US2609470A - Resistance materials and elements - Google Patents

Resistance materials and elements Download PDF

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US2609470A
US2609470A US106293A US10629349A US2609470A US 2609470 A US2609470 A US 2609470A US 106293 A US106293 A US 106293A US 10629349 A US10629349 A US 10629349A US 2609470 A US2609470 A US 2609470A
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sulfide
resistance
metal
percent
elements
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Frederic R Quinn
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General Electric Co
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General Electric Co
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    • 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
    • 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
    • H01B1/10—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances sulfides

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  • New-York 'I'he "present .invention relates ,to resistance materials .and ⁇ elements ⁇ and .more particularly to metal -sl'li'de resistance ,materials and elements.
  • a further*object offthe present invei'itio'n kis to ⁇ provide al process yforl stabilizingI theelectrical characteristics of l*metal sulfide resistance elements.
  • While 1 the elements of the .present l invention may be vprovided infanyfgof aznumberraofizforms, a simple :"forme. oifelementzo'f fthe thermis'torttype -isnish'ownin Fig. 1l fiinuwh'ich snumeral -.I indicates a body of lairnixture 'fof metal .sull-idas :including at least one of the group IL-'metalsuldeswith the ends ofthe ,leads .2 tand,3 :embedded in opposite ends ofthe body l.
  • resistance @and because of theiact :that zit for-ms a :fheat: resistant -glassy lexterior surface Electrical contact may be. made .directly with the :case l 4 gor fby meansy of a z suitable :lead
  • the present invention is primarily based on the discovery that pressed, and preferably sintered, mixtures of metal sulfides essentially including at least one sulfide of a metal of group II of the periodic table, particularly a sulfide of magnesium, calcium, cadmium, zinc, barium or mercury, are characterized by a time and temperature stability much greater than exhibited by any of the known metal sulfide compositions.
  • the products of the present invention comprise a resistance or semi-conducting body consisting essentially of at least one group II metal sulfide hereinafter referred to as the essential sulfide, and at least one additional metal sulfide referred to hereinafter as the base sulfide or sulfides.
  • the base sulfide may or may not be a group II metal sulfide.
  • the resistance bodies of the invention also preferably include small amounts of molybdenum sulfide or sulfur or both. Further aspects of the invention include .the combination of the sulfide bodies With contacts or leads of a particular type and the processing of the combination to provide an element having stable electrical characteristics for both A.C. and D.C. applications.
  • Essential and base sulfdcs Ordinarily the essential sulfide is present in an amount ranging from about 3 to 95 percent, .generally at least about percent, by weight of the sulfide mixture.
  • the preferred content of theessential sulfide is dependent upon the particular suldes employed in making the elements.
  • the primary function of the essential sulfide is to provide a composition which is stable and will exhibit the same resistance characteristics, i.
  • compositions and'electrical elements of the present invention have resistance characteristics which change markedly with change in temperature. Practically all of them have substantial negative coefficients of electrical resistance.
  • products may be prepared which either havea constant or substantially constant decrease in resistance with increased temperature or which exhibit a sharp break in electrical resistance at a certain critical temperature, or narrow range of temperatures, the break-point temperature depending upon the composition of the metallic sulfide mixture and to a lesser extent upon the particular process employed in making the resistance element.
  • sulfide mixtures which in certain proportions exhibit such sharp breaks in their resistance-temperature curves are silver calcium sulfide with a break temperature of around 175 C., and copper calcium sulfide with a break temperature slightly below C.
  • Molybdenum calcium sulfide mixtures can be prepared having break temperatures anywhere from 250 to 400 C. rdepending upon proportions used.
  • the choice of a particular essential sulfide or sulfides will depend upon a number of factors. When the product is to operate at temperatures less than 500 C., the generally less lexpensive calcium, cadmium or magnesium sulfides are preferred. Calcium sulfide has the further advantage in that mixtures including it have very low temperature coefficients of expansion. If higher temperatures are to be encountered, the sulfide of mercury, and particularly the sulfides of zinc or barium should be used since polysulflde compositions containing these essential sulfides are stable at temperatures up to 1200 C.
  • Cadmium sulfide compositions in general exhibit comparatively sharp break points, and steep temperature-resistance curves With calcium sulfide ranking next to the cadmium sulfide in this respect.
  • Calcium sulfide exhibits no break temperature of its own so that the temperature-resistance characteristics, and particularly the break-point temperature of compositions containing this sulfide, will be primarly those of the base sulfide.
