EP0355431B1 - Alloy as material for control and heating elements having a positive temperature coefficient - Google Patents
Alloy as material for control and heating elements having a positive temperature coefficient Download PDFInfo
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- EP0355431B1 EP0355431B1 EP89113621A EP89113621A EP0355431B1 EP 0355431 B1 EP0355431 B1 EP 0355431B1 EP 89113621 A EP89113621 A EP 89113621A EP 89113621 A EP89113621 A EP 89113621A EP 0355431 B1 EP0355431 B1 EP 0355431B1
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- 239000000463 material Substances 0.000 title claims abstract description 30
- 238000010438 heat treatment Methods 0.000 title claims abstract description 16
- 229910045601 alloy Inorganic materials 0.000 title claims description 31
- 239000000956 alloy Substances 0.000 title claims description 31
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 62
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 38
- 229910052742 iron Inorganic materials 0.000 claims description 30
- 229910052759 nickel Inorganic materials 0.000 claims description 18
- 229910017052 cobalt Inorganic materials 0.000 claims description 12
- 239000010941 cobalt Substances 0.000 claims description 12
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 12
- 239000000654 additive Substances 0.000 claims description 7
- 230000008859 change Effects 0.000 abstract description 2
- 239000000203 mixture Substances 0.000 description 9
- 230000009466 transformation Effects 0.000 description 7
- 238000000034 method Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 238000005245 sintering Methods 0.000 description 5
- 230000007704 transition Effects 0.000 description 5
- 239000011572 manganese Substances 0.000 description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 229910052748 manganese Inorganic materials 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 229910020598 Co Fe Inorganic materials 0.000 description 1
- 229910001313 Cobalt-iron alloy Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000156 glass melt Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000010309 melting process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000007781 pre-processing Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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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
- H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
Definitions
- the invention relates to an alloy as a material for control or heating elements according to the preamble of claim 1.
- Materials for control or heating elements with a positive temperature coefficient of electrical resistance have an electrical resistance that increases with increasing temperature. After a voltage is applied, a comparatively high current flows, which then decreases with increasing heating of the resistance element. There is thus a certain self-regulation effect. For this reason, materials for resistance elements with a positive temperature coefficient of electrical resistance are often used for control or heating elements. Due to their initially low resistance, they allow a high heating rate. By limiting the current as the temperature rises due to the positive temperature coefficient of the resistor, damage to the resistor element or its surroundings can be prevented even at high heating rates.
- An electrical resistance heating element made of a material with a high positive temperature coefficient of electrical resistance is known for example from DE-OS 25 39 841. Nickel is mentioned as the material there.
- the same document discloses the use of the element for thermal switches.
- the object of the invention is to provide a material for a control and heating elements, which allows an increased heating rate with improved control behavior.
- An essential advantage of the material according to the invention for resistance elements is the special course of the resistance curve as a function of the temperature.
- 2 shows the corresponding resistance ratio for an alloy with the composition of 71% by weight cobalt and 29% by weight iron (3).
- the course of the resistance ratio of the materials according to the invention shows a relatively small increase up to the temperature T1 and then a steep, e.g. T. even abrupt increase. It therefore favors short heating-up times when temperatures of around 1000 ° C are to be reached.
- the material according to the invention has a cubic body-centered structure ( ⁇ ), in the range between 750 and 900 ° C. there is a transition to a cubic face-centered structure ( ⁇ ).
- the transition temperature T1 depends on the iron content in the respective alloy composition and increases with increasing iron content.
- the conversion from the face-centered cubic structure ( ⁇ ) to the body-centered cubic structure ( ⁇ ) takes place at a temperature lower than T1, which results in a hysteresis curve.
- the hysteresis decreases with increasing iron content.
- the course of the resistance ratio for the material according to the invention initially shows a relatively flat increase, which enables higher heating rates.
- the resistance then rises steeply, the current intensity and thus the heat output generated correspondingly decrease sharply. This self-regulation allows the final temperature to be reached quickly without the resistance element itself being damaged.
- the ⁇ / ⁇ conversion occurs in cobalt-iron alloys with an iron content of more than 20% by weight.
- the alloys can also contain nickel, but only to such an extent that the body-centered cubic structure is retained at room temperature.
- the permissible nickel content increases with increasing iron content.
- the maximum nickel content at which the alloy has a body-centered cubic structure at room temperature can be approximated by linear interpolation between the values of approximately 0% by weight with an iron content of 20% by weight and 15% by weight with an iron content of 35% by weight can be determined. With an iron content of 25% by weight, the nickel content can be a maximum of 5% by weight and with an iron content of 30% by weight a maximum of 10% by weight. be.
- the alloys can contain other elements, e.g. B. as processing additives with a proportion of up to 1 wt.% Contain.
