SE186103C1

SE186103C1 -

Info

Publication number: SE186103C1
Authority: SE
Publication date: 1963-01-01

Description

Uppfinnare: H J Goldsmid och A R Sheard Prioritet begard treat den 18 december 1956 (Storbritannien) Ett andamal med foreliggande uppfinning är att astadkomma ett forbattrat termoelement under anvandning av halvledarmaterial. Inventors: H J Goldsmid and A R Sheard Priority Begard Treat 18 December 1956 (United Kingdom) An object of the present invention is to provide an improved thermocouple using semiconductor materials.

Det är kant, att ett matt pa effektiviteten av ett termoelement, (la det anvandes i en anordning, shsom ett termoelektriskt kylelement eller generatorelement, utgores av godhetstalet 0, vilket bestammes enligt ekvationen cr vAiia,+ 1/221a2 dar siffrorna 1 och 2 hanfor sig till var sitt av termoelementets bagge skanklar, T utgor det aritmetiska medeltalet av den absoluta temperaturen vid temoelementets varma och kalla fog, samt n, och ci beteckna en skankels termoelektriska effekt, vanneledningsformaga respektive elektriska ledningsformaga matt vid temperaturen T i skankelns langdriktning mellan den varma och den kalla fogen.och n, bOra uppenbarligen ha motsatt tecken. For detta andamal kunna termoelementets skanklar framstallas av halvledarmaterial med ledningsformaga av p-typ och n-typ. It is true that a measure of the efficiency of a thermocouple (when used in a device such as a thermoelectric cooling element or generator element) is formed by the goodness number 0, which is determined according to the equation cr vAiia, + 1 / 221a2 where the numbers 1 and 2 to each of the ram shanks of the thermocouple, T constitutes the arithmetic mean of the absolute temperature at the hot and cold joints of the thermocouple, and n, and ci denote the thermoelectric power of a shank, water conduction shape and electrical conduction mat at the temperature T in the longitudinal direction of the shank between the hot and the cold joint.and n, should obviously have opposite signs.For this purpose, the shanks of the thermocouple can be made of semiconductor material with p-type and n-type conductors.

Vid bedOmning av ett visst halvledarmaterials lamplighet fOr anyandning i ett termoelement är det lampligt att bestamma ett individuellt godhetstal o lika med 07) VTo/A. Det ma framhallas att for ett termoelement med skanklar bestaende av halvledare av p-typ och n-typ, vilka ha godhetstalen op och on, da halvledarnas ifrhgavarande egenskaper matas i elementets langdriktning vid temperaturen T, det totala godhetstalet 0 vid en genomsnittlig drifttemperatur av T kommer att ligga mellan ap och 0., och Oro lika med ap och i gransfallet, da dessa bagge varden aro lika. Det Or vidare lampligt att betrakta varmeledningsformagan A som summan av tva. komponenter, AL och I.E. av vilka den forsta betecknar varmeledningsformagan pa grund av atomerna i halvledarens kristallgitter och den andra betecknar varmeled ningsformagan till foljd av ledande elektroner och/ eller hal. When assessing the suitability of a certain semiconductor material for any breathing in a thermocouple, it is appropriate to determine an individual goodness number equal to 07) VTo / A. It should be pointed out that for a thermocouple with p-type and n-type semiconductors which have the goodness numbers op and on, since the respective properties of the semiconductors are fed in the longitudinal direction of the element at temperature T, the total goodness number 0 at an average operating temperature of T will be between ap and 0., and Oro equal to ap and in the spruce case, as these ram values aro equal. It is also appropriate to consider the thermal conductivity form A as the sum of two. components, AL and I.E. of which the first denotes the thermal conductivity due to the atoms in the semiconductor crystal lattice and the second denotes the thermal conductivity due to conducting electrons and / or halo.

For en viss halvledare varierar vid en faststalld temp eratur kvantiterna n, y och 2E i allmanhet avsevart alit efter halvledarmaterialets halt av en storsubstans, varjamte aim vardena n, o, h och kunna uppvisa en viss grad av anisotropi. I fOrbindelse med den forstnamnda effekten Or det lampligt att sasom vanligt inom halvledartekniken uttrycka halten storsubstans i halvledarens elektriska ledningsfOrmaga. Sasom bekant 'Aar den elektriska ledningsfOrmagan fOr en halvledare av en given ledningstyp vid en given temperatur med okande nettohalt av storsubstans (dvs. skillnaden mellan koncentrationen av donatorstorsubstans och halten av acceptorstorsubstans). Verkan av halten storsubstans pa a for en given halvledare kan anges med matresultaten for vardena n, o och A Mr en serie prov av halvledaren, vilka samtliga aro av samma ledningstyp men ha olika varden for den elektriska ledningsfOrmaganvarvid samtliga matningarna genomforas vid en bestamd temperatur. Dã halvledaren Or anisotrop betraffande nagon av ifragavarande egenskaper, bor varje prov besta av en enkelkristall eller flera trimmade kristaller och matningarna genomforas i en riktning, som bar angiven °neutering i fOrhallande till kristallaxlarna. For en sadan serie prov visar det sig i allmanhet, att 0 utgor en entydig funktion av r med ett enda maximivarde. Variationenen for a med a avviker naturligtvis i allmanhet frail en halvledare till en annan och Or ofta olika for ett och samma halvledarmaterials bagge ledningstyper. Bortsett frau de ovan diskuterade variationerna varierar vardet for a for ett visst prov ph en halvledare i allmanhet med temperaturen T bade betraffande direkt andring av T och p0. grund av andring av en eller flera av kvantiteterna n, r, och 1 med T. For a given semiconductor, at a fixed temperature, the quantities n, y and 2E generally vary considerably according to the content of a large substance in the semiconductor material, and also the values n, o, h and may exhibit a certain degree of anisotropy. In connection with the first-mentioned effect, it is appropriate, as usual in semiconductor technology, to express the content of large matter in the semiconductor's electrical conductivity. As is well known, the electrical conductivity of a semiconductor of a given type of conductor at a given temperature has an increasing net content of bulk (ie the difference between the concentration of donor bulk and the acceptor bulk). The effect of the large substance content on a for a given semiconductor can be stated with the feed results for the values n, o and A Mr a series of samples of the semiconductor, all of which are of the same conductor type but have different values for the electrical conductivity. When the semiconductor is anisotropic to any of the properties in question, each sample should consist of a single crystal or several tuned crystals and the feeds are carried out in a direction which has the indicated neutering in relation to the crystal axes. For such a series of tests, it generally turns out that 0 constitutes an unambiguous function of r with a single maximum value. The variation for a with a naturally differs from one semiconductor to another in general, and Or is often different for the ram conduction types of one and the same semiconductor material. Apart from the variations discussed above, the value of a for a given sample of a semiconductor generally varies with the temperature T both with respect to direct change of T and p0. due to the change of one or more of the quantities n, r, and 1 by T.