  • the remaining essential sulfides all have their individual break-point temperatures and many of the compositions including. these sulfides may have temperature-resistance curves with a plurality of break points characteristic of each of the sulfide components which are present in substantial amounts.
  • the base sulfide is in general responsible for the electrical characteristics of the product. Any of the usual metal sulfides can be used at the base orsulfide in the practice of the present invention.
  • staple compositions have been prepared employing mixtures of an essential sulfide and one or more suldes of' the metals such as sodium, potassium, copper, silver, cadmium, platinum, mercury, lead, antimony, molybdenum, chromium, and nickel.
  • the polysulfides of the present invention may be prepared from a mixture of two 1 or more of the sulfides which are referred to herein as the essential sulfldes in which case one of the group II metal sulfides may assume the role of the base sulfide component.
  • Such stable products include for example calcium cadmium sulfide, calcium magnesium sulfide. zinc cadmium sulfide and mercury calcium sulfide.
  • compositions of the present invention also contain from about 0.03 to 10 percent, preferably less than 1 percent by weight, of molybdenum sulfide. It has been found specifically that molybdenum disulfide acts both as a lubricant and as a binder during the pressing y molybdenum'sulfide to function as a depolarizer,
  • the leads 4or ycontacts employed in-rthe ipracticefof the presentl invention possess the property "of reacting-only'to a limited extent with free sul-furlto f'form Von ythe surface ofthelead a thin, stable,Yprotectiveflmfof metal sulfide vrwhich apparently 'prevents ⁇ further reacti'onb'etween thametal andthe Ssulfuror sulii'e content of the-sulfide body.
  • the metal .sulfides .are preferablyrpulverized'tofa nely .divided'statefandmixedl inthezidesired'proportions. Alternatelyravmixture:
  • orfall'oyr of .twoxmetals .including .a Zgroup II. metal may beconverted to fa ⁇ mixture of lsulii'des by treatment with hydrogen :sulfide tor sulfur zdiox- ,The ymixtures .which Imust contain .at l'east ide. two vmetal sulfldes, at least l'one of "which pis fone of the essentialvsulfides .are Upressed .to thedesred' form iorzshape. It has been;foundthatfapressurel ofthe Yord'erfof 20,000 ip. s. i.
  • the sintering temperature should at' least' be abovethe'break temperature.
  • compositions containing a base sulfide which in the proper proportions would give .a product having l ⁇ a 'break point temperature vv'below about 200 C., "the :preferred "sintering temperature ranges yfrom 200 to '40 ⁇ 0C. and :the'flements "aref'ordinaily ⁇ subjectedxto .fsuch vtemperature 'ifor y.about one hour; Higher sintering ⁇ temperatures'up to 1500o C.
  • one aspect of the present invention is the pre-conditioning or stabilization of such elements by a process which comprises alternately passing a direct current through the element rst in one direction and then in the reverse direction until the ionic sulfur is plated out on the surfaces of both metal contacts to form a stable and indestructible film of metal sulfide.
  • the stabilization process removes the sulfurand metal ions by plating them on the leads to form a stable sulfide or suldes.
  • the current is reversed a suitable number of times during the stabilization treatment and the treatment is continued up to, for example, about 8 hours or until the resistance of the element is constant and the same in both directions.
  • the metal sulfide formed on the lead during the passage of a current in one direction is not removed or otherwise aifected by the reversal of the current so that after this polarization has been completed and the ionic sulfur plated out, the stabilized elements can be employed in any direct-current circuit without consideration'being given the question of direction of current flow.
  • a further and important advantage of this stabilization treatment is that the migration of sulfur to the vicinity of the contacts and the formation of the metal sulde layer on the contact surfaces results in an anchoring of the contacts in or to the sintered sulfide mixture giving improved electrical and mechanical bonding and decreased contact resistance between the leads or contacts and the sulfide bodies.
  • a D.C. current of reasonably high density e. g. -200 amps/sq. in. at the smaller electrode ' is conducted through the element while the element is held at a temperature where the resistance is low or at a minimum value.
  • Sulfur ions are conducted to the anode and deposit thereon to form a good bond between the electrode (anode) and the semi-conducting sulfide material.
