CH205653A - Process for manufacturing voltage sensitive resistors. - Google Patents
Process for manufacturing voltage sensitive resistors.Info
- Publication number
- CH205653A CH205653A CH205653DA CH205653A CH 205653 A CH205653 A CH 205653A CH 205653D A CH205653D A CH 205653DA CH 205653 A CH205653 A CH 205653A
- Authority
- CH
- Switzerland
- Prior art keywords
- oxide
- metal
- granular
- parts
- metal oxides
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- 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
- H01C7/10—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 voltage responsive, i.e. varistors
-
- 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
- H01C7/10—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 voltage responsive, i.e. varistors
- H01C7/105—Varistor cores
- H01C7/108—Metal oxide
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Non-Adjustable Resistors (AREA)
- Apparatuses And Processes For Manufacturing Resistors (AREA)
Description
Verfahren zur Herstellung spaunungsempfindlicher Widerstände. Die vorliegende Erfindung bezieht sieh auf sogenannte spannungsempfindlielleWider- stände, das heisst solche Leiter, deren elek- trieclier Widerstand bei erhöhtem elek- trIschem Spannungsabfall mehr oder weniger schnell herabgesetzt wird, weshalb die Stromstärke mehr als proportional mit dem Spannungsabfall wächst.
Solche Widerstände ssin-d in letzter Z & it unter anderem als Über- spannungesicherungen (Gewitterss,ellutz) bei elektrischen Anlagen weitgehend verwendet worden, wobei eine Anzahl spannungsemp- findlieher Widerstandsblöcke aewöhnlich,
mit Funkenstrecke und Schmelzsieherungen oder mechanischen Aussehaltvorrichtungen in Reihe geschaltet wer-den. Auch bei ver schiedenen andern Regulier- und Schaltein- riehtungen sind solche spannungsempfind liche Widerstände von Bedeutung.
Es ist schon bekannt, Widerstandsblöcke dieser Art aus körnigen Halbleitern, bei spielsweise Siliziumkarbid oder Kohle (Gra phit) anzufertigen, die durch ein Binde mittel zusammengehalten werden.
Beider Anfertigung,der Blöcke wird das Körnermaterial in eine geeignete Form nach Zusatz eines Bindemittels gepresst, wonach man dasselbe eventuell durch Trocknen oder Brennen erhärten lässt. Es hat sieh dabei herausgestellt, dass es erhebliche Schwierig keiten bietet, ein Bindemittel zu erzeugen, das dem Widerstandsblojck zufriedenstellende sowohl merhanistlie als elektrische Eigen- echaften gibt.
Einerseits muss nämlieh der Widerstandskörper genügende mechanieehe Druckfestigkeit erhalten, anderseits darf das Bindemittel nach dem Trocknen oder Bren nen die Ilalbleiterkörner nicht voneinander isolieren.
Eingehende Versuche haben gezeigt, dass der Widerstandder Halbleiterkörner an sich mit der Spannung nicht wechselt, sondern dass die Spannungsempfindlichkeit ihren Ursprung in den Kontaktpunkten zwischen angrenzenden. Halbleiterkörnern bezw. den Mikroabständen zwischen denselben hat. Es ist deshalb von grösster Wichtigkeit, dass die Bindung zwisehen,den Halbleiterkörnern
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selndem Gehalt an kolloidalem Zirkonoxyd, EisenoxyJ uGw.) verwendet werden.
Es leueUtet ein, dass auch Mischungen der betreffenden Stoffe verwendet werden können. Hauptsache ist, dass solche Kombi nationen vorliegen, dass ein Metallsalz einer Sauerstoffslure eines Elementes der fünften Gruppe des periodischen Systems, beispiels weise Pho#spliat oder Arsenat der genannten Metalle, bei der Erhitzung gebildet wird.
Die sauren Erdalkaliphosphate und Ammonium- phosphate bezw. die analogen Arsenverbin dungen werden bei der Reaktion unter<B>Ab-</B> gabe von Wasser bezw. Ammoniak zerlegt, wobei Phosphorsäure bezw. Arsensäure ent bunden wird, die mit den übrigen Bestand teilen reagiert.
Es hat sieh herausgestellt, dass im all gemeinen<B>0,5</B> bis<B>5</B> GewieUtsteile,der sauren Verbindung und 2 bis 20 Teile der Metall oxyde bezw. Oxydhydrate genügen, um<B>100</B> Teile körnigen Halbleitermaterials zu binden.
Gute Resultate wurden zum Beispiel durch Zugabe von<B>5</B> bis<B>10</B> Gewichtsteilen Aluminiumoxyd'hydrat (wie Bauxit oder Laterit) bezw. Chromoxyd (Chromgrün) oder gefälltem Zirkonoxyd nebst<B>5</B> bis<B>10</B> Ge- wielltsteilen einer aus<B>1</B> Raumteil konz. Phosplior,säure (spez. Gew.#1,70)
und 2 Raum teilen Wasser bereiteten Lösung zu<B>100</B> Ge- wielitsteilen körnigen Siliziumkarbids, sowie Pressen, Trocknen und Erhitzen der Mischung auf<B>500</B> bis<B>1100'C</B> erzielt.