Av det foregaende torde framga, att det vid 2— — jamforelse av tva halvledarmaterial betraffande detta godhetstal ar lampligt att definiera standardgrundvalar for jamforelse betraffande halvledarnas halt av storsubstans, orientering av de matningar, pa vilka vardena pa 0 baseras, samt den temperatur, vid vilken matningarna ha genomforts. From the foregoing it should be seen that in the 2 - - comparison of two semiconductor materials concerning this goodness number it is appropriate to define standard bases for comparison concerning the semiconductor content of large matter, orientation of the feeds on which the values of 0 are based, and the temperature at which the feeds have been completed.

Fore fOreliggande uppfinning synas de basta resultaten vid anvandning av halvledare i termoelement ha uppnatts med termoelement omfattande skanklar av vismuttellurid (Bi,Te,), av p-typ respektive n-typ. Foreliggande uppfinning grundar sig p4 en undersokning av den inverkan, sarskilt i avseende pa de egenskaper, pa vilka godhetstalet 0 beror, som uppnas genom en delvis ersattning av vismut med antimon och/eller delvis ersattning av tellur med selen och/eller svavel i vismuttelluriden. De pa detta satt framstallda materialen utgora halvledare med en kristallstruktur, som liknar vismuttelluridens, och kunna betraktas som genom substitution erhallna fasta losningar av vismuttellurid och en eller flera av foreningarna antimontellurid (Sb,Te3), vismutselenid (Bi.2Se3) och vismutsulfid (Bi2S3), eller kunna betraktas som fOreningar med exempelvis formlerna BixSb,,Te, och Bi,TeySea..y. For the present invention, it seems that the best results in the use of semiconductors in thermocouples have been obtained with thermocouples comprising shank of bismuth telluride (Bi, Te,), of p-type and n-type, respectively. The present invention is based on an investigation of the effect, particularly with respect to the properties on which the goodness number 0 depends, which is obtained by a partial replacement of bismuth with antimony and / or a partial replacement of tellurium with selenium and / or sulfur in the bismuth telluride. The materials thus prepared form semiconductors with a crystal structure similar to that of bismuth telluride, and can be considered as substituted solid solutions of bismuth telluride and one or more of the compounds antimony montelluride (Sb, Te3), bismuth selenide (Bi.2Se3) and bismuth sulfide ), or can be considered as compounds with, for example, the formulas BixSb ,, Te, and Bi, TeySea..y.

Enligt uppfinningen bestar atminstone den ena skankeln i termoelementet huvudsakligen av en halvledare med konsitutionsformeln BimSbnTepSegSr, i vilken n har ett varde av 0-1,8, q ett varde av 0-0,4 och r ett varde av 0-0,24, varjamte m+n =2, p +q+r =3, 3n-1-2q+2r Or minst 0,03 och 3q+5r Or hogst 1,2. Denna halvledare liar samma kristallstruktur som vismuttellurid och kristallen eller varje kristall i halvledaren eller ledaren Or orienterad med sin huvudaxel i huvudsak vinkelratt mot ledarens langdriktning mellan termoelementets lodfogar. According to the invention, at least one shank in the thermocouple consists essentially of a semiconductor with the constitution formula BimSbnTepSegSr, in which n has a value of 0-1.8, q a value of 0-0.4 and r a value of 0-0.24, varjamte m + n = 2, p + q + r = 3, 3n-1-2q + 2r Or at least 0.03 and 3q + 5r Or at most 1.2. This semiconductor has the same crystal structure as bismuth telluride and the crystal or each crystal in the semiconductor or conductor Or is oriented with its major axis substantially perpendicular to the longitudinal direction of the conductor between the vertical joints of the thermocouple.

Halvledarens konstitutionsformel Or lampligen sadan att n har ett varde av 0,35-1,6 och 3q+liar ett varde av 0-0,9, varjamte halvledaren har en elektrisk ledningsformaga matt i ledarens langdriktning vid en temperatur av 290° K av 500-2000 (ohincentimeter),. The constituent formula of the semiconductor Or suitably such that n has a value of 0.35-1.6 and 3q + liar a value of 0-0.9, each semiconductor having an electrical conduction mat in the longitudinal direction of the conductor at a temperature of 290 ° K of 500 -2000 (ohincentimeter) ,.

Ett satt att framstalla halvledare for termoelement enligt uppfinningen bestar i att vismut och tellur smaltas tillsammans i vakuum jamte minst ett av grundamnena antimon, selen och svavel i proportioner som svara mot konstitutionsformeln BimSbnTepSeqSr, sã att n har ett varde av 0-1,8, q liar ett yard e av 0-0,4 och r har ett varde av 0-0,24, varjamte m+n-2, p+q+r-3, 3n+2q+2e Or minst 0,03 och 3q+5r Or hogst 1,2, varefter man av det smalta materialet framstaller ett langstrackt, massivt got och underkastar detta sh kallad zonsmaltning. A method of producing semiconductors for thermocouples according to the invention consists in melting bismuth and tellurium together in a vacuum together with at least one of the basic elements antimony, selenium and sulfur in proportions corresponding to the constitutional formula BimSbnTepSeqSr, so that n has a value of 0-1.8. q liar a yard e of 0-0.4 and r has a value of 0-0.24, each m + n-2, p + q + r-3, 3n + 2q + 2e Or at least 0.03 and 3q + 5r Or hogst 1,2, after which the elongated material produces an elongated, solid cast and undergoes this sh called zone melting.

Uppfinningen kommer i det foljande att beskrivas narmare med hanvisning till bifogade ritning. Fig. 1 utgor ett diagram Over vissa egenskaper hos vismuttellurid av p-typ. Fig. 2 utgOr ett diagram, som visar vissa andra egenskaper hos vismuttellurid av p-typ. Fig. 3 är ett diagram, som visar vissa egenskaper hos halvledare, vilka kunna anvandas i termoelement enligt foreliggande uppfinning. Fig. 4 Or ett diagram, som visar andra egenskaper hos halvledare, vilka kunna anvandas i termoelement enligt foreliggande uppfinning. Fig. 5 Or en schematisk perspektivoy av ett termoelement. The invention will be described in more detail below with reference to the accompanying drawing. Fig. 1 is a diagram of certain properties of p-type bismuth telluride. Fig. 2 is a diagram showing some other properties of p-type bismuth telluride. Fig. 3 is a diagram showing certain properties of semiconductors which can be used in thermocouples according to the present invention. Fig. 4 is a diagram showing other properties of semiconductors which can be used in thermocouples according to the present invention. Fig. 5 is a schematic perspective view of a thermocouple.

Innan egenskaperna hos halvledare, vilka anvandas i termoelement enligt foreliggande uppfinning, diskuteras narmare, torde det for jamfOrelses skull vara lampligt att ga narmare in pa vissa av vismuttelluridens egenskaper. Before the properties of semiconductors used in thermocouples according to the present invention are discussed in more detail, for the sake of comparison, it would be appropriate to go into more detail on some of the properties of bismuth telluride.