- the alloys according to the invention are readily cold-formable and can be processed well into wires and strips or the like. Alloys with an iron content of more than 35% by weight, on the other hand, are becoming increasingly brittle due to the development of order.
- the alloys according to the invention can be used particularly advantageously as a material for glow plugs for diesel engines. There they can be used directly as a heating element or as a control element in connection with a heating element with a lower positive temperature coefficient.
- the table lists the ⁇ / ⁇ transformation temperature T1, the specific electrical resistance at room temperature and at 1000 ° C. and the resulting temperature factor TF both for materials according to the invention and for iron and nickel.
- Example a An alloy consisting of 79% by weight cobalt and 21% by weight iron was produced in the sintering process.
- the ⁇ / ⁇ transformation temperature is 750 ° C.
- the temperature factor TF 15 is calculated from the values of the specific resistance at room temperature and at 1000 ° C.
- Example b): For an alloy also produced in the sintering process, consisting of 77% by weight of cobalt and 23% by weight of iron, the ⁇ / ⁇ transformation temperature T1 is 780 ° C. and the temperature factor is TF 16.
- Example e A material with a composition of 71% by weight cobalt and 29% by weight iron was produced in the sintering process.
- T1 850 ° C
- TF 16.5
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Abstract
Description
Die Erfindung betrifft eine Legierung als Werkstoff für Regel- oder Heizelemente nach dem Oberbegriff des Patentanspruchs 1.The invention relates to an alloy as a material for control or heating elements according to the preamble of claim 1.
Werkstoffe für Regel- oder Heizelemente mit einem positiven Temperaturkoeffizienten des elektrischen Widerstandes weisen einen elektrischen Widerstand auf, der mit steigender Temperatur zunimmt. Nach Anlegen einer Spannung fließt zunächst ein vergleichsweise hoher Strom, der dann mit zunehmender Erwärmung des Widerstandselementes abnimmt. Es findet somit ein gewisser Selbstregelungseffekt statt. Aus diesem Grunde werden Werkstoffe für Widerstandselemente mit einem positiven Temperaturkoeffizienten des elektrischen Widerstandes häufig für Regel- oder Heizelemente eingesetzt. Durch ihren zunächst niedrigen Widerstand erlauben sie eine hohe Aufheizrate. Durch die Strombegrenzung bei steigender Temperatur aufgrund des positiven Temperaturkoeffizienten des Widerstandes kann eine Schädigung des Widerstandselementes oder seiner Umgebung auch bei hohen Aufheizraten verhindert werden.Materials for control or heating elements with a positive temperature coefficient of electrical resistance have an electrical resistance that increases with increasing temperature. After a voltage is applied, a comparatively high current flows, which then decreases with increasing heating of the resistance element. There is thus a certain self-regulation effect. For this reason, materials for resistance elements with a positive temperature coefficient of electrical resistance are often used for control or heating elements. Due to their initially low resistance, they allow a high heating rate. By limiting the current as the temperature rises due to the positive temperature coefficient of the resistor, damage to the resistor element or its surroundings can be prevented even at high heating rates.
Ein elektrisches Widerstandsheizelement aus einem Werkstoff mit einem hohen positiven Temperaturkoeffizienten des elektrischen Widerstandes ist zum Beispiel aus der DE-OS 25 39 841 bekannt. Als Werkstoff wird dort Nickel genannt. Zusätzlich wird in der gleichen Schrift die Verwendung des Elements für Thermoschalter offenbart.An electrical resistance heating element made of a material with a high positive temperature coefficient of electrical resistance is known for example from DE-OS 25 39 841. Nickel is mentioned as the material there. In addition, the same document discloses the use of the element for thermal switches.
Weiterhin ist die Ausnutzung des Regelverhaltens von Widerstandselementen mit hohem positivem Temperaturkoeffizienten des elektrischen Widerstandes in Glühkerzen für Dieselmotoren aus mehreren Patentschriften bekannt. Anordnungen mit Widerstandselementen nach dem Stand der Technik sind zum Beispiel aus der DE-PS 28 02 625, der DE-OS 21 15 620 oder der GB-PS 254 482 sowie aus dem Artikel von H. Weil in "Bosch Techn. Berichte" 5 (1977), S. 279 - 286 bekannt. Als entsprechende Werkstoffe werden in der GB-PS 254 482 Eisen, Nickel und Platin genannt. Aus der DE-OS 2 115 620 ist die Verwendung einer Nickel-Eisen-Legierung bekannt.
