Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C5/00—Alloys based on noble metals
  • C22C5/06—Alloys based on silver
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
  • H10N10/80—Constructional details
  • H10N10/85—Thermoelectric active materials
  • H10N10/851—Thermoelectric active materials comprising inorganic compositions
  • H10N10/852—Thermoelectric active materials comprising inorganic compositions comprising tellurium, selenium or sulfur

Definitions

• thermo-electric devices consist of improvements in or relating to thermo-electric devices.
• Many different proposals have been made for producing suitable elements for thermocouples and in particular for'obtaining a high degree of sensitivity in thermopiles. It is known that to obtain a high sensitivity it is necessary that the substances used must possess a high thermo-electric power and that the loss of heat from the irradiated surface must be kept as small as possible.
• To minimize heat loss it has been customary to use the thermo-electric elements in the form of fine wires or strips sometimes joined end to end but these arrangements are delicate and are apt to be injured by shockor vibration.
• One object of this invention is to provide compositions suitable for thermo-electric elements of high and variable thermo-electric power and low heat conductivity which shall be strong and tough and readily worked.
• compositions should have the following properties:
• composition is made from a metal or from two or more metals combined with two or more elements of the sulphur group.
• composition consists of one, two or three metals with elements of the sulphur group.
• the convenient metals are silver, copper, lead and thallium and the elements of the sulphur group are sulphur, selenium and tellurium.
• thermoelectric elements contain two or more metals combined with two or more elements of the sulphur group the thermo-electric effect is secured by arranging that in one thermo-el-ctric composition the proportion of a certain metal or compound (or of certain metals 'or compounds), is comparatively high whereas in the other thermo-electric composition the proportion of the constituent metals and elements is substantially difierent.
• a metal such as silver may be melted with sulphur and selenium to form a composition for use as one element in a thermo-electric device.
• This composition may contain minor proportions of other metals such as copper or lead and/or tellurium.
• one element herein referred to as the positive element may have a composition as follows:
• thermo-electric power against platinum can be varied within a range of about 130 to 1200 microvolts per degree centigrade.
• An increase of sulphur and reduction in selenium increases the thermo-power.
• Increase in tellurium decreases the specific resistance and the rate of change of resistance with temperature.
• the amount of copper is preferably less than 2%
• the amount of silver may range between 70 and 80%
• the amount of selenium may range between 10 and 15%
• the amount of sulphur may range between 5 and 10%
• the amount of tellurium is preferably less than Copper and silver and tellurium with selenium and sulphur are melted together to form a composition for use as another element of a thermoelectric device (say the negative element) and the following is one example of an appropriate composition, the figures being given as percentages by weight:
• thermopiles for detecting and measuring 7 radiation V 1. In thermopiles for detecting and measuring 7 radiation:
• compositions are not brittle but quite tough and they can be made into suitable forms for securing, say'by welding, toconducting supports and to irradiation surfaces.
• the present invention can be used in conjunction with that described in my United States patent application Serial No. 470,031 filed December 24, 1942, that is to say, the two compositions may be used in the form of little sturdy bodies (say conical or cylindrical bodies) secured to the outer ends of supporting pillars of conducting material and the tips of these bodies may be secured to the back of a metallic foil the outer sur-' face of which is the irradiation surface.
• little sturdy bodies say conical or cylindrical bodies
• thermo-electric powers of the two bodies may be of opposite sign so that their thermo-electric effects are added when the deviceis in operation in a completed circuit.
• thermo-electric couples the conditions or requirements may vary and, as has been pointed out, the thermoular use of this invention-a simple test. may be necessary to determine the optimum composition it is a subsidiary feature of this invention that in- 2.
• thermo-converters for converting alternating to direct current In,thermo-converters for converting alternating to direct current;
• thermopile selection of the resistance and sensitivity of the thermopile. It is one of the practical advantages of the present invention that the resistance and the sensitivity of the thermopile can be independently varied to an outstanding extent.
• thermo-electric couple having a positive thermo-electric element-comprising a fused material'containing between 70 and 80% silver, less than 2% copper,'10 to 15% selenium, 5 to 10% suliur, and less than 2% tellurium, and a negative thermo-electric element comprising a fused material containing 25 -to copper, 25 to silver, 30 to 35% tellurium, 5 to 10% selenium, and less than2% sulphur.
• thermo-electric element comprising a fused material containing between to silver, less than 2% copper, 10 to 15% selenium.
• thermo-electric element comprising a fused material containing 25 to 30% copper, 25 to;35% silver, 30 to tellurium, 5 to 10% selenium. and less than 2% sulphur-r ERNST SCHWARZ.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Photometry And Measurement Of Optical Pulse Characteristics (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

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Cited By (20)

• 0
  • NL NL65724D patent/NL65724C/xx active
• 1942
  • 1942-12-24 US US470032A patent/US2397756A/en not_active Expired - Lifetime

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