Det ma framst framhallas, att vismuttellurid utvecklar anisotropi betraffande vissa av sina fysikaliska egenskaper. Foreningen kristalliserar i det trigonla systemet och en vismuttellurid-kristall kan latt spaltas langs plan, som Oro vinkelratta mot huvudaxeln. Det har for vismuttellurid av bade p-typ och n-typ visat sig, att bade den elektriska ledningsformagan a och varmeledningsformagan 2. variera avsevart med lutningen mot kritallhuvudaxeln for den riktning, i vilken dessa egenskaper maths. FOr vismuttellurid av p-typ Or den termoelektriska effekten i huvudsak isotrop, medan den for vismuttellurid av n-typ varierar nagot alltefter lutningen mot kristallhuvudaxeln for den riktning, i vilken egenskapen mates. Nettoresultatet av anisotropien är, att for bagge ledningstyperna godhetstalets 0 varde liar ett maximum i riktningar, som Oro vinkelratta mot kristallhuvudaxeln, dvs. parallella med spaltningsplanen. Den fortsatta beskrivningen av vismuttelluridens egenskaper kommer darfor att begransas till de i denna riktning matta egenskaperna. Med hansyn till godhetstalets 0 anisotropi bor for uppnaende av maximal effektivitet en skankel av vismuttellurid i ett termoelement besta av en eller flera kristaller, vilkas kristallhuvuda:dar Oro anordnade i huvudsak vinkelratt mot skankelns langdriktning mellan den heta och den kalla fogen. It must first be pointed out that bismuth telluride develops anisotropy regarding some of its physical properties. The compound crystallizes in the trigonal system and a bismuth telluride crystal can be easily cleaved along planes, which Oro is perpendicular to the major axis. It has been found for bismuth tellurium of both p-type and n-type that both the electrical conductor shape a and the thermal conductor shape 2 vary considerably with the inclination towards the crystal main axis for the direction in which these properties are maths. For p-type bismuth telluride Or the thermoelectric effect is substantially isotropic, while for n-type bismuth telluride it varies slightly according to the inclination towards the crystal major axis for the direction in which the property is fed. The net result of the anisotropy is that for ram the wire types the value of the number of goodness numbers is a maximum in directions which Oro is perpendicular to the crystal major axis, i.e. parallel to the division plan. The further description of the properties of the bismuth telluride will therefore be limited to the properties which are dull in this direction. In view of the anisotropy of the goodness number, in order to achieve maximum efficiency, a shank of bismuth telluride in a thermocouple consists of one or more crystals, the crystal heads of which are arranged substantially perpendicular to the longitudinal direction of the shank between the hot and cold joints.

Fig. 1 och 2 visar kurvor Over nagra egenskaper for vismuttellurid av p-typ. Dessa kurvor ha erhallits genom matningar av en serie prov pa vismuttellurid pa det ovan beskrivna sattet, I fig. 1 Or den termoelektriska effektenuttryckt i iuV1°C, avsatt mot den elektriska ledningsformagan a, uttryckt i (ohm-centimeter), fOr ternperaturerna 200 och 290° K. Vid en given temperatur okar vid iikande ledningsformaga a den termoelektriska effekten i forst, passerar genom ett maximum och sjunker sedan. Detta maximums lage och storlek varierar for olika temperaturer_ Kurvorna feu' olika temperaturer sammanfalla dock ftir hogre varden pa ledninsformagan a. I fig. 2 Or varmeledningsfOrmagan 4 uttryckt i W/cm°C, avsatt mot produkten av elektrisk ledningsformOga a och den absoluta temperaturen T, uttryckt i °K/ohm-centimeter for en temperatur av 290° C. DO den elektriska ledningsformagan okar, sjunker forst varmeledningsformagan A. passerar genom ett minimum och okar sedan, medan de delar av kurvan, som svara mot hogre varden ph den elektriska ledningsformagan a, Oro raka och ha en lutning, vilken sasom kan vantas teoretiskt Or lika med 2 (K/E)2 dar K betecknar — —3 Boltzmanns konstant och E är elektronladdningen. Korsningen mellan den raka delen av kurvan och A-axeln ger ett varde ph varmeledningsformagans gitterkomponent AL. Motsvarande kurvor for andra temperaturer ha liknande form mot en rak del med samma lutning, ehuru minimumets lage och varde samt vardet pa AL aro olika. Figs. 1 and 2 show curves of some properties of p-type bismuth telluride. These curves have been obtained by feeding a series of samples of bismuth telluride in the manner described above, In Fig. 1 Or the thermoelectric power expressed in iuV1 ° C, plotted against the electrical conductivity a, expressed in (ohm-centimeters), for the temperatures 200 and 290 ° K. At a given temperature, with similar conductivity, the thermoelectric power increases at first, passes through a maximum and then decreases. The maximum and size of this maximum vary for different temperatures. However, the curves at different temperatures coincide with the higher values of the conductor shape a. In Fig. 2, the heat conductor shape 4 expressed in W / cm ° C, plotted against the product of electrical conductor shape a and the absolute temperature T , expressed in ° K / ohm-centimeter for a temperature of 290 ° C. DO the electrical conductor shape increases, first the thermal conductor shape A. decreases through a minimum and then increases, while the parts of the curve which correspond to the higher value ph the electrical the lead shape a, Oro straight and have a slope, which can be used theoretically Or equal to 2 (K / E) 2 where K denotes - —3 Boltzmann's constant and E is the electron charge. The intersection between the straight part of the curve and the A-axis gives a grid component AL of each ph heat conductor form. Corresponding curves for other temperatures have a similar shape to a straight part with the same slope, although the minimum and value of the minimum and the value of AL are different.

Av uppgifter uttagna ur de i fig. 1 och 2 visade kurvorna är det mojligt att rita en kurva for godhetstalet 0 mot den elektriska ledningsformagan a for vismuttellurid av p-typ vid en given temperatur. Om en sadan kurva ritas f8r en ternperatur av 290° K, visar det sig, att maximivardet for o är c:a 0,73, om den termoelektriska effekten uttryckes i V/°C och de andra faktorer, som ligga till grund for godhetstalet, uttryckas i de ovan angivna enheterna. From data taken from the curves shown in Figs. 1 and 2, it is possible to draw a curve for the goodness number 0 against the electrical lead shape a for p-type bismuth telluride at a given temperature. If such a curve is drawn for a temperature of 290 ° K, it turns out that the maximum value for o is about 0.73, if the thermoelectric effect is expressed in V / ° C and the other factors that form the basis for the goodness number , is expressed in the above units.