Schließlich wird in "Siemens Forschungs- und Entwicklungsbericht" Band 4, Nr. 5, 1975, S. 257 - 264, Springer Verlag, F. Geyer et al.:"Magnetisch halbharte Legierungen auf Co-Fe-Ni-Basis mit 40 - 60 % Kobalt-Massengehalt" in Tabelle 1 eine Legierung beschrieben, die aus 55 Gew.% Co, 12 Gew.% Ni und 33 Gew.% Fe besteht. In dieser Veröffentlichung wird die Wärmeausdehnung unter anderem dieser Legierung als Glaseinschmelzung für Metall/Glas-Verbundwerkstoffe untersucht, wobei der Zerfall der kubisch-raumzentrierten Phase in raumzentrierte und flächenzentrierte Gefügebestandteile mittels der Messung des elektrischen Widerstandes ermittelc, wodurch Hinweise auf die verbundstoffspezifischen Probleme der Wärmeausdehnung bei Glaseinschmelzungen solcher Legierungen gewonnen werden.
Aufgabe der Erfindung ist es, einen Werkstoff für ein Regel- und Heizelemente anzugeben, der eine erhöhte Aufheizgeschwindigkeit bei gleichzeitig verbessertem Regelverhalten erlaubt.Furthermore, the exploitation of the control behavior of resistance elements with a high positive temperature coefficient of electrical resistance in glow plugs for diesel engines is known from several patents. Arrangements with resistance elements according to the prior art are, for example, from DE-PS 28 02 625, DE-OS 21 15 620 or GB-PS 254 482 and from the article by H. Weil in "Bosch Technical Reports" 5 (1977), pp. 279-286. GB-PS 254 482 mentions iron, nickel and platinum as corresponding materials. The use of a nickel-iron alloy is known from DE-OS 2 115 620.
Finally, in "Siemens Research and Development Report"
The object of the invention is to provide a material for a control and heating elements, which allows an increased heating rate with improved control behavior.
Diese Aufgabe wird durch die Merkmale des Patentanspruchs 1 gelöst.
Weitere vorteilhafte Ausgestaltungen der Erfindungen ergeben sich aus dem nachfolgenden Anspruch 2.
Wählt man zur Darstellung der Widerstands-Charakteristik der Werkstoffe für Widerstandselemente mit positivem Temperaturkoeffizienten, den Temperaturfaktor TF = R(1000°C) / R(20°C), der das Widerstandsverhältnis bei einer Temperatur von 1000°C und bei Raumtemperatur angibt, so ergibt sich TF = 4 für Platin, TF = 7 für Nickel und TF = 12 für Eisen. Mit dem erfindungsgemäßen Werkstoff werden dagegen Temperaturfaktoren TF > 12 erzielt. Desweiteren weist bei dem erfindungsgemäßen Werkstoff die Widerstandskurve in Abhängigkeit von der Temperatur einen Verlauf auf, der kurze Aufheizzeiten begünstigt.
Anhand der in der Tabelle aufgeführten Ausführungsbeispiele und des in Fig. 1 und 2 dargestellten Widerstandsverhältnisses R(T) / R(20°C) in Abhängigkeit von der Temperatur für erfindungsgemäße Werkstoffe und für Werkstoffe nach dem Stand der Technik soll die Erfindung näher erläutert werden.This object is achieved by the features of patent claim 1.
Further advantageous embodiments of the inventions result from the following
To display the resistance characteristics of the materials for resistance elements with a positive temperature coefficient, choose the temperature factor TF = R (1000 ° C) / R (20 ° C), which indicates the resistance ratio at a temperature of 1000 ° C and at room temperature TF = 4 for platinum, TF = 7 for Nickel and TF = 12 for iron. In contrast, temperature factors TF> 12 are achieved with the material according to the invention. Furthermore, in the material according to the invention, the resistance curve has a profile as a function of the temperature, which promotes short heating-up times.
On the basis of the exemplary embodiments listed in the table and the resistance ratio R (T) / R (20 ° C.) shown in FIGS. 1 and 2 as a function of the temperature for materials according to the invention and for materials according to the prior art, the invention will be explained in more detail .
Ein wesentlicher Vorteil des erfindungsgemäßen Werkstoffes für Widerstandselemente ist der spezielle Verlauf der Widerstandskurve in Abhängigkeit von der Temperatur. In Fig. 1 ist das Widerstandsverhältnis R(T) / R(20°C) für eine Legierung, bestehend aus 79 Gew.% Kobalt und 21 Gew.% Eisen (1), sowie für eine Legierung bestehend aus 75 Gew.% Kobalt und 25 Gew.% Eisen (2) dargestellt. Fig. 2 zeigt das entsprechende Widerstandsverhältnis für eine Legierung mit der Zusammensetzung von 71 Gew.% Kobalt und 29 Gew.% Eisen (3). Der Verlauf des Widerstandsverhältnisses der erfindungsgemäßen Werkstoffe zeigt bis zur Temperatur T1 einen relativ geringen Anstieg und daran anschließend einen steilen, z. T. sogar sprungartigen Anstieg. Er begünstigt somit kurze Aufheizzeiten, wenn Temperaturen um etwa 1000°C erreicht werden sollen.An essential advantage of the material according to the invention for resistance elements is the special course of the resistance curve as a function of the temperature. In Fig. 1, the resistance ratio R (T) / R (20 ° C) for an alloy consisting of 79 wt.% Cobalt and 21 wt.% Iron (1), and for an alloy consisting of 75 wt.% Cobalt and 25% by weight of iron (2). 2 shows the corresponding resistance ratio for an alloy with the composition of 71% by weight cobalt and 29% by weight iron (3). The course of the resistance ratio of the materials according to the invention shows a relatively small increase up to the temperature T1 and then a steep, e.g. T. even abrupt increase. It therefore favors short heating-up times when temperatures of around 1000 ° C are to be reached.