  • the best time schedule for the treatment will depend upon the relative areas of the two elec-v trodes. For example, for an element in which the embedded surface areas of the two leads are about the same, the current is merely reversed a suitable number of times until the element has a constant resistance in both directions. On the other hand when the embedded area of one lead is greater than that of the other lead, it may be desirable during the first cycle of operations to proportion the times so that the lead with the greatest area is the anode for a comparatively longer time. For example, in processing an element such as shown in Fig. 4 in which the case is the larger lead or contact, the case is first made the anode for one hour and the lead having about one-tenth the area of the case is made the anode for ten minutes.
  • the current is reversed about every ten minutes for a total of eighthours, about every one-half hour for the next four hours and every hour for the next four hours.
  • the ammeter is checked and the current flowing in each p0- larity noted, and the times varied to get a product having the same resistance in both directions.
  • the current flowing should be 0f the same value in either polarity with the temperature constant.
  • the total time is dependent also upon the amount of free (ionic) sulfur in the element.
  • molbydenum disulfide When molbydenum disulfide is present in the mixture it appears to act as a depolarizer in the sense that it polarizes in the opposite direction from any Of the other metal suldes.
  • a molybdenum sulfide film forms on the lead in combination with the nickel sulfide of the lead material.
  • the depolarizing effect of the molybdenum sulfide is a general one and is independent of the remaining sulfide or suliides in the composition.
  • molybdenum sulfide in thev polarization phenomena may best be understood by considering the electrical characteristics of two elements differing only in the fact that one contains a small amount of molybdenum sulfide and the other no molybdenum sulde. Two such elements would otherwise consist of about 25 percent calcium sulfide, percent silver sulfide and a small amount of free sulfur with molybdenum leads embedded at opposite ends of the elements.
  • the element containing no molybdenum sulfide will have a resistance of, for example, 1,000 ohms in the direction of flow of the current during the polarization step and will have a high resistance in the neighborhood of 100,000 ohms in the o'pposite polarity.
  • the element containing molybdenum sulfide will be found to. have a re- 9, sistenceofabout 1,000.0hms. in the first. direction and.a..ver-y low resistance.of ⁇ ,.,for example, .2 ohms intheoppositedirection.
  • the resistance values ofk both elements in bothv directions. are the same, .for example,y about 100G-ohms. at theelevatedtemperature of 180 C. and anywhere from 50,000v toA 100,000 ohms de pendingl upon. the free. (ionic)y sulfur content at room4 temperature.
  • the room temperature resistance of. the molybdenum sulfide element is stabilized at. the. higher resistance of about 100,000 olimsiby the stabilization treatment.
  • Calcium silver sulfide element The calcium silver sulfide element is representative-ofthe polymet-al sulfide elements of the invention and the effectsof changing proportions, composition, sinter-ing temperatures, etc. will be described in detail in connection with this modiiication of the invention.
  • Calcium silver sulfide elements can be prepared which, dependingupon thecomposition, will exhibit either a continuous or substantially continuous decrease in resistance with increased temperature or a denitebreak point in the temperature-resistance curve.
  • the nature of the curve as well as the resistance of the element of any given temperature depends primarily upon therelativeproportions of calcium and silver sulfide. 'I'he effects. of. varying the ratio of these two materials is illustrated in Fig. 6 of the-drawing.
  • The. curves plotted .in this figure were obtained by varying the proportions of cal'ciumand silver suliides of stabilizedelements prepared from mixtures containing about l percent molybdenum disulfide and about 1. percent sulfur.
  • the elements were provided with either molybdenum or nickel chromium leads and', during the stabilization process, that sulfur which had not become chemically combined with the. calcium silver sulfide composition was plated out on. the leads in the form of .metal sulfide coating.
  • any of the leads described hereinbefore can be used, there beingvno noticeable difference in the resultant. resistance characteristics f the elements.
  • Some leads, such as those of Chromaloy may require. a. slightly longer time for polarizatiomi. e., sulndation.
  • compositions. containing. about 10 percent calcium. sulfide have a;temperature-resistance curve which is. substantiallyy a straight line.
  • the temperature-resistance curve bulges upwardly at temperatures below C. until at a composition which contains about 25 percent calcium sulfide, a curve is obtained which is characterized byj a maximum break point, i. e., a maximum drop in resistance over. a, relatively narrow temperature range. It is to be noted that during this entire increase in the calcium sulfide. content from 10 to about 25 percent, the resistance of the compositions at and above 175 C. isextremely small and for all practical purposes. zero. In fact, the temperature of 175" C..represents the break point o'f'those calcium silversulde velements havnga calcium sulfide content of. from about 20 tc13 ⁇ 0 percent by weight.