Kurvor liknande de i fig. 1 och 2 visade kunna aven uppritas for vismuttellurid av n-typ och pa grundval av dem kan man rita en kurva, som visar godhetstalets 0 variation med den elektriska ledningsformagan a for vismuttellurid av n-typ vid en given temperatur. Sadana kurvor visa sig vara mycket lika kurvorna for vismuttellurid av p-typ med mindre numeriska skillnader, varfor de icke behova diskuteras i detalj i detta sammanhang. Det ma emellertid framhallas, aft maximivardet fOr godhetstalet 0 for vismuttellurid av n-typ vid 290° K Or c:a 0,78, samt aft maximivardet [Or det totala godhetstalet 0 som kan erhallas vid en genomsnittlig arbetstemperatur av 290° K med ett termoelement med ledare av vismuttellurid av ptyp och n-typ Or c:a 0,75, varvid dessa bagge varden Oro beraknade pa samma underlag som det fOr vismuttellurid av p-typ angivna. Curves similar to those shown in Figs. 1 and 2 can also be plotted for n-type bismuth telluride and on the basis of these a curve can be drawn showing the variation of the goodness number 0 with the electrical conductivity a of n-type bismuth telluride at a given temperature. . Such curves prove to be very similar to the curves for p-type bismuth telluride with minor numerical differences, so they do not need to be discussed in detail in this context. However, it must be emphasized that the maximum value for the goodness number 0 for n-type bismuth telluride at 290 ° K or about 0.78, and the maximum value [or the total goodness number 0 which can be obtained at an average working temperature of 290 ° K with a thermocouples with p-type and n-type bismuth conductors or about 0.75, these bags being calculated on the same basis as those specified for p-type bismuth telluride.

Egenskaperna fOr de halvledare, villa anvandas i termoelement enligt foreliggande uppfinning, komma nu att diskuteras. For korthetens skull komma dessa halvledare att generellt betecknas som halvledarna enligt uppfinningen. The properties of the semiconductors used in thermocouples according to the present invention will now be discussed. For the sake of brevity, these semiconductors will be generally referred to as the semiconductors according to the invention.

Sasom ovan angetts ha halvledarna enligt uppfinningen en kristallstruktur, som liknar vismuttelluridens, varfor de uppvisa samma anisotropi betraffande vissa egenskaper. Liksom for vismuttellurid av bagge ledningstyperna har godhetstalet 0 ett maximum for riktningar, som Oro vinkelrata mot kristallhuvudaxeln. Den fortsatta diskussion av de enligt uppfinningen sammansatta halvledarnas egenskaper kommer darfor att, liksom betraffande vismuttelluridens egenskaper, begransas till de i denna riktning matta egenskaperna. Pa grund av denna anisotropi bor kristallen eller varje kristall i en termoelementskankel av nagon av de angivna halvledarna orienteras med huvudkristallaxeln i huvudsak vinkelratt mot skankelns langdriktning mellan termoelementets fogar. As stated above, the semiconductors of the invention have a crystal structure similar to that of bismuth telluride, for which they exhibit the same anisotropy with respect to certain properties. As for the bismuth lead types of bismuth telluride, the goodness number 0 has a maximum for directions such as Oro perpendicular to the crystal major axis. The further discussion of the properties of the semiconductors composed according to the invention will therefore, like the properties of the bismuth telluride, be limited to the properties which are dull in this direction. Due to this anisotropy, the crystal or each crystal resides in a thermocouple shank of any of the indicated semiconductors is oriented with the main crystal axis substantially perpendicular to the longitudinal direction of the shank between the thermocouple joints.

Pa grundval av matningar av den termoelektriska effekten n, den elektriska ledningsformagan och vOrmeledningsformagan A pa prov av de angivna halvledarna, kan man upprita kurvor av de i fig. 1 och 2 visade typerna for varje sammansatt ning, varvid naturligtvis shrskilda kurvor Oro nOdvandiga [Or material av p-typ och n-typ. Jamforelse av sadana kurvor med motsvarande kurvor for vismuttellurid leder till f olj ande slutsatser betraffande de vid temperaturer Over 250° K erhallna resultaten. On the basis of feeds of the thermoelectric power n, the electrical conductor shape and the heat conduction shape A on samples of the indicated semiconductors, curves of the types shown in Figs. 1 and 2 can be drawn for each compound, whereby of course different curves are necessary. p-type and n-type materials. Comparison of such curves with the corresponding curves for bismuth telluride leads to the following conclusions regarding the results obtained at temperatures above 250 ° K.

For var och en av de angivna halvledarna Or kurvan for forhallandet mellan varmeledningsfOrmagan A och produkten av den elektriska ledningsfOrmagan a och den absoluta temperaturen T for en given ledningstyp och temperatur i huvudsak identisk med motsvarande kurva for vismuttellurid med samma ledningstyp och vid samma temperatur med undantag for en forflyttning neat av hela kurvan parallellt med 1-axeln, vilket svarar mot eft lagre varde for varmeledningsformagans gitterkomponent AL On for vismuttellurid. Gitterkomponentens AL varde beror pa halvledarens sammansattning. Del satt, ph vilket gitterkomponenten AL varierar med sammansattningen visas for vismut-antimon-tellurider (dvs. de av halvledarna enligt uppfinningen som icke innehalla selen eller svavel) och vismut-selenotellurider (dvs. de av halvledarna enligt uppfinningen som icke innehalla antimon eller svavel) genom de i fig. 3 och 4 visade kurvorna, i villa varmeledningsformagans gitterkomponent AL, uttryekt i AV/cm°C, Or avsatt mot molprocenten antimontellurid eller vismutselenid i materialet for en temperatur av 290° K. I stort samma resultat erhallas for vismut-sulfo-tellurider (dvs. de av de enligt uppfinningen sammansatta halvledarna, som icke innehalla antimon eller selen). Genom att en del av telluren ersattes med selen och/eller svavel i en av vismut-antimontelluriderna sankes gitterkomponentens AL varde ytterligare, dock icke at mycket som vid ersattning av telluren med samma mhngd selen och/eller svavel i vismuttellurid. For each of the specified semiconductors Or the curve for the ratio between the thermal conductivity A and the product of the electrical conductivity a and the absolute temperature T for a given conduit type and temperature substantially identical to the corresponding curve for bismuth lurid with the same conductivity and at the same temperature except for a displacement neat of the whole curve parallel to the 1-axis, which corresponds to the aft bearing value of the lattice component of the heat conduction shape AL On for bismuth telluride. The AL value of the lattice component depends on the composition of the semiconductor. The part set, ph which the lattice component AL varies with the composition is shown for bismuth-antimony tellurides (i.e. those of the semiconductors according to the invention which do not contain selenium or sulfur) and bismuth-selenium tellurides (i.e. those of the semiconductors according to the invention which do not contain antimony or sulfur ) by the curves shown in Figs. 3 and 4, in the grating component AL of the thermal conductor, expressed in AV / cm ° C, Or plotted against the mole percent antimontelluride or bismuth selenide in the material for a temperature of 290 ° K. -sulphotellurides (ie those of the semiconductors composed according to the invention, which do not contain antimony or selenium). By replacing part of the tellurium with selenium and / or sulfur in one of the bismuth anti-montellurides, the value of the lattice component AL was further reduced, but not as much as when replacing the tellurium with the same amount of selenium and / or sulfur in bismuth telluride.