Die Ursache für diesen besonderen Verlauf der Widerstandskurve ist in einer Phasenumwandlung zu sehen. Bei Raumtemperatur weist der erfindungsgemäße Werkstoff eine kubisch raumzentrierte Struktur (α) auf, im Bereich zwischen 750 und 900°C findet ein Ubergang zu einer kubisch flächenzentrierten Struktur (γ) statt. Die Umwandlungstemperatur T1 ist vom Eisenanteil in der jeweiligen Legierungszusammensetzung abhängig und steigt mit zunehmendem Eisengehalt an. Bei der Abkühlung erfolgt die Umwandlung von der kubisch flächenzentrierten Struktur (γ) zur kubisch raumzentrierten Struktur (α) bei einer Temperatur, die niedriger liegt als T1, wodurch eine Hysteresekurve entsteht. Die Hysterese wird mit steigendem Eisengehalt kleiner.The reason for this special course of the resistance curve can be seen in a phase change. At room temperature, the material according to the invention has a cubic body-centered structure (α), in the range between 750 and 900 ° C. there is a transition to a cubic face-centered structure (γ). The transition temperature T1 depends on the iron content in the respective alloy composition and increases with increasing iron content. When cooling, the conversion from the face-centered cubic structure (γ) to the body-centered cubic structure (α) takes place at a temperature lower than T1, which results in a hysteresis curve. The hysteresis decreases with increasing iron content.
In Fig. 1 und 2 ist zusätzlich zum Vergleich in Kurve 4 das Widerstandsverhältnis R(T) / R(20°C) für Eisen und in Fig. 1 in Kurve 5 dasjenige für Nickel aufgetragen, also von Werkstoffen für Widerstandselemente mit positivem Temperaturkoeffizienten nach dem Stand der Technik. Die Kurve 5 für Nickel flacht bereits bei einer Temperatur von weniger als 400°C und diejenige für Eisen bei einer Temperatur von 800°C ab. Dieses Abflachen ist auf das Erreichen der Curietemperatur zurückzuführen.1 and 2, in addition to the comparison in
Der Verlauf des Widerstandsverhältnisses für den erfindungsgemäßen Werkstoff weist demgegenüber zunächst einen relativ flachen Anstieg auf, wodurch höhere Aufheizraten ermöglicht werden. Bei Erreichen der α/γ -Umwandlungstemperatur T1 steigt der Widerstand dann steil an, die Stromstärke und damit die erzeugte Wärmeleistung nehmen entsprechend stark ab. Diese Selbstregelung erlaubt die schnelle Erzielung der Endtemperatur, ohne daß das Widerstandselement selbst geschädigt wird.In contrast, the course of the resistance ratio for the material according to the invention initially shows a relatively flat increase, which enables higher heating rates. When the α / γ transformation temperature T1 is reached, the resistance then rises steeply, the current intensity and thus the heat output generated correspondingly decrease sharply. This self-regulation allows the final temperature to be reached quickly without the resistance element itself being damaged.
Die α/γ-Umwandlung tritt bei Kobalt-Eisen-Legierungen mit einem Eisengehalt von mehr als 20 Gew.% auf. Die Legierungen können zusätzlich auch noch Nickel enthalten, jedoch nur bis zu einem solchen Anteil, daß die kubisch raumzentrierte Struktur bei Raumtemperatur erhalten bleibt. Der zulässige Nickelanteil steigt mit zunehmendem Eisenanteil an. Der maximale Nickelgehalt, bei dem die Legierung bei Raumtemperatur eine kubisch raumzentrierte Struktur aufweist, kann annähernd durch lineare Interpolation zwischen den Werten von etwa 0 Gew.-% bei einem Eisenanteil von 20 Gew.-% und 15 Gew.-% bei einem Eisenanteil von 35 Gew.-% ermittelt werden. Bei einem Eisengehalt vcn 25 Gew.% kann der Nickelanteil maximal 5 Gew.% und bei einem Eisengehalt von 30 Gew.% maximal 10 Gew.% betragen. Zusätzlich können die Legierungen andere Elemente, z. B. als Verarbeitungszusätze mit einem Anteil von bis zu 1 Gew.% enthalten.The α / γ conversion occurs in cobalt-iron alloys with an iron content of more than 20% by weight. The alloys can also contain nickel, but only to such an extent that the body-centered cubic structure is retained at room temperature. The permissible nickel content increases with increasing iron content. The maximum nickel content at which the alloy has a body-centered cubic structure at room temperature can be approximated by linear interpolation between the values of approximately 0% by weight with an iron content of 20% by weight and 15% by weight with an iron content of 35% by weight can be determined. With an iron content of 25% by weight, the nickel content can be a maximum of 5% by weight and with an iron content of 30% by weight a maximum of 10% by weight. be. In addition, the alloys can contain other elements, e.g. B. as processing additives with a proportion of up to 1 wt.% Contain.
