases may be contained in the sintered products to a content of about 15% by volume. If desired, fluxes, for example copper oxide, zinc oxide, clay and glass may be added to a quantity of about 10% by weight.
The products according to the invention may be obtained from the composing oxides, if desired in the form of double oxides or compounds, for example carbonates, changing into oxides during sintering. The said constituents are ground, mixed, worked up to obtain a paste, for example with an organic binder, and then, subsequent to shaping, sintered in an oxygen containing atmosphere. The constituents may, as an alternative, be caused to react, subsequent to mixing, at a higher temperature: they may then be ground again and sintered subsequent to shaping.
The invention will be illustrated with reference to the examples indicated in the following table. This table indicates a few compositions of the sintered products with the corresponding specific resistances p in 9 cm. at room temperature, the activation energy q being indicated in e. v., which is a measure for the temperature coefficient in accordance with the formula L p=pand the temperature coefiicient itself in percent per degree centigrade at room temperature.
Ca Sr Pb) (Fe 99999999999 8&3838583838 llllllillillllllllillllllll 9999999999999999999999 +27 by weight 2110 +27; by weight T:
MafiNNCRW 9999999999999999999999999999999999999 823255855E85 $585GG$5585E885583$88882555 l I I I l I l I I 99999999999999!- What is claimed is:
l. A sintered electrical resistor having a conductive phase consisting of crystals having a perovskite structure and a composition corresponding approximately to the formula AB D ,,O wherein A represents a mixture of at least one trivalent metal ion selected from the group consisting of La+++, Nd and Pr+++ and at least one bivalent metal ion selected from the group consisting of Ca++, Sr++, Ba++ and Pb++; B represents at least one trivalent metal ion selected from the group consisting of Fe+++, Cr+++, and Co+++, D represents at least one tetravalent metal ion selected from the group consisting of Fe++++ cr++++ Co++++ and Mn++++; Mn++++ Co+++ and Co++++ being present only when at least one of the other metal ions other than the metal ions represented by A in said formula is present, the elements Co, Fe and Cr being present in both the trivalent and tetravalent states, and wherein n represents a numeral having a value greater than zero but less than one.
2. The resistor of claim 1 in which the conductive phase contains Co in an amount up to atom percent of the total content of Fe, Cr, Co and Mn.
3. The resistor of claim 1 wherein the conductive phase contains in addition at least one metal selected from the group consisting of Al, Ti and Ni in an amount up to 20 atom percent of the total content of Fe, Cr, Co and Mn.
4. The resistor of claim 1 wherein in addition up to 10 percent of a flux is present.
References Cited in the file of this patent Physica, v. 16, No. 3, March 1950, pages 337-349. Physica, v. 19, 1953, pages -123.

Claims (1)

1. A SINSTERED ELECTRICAL RESISTOR HAVING A CONDUCTIVE PHASE CONSISTING OF CRYSTALS HAVING A PEROVSKITE STRUCTURE AND A COMPOSITION CORRESPONDING APPROXIMATELY TO THE FORMULA ABND1-N03 WHEREIN A REPRESENTS A MIXTURE OF AT LEAST ONE TRIVALENT METAL ION SELECTED FROM THE GROUP CONSISTING OF LA+++, ND+++ AND PR+++ AND AT LEAST ONE BIVALENT METAL ION SELECTED FROM THE GROUP CONSISTING OF CA++, SR++, BA++ AND PB++; B REPRESENTS AT LEAST ONE TRIVALENT METAL ION SELECTED FROM THE GROUP CONSISTING OF FE+++, CR+++, AND CO+++, D REPRESENTS AT LEAST ONE TETRAVALENT METAL ION SELECTED FROM THE GROUP CONSISTING OF FE++++, CR++++, CO++++ AND MN++++; MN++++, CO+++ AND CO++++ BEING PRESENT ONLY WHEN AT LEAST ONE OF THE OTHER METAL IONS OTHER THAN THE METAL IONS REPRESENTED BY A IN SAID FORMULA IS PRESENT, THE ELEMENTS CO. FE AND CR BEING PRESENT IN BOTH THE TRIVALENT AND TETRAVALENT STATES, AND WHEREIN N REPRESENTS A NUMERAL HAVING A VALUE GREATER THAN ZERO BUT LESS THAN ONE.
US518388A 1954-06-26 1955-06-27 Sintered electrical resistor Expired - Lifetime US2862891A (en)

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BE (1) BE539287A (en)
DE (1) DE1042080B (en)
GB (1) GB791167A (en)
NL (1) NL95807C (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3258434A (en) * 1962-08-01 1966-06-28 Gen Electric Semiconducting glass
US3779948A (en) * 1970-07-31 1973-12-18 Anvar Vitreous compounds with bistable electrical characteristics
US3968303A (en) * 1974-06-17 1976-07-06 The Bendix Corporation Electrical discharge device comprising an insulator body having an electrically semi-conducting coating formed thereon
US4159961A (en) * 1975-11-07 1979-07-03 Thomson-Csf Dielectric and non-magnetic ceramic for high frequency applications
DE2824408A1 (en) * 1978-06-03 1979-12-06 Dornier System Gmbh Electrically conductive mixed oxide prodn. by reactive spray drying - of mixed oxide of lanthanum with manganese, nickel, or cobalt contg. chromium and small amts. of other metal cations
EP0028510A1 (en) * 1979-11-02 1981-05-13 Matsushita Electric Industrial Co., Ltd. Oxide thermistor compositions and thermistors containing them

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3050407A (en) * 1959-08-25 1962-08-21 Bell Telephone Labor Inc Single crystal garnets
US3193502A (en) * 1960-09-16 1965-07-06 Weizmann Inst Of Science Rare earth ferrites
US4162631A (en) * 1977-12-05 1979-07-31 Ford Motor Company Rare earth or yttrium, transition metal oxide thermistors
FR2445680A1 (en) * 1978-12-29 1980-07-25 Anvar Electrically resistive perovskite compsns. - suitable for electrical heaters operating at high temps.
TW457498B (en) * 1998-12-03 2001-10-01 Murata Manufacturing Co Semiconductor ceramic and semiconductor ceramic device
DE102015121982A1 (en) 2015-12-16 2017-06-22 Epcos Ag NTC ceramic, electronic component for inrush current limiting and method for producing an electronic component
DE102018216352A1 (en) * 2018-09-25 2020-03-26 Robert Bosch Gmbh NTC resistance module

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH272927A (en) * 1946-08-23 1951-01-15 Philips Nv Process for the production of a semiconducting material.

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3258434A (en) * 1962-08-01 1966-06-28 Gen Electric Semiconducting glass
US3779948A (en) * 1970-07-31 1973-12-18 Anvar Vitreous compounds with bistable electrical characteristics
US3968303A (en) * 1974-06-17 1976-07-06 The Bendix Corporation Electrical discharge device comprising an insulator body having an electrically semi-conducting coating formed thereon
US4159961A (en) * 1975-11-07 1979-07-03 Thomson-Csf Dielectric and non-magnetic ceramic for high frequency applications
DE2824408A1 (en) * 1978-06-03 1979-12-06 Dornier System Gmbh Electrically conductive mixed oxide prodn. by reactive spray drying - of mixed oxide of lanthanum with manganese, nickel, or cobalt contg. chromium and small amts. of other metal cations
EP0028510A1 (en) * 1979-11-02 1981-05-13 Matsushita Electric Industrial Co., Ltd. Oxide thermistor compositions and thermistors containing them

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BE539287A (en) 1959-07-17
DE1042080B (en) 1958-10-30
GB791167A (en) 1958-02-26
NL95807C (en) 1960-11-15

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