For var och en av de enligt uppfinningen sammansatta halvledarna ham kurvan for den termoelektriska effektens oj beroende av elektrisk lednMgsformaga a for en given ledningstyp och temperatur samma form som motsvarande kurva for -vismuttellurid med samma ledningstyp och vid samma temperatur, ehuru den for vissa material forskjutes uppat eller neat i jamforelsekur- van for vismuttellurid, atminstone Mom nagot intervall av varden pa den elektriska ledningsformagan a. For vismut-antimon-tellurider, som innehalla mindre On 50 % antimontellurid, Or kurvan salunda i huvudsak identisk med vismuttelluridens kurva. For vismut-antimon-tellurider, som innehalla mer an antimontellurid, Or kurvan for de hOgre vardena pa den elektriska ledningsformagan a forskjuten uppat i jamfbrelse med kurvan for vismuttellurid. For de av halvledarna enligt uppfinningen som innehalla en avsevard mangd selen och/eller svavel, uppvisar kurvan atminstone for hogre varden pa den elektriska ledningsformagan a, en fOrskjutning nedat jamfort med kurvan for vismuttellurid. For each of the semiconductors composed according to the invention, the curve for the thermoelectric power and the dependence of the electrical conduction shape a for a given wire type and temperature has the same shape as the corresponding curve for -vismutelluride with the same wire type and at the same temperature, although for some materials up or not in the comparison curve for bismuth telluride, at least Mom some range of the value of the electrical wiring a. For bismuth antimony tellurides, which contain less On 50% antimontelluride, the curve is thus essentially identical to the bismuth telluride curve. For bismuth antimony tellurides, which contain more antimony montelluride, the curve for the higher values of the electrical conductivity is offset upwards in comparison with the curve for bismuth telluride. For those of the semiconductors according to the invention which contain a considerable amount of selenium and / or sulfur, the curve shows, at least for the higher value of the electrical conductivity a, a downward displacement compared with the curve for bismuth telluride.

Om salunda ett prov p0 en av halvledarnas enligt uppfinningen jamfores med ett prov pa vis- 4-- --- muttellurid och de bagge proven aro av samma ledningstyp och ha samma elektriska ledningsformaga a vid en given temperatur T, som är hOgre an 250° K, uppvisa de bagge proven samma elektroniska komponent AE for varmeledningsfOrmagan vid temperaturen T, ehuru pro-vet pa halvledaren enligt uppfinningen vid temperaturen T kommer att ha lagre gitterkomponent,for varmeledningsformagan an provet av vismuttellurid och salunda lagre, totalt varde for varmeledningsformagan A. Det ma vidare framhallas, att de bagge proven vid temperaturen T uppvisa varden pa den termoelektriska effekten n av sarnma storlek och att, ehuru i vissa fall den termoelektriska effektenan nagot lagre fOr provet pa halvledaren enligt uppfinningen an for provet pa vismuttellurid, skillnaden i intet fall kommer att i detta hanseende vara sa stor, att den heft uppvager fOrdelen med ett lagre yards pa varmeledningsformagan A. I samtliga fall kommer salunda provet pa halvledaren enligt uppfinningen att ha hogre varde pa godhetstalet a vid temperaturen T On provet pa vismuttellurid, varf Or man kan dra den slutsatsen, att alla halvledarna enligt uppfinningen aro overlagsna vismuttellurid for anvandning som ledare i termoelement. Thus, if a sample on one of the semiconductors according to the invention is compared with a sample on vis- 4-- --- muttelluride and the ram samples are of the same conductivity type and have the same electrical conductivity a at a given temperature T, which is higher than 250 ° K, the bag samples have the same electronic component AE for the thermal conductivity at temperature T, although the sample of the semiconductor according to the invention at temperature T will have lower lattice component, for the thermal conductivity than the sample of bismuth telluride and salunda lower, total value for the thermal conductive A. It should also be pointed out that the bagged samples at temperature T show the value of the thermoelectric effect n of the same magnitude and that, although in some cases the thermoelectric effect is somewhat lower for the sample on the semiconductor according to the invention than for the sample on bismuth telluride, the difference will in no case to be so large in this respect that the booklet outweighs the advantage of a lower yard on the heat conduction form A. I In all cases the sample of the semiconductor according to the invention will have a higher value of the goodness number at the temperature T On the sample of bismuth telluride, from which it can be concluded that all the semiconductors according to the invention are superior bismuth telluride for use as conductors in thermocouples.

Den fOrbattring, som uppnas i detta hanseende beror naturligtvis pa halvledarens sammansattning. En sarskilt lamplig sammansattning Or den, vid vilken i konstitutionsformeln BimSbnTepSeqS är sadan, att m har ett varde av 0,35-1,6 och 3q +5r eft varde av 0-0,9. For vane sammansattning inom dessa intervall finnes for bagge ledningstyperna ett relativt vidstrackt intervall fOr vardena pa den elektriska ledningsfOrmagan a vid en given temperatur, vid vilket vardet pa godhetstalet a icke Or avsevart mindre an det maximivarde pa godhetstalet 0, vilket kan uppnas med vismuttellurid med samma ledningstyp och vid samma temperatur. Detta galler sarskilt for alla sammansattningar mom det angivna intervallet for vardeu pa den elektriska ledningsformagan mom intervallet 500-2000 (ohm-centimeter)—Ivid temperaturen 290° K. The improvement achieved in this respect depends, of course, on the composition of the semiconductor. A particularly suitable composition Or the one in which in the constitutional formula BimSbnTepSeqS is such that m has a value of 0.35-1.6 and 3q + 5r after a value of 0-0.9. For customary composition within these ranges, for ram types there is a relatively wide range for the values of the electrical conductivity a at a given temperature at which the value of the goodness number is not Or considerably less than the maximum value of the goodness number 0, which can be achieved with bismuth wire type and at the same temperature. This applies in particular to all assemblies at the specified range for the value of the electrical wiring at the range of 500-2000 (ohm-centimeters) —At the temperature 290 ° K.

De halvledare, som anvandas i termoelement enligt foreliggande uppfinning, kunna framstallas pd foljande satt. Vismut, tellur och minst ett av elementen antimon, selen och svavel placeras tillsammans i en cylindrisk kvartsbomb med en langd av c:a 17,5 cm och en diameter av 2,5 cm. Beskickningens totala vikt installes pa c:a 300 g och proportionerna mellan metallerna svara mot halvledarens onskade sammansattning. Bomben evakueras sa att i densamma erhalles ett absolut tryck, som Or mindre On -6 mm Hg, varefter bomben tillslutes tatt. The semiconductors used in thermocouples according to the present invention can be manufactured in the following manner. Bismuth, tellurium and at least one of the elements antimony, selenium and sulfur are placed together in a cylindrical quartz bomb with a length of about 17.5 cm and a diameter of 2.5 cm. The total weight of the charge is installed at about 300 g and the proportions between the metals correspond to the desired composition of the semiconductor. The bomb is evacuated so that in it an absolute pressure is obtained, such as Or less On -6 mm Hg, after which the bomb is closed taken.