Die erfindungsgemäßen Legierungen sind gut kalt umformbar und können gut zu Drähten und Bändern oder dergleichen verarbeitet werden. Legierungen mit einem Eisengehalt von mehr als 35 Gew.% werden dagegen aufgrund der sich ausbildenden Ordnungseinstellung zunehmend spröde. Besonders vorteilhaft können die erfindungsgemäßen Legierungen als Werkstoff für Glühkerzen für Dieselmotore eingesetzt werden. Sie können dort direkt als Heizelement verwendet werden oder auch als Regelelement in Verbindung mit einem Heizelement mit geringerem positiven Temperaturkoeffizienten.The alloys according to the invention are readily cold-formable and can be processed well into wires and strips or the like. Alloys with an iron content of more than 35% by weight, on the other hand, are becoming increasingly brittle due to the development of order. The alloys according to the invention can be used particularly advantageously as a material for glow plugs for diesel engines. There they can be used directly as a heating element or as a control element in connection with a heating element with a lower positive temperature coefficient.
Weitere vorteilhafte Anwendungsgebiete sind zum Beispiel die Verwendung als Heizelement bei Haushalts-Durchlauferhitzern oder auch die Verbindung in Thermoschaltern.Further advantageous fields of application are, for example, the use as a heating element in domestic instantaneous water heaters or also the connection in thermal switches.
In der Tabelle sind die α/γ-Umwandlungstemperatur T1, der spezifische elektrische Widerstand bei Raumtemperatur und bei 1000°C sowie der sich daraus ergebende Temperaturfaktor TF sowohl für erfindungsgemäße Werkstoffe, als auch für Eisen und Nickel aufgelistet.The table lists the α / γ transformation temperature T1, the specific electrical resistance at room temperature and at 1000 ° C. and the resulting temperature factor TF both for materials according to the invention and for iron and nickel.
Beispiel a): Eine Legierung, bestehend aus 79 Gew.% Kobalt und 21 Gew.% Eisen wurde im Sinterverfahren hergestellt. Für diese Legierungszusammensetzung beträgt die α/γ-Umwandlungstemperatur 750°C. Aus den Werten des spezifischen Widerstandes bei Raumtemperatur und bei 1000°C errechnet sich der Temperaturfaktor TF = 15.Example a): An alloy consisting of 79% by weight cobalt and 21% by weight iron was produced in the sintering process. For this alloy composition, the α / γ transformation temperature is 750 ° C. The temperature factor TF = 15 is calculated from the values of the specific resistance at room temperature and at 1000 ° C.
Beispiel b): Für eine ebenfalls im Sinterverfahren hergestellte Legierung bestehend aus 77 Gew.% Kobalt und 23 Gew.% Eisen beträgt die α/γ-Umwandlungstemperatur T1 780°C und für den Temperaturfaktor ergibt sich TF = 16.Example b): For an alloy also produced in the sintering process, consisting of 77% by weight of cobalt and 23% by weight of iron, the α / γ transformation temperature T1 is 780 ° C. and the temperature factor is TF = 16.
Beispiel c): Eine Legierung mit einer Zusammensetzung von 75 Gew.% Kobalt und 25 Gew.% Eisen, die ebenfalls im Sinterverfahren hergestellt wurde, wies die folgenden Werte auf: T1 = 825°C, TF = 17,5.
Beispiel d): Eine Legierung mit der im wesentlichen gleichen Zusammensetzung wie in Beispiel c) wurde im Schmelzverfahren hergestellt. Zu diesem Zweck wurden 0,2 Gew.% Mangan und 0,1 Gew.% Silizium als Verarbeitungszusätze hinzugefügt, der Eisenanteil betrug 25 Gew.% , der Rest war Kobalt. Die α/γ-Umwandlungstemperatur T1 war unverändert gegenüber der im Sinterverfahren hergestellten Legierung aus Beispiel c). Bedingt durch die Verarbeitungszusätze erhöhte sich jedoch der spezifische Widerstand. Dadurch war auch der Temperaturfaktor TF mit dem Wert TF = 15 etwas niedriger als bei dem gesinterten Werkstoff ohne Legierungszusätze aus Beispiel c).Example c): An alloy with a composition of 75% by weight cobalt and 25% by weight iron, which was also produced by the sintering process, had the following values: T1 = 825 ° C, TF = 17.5.