  • the low vtemperature-resistance Ofjthe element With further-increase in the calcium sulfide content, the low vtemperature-resistance Ofjthe element remains substantially the same asfth'e low temperature resistance of the compositions containing less than 30 percent calcium sulfide.
  • The-high temperature resistance of such calcium sulfide krich mixtures gradually increases with increased calcium sulfide content and the temperature-resistance curve again approaches' a straight line.
  • the .resistance characteristics of the elements ofY the. presentinvention can be further modified without affecting theirv stability by the addition thereto of min'or proportions, for. example, up. to 30 percentvby Weight of powdered metal.
  • min'or proportions for. example, up. to 30 percentvby Weight of powdered metal.
  • lthe addition of up to- 30 percent powdered silverto the-.calcium silver sulfide compositions results in a product, the resistance value of which decrease extremely rapidly with increased temperature.
  • Thetemperature-resistance curve of a stabilized element containing 18 parts calcium sulfide-.80 parts silver sulfide, 18 partsmolybdenum sulfide, 1 part sulfur, and. 20 partsv powdered silver. is shown nFig. 8.
  • the resistance value-of this eletment decreases toits lowest value ata tempera ture of about 175 C.
  • a composition containing 50 percent cadmium suliide, 40 percent calcium sulfide, percent molybdenum disulfide and 5 percent added sulfur exhibits a break point voi' 550 C.
  • the cadmium calcium sulfide elements are preferably sintered at temperatures up to 1200 C. for maximum freedom from aging. In general, satisfactory elements can be obtained from compositions containing from 40 to 90 percent cadmium sulfide, to 60 percent calcium sulfide, 0.03 to 10 percent molybdenum disulfide and 0.03 to 10 percent excess sulfur.
  • the sulfur may also be omitted particularly when it is not required for suliiding the leads.
  • Y Molybdenum calcium sulyide elements Particularly good elements are those in which the molybdenum disulfide is the base sulfide as Well as the binder and depolarizer.
  • One such element is prepared from calcium sulfide, molybde'numV sulfide and, if desired, some added sulfur.
  • the elements containing molybdenum sulfide as the base sulfide are representative of those in which the break-point temperature is affected by composition.
  • an element containing a sintered mixture of about 91.7 percent calcium sulfide and 8 percent molybdenum disulfide, and 0.3 percent sulfur exhibits a definite break in the temperature-resistance curve at about 250 C.V
  • the break temperature increases with increased molybdenum disulfide content.
  • An element containing 55 percent calcium sulfide, 35 percent molybdenum disulfide, and 10 percent sulfur exhibits a break point of about 350 C.
  • the break point is independent of the sulfur or excess sulfur content within the range of 0 to 10 percent added sulfur and appears to be entirely dependent upon the relative proportions of the essential sulfide and molybdenum sulfide.
  • the molybdenumy sulfidel is present in only a minor proportion.
  • the reason for this is that when the content of molybdendum sulfide substantially exceeds 35 percent of the composition, the high temperature stability of the element is impaired and when an element containing more than 35 percent molybdenum sulfide is substantially overheated, a permanent change in the resistance characteristics in one direction will result.
  • Elements containing mercury sulfide as the base sulfide are another example of elements in which the quantity of the base sulfide is kept low, however, for a different purpose. With a mercury sulfide element, a high dilution of the mercury sulfide is desirable to prevent spontaneous combustion or explosion of the mixture.
  • chromium sulfide and calcium sulfide yield a product having a high and constant resistance at temperatures of from 0 C. to 900 C., i. e., products having a zero temperaturecoefficient of resistance.
  • Platinum sulfide as the base sullide gives a material having a high negative coefficient below about C., a rather low coefficient from 150 to 280 C., and arather sharp break in the resistance values at about 280 C.
  • the calcium sulfide (or its equivalent essential sulde) is usu ally employed in a minor proportion and preferably from 15 to 25 percent when a maximum break point is desired. Exceptions to this general statement are the molybdenum sulfide, mercury sulfide and chromium sulfide elements and the elements containing zinc sulfide as the essential sulfides.Y As to the last mentioned sulfide, best results have been noted with the silver Zinc suliides when the zinc sulre content was about 50 percent with satisfactory elements being obtained from mixtures containing as much as 70 percent Zinc sulde.