Den fOrslutna bomben varmes sedan i en ugn till 900° C under minst 3 h, fOr att astadkomma fullstandig bildning av halvledaren. Efter kylning till rumstemperatur och urtagning ur bomben in-f Ores satsen i en kvartsskepp med de ungefarliga dimensionerna 15 x 2,5 x 1,8 cm. Beskickningen smaltes sedan natt och jamnt genom hUgfrekvensupphettning under inert atmosfar, sa att den formas efter skeppet och kyles sedan omedelbart till rumstemperatur till bildning av ett fast got. The sealed bomb is then heated in an oven to 900 ° C for at least 3 hours, to achieve complete semiconductor formation. After cooling to room temperature and removing from the bomb, the ores are placed in a quartz vessel with the harmless dimensions of 15 x 2.5 x 1.8 cm. The charge was then melted overnight and evenly by high frequency heating under an inert atmosphere, so that it is formed after the ship and then cooled immediately to room temperature to form a solid cast.

Det stelnade gotet i skeppet underkastas sedan den behandling, vilken Or kand som »zonsmaltping tur och retun, vid vilken en smalt zon bildas vid gotets ena arida och bringas att forflytta sig langs hela gotet forst i den ena riktningen och sedan i motsatt riktning. Denna behandling genomf Ores under langsamt flOde av inert gas vid atmosfarstryck och den smalta zonen fOrflyttas lampligen langs gotet med en hastighet av c:a 2,5 cm/h. The solidified litter in the ship is then subjected to the treatment, which Or kand as "zonmaltping tur and retun, in which a narrow zone is formed at one of the goats' arida and is made to move along the whole litter first in one direction and then in the opposite direction. This treatment is carried out under a slow flow of inert gas at atmospheric pressure and the narrow zone is suitably moved along the gutter at a speed of about 2.5 cm / h.

Gotet visar sig efterat besta. av en slier flera kristaller, vilka samtliga ha sin huvudkristallaxel anordnad vinkelratt mot gotets langdaxel. Det ma framhallas, att vid ett polykristalliserat got de olika kristallernas huvudaxlar icke nodvandigtvis aro parallella med varandra. Om skanklar for termoelement enligt uppfinningen skaras fran ett sadant got, skola de uttagas pa sadant satt, aft deras langdriktning Or parallell med gotets langdaxel. Gotet shows up after best. of a slier several crystals, all of which have their main crystal axis arranged perpendicular to the longitudinal axis of the Goth. It must be pointed out that in a polycrystallized cast the main axes of the different crystals are not necessarily parallel to each other. If shackles for thermocouples according to the invention are cut from such a cast, they should be removed in such a way that their longitudinal direction is parallel to the long axis of the cast.

GOt framstallda ph detta satt ha visat sig vara av p-typ. Gotens elektriska ledningsformaga okar med okning av antimonhalten och minskar med &fling av selen- eller svavelhalten i halvledaren. Well produced ph this sat have turned out to be of p-type. Goten's electrical conductivity increases with increasing the antimony content and decreases with & fling of the selenium or sulfur content in the semiconductor.

For framstallning av material av n-typ Or det nOdva.ndigt att infora nagon donatorstorsubstans i halvledaren. Det kan i manga fall vidare vara lampligt att infora flagon donatorstorsubstans Oven da man onskar material av p-typ, for att det bildade materialets elektriska ledningsfOrmaga skall ligga narmare den optimala ledningsformagan for anvandning av materialet vid framstallning av termoelementskanklar On som skulle vara fallet om nagon sa.dan storsubstans icke tillfordes. Lampliga sLOrsubstanser fOr detta andamal utgoras av jod, brom,klor, tellur och litium. I vissa fall kan det vara lampligt att tillsatta en acceptorstorsubstans. For detta andamal lampa sig metallema bly, kadmium och vismut. Om nagot av dessa grundamnen med undantag for halogenerna anvandes, framstalles halvledaren pa ovan beskrivet satt, varvid storsubstansen i Onskad mangd sattes till ingrediensema for halvledaren i utgangsmaterialet. Om man daremot anvander en halogen, foredras en nagot modifierad metod pa grund av halogenernas flyktighet. For the production of n-type materials, it is necessary to introduce a large donor substance into the semiconductor. Furthermore, in many cases it may be appropriate to introduce the donor large substance flake. Even when p-type material is desired, so that the electrical conductivity of the formed material is closer to the optimal conductivity for use of the material in making thermocouple shackles On which would be the case if any sa.dan large substance was not supplied. Suitable chlorine substances for this purpose are iodine, bromine, chlorine, tellurium and lithium. In some cases it may be appropriate to add an acceptor large substance. For this purpose, the metals lead, cadmium and bismuth light up. If any of these elements, with the exception of the halogens, are used, the semiconductor is prepared in the manner described above, the bulk being added to the desired amount of the semiconductor in the starting material in the desired amount. If, on the other hand, a halogen is used, a slightly modified method is preferred due to the volatility of the halogens.

Ett exempel pa anvandning av jod enligt detta modifierade fOrfarande skall nu beskrivas betraffande ett satt att framstalla vismut-antimontellurid av n-typ och med konstitutionsformeln Bi1,59Sb0,41Te3. Harvid inferes vismut, antimon och tellur samt jod i en cylindrisk kvartsbomb med en langd av c:a 17,5 cm och en diameter av 2,5 cm. Bestandsdelarnas sammanlagda vikt avpassas till c:a 300 g, av vilka joden utgor c:a 0,18 %, varvid proportionerna mellan vismut, antimon och tellur svarar mot vismut-antimon-tellurid med den angivna sammansattningen. Bomben evakueras sedan for astadkommande av ett inre, absoiut tryck, understigande .6 mm Hg och tillslutes sedan tatt. Evakueringstiden standardi- - - seras till c:a 15 min for att joden skallforflyktigas j amnt. An example of the use of iodine according to this modified process will now be described with respect to a method of producing n-type bismuth antimontelluride and having the constitutional formula Bi1.59Sb0.41Te3. Bismuth, antimony and tellurium as well as iodine are then introduced into a cylindrical quartz bomb with a length of about 17.5 cm and a diameter of 2.5 cm. The total weight of the constituents is adjusted to about 300 g, of which the iodine constitutes about 0.18%, the proportions of bismuth, antimony and tellurium corresponding to bismuth-antimony telluride with the stated composition. The bomb is then evacuated to create an internal, absolute pressure, below .6 mm Hg and then sealed. The evacuation time is standardized to about 15 minutes for the iodine to evaporate evenly.