Example d): An alloy with essentially the same composition as in example c) was produced by the melting process. For this purpose, 0.2% by weight of manganese and 0.1% by weight of silicon were added as processing additives, the iron content was 25% by weight, the rest was cobalt. The α / γ transformation temperature T1 was unchanged compared to the alloy from example c) produced by the sintering process. However, the specific resistance increased due to the processing additives. As a result, the temperature factor TF with the value TF = 15 was somewhat lower than with the sintered material without alloy additives from example c).
Beispiel e): Ein Werkstoff mit einer Zusammensetzung von 71 Gew.% Kobalt und 29 Gew.% Eisen wurde im Sinterverfahren hergestellt. Die α/γ-Umwandlungstemperatur T1 betrug 900°C, für den Temperaturkoeffizient wurde der Wert TF = 20 ermittelt. Ein Vergleich mit den vorgenannten Beispielen, die einen geringeren Eisengehalt aufweisen, zeigt, daß sowohl die α/γ-Umwandlungstemperatur T1 als auch der Temperaturfaktor TF mit zunehmendem Eisenanteil ansteigen.Example e): A material with a composition of 71% by weight cobalt and 29% by weight iron was produced in the sintering process. The α / γ transformation temperature T1 was 900 ° C, the value TF = 20 was determined for the temperature coefficient. A comparison with the aforementioned examples, which have a lower iron content, shows that both the α / γ transformation temperature T1 and the temperature factor TF increase with increasing iron content.
Beispiel f): Ein aus der Schmelze hergestellter Werkstoff mit einer Zusammensetzung von 25 Gew.% Eisen, 5 Gew.% Nickel, 0,2 Gew.% Mangan und 0,1 Gew.% Silizium als Verarbeitungszusätze, Rest Kobalt wies eine α/γ-Umwandlungstemperatur T1 von 810°C und einen Temperaturfaktor TF = 17 auf.Example f): A material produced from the melt with a composition of 25% by weight iron, 5% by weight nickel, 0.2% by weight manganese and 0.1% by weight silicon as processing additives, the rest cobalt had an α / γ transition temperature T1 of 810 ° C and a temperature factor TF = 17.
Beispiel g): Ein aus der Schmelze hergestellter Werkstoff mit einer Zusammensetzung von 30 Gew.% Eisen, 10 Gew.% Nickel, 0,2 Gew.% Mangan und 0,1 Gew.% Silizium als Vorarbeitungszusätze, Rest Kobalt wies eine α/γ-Umwandlungstemperatur T1 von 850°C und einen Temperaturfaktor TF = 16,5 auf. Es werden somit auch bei Legierungen, die einen Nickelanteil aufweisen, hohe Temperaturkoeffizienten TF erreicht. Bei weiter steigendem Nickelanteil weisen die Legierungen jedoch auch bei Raumtemperatur bereits die kubisch flächenzentrierte Struktur auf und die spezielle Charakteristik der Widerstandskurve, die auf dem Übergang von kubisch raumzentrierter zu kubisch flächenzentrierter Struktur beruht, geht verloren.Example g): A material produced from the melt with a composition of 30% by weight iron, 10% by weight nickel, 0.2% by weight manganese and 0.1% by weight silicon as preprocessing additives, the rest cobalt had an α / γ transition temperature T1 of 850 ° C and a temperature factor TF = 16.5. Thus, even with alloys that have a nickel content, high temperature coefficients TF reached. If the proportion of nickel continues to increase, however, the alloys already have the face-centered cubic structure even at room temperature and the special characteristic of the resistance curve, which is based on the transition from face-centered cubic to face-centered structure, is lost.
Die in Tab. I aufgeführten Beispiele belegen, daß mit einem erfindungsgemäßen Werkstoff ein Temperaturfaktor TF > 12 erreicht wird, d. h. ein Temperaturfaktor, der größer ist, als bei den bisher bekannten Werkstoffen für Widerstandselemente mit positivem Temperaturkoeffizienten.The examples listed in Tab. I demonstrate that a temperature factor TF> 12 is achieved with a material according to the invention, i. H. a temperature factor that is greater than that of the previously known materials for resistance elements with a positive temperature coefficient.
