Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01C—RESISTORS
  • H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
  • H01C17/06—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base
  • H01C17/065—Apparatus or processes specially adapted for manufacturing resistors adapted for coating resistive material on a base by thick film techniques, e.g. serigraphy
  • H01C17/06506—Precursor compositions therefor, e.g. pastes, inks, glass frits
  • H01C17/06513—Precursor compositions therefor, e.g. pastes, inks, glass frits characterised by the resistive component
  • H01C17/06533—Precursor compositions therefor, e.g. pastes, inks, glass frits characterised by the resistive component composed of oxides
• • 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
  • C04B35/03—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 magnesium oxide, calcium oxide or oxide mixtures derived from dolomite
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
  • H01B1/08—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances oxides
• • 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
  • H01C7/06—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 including means to minimise changes in resistance with changes in temperature

Definitions

• the invention relates to a method of producing an electrically semiconductive material and to a semiconductor made from this material.
• electrically semiconductive material having a small temperature coeflicient of resistance may be made from a mixture of an insulating oxide, such as magnesium oxide, and at most 3% of an oxide of one of the metals titanium, vanadium or niobium, by sintering the mixture at a temperature above 1700 C. in a reducing atmosphere.
• an insulating oxide such as magnesium oxide
• an oxide of one of the metals titanium, vanadium or niobium by sintering the mixture at a temperature above 1700 C. in a reducing atmosphere.
• semiconductors satisfying the aforementioned stringent requirements can be produced from semiconductor material obtained by sintering under reducing conditions a mixture consisting mainly of magnesiumoxide and containing from 0.5% to 3% by weight of titanium dioxide and from 1% to 30% by weight, preferably from 1.3% to 2.0% by weight, of silicon dioxide.
• the invention relates to a method of producing electrically semiconductive material by sintering in a reducing atmosphere a mixture consisting mainly of magnesium oxide and containing titanum doxide, and is characterized in that the mixture contains from 0.5% to 3.0% by weight of titanium dioxide and from 1.0% to 3.0% by weight of silicon dioxide, the proportion of both oxides together ice amounting to from 2% to 5% by weight.
• the specific resistivity of these materials ranges from about 300 to 3000 ohm/cm.
• semiconductors of high temperature stability i.e. semiconductors the resistance values of which change hardly or not at all when they are exposed to high temperatures for long periods of time, are obtained by starting from a mixture containing from 2.5% to 4.0% by weight and particularly from 2.8% to 3.6% by weight of titanium dioxide and silicon dioxide taken together, and especially if the proportion of titanium dioxide is from 1.5% to 2.5% by weight and the proportion of silicon dioxide is from 1.3 to 2.0% by weight and more particularly if these proportions are approximately 1.7% by weight and 1.4% by weight respectively.
• magnesium oxide may be capable of producing magnesium oxide upon heating, for example magnesium carbonate.
• titanium dioxide and silicon dioxide may be present as such or entirely or in part, in combined form, for example, as magnesium titanate and magnesium silicate respectively.
• the use of at least one oxide and preferably of both oxides as such is preferred. In these cases the sintering process yields semiconductors having very satisfactory chemical properties.
• the starting mixture preferably contains, in addition to the aforementioned components, an organic binder, such as methyl cellulose or nitrocellulose.
• an organic binder such as methyl cellulose or nitrocellulose.
• the binder may be removed by heating to a lower temperature, for example, to a temperature of from 1300 C. to 1400 C. During this lower temperature heating process a small amount of sintering takes place.
• the process of sintering in a reducing atmosphere may be effected in a gas mixture consisting of approximately by volume of nitrogen and approximately 15% by volume of hydrogen containing up to 0.1% by volume and preferably less than 0.01 by volume of oxygen, at temperatures between 1700 C., and 2000" C. and preferably by heatin g at about 1800 C., for example, for about from 5 to 30 minutes.
• the temperature coefiicient of resistance of the rods is rather small; by increasing the temperature from 20 C. to 350 C. the resistance increases by about 50% in total, between 350 C. and 500 C. the resistance remains almost constant and above 500 C. the temperature coefficient of resistance shows a small negative value.
• Resistances containing less than 1% by 'weight of silicon dioxide show at temperatures above about 500 C. a negative temperature coefiicient of relatively high value. Due thereto such resistances cannot be used in the highpressure mercury-vapor lamps as referred to above.

Landscapes

• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Chemical & Material Sciences (AREA)
• Electromagnetism (AREA)
• Physics & Mathematics (AREA)
• Ceramic Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Organic Chemistry (AREA)
• Apparatuses And Processes For Manufacturing Resistors (AREA)
• Conductive Materials (AREA)
• Compositions Of Oxide Ceramics (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=19755090

Family Applications (1)

Country Status (6)

Cited By (3)

Citations (3)

Family Cites Families (1)

• 1963
  • 1963-09-27 NL NL298534D patent/NL298534A/xx unknown
  • 1963-09-27 NL NL63298534A patent/NL139838B/nl unknown
• 1964
  • 1964-09-23 DE DEN25561A patent/DE1261437B/de not_active Withdrawn
  • 1964-09-24 CH CH1238564A patent/CH463604A/de unknown
  • 1964-09-24 GB GB38956/64A patent/GB1023260A/en not_active Expired
  • 1964-09-25 FR FR989294A patent/FR1409070A/fr not_active Expired
• 1969
  • 1969-07-22 US US849234A patent/US3549561A/en not_active Expired - Lifetime

Patent Citations (3)

Also Published As

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