Den forseglade bomben upphettas sedan i en ugn till c:a 900° C under minst 3 h for att astadkomma fullstandig bildning av vismut-antimontelluriden och jamn fOrdelning av joden. Sedan beskickningen har svalnat till rumstemperatur och tagits ut ur bomben infores den i ett kvartsskepp med dimensionerna c:a 15 x 2,5 x 1,8 cm. Beskickningen smaltes sedan natt och jamnt genom induktionsupphettning med hogfrekvens under en inert atmosfar, sa att den antar skeppets form, varefter den omedelbart kyles till rumstemperatur till bildning av ett stelnat got. The sealed bomb is then heated in an oven at about 900 ° C for at least 3 hours to achieve complete formation of the bismuth antimontelluride and even distribution of the iodine. After the mission has cooled to room temperature and been taken out of the bomb, it is introduced into a quartz ship with the dimensions approx. 15 x 2.5 x 1.8 cm. The charge was then melted overnight and evenly by high frequency induction heating under an inert atmosphere so that it assumes the shape of the vessel, after which it is immediately cooled to room temperature to form a solidified can.

Det stelnade gotet i skeppet underkastas sedan en enkel zonsmaltning, vid vilken en smalt zon bildas vid gotets ena ande och bringas att passera langs hela gotet. Denna behandling genomfores under en langsam strom av inert gas vis atmosfarstryck, och den smalta zonen bringas lampligen att rora sig langs g6tet med en hastighet av 2,5 cm/h. The solidified gutter in the ship is then subjected to a simple zone melting, in which a narrow zone is formed at one spirit of the goth and is brought to pass along the entire gutter. This treatment is carried out under a slow stream of inert gas at atmospheric pressure, and the narrow zone is suitably caused to move along the hole at a speed of 2.5 cm / h.

Ocksa efter behandling ph detta salt visar sig det bildade gOtet besta av en eller flera kristaller, vilka samtliga ha huvudkristallaxeln anordnad vinkelratt mot gotets langdaxel. Samma regler galla darfOr aven i detta fall som ovan betraffande orienteringen av termoelementskanklar utskurna ur ett sadant got. Even after treatment with this salt, the formed gout is found to consist of one or more crystals, all of which have the main crystal axis arranged at right angles to the long axis of the goth. The same rules apply therefore in this case as above concerning the orientation of thermocouple shanks cut out of such a cast.

Ett got framstallt enligt ovan visade sig vara likformigt av n-typ, vid en temperatur av 290° K ha en termoelektrisk effekt av c:a - 195 itlirC och en elektrisk ledningsformaga matt i gOtets langdriktning av c:a 1000 (ohm-centimeter)'. A cast made as above was found to be n-type uniform, at a temperature of 290 ° K having a thermoelectric power of about - 195 itlirC and an electrically conductive mat in the longitudinal direction of the cast of about 1000 (ohm-centimeters) '.

I foljande tabell 1 och 2 lamnas uppgifter betraffande halvledare, som kunna anvandas i termoelement enligt foreliggande uppfinning. For vart och ett av exemplen framstalldes ett got pa det lampligaste av de ovan beskrivna forfarandena. Detaljerade uppgifter betraffande sammansattningen framga av tabe111. I denna tabell anges I samtliga fall vardena pa koefficienterna n, q och r i konstitutionsformeln BimSb„TepSec/S, tillsammans med en uppgift pa mangden och arten av den tillsatta storsubstansen i utgangsmaterialet, varvid mangden storsubstans uttryckes som viktforhallandet mellan storsubstansen och den totala vikten pa de i halvledaren ingaende grundamnena. For vart och ett av dessa exempel genomfOrdes matningar vid en temperatur av 290° K pa prov uttagna ur ifragavarande got. Matningarna genomfordes i en riktning, som svarar mot gotets langdaxel. Resultaten av dessa matningar framgh av Label! 2, i vilken for varje exempel anges vardena pa den termoelektriska effekten s (positiv for material av p-typ och negativ for material av n-typ) uttryckt i ,011°C, den elektriska ledningsformagan r, uttryckt i (ohmcentimeter)-1, varmeledningsformagan uttryckt i W/cm°C, godhetstalet 0 beraknat pa det ovan i samband med vismuttellurid angivna sattet, och motsvarande varde for godhetstalet 0 fOr vismuttellurid med samma ledningstyp och elektriska ledningsformaga. The following Tables 1 and 2 disclose data concerning semiconductors which can be used in thermocouples according to the present invention. For each of the examples, a goodness was obtained in the most suitable of the procedures described above. Detailed information regarding the composition can be found in tabe111. In all cases, the values of the coefficients n, q and ri in the constitutional formula BimSb „TepSec / S are given in this table, together with an indication of the amount and nature of the added large substance in the starting material, the amount of large substance being expressed as the weight ratio between the large substance and the total weight of the basic elements contained in the semiconductor. For each of these examples, feeds were performed at a temperature of 290 ° K on samples taken from the cast. The feeds were passed through in a direction corresponding to the longitudinal axis of the goth. The results of these feeds are shown by Label! 2, in which for each example the values of the thermoelectric power s (positive for p-type material and negative for n-type material) expressed in .011 ° C, the electrical conductivity r, expressed in (ohm centimeter) -1 , thermal conductivity expressed in W / cm ° C, the goodness number 0 calculated in the manner specified above in connection with bismuth telluride, and the corresponding value for the goodness number 0 for bismuth telluride with the same type of wire and electrical conductivity.

Tabell 1. Table 1.

Exempel 1 2 71 0,23 0,41 storsubstans 3 0,41 0,18 % jod 4 0,90 0,90 0,12 % jod 6 0,33 7 0,33 0,06 % bly - 0,13 0,075 % bly - 0,22 0,06 % jod 0,38 0,16 0,1 % jod 11 0,82 0,27 12 1,48 0,04% tellur 13 1,58 0,21 5 % tellur 14 0,86 0, 0,83 0,0, Tabell 2. Example 1 2 71 0.23 0.41 large substance 3 0.41 0.18% iodine 4 0.90 0.90 0.12% iodine 6 0.33 7 0.33 0.06% lead - 0.13 0.075 % lead - 0.22 0.06% iodine 0.38 0.16 0.1% iodine 11 0.82 0.27 12 1.48 0.04% tellur 13 1.58 0.21 5% tellur 14 0 , 86 0, 0.83 0.0, Table 2.