Claims (2)
- Alloy as a material for control or heating elements, especially in glow plugs for diesel engines, domestic flow heaters and thermal switches, having a high positive temperature coefficient of electrical resistance, wherein the alloy has a high ratio of resistance values at temperatures above 750°C and at room temperature and also a non-linear, initially flat and then steep increase in resistance with temperature and at room temperature a cubic body-centred structure which becomes a face-centred structure when heated in the range of between room temperature and 1000°C, wherein the alloy comprises from 20 to 35% by weight of iron, from 0 to 15% by weight of nickel, up to 1% by weight of processing additives with the remainder being cobalt, except for the alloy comprising 55% by weight of Co, 12% by weight of Ni and 33% of Fe.
- Alloy according to Claim 2, characterised in that the maximum nickel content is determined by approximately linear interpolation between the values 0% by weight of nickel with an iron content of 20% by weight and 15% by weight of nickel with an iron content of 35% by weight.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3825012A DE3825012A1 (en) | 1988-07-22 | 1988-07-22 | MATERIAL FOR AN ELECTRICAL RESISTANCE ELEMENT WITH POSITIVE TEMPERATURE COEFFICIENT |
| DE3825012 | 1988-07-22 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0355431A2 EP0355431A2 (en) | 1990-02-28 |
| EP0355431A3 EP0355431A3 (en) | 1991-11-06 |
| EP0355431B1 true EP0355431B1 (en) | 1997-01-15 |
Family
ID=6359357
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP89113621A Expired - Lifetime EP0355431B1 (en) | 1988-07-22 | 1989-07-24 | Alloy as material for control and heating elements having a positive temperature coefficient |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5093555A (en) |
| EP (1) | EP0355431B1 (en) |
| JP (1) | JP2961124B2 (en) |
| AT (1) | ATE147881T1 (en) |
| DE (2) | DE3825012A1 (en) |
| ES (1) | ES2099694T3 (en) |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3825013A1 (en) * | 1988-07-22 | 1990-01-25 | Beru Werk Ruprecht Gmbh Co A | Heater plug |
| DE4010479A1 (en) * | 1990-03-31 | 1991-10-02 | Bosch Gmbh Robert | GLOW PLUG FOR INTERNAL COMBUSTION ENGINES |
| JP2806195B2 (en) * | 1993-01-14 | 1998-09-30 | 株式会社デンソー | Glow plug |
| DE4301252A1 (en) * | 1993-01-19 | 1994-07-21 | Beru Werk Ruprecht Gmbh Co A | Pole flame glow plug |
| JP3802599B2 (en) * | 1995-12-28 | 2006-07-26 | 日本特殊陶業株式会社 | Electrically heated sheathed heater and self-temperature control type glow plug |
| DE19621689A1 (en) * | 1996-05-30 | 1997-12-04 | Ego Elektro Geraetebau Gmbh | Electrical resistance temperature sensor |
| US6064039A (en) * | 1998-04-15 | 2000-05-16 | Ngk Spark Plug Co., Ltd. | Glow plug with small-diameter sheath tube enclosing heating and control coils |
| WO2001016528A1 (en) * | 1999-08-27 | 2001-03-08 | Robert Bosch Gmbh | Ceramic sheathed element glow plug |
| DE10014526B4 (en) * | 2000-03-23 | 2006-07-27 | NGK Spark Plug Co., Ltd., Nagoya | Self-regulating quick heating rod glow plug |
| JP2002098333A (en) | 2000-09-26 | 2002-04-05 | Ngk Spark Plug Co Ltd | Glow plug |
| DE10060273C1 (en) * | 2000-12-05 | 2001-12-13 | Vacuumschmelze Gmbh & Co Kg | Glow plug for use in combustion chamber of IC engine comprises a dielectric resistance element composed of two resistance coils, one of which maintains a body-centered cubic crystal structure during all operational states |
| EP2378111A1 (en) * | 2002-05-14 | 2011-10-19 | NGK Spark Plug Co., Ltd. | Glow plug |
| DE10248812A1 (en) | 2002-10-19 | 2004-04-29 | Robert Bosch Gmbh | Standard filament material for a glow plug |
| AU2003201228A1 (en) * | 2003-01-02 | 2004-07-29 | Genadiy A. Govor | Monolithic self-regulating metal-ceramic heater |
| DE10314218A1 (en) | 2003-03-28 | 2004-10-14 | Vacuumschmelze Gmbh & Co. Kg | Electric heating element |