Bei Verwendung von Laterit (das heisst einem "Bauxit" mit hohem Gehalt an gebun denem Wasser, etwa<B>25</B> biss <B>35 %)</B> in Verbin dung mit Phosphorsäure wird der Vorzug erzielt, dass die Bildung von Aluminiumplios- phat schon bei etwa<B>100'</B> eintritt, und dass die gepressten Körper aus diesem Grunde gute Druckfestigkeit; schon bei der genannten Temperatur erhalten. Durch Erhitzen auf höhere Temperaturen können die elektrischen Eigenschaften des Mateilials abgeändert wer den.
Process for manufacturing resistors sensitive to sparks. The present invention relates to so-called voltage-sensitive resistors, that is to say those conductors whose electrical resistance is reduced more or less quickly with an increased electrical voltage drop, which is why the current strength increases more than proportionally with the voltage drop.
Such resistors ssin-d have recently been used extensively as overvoltage protection (thunderstorms, ellutz) in electrical systems, whereby a number of voltage-sensitive resistor blocks are common,
connected in series with spark gaps and fusible links or mechanical shut-off devices. Such voltage-sensitive resistors are also important for various other regulating and switching devices.
It is already known to make resistor blocks of this type from granular semiconductors, for example silicon carbide or carbon (Gra phite), which are held together by a binding agent.
When making the blocks, the granular material is pressed into a suitable shape after adding a binding agent, after which it is allowed to harden by drying or firing. It has been found that there are considerable difficulties in producing a binder which gives the resistor block satisfactory merhanistic and electrical properties.
On the one hand, the resistance body must have sufficient mechanical compressive strength; on the other hand, the binder must not isolate the semiconductor grains from one another after drying or firing.
Extensive tests have shown that the resistance of the semiconductor grains per se does not change with the voltage, but that the voltage sensitivity has its origin in the contact points between adjacent ones. Semiconductor grains respectively. has the micro-gaps between them. It is therefore of the greatest importance that the bond between the semiconductor grains
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because of the content of colloidal zirconium oxide, iron oxide, etc.).
It implies that mixtures of the substances in question can also be used. The main thing is that there are combinations such that a metal salt of an oxyacid of an element of the fifth group of the periodic table, for example phosphate or arsenate of the metals mentioned, is formed on heating.
The acidic alkaline earth phosphates and ammonium phosphates respectively. the analog arsenic compounds are resp. during the reaction with <B> release </B> release of water. Ammonia decomposed, with phosphoric acid BEZW. Arsenic acid is released, which reacts with the other components.
It has been shown that in general <B> 0.5 </B> to <B> 5 </B> weight parts, the acidic compound and 2 to 20 parts of the metal oxides or. Oxide hydrates are sufficient to bind <B> 100 </B> parts of granular semiconductor material.
Good results were achieved, for example, by adding <B> 5 </B> to <B> 10 </B> parts by weight of aluminum oxide hydrate (such as bauxite or laterite) or. Chromium oxide (chrome green) or precipitated zirconium oxide together with <B> 5 </B> to <B> 10 </B> corrugated parts one of <B> 1 </B> conc. Phosphorus acid (spec. Weight # 1.70)
and 2 rooms share water prepared solution to <B> 100 </B> by weight of granular silicon carbide, as well as pressing, drying and heating the mixture to <B> 500 </B> to <B> 1100'C </B> achieved.
When using laterite (that is, a "bauxite" with a high content of bound water, about <B> 25 </B> to <B> 35%) </B> in conjunction with phosphoric acid, the advantage is achieved that the formation of aluminum phosphate already occurs at about <B> 100 '</B>, and that the pressed bodies have good compressive strength for this reason; obtained at the temperature mentioned. The electrical properties of the material can be changed by heating to higher temperatures.
Claims (1)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE205653X | 1936-10-17 |
Publications (1)
Publication Number | Publication Date |
---|---|
CH205653A true CH205653A (en) | 1939-06-30 |
Family
ID=20305020
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CH205653D CH205653A (en) | 1936-10-17 | 1937-09-18 | Process for manufacturing voltage sensitive resistors. |
Country Status (1)
Country | Link |
---|---|
CH (1) | CH205653A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2445296A (en) * | 1942-10-20 | 1948-07-13 | Wejnarth Axel Richard | Process of manufacturing resistance elements durable at high temperature and proof against chemical action |
US2465672A (en) * | 1943-10-20 | 1949-03-29 | Selas Corp Of America | Refractory composition and method of making |
-
1937
- 1937-09-18 CH CH205653D patