GB900771A - Resistors and methods for the manufacture thereof - Google Patents
Resistors and methods for the manufacture thereofInfo
- Publication number
- GB900771A GB900771A GB2247958A GB2247958A GB900771A GB 900771 A GB900771 A GB 900771A GB 2247958 A GB2247958 A GB 2247958A GB 2247958 A GB2247958 A GB 2247958A GB 900771 A GB900771 A GB 900771A
- Authority
- GB
- United Kingdom
- Prior art keywords
- conductivity
- moles
- temperature
- ferro
- oxide
- 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.)
- Expired
Links
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
- C04B35/495—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 vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates
-
- 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
- C04B35/46—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 titanium oxides or titanates
- C04B35/462—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 titanium oxides or titanates based on titanates
- C04B35/465—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 titanium oxides or titanates based on titanates based on alkaline earth metal titanates
- C04B35/468—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 titanium oxides or titanates based on titanates based on alkaline earth metal titanates based on barium titanates
- C04B35/4682—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 titanium oxides or titanates based on titanates based on alkaline earth metal titanates based on barium titanates based on BaTiO3 perovskite phase
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Manufacturing & Machinery (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Thermistors And Varistors (AREA)
- Adjustable Resistors (AREA)
- Conductive Materials (AREA)
Abstract
900,771. Temperature dependent resistors. SIEMENS & HALSKE A.G. July 14, 1958 [July 15, 1957], No. 22479/58. Class 37. A resistor with a positive temperature coefficient over a certain temperature range comprises a ferro-electric substance with a Curie temperature below the upper limit of the range to which conductivity is imparted in such manner that the spacing between the donor and conductivity bands or between the acceptor and valence bands is less than half the width of the prohibited zone between the valence and conductivity bands, and in which the contribution to the conductivity of these donors or acceptors is great compared with the intrinsic conductivity of the substance or conductivity due to other donors and acceptors in said temperature range. The resistor is produced by sintering a number of crystallites and is subsequently electroformed with a series of high voltage pulses to eliminate its voltage dependence. It may be made of a perovskite consisting of mixed oxides of bi- and tetravalent elements, e.g. BaTiO 3 , (Ba, Sr) TiO 3 , (Ba, Pb) TiO 3 substituted by trivalent or quinquevalent elements such as niobium, lanthanum and tungsten, of a ferro-electric perovskite consisting of mixed oxides of mono- and quinquevalent elements, e.g. NaNbO 3 , KTaO 3 , or (Na, K) TaO 3 doped with bivalent or hexavalent elements such as barium, strontium, molybdenum and tungsten, or of the ferro-electric Cd 2 Nb 2 O 7 similarly substituted. A suitable material is made by heating a powdered mixture of 100.2 moles of titanium dioxide, 72 moles barium carbonate, 28 moles strontium carbonate and 0.2 moles of lanthanum oxide to react them. The product is then powdered, pressed to the desired shape and sintered at below 1300‹ C. in air or oxygen, after which metal electrode coatings are applied to which current leads are affixed. 0.1 mole of tungsten oxide WO 3 or 1.15 moles of niobium oxide Nb 2 O 5 may be used in place of the lanthanum oxide. In an alternative method the mixed titanate is formed in a preliminary heating and the substituting oxide incorporated during the sintering process. For instance 0.2 moles of lanthanum oxide may be added to powdered barium titanate and sintered at 1270-1300‹ C. The sintering temperature is critical since it determines the manner in which the substituted atoms are incorporated in the crystal lattice, and the crystal size which determines the conductivity of the material. The positive temperature coefficient is attributed to the fact that the activation energy of the impurity centres, which determines the number of free charge carriers at a given temperature is inversely proportional to the square of the effective polarisibility. In a ferro-electric in which the spacing between the donor or acceptor and the conductivity or valence band is small the fall of the effective polarisibility with rising temperature above the Curie point causes n, which is proportional to e(-E/kT), to rise with temperature. Consequently, if n represents a large fraction of the total number of carriers the material will have a positive temperature coefficient. Specifications 900,772, 900,773 and German Specification 660,971 are referred to.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DES54291A DE1140628B (en) | 1957-07-15 | 1957-07-15 | Semiconductor resistor with a positive temperature coefficient and method for its manufacture |
Publications (1)
Publication Number | Publication Date |
---|---|
GB900771A true GB900771A (en) | 1962-07-11 |
Family
ID=7489728
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB2247958A Expired GB900771A (en) | 1957-07-15 | 1958-07-04 | Resistors and methods for the manufacture thereof |
GB1078362A Expired GB900772A (en) | 1957-07-15 | 1958-07-14 | Resistors and methods for the manufacture thereof |
GB1078462A Expired GB900773A (en) | 1957-07-15 | 1958-07-14 | Resistors and methods for the manufacture thereof |
Family Applications After (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB1078362A Expired GB900772A (en) | 1957-07-15 | 1958-07-14 | Resistors and methods for the manufacture thereof |
GB1078462A Expired GB900773A (en) | 1957-07-15 | 1958-07-14 | Resistors and methods for the manufacture thereof |
Country Status (4)
Country | Link |
---|---|
CH (1) | CH374740A (en) |
DE (1) | DE1140628B (en) |
FR (1) | FR1200396A (en) |
GB (3) | GB900771A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109928747A (en) * | 2019-03-22 | 2019-06-25 | 上海大学 | The method for improving PTCR ceramic material temperature coefficient and NTC effect |
CN113465660A (en) * | 2021-05-25 | 2021-10-01 | 湖南大学 | Non-contact temperature measurement and material component detection device and method based on conductivity |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE511613A (en) * | 1951-05-23 |
-
1957
- 1957-07-15 DE DES54291A patent/DE1140628B/en active Pending
-
1958
- 1958-05-28 FR FR1200396D patent/FR1200396A/en not_active Expired
- 1958-07-04 GB GB2247958A patent/GB900771A/en not_active Expired
- 1958-07-14 CH CH6175958A patent/CH374740A/en unknown
- 1958-07-14 GB GB1078362A patent/GB900772A/en not_active Expired
- 1958-07-14 GB GB1078462A patent/GB900773A/en not_active Expired
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109928747A (en) * | 2019-03-22 | 2019-06-25 | 上海大学 | The method for improving PTCR ceramic material temperature coefficient and NTC effect |
CN109928747B (en) * | 2019-03-22 | 2022-01-07 | 上海大学 | Method for improving temperature coefficient and NTC effect of PTCR ceramic material |
CN113465660A (en) * | 2021-05-25 | 2021-10-01 | 湖南大学 | Non-contact temperature measurement and material component detection device and method based on conductivity |
CN113465660B (en) * | 2021-05-25 | 2022-07-05 | 湖南大学 | Non-contact temperature measurement and material component detection device and method based on conductivity |
Also Published As
Publication number | Publication date |
---|---|
DE1140628B (en) | 1962-12-06 |
GB900772A (en) | 1962-07-11 |
CH374740A (en) | 1964-01-31 |
GB900773A (en) | 1962-07-11 |
FR1200396A (en) | 1959-12-21 |
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