  • the stabilizationzprocessi is '.not” limited-l tosulde resistance elements. but J is broadly-applicable to other' non-metallic; inor- 'tr'ius obtained? not. only a temperature fstab'leele'- ment but abonne-.Within which'. the leads; are v 'rmly. anchored orI secured'toi the 4res'i'stancemaryteriall as a'. result:v of the formationzof the stable compound or.rv compounds onutliez. leads. As in itl-ie caseY ofthe'sul'de elements'it may also.. be
  • vion-providing'.N element or' compoundv to.. ⁇ thematerialf prior to the pressing or forming of:A the elementsor'in the. case',offthe,o.xides;..byfsintering or firingthe elementsin'anzoxygen or amoxyeen ⁇ ricii atmosphere.
  • a stable' electric resistance uniti'. comprising a-body of resistance material consistingfessenftially offV a pressed mixture of metall sulides lirrcludingf (1li from 3r t'o 95per" cent of? af sulfide of a meta-l of group II of ⁇ the periodic table selected from the class ⁇ consisting of magnesium, calcium,y zinc, cadmium, barium and mercury,
  • a stable resistancev unit composed off'a ⁇ body of" resistance material consisting essentially Y' of? a compressed', sintered mixture of metal sulildes including" at least 0.03 per cent molybdenum sulde and from l0 to 60 per cent oi at least one suliide4 of a ⁇ metal of group II ofthe periodic table and metal leadsffelectri'cally connected to saidl body of" resistance material.
  • A' stable', thermally sensitive-resistanceeunit composed ofr a'- body of resistance materia-ly consisting'of' a.' compressed,- sintered mixtureofa plurality of metal-subidos includingmolybdenum suliide, from 3 to 95 per'cent'of la sul'ilde' ofi-a. metal of group II'of theY periodi'otableand a substantial portion'of' a third metal suliide'- and metal leads electrically*connected-to"saidbodyof resistance material.
  • A'stable, thermally sensitive resistance-unit composed of a body of resistancel materiali com'- prising ai pressedV and sinteredrmixture of metal suliides essentiallyl includingjfrom aboutA 0.03"t"o 35A percentr molybdenum disulfide andv from 3 to 95 ⁇ percent of asul'de of a metal of' group II ofthe periodic table and ⁇ metal contacts electrically connected' to saidl body of resistance material, at least one of said contacts being molybdenum.
  • a stable'polysulde' resistance' element com'- prsinga' body 'of resistance material consisting of a sintered ⁇ compressedI mixture of' at least' t'wo metal sulldes including from 10 to 95- percent off at'leaston'e sulfide of a' group, II' 'metal' and at least 0:03 percent'H molybdenumy sul'deA and metal contactsY electrically connected to said body;y at leastu one of said contacts being' a molybdenum contact embedded'in said body.
  • a stable, thermally sensitive resistance element comprising a bodyv of," resistancev material consisting' ofA a compressed, sintered' mixture v'of metali sul'des including from about ⁇ 0.03 to I0 percent molybdenum sulfide, 10't'o' b'percentof a sullide of'a groupII metal and a substantial portionY of' a' third rnetalsuliideY and' inet'al contacts electrically connected to' said body.
  • a stable resistance element comprising" a body oil resistance .material consisting of. ai com*- pressedLsinter-ed. mixture. of' 0103 to l0 percent molybdenum disulde 40. to. percent cadmium sulfide and.. 10. to... 6.0y percent. calcium suliideA and metal. contacts. electricallyA connectedV to..l said body..
  • a stable thermistor consisting essentially of a body of resistance material consisting of a pressed, sintered mixture of a plurality of metal sulfides including molybdenum sulfide, 3 to 95 percent of a group II metal sulfide and silver sulfide and metal contacts electrically connected to said body.
  • a stable thermistor consisting essentially of -a body of resistance material consisting of a compressed sintered mixture of from 0.03 to 10 percent molybdenum disulde, 15 to 35 percent calcium suliide, balance substantially all silver sulfide and metal contacts electrically connected to said body.
  • a stable thermistor composed of a body of resistance material consisting,r of a pressed sintered mixture oi metal sulfides consisting of from 0.03 to l percent molybdenum sulfide, l5 to 25 percent calcium sulfide and. balance silver sulfide and metal contacts electrically connected to said body, at least one of said contacts being a molybdenum contact embedded in said body.
  • a stable resistance element comprising a body of resistance material consisting of a sintered mixture of .03 to l0 percent molybdenum suliide, l0 to 60 percent of a sulfide of a group II -metal, silver sulfide, and a small amount of sulfur and metal contacts electrically connected to said body.