Exempel s n(Bi2 Te3) 1 +217 70,0171 0,76 0,73 2 +176 120,0160,82 0,71 3 -196 0,00,86 0,78 4 +147 170,0169 0,80 0,63 +202 80,0134 0,80,73 6 +273 0,0129 0,72 0,52 7 +204 70,0139 0,80 0,73 8 +70,010,80 0,73 9 -228 0,0122 0,82 0,72 -226 590 0,0123 0,84 0,72 11 +181 860 0,010,81 0,73 12 +181400 0,0158 0,94 0,68 13 +156 140,0164 0,79 0,68 14 +169 1100 0,0133 0,83 0,73 +191 60,0113 0,77 0,72 Ett Lerrnoelement framstallt cnligt uppfinningen kommer nu aft beskrivas som exempel med hfinvisning till fig. 5, som Or en schematisk perspektivvy av termoelementet. Detta omf attar en skankel 1 av p-typ och en skankel av n-typ med den sammansattning, som framgar av exemplen 12 och 3 i tabell 1. De bagge skanklarna 1 och 2 ha bagge en langd av 1 cm och en tvarsnittsarea av 0,5 cm. De ha utskurits ur got framstallda pa det fOrsta och det andra av de ovan beskrivna satten sa att deras langdaxlar Oro parallella med motsvarande tackors langdaxlar. Motsvarande andar av skanklarna 1 och 2 Oro elektriskt forbundna medelst en kopparplat 3, som ar fastliidd i skanklarna 1 och 2 och bildar den kalla lOdfogen i termoelementet. Skanklarnas 1 och 2 andra andar aro fastlodda i kopparblock 4 och 5, som bilda den varma fogen i termoelementet och aro forsedda med kylflansar 6 och 7. Skanklarnas 1 och 2 andytor fOrnicklas fore lodningen. Example sn (Bi2 Te3) 1 +217 70.0171 0.76 0.73 2 +176 120.0160.82 0.71 3 -196 0.00.86 0.78 4 +147 170.0169 0.80 0 .63 +202 80.0134 0.80.73 6 +273 0.0129 0.72 0.52 7 +204 70.0139 0.80 0.73 8 +70.010.80 0.73 9 -228 0.0122 0.82 0.72 -226 590 0.0123 0.84 0.72 11 +181 860 0.010.81 0.73 12 +181400 0.0158 0.94 0.68 13 +156 140.0164 0.79 0 , 68 14 +169 1100 0.0133 0.83 0.73 +191 60.0113 0.77 0.72 A learning element according to the invention will now be described by way of example with reference to Fig. 5, which is a schematic perspective view of the thermocouple. This comprises a p-type shank 1 and an n-type shank with the composition shown in Examples 12 and 3 in Table 1. The ram shanks 1 and 2 have a ram a length of 1 cm and a cross-sectional area of 0 , 5 cm. They have been cut out of the well made in the first and second of the ways described above so that their longitudinal axes are parallel to the longitudinal axes of the corresponding ewes. Corresponding spirits of the shanks 1 and 2 are electrically connected by means of a copper plate 3, which is fixed in the shanks 1 and 2 and forms the cold lead joint in the thermocouple. The other ends of the shanks 1 and 2 are soldered to copper blocks 4 and 5, which form the hot joint in the thermocouple and are provided with cooling flanges 6 and 7. The end surfaces of the shanks 1 and 2 are nickel plated.

Detta termoelement lampar sig for kylning av ett foremhl, som anbringas i kontakt med platen 3, exempelvis en. detalj i en daggpunktshygrometer. Harvid seriekopplas ett batten i 8 och ett variabelt motstand 9 mellan kopparblocken 4 och 5, varvid batteriets 8 polar aro installda sasom visas pa ritningen, medan motstandet 9 anvandes for att 6— — variera strommen genom termoelementet och clamed remsans 3 temperatur. This thermocouple is suitable for cooling a mold which is placed in contact with the plate 3, for example one. detail in a dew point hygrometer. In this case a battery 8 and a variable resistor 9 are connected in series between the copper blocks 4 and 5, the poles 8 of the battery being set as shown in the drawing, while the resistor 9 is used to vary the current through the thermocouple and the temperature of the strip 3.

Far en genomsnittlig arbetstemperatur av 290° K dr det nu beskrivna termoelementets totala godhetstal 0 c:a 0,90 berdknat pa samma satt som har beskrivits for vismuttellurid. Vid detta godhetstal dr den storsta, vid en genomsnittlig drifttemperatur av 290° K uppnaeliga temperaturskillnaden mellan den varma och den kalla fogen i termoelernentet c:a 86° C. If the average working temperature is 290 ° K, the total goodness number of the thermocouple now described is about 0.90 in the same way as has been described for bismuth telluride. At this goodness number, the largest, at an average operating temperature of 290 ° K, the achievable temperature difference between the hot and the cold joint in the thermocouple is about 86 ° C.

Claims

Patent claim:

A thermocouple in which at least one shank consists essentially of a semiconductor, which may contain a large substance or impurity, and whose constitutional formula is BiniSbnTepSeqSr, ddr m + n = 2 and p + q-Fr = 3, characterized in that in said formula it has a value of 0-1.8, q a value of 0-0.4 and r a value of 0-0.24, and that 3n-F2q + 2r dr is at least 0.03 and 3q + 5r dr is at most 1,2 and that the semiconductor has a crystal structure similar to bismuth telluride, and the crystal or each crystal in the semiconductor is oriented with its main crystal axis substantially perpendicular to the longitudinal direction of the shank between the joints of the thermocouple.

2. A thermocouple according to claim 1, characterized in that the semiconductor has such a constitutional formula that both q and r are 0.

3. A thermocouple according to claim 1, characterized in that the semiconductor has such a constitutional formula that n has a value of 0.35-1.6 and has a value of 0-0.9, each semiconductor having an electrical conductor shape in the longitudinal direction of the shank at a temperature of 290 ° K, which is at 500-2000 (ohm centimeters) -1.

4. A thermocouple according to any one of claims 1-3, characterized in that the semiconductor contains at least one of the basic elements iodine, bromine, chlorine, tellurium and lithium as donor star substance.

5. A thermocouple according to any one of claims 1-3, characterized in that the semiconductor contains at least one of the basic elements lead, cadmium and bismuth as acceptor substance.

6. Thermocouples according to any one of claims 1-5, characterized in that the shank is made of an elongated cast of semiconductor material, which has been subjected to such zoning as can be treated in such a way that the longitudinal direction of the shank is parallel to the long axis of the cast.

7. Thermocouples according to any one of claims 1-6, characterized in that the semiconductor is of the p-wire type.

Thermocouple according to claim 7, in which ram the conductors drew challenge according to claim 1, one being of p-wire type and the other of n-wire type.

9. In the manufacture of thermocouples according to claim 1, optionally containing a major substance or impurity, and having the general formula BiniSbnTepSegSr, where m + n = 2 and p + q + r = 3, can denote that bismuth, tellurium and at least one of the elements antirnon, selenium and sulfur smalls together in proportions corresponding to said constitutional formula, so that it has a value of 0-1.8, q a value of 0-0.4 and r a value of 0-0 , 24 and 3n + 2q + 2r where at least 0.03 and 3q + 5r are at most 1.2, after which the molten alloy is cast into an elongated, solid cast, which is subjected to zone melting.

10. 8a: ft according to patent claim 9, can be signed & ray, that the zone melting is carried out round trip.

11. According to claim 10, characterized in that a small amount of at least one of the basic elements tellurium, lithium, lead, cadmium and bismuth was added to the starting material.

12. A kit according to claim 9, characterized in that a small amount of at least one of the basic elements iodine, bromine and chlorine was added to the starting material and that the zone melting is carried out as an entouring process. Request publications: Patent Office Germany 872 210; USA 2 762 857. Other publications: Zurnal techni6eskoj fiziki 1956. No. 10, p. 2398. Physical society. London. Journal 69 B (1956): Feb., pp. 203-209.