| DE102004025854B4 (en) * | 2004-05-24 | 2006-09-21 | Vacuumschmelze Gmbh & Co. Kg | Glow plug for internal combustion engines |
| JP4854459B2 (en) * | 2006-10-06 | 2012-01-18 | 住友電気工業株式会社 | Glow plug |
| DE102008043228A1 (en) * | 2008-10-28 | 2010-04-29 | Hilti Aktiengesellschaft | Internal combustion setting device |
Family Cites Families (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB254482A (en) * | 1925-06-05 | 1926-07-08 | Bernard Hopps | Improvements relating to ignition plugs for internal combustion engines |
| DE678324C (en) * | 1931-10-16 | 1939-07-15 | Kohle Und Eisenforschung G M B | Use of a steel alloy known per se for the production of electrical heating wires |
| DE739626C (en) * | 1940-01-23 | 1943-09-30 | Graetz A G | Heating device for electric travel equipment |
| GB1127454A (en) * | 1965-10-11 | 1968-09-18 | Cav Ltd | Starting aids for internal combustion engines |
| DE1927334C3 (en) * | 1969-05-29 | 1978-04-20 | Vacuumschmelze Gmbh, 6450 Hanau | Heat-resistant nickel-iron alloy |
| DE2115620A1 (en) * | 1971-03-31 | 1972-10-12 | Robert Bosch Gmbh, 7000 Stuttgart | Flame glow plug for starting diesel engines |
| DE2539841A1 (en) * | 1975-09-08 | 1977-03-17 | Krah & Co Elektrotechnische Fa | Heating element for fluids - has resistance wire with high positive temp. coefficient of resistance to give rapid heat up |
| US4168344A (en) * | 1975-11-19 | 1979-09-18 | Trw Inc. | Vitreous enamel material for electrical resistors and method of making such resistors |
| DE2802625C3 (en) * | 1978-01-21 | 1985-07-18 | BERU Ruprecht GmbH & Co KG, 7140 Ludwigsburg | Glow plug |
| JPS56119422A (en) * | 1980-02-26 | 1981-09-19 | Jidosha Kiki Co Ltd | Fast-heated preheating plug for use in diesel engine |
| JPS57115623A (en) * | 1981-01-07 | 1982-07-19 | Hitachi Ltd | Heat resistant member in preheating plug for diesel engine |
| JPS57115622A (en) * | 1981-01-07 | 1982-07-19 | Hitachi Ltd | Heat resistant member in preheating plug for diesel engine |
| JPS5883124A (en) * | 1981-11-13 | 1983-05-18 | Hitachi Ltd | Heating resistance unit for glow plug |
| US4423309A (en) * | 1982-06-28 | 1983-12-27 | General Motors Corporation | Quick heat self regulating electric glow heater |
| JPS59231321A (en) * | 1983-06-13 | 1984-12-26 | Ngk Spark Plug Co Ltd | Self-control type glow plug |
| DE8705865U1 (en) * | 1987-04-22 | 1987-09-17 | Ngk Spark Plug Co., Ltd., Nagoya, Aichi | Glow plug |
| GB2216952B (en) * | 1988-03-16 | 1991-10-02 | Wellman Automotive Products Li | Glow plugs |
-
1988
- 1988-07-22 DE DE3825012A patent/DE3825012A1/en not_active Withdrawn
-
1989
- 1989-07-21 JP JP1190418A patent/JP2961124B2/en not_active Expired - Fee Related
- 1989-07-21 US US07/384,632 patent/US5093555A/en not_active Expired - Lifetime
- 1989-07-24 AT AT89113621T patent/ATE147881T1/en active
- 1989-07-24 DE DE58909765T patent/DE58909765D1/en not_active Expired - Fee Related
- 1989-07-24 ES ES89113621T patent/ES2099694T3/en not_active Expired - Lifetime
- 1989-07-24 EP EP89113621A patent/EP0355431B1/en not_active Expired - Lifetime
Non-Patent Citations (3)
| Title |
|---|
| PATENT ABSTRACTS OF JAPAN, Band 6, Nr. 210 (M-166)(1088), 22. Oktober 1982;& JP-A-57115622 * |
| PHYSICAL REVIEWS, Band 65, II, 1.Januar - 15.Juni 1944, Seite 347, B2, S.SIEGEL et al.: "Anamalous behavior of the electrical resistivity of some iron-cobalt alloys" * |
| SIEMENS FORSCHUNGS-UND ENTWICKLUNGSBERICHT, Band 4, Nr. 5, 1975, Seiten 257-264, Springer Verlag, F.GEYER et al.: "Magnetisch halbharte Legierungen auf Co-Fe-Ni-Basis mit 40% bis 60% Kobalt-Massengehalt" * |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2961124B2 (en) | 1999-10-12 |
| EP0355431A2 (en) | 1990-02-28 |
| US5093555A (en) | 1992-03-03 |
| ES2099694T3 (en) | 1997-06-01 |
| DE58909765D1 (en) | 1997-02-27 |
| EP0355431A3 (en) | 1991-11-06 |
| DE3825012A1 (en) | 1990-01-25 |
| ATE147881T1 (en) | 1997-02-15 |
| JPH02133901A (en) | 1990-05-23 |
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