  • a stable thermistor element comprising a body of resistance material consisting of a pressed, sintered mixture of at least 0.03 percent molybdenum sulfide, from to 60 percent of ,a sulde of a group II metal, silver suliide, a small amount of sulfur and a minor portion of powdered silver and metal contacts electrically connected to said body.
  • a stable thermistor element comprising a body of resistance material consisting of a pressed sintered mixture of at least 0.03 percent molybdenum suliide, 3 to 95 percent zinc sulfide and a third metal suliide and metal contacts electrically connected to said body.
  • a stable thermistor element comprising a body of resistance material consisting of a sintered mixture of at least 0.03 percent molybdenum sulfide, 3 to 95 percent cadmium sulfide ⁇ and. a third metal sulfide and metal contacts electrically connected to said body.
  • a stable thermistor comprising a body of resistance material consisting of a sintered mixture of at least 0.03 percent molybdenum sulde, 3 to 95 percent calcium sulde and a third metal sulde and metal contacts electrically connected to said body.
  • a stable resistance element comprising Va body of resistance material consisting of a ⁇ sintered mixture of molybdenum sulde, chromium sulfide and 3 to 95 percent calcium sulfide and metal contacts electrically connected to said body.
  • a stable resistance unit comprising a body of resistance material consisting essentially of a sintered mixture of metal suldes including molybdenum sulfide and 3 to 95 percent of a sulde of a group II metal and metal leads electrically connected with said resistance material.
  • a stable resistance unit comprising a body of resistance material consisting of a sintered vmixture of suldes including at least 0.03 percent molybdenum suliide and 3 to 95 percent of a sulfide of a group II metal and molybdenum contacts electrically connected to said body.
  • a stable resistance unit comprising a body ofresistance material consisting of a compacted mixture of suliides including a small amount of y16 molybdenum sulfide and 3 tov95 percent of a sulfide of a, group II metal and metal leads electrically connected to said body including a molybdenum lead embedded in said body in electrical contact therewith, said lead having thereon a lm of molybdenum disulfide.
  • a stable resistor unit comprising a sintered, body of resistance material consisting of a sintered compressed mixture of metal sulfides including a small amount of molybdenum sulfide. 3 lto 95 percent of a sulde of a group II metal and. a third metal sulfide, and metal leads electrically connected with said body, at least one of said leads having a nickelous surface and having a sulfide layer on the surface thereof in contact with said body.
  • a stable resistance unit comprising a body of resistance material consisting of a sintered compressed mixture of metal suliides including a small amount of molybdenum sulfide, l0 to 60 percent of a sulde of a group II metal and a major portion of a third metal sulfide and metal leads including a suliide-coated metal lead electrically connected with said sulfide-coated body, said lead being an alloy of 35 percent nickel, 15 percent chromium, balance substantially iron.
  • a stable resistance unit comprising a sintered compacted body of resistance material consisting of a mixture of metal suliides including a small amount or" molybdenum sulfide, 3 to percent of a sulde of a group II metal and a major portion of a third metal sulfide and metal leads electrically connected with said body, one of said leads being of a nickel-chromium alloy and having a sulfide coating thereon.
  • the method of preparing a stable sulfide resistance element which comprises forming a mixture of at least two metal suliides including at least 0.03 percent molybdenum sulde and 3 to 95 percent of at least one sulfide of a group II metal, pressing said mixture into contact with a metal lead which Will react with sulfur to form a stable sulfide film thereon but which does not sulde to the point of disintegration of the lead, sintering the suliide mixture and thereafter passing a current through said mixture and lead to form a sulfide layer on said lead.
  • the method of obtaining a good mechanical and electrical connection between a polysuliide resistance element and an electrical contact element therefor which comprises pressing a powdered mixture of the suliides comprising the polysulflde element into contact with the contact element with a portion of one of said elements encompassing a portion of the other of said elements, heating the resultant product to sinter the polysuliide mixture and thereafter passing a direct current through the product to build up a suliide iilm on the surface of the contact element in engagement with the polysulde element.
  • the method ci obtaining a good mechanical and electrical connection between a resistance element comprising a sintered mixture of metal sulfides and a metal lead which comprises pressing a powdered mixture of the sulfldes including at least 0.03 percent molybdenum sulde and 3 to 95 percent of a sulfide of a group II metal and a small amount of sulfur into contact with a metal lead which has the property of reacting with sulfur to form a stable protective sulfide lm on the surface thereof, heating the resultant product to a temperature sufficient to sinter the sulfide mixture, and passing a direct current through said product to form on the surface of the lead in contact with the sintered sulfide mixture a layer of metal sulfide, said layer forming a good mechanical bond between said lead and said mixture.
  • the method of stabilizing the resistance characteristics of a sulfide resistance element containing at least 0.03 percent molybdenum sulfide and 3 to 95 percent of a sulfide of a metal of 18 group I1 of the periodic table which comprises passing a direct current through said element While holding the element at a temperature at Y which its electrical resistance is at a minimum value.
  • the method of forming a stable resistance element which comprises forming a mixture of a plurality of metal sulfides including molybdenum sulfide, 3 to 95 percent of a sulfide of a group II metal and a small amount of sulfur, pressing said mixture into contact with metal leads which will react with sulfur to form a stable surface layer of metal sulfide, sintering the pressed sulfide mixture and thereafter passing a direct current between said leads through the sintered mixture while the sintered sulde mixture is held at a, temperature above that at which its electrical resistance approaches a minimum, periodically reversing the direction of current flow, and continuing said process until the ionic sulfur remaining in the sintered mixture is deposited on said leads to form on the surfaces thereof sulfide films which mechanically and electricaly bond and connect said leads to the sintered sulfide mixture.

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  • Thermistors And Varistors (AREA)
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US106293A 1949-07-22 1949-07-22 Resistance materials and elements Expired - Lifetime US2609470A (en)

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GB17214/50A GB682887A (en) 1949-07-22 1950-07-10 Improvements in and relating to resistance materials and elements
DEI1633A DE857984C (de) 1949-07-22 1950-07-19 Elektrischer Widerstand und Verfahren zu seiner Herstellung
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Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2740030A (en) * 1952-07-12 1956-03-27 Gen Electric Metal sulfide resistance elements
US2744988A (en) * 1952-02-07 1956-05-08 Sprague Electric Co Molded resistors
US2750657A (en) * 1952-04-21 1956-06-19 Plessey Co Ltd Method of applying a metal electrode to a high permittivity ceramic
US2880497A (en) * 1955-12-13 1959-04-07 Harry H Hall Method of making pressure measuring gage means
US2958100A (en) * 1955-05-16 1960-11-01 Erie Resistor Corp Mold for forming a plurality of electrical elements with embedded terminals
US3054035A (en) * 1956-05-17 1962-09-11 Gulton Ind Inc Ceramic components and method of making same
US3110875A (en) * 1961-05-18 1963-11-12 Victory Engineering Corp Bead type thermistor and method
US3111567A (en) * 1962-11-15 1963-11-19 Dowsmith Inc Arc extinguisher containing molybdenum disulfide
US3149298A (en) * 1960-12-09 1964-09-15 Bell Telephone Labor Inc Neel effect switching device
US3186228A (en) * 1960-06-30 1965-06-01 Gen Electric Time-temperature integrator
US3266001A (en) * 1963-12-19 1966-08-09 Texas Instruments Inc Temperature sensors and their manufacture
US3295087A (en) * 1965-10-20 1966-12-27 Texas Instruments Inc Temperature sensor
US3307134A (en) * 1959-12-14 1967-02-28 Corning Glass Works Encapsulated impedance element
US3327272A (en) * 1964-06-22 1967-06-20 Barry J Stern Negative resistance device
US3465278A (en) * 1965-12-22 1969-09-02 Dow Corning Molybdenum disulfide electrical resistance devices
US3489554A (en) * 1969-03-13 1970-01-13 Sylvania Electric Prod Art of producing emitter-type electrode structures
US3735321A (en) * 1971-06-18 1973-05-22 Gen Electric Thermistor
US3766510A (en) * 1969-12-05 1973-10-16 Zyrotron Ind Inc Voltage sensor and method of using same
US4389876A (en) * 1980-08-26 1983-06-28 Honeywell Inc. Temperature sensor and detector cell utilizing the same
US20100074299A1 (en) * 2008-09-04 2010-03-25 Nyffenegger Johannes F Very high speed temperature probe

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1031407B (de) * 1953-09-29 1958-06-04 Gen Electric Verfahren zum Herstellen der Stromzuleitungen fuer temperaturempfindliche Widerstandsanordnungen
US3105229A (en) * 1958-12-08 1963-09-24 Sturm Justin Temperature sensing device
US3131562A (en) * 1961-03-30 1964-05-05 Cook Electric Co High temperature measuring probe
US4532186A (en) * 1982-06-16 1985-07-30 Nitto Electric Industrial Co., Ltd. Circuit substrate with resistance layer and process for producing the same

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US959068A (en) * 1907-09-12 1910-05-24 Rheolite Company Composition of matter and method of making the same.
FR701172A (fr) * 1929-08-16 1931-03-12 Contact constituant une résistance négative
US1820591A (en) * 1926-11-17 1931-08-25 Andre Henri Variable conductor of high negative temperature co-efficient
GB360920A (en) * 1929-08-16 1931-11-13 Erich Habann Improvements in or relating to electric negative resistances
AT144608B (de) * 1934-02-12 1936-02-10 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Widerstandskörper aus Halbleiterstoffen.
US2197115A (en) * 1937-01-27 1940-04-16 Gen Motors Corp Electric thermogauge engine unit

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US959068A (en) * 1907-09-12 1910-05-24 Rheolite Company Composition of matter and method of making the same.
US1820591A (en) * 1926-11-17 1931-08-25 Andre Henri Variable conductor of high negative temperature co-efficient
FR701172A (fr) * 1929-08-16 1931-03-12 Contact constituant une résistance négative
GB360920A (en) * 1929-08-16 1931-11-13 Erich Habann Improvements in or relating to electric negative resistances
GB367790A (en) * 1929-08-16 1932-02-15 Erich Habann Improvements in or relating to electric negative resistances
AT144608B (de) * 1934-02-12 1936-02-10 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Widerstandskörper aus Halbleiterstoffen.
US2197115A (en) * 1937-01-27 1940-04-16 Gen Motors Corp Electric thermogauge engine unit

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2744988A (en) * 1952-02-07 1956-05-08 Sprague Electric Co Molded resistors
US2750657A (en) * 1952-04-21 1956-06-19 Plessey Co Ltd Method of applying a metal electrode to a high permittivity ceramic
US2740030A (en) * 1952-07-12 1956-03-27 Gen Electric Metal sulfide resistance elements
US2958100A (en) * 1955-05-16 1960-11-01 Erie Resistor Corp Mold for forming a plurality of electrical elements with embedded terminals
US2880497A (en) * 1955-12-13 1959-04-07 Harry H Hall Method of making pressure measuring gage means
US3054035A (en) * 1956-05-17 1962-09-11 Gulton Ind Inc Ceramic components and method of making same
US3307134A (en) * 1959-12-14 1967-02-28 Corning Glass Works Encapsulated impedance element
US3186228A (en) * 1960-06-30 1965-06-01 Gen Electric Time-temperature integrator
US3149298A (en) * 1960-12-09 1964-09-15 Bell Telephone Labor Inc Neel effect switching device
US3110875A (en) * 1961-05-18 1963-11-12 Victory Engineering Corp Bead type thermistor and method
US3111567A (en) * 1962-11-15 1963-11-19 Dowsmith Inc Arc extinguisher containing molybdenum disulfide
US3266001A (en) * 1963-12-19 1966-08-09 Texas Instruments Inc Temperature sensors and their manufacture
US3327272A (en) * 1964-06-22 1967-06-20 Barry J Stern Negative resistance device
US3295087A (en) * 1965-10-20 1966-12-27 Texas Instruments Inc Temperature sensor
US3465278A (en) * 1965-12-22 1969-09-02 Dow Corning Molybdenum disulfide electrical resistance devices
US3489554A (en) * 1969-03-13 1970-01-13 Sylvania Electric Prod Art of producing emitter-type electrode structures
US3766510A (en) * 1969-12-05 1973-10-16 Zyrotron Ind Inc Voltage sensor and method of using same
US3735321A (en) * 1971-06-18 1973-05-22 Gen Electric Thermistor
US4389876A (en) * 1980-08-26 1983-06-28 Honeywell Inc. Temperature sensor and detector cell utilizing the same
US20100074299A1 (en) * 2008-09-04 2010-03-25 Nyffenegger Johannes F Very high speed temperature probe
US8118486B2 (en) * 2008-09-04 2012-02-21 AGlobal Tech, LLC Very high speed temperature probe

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GB682887A (en) 1952-11-19
BE497148A (en(2012)) 1950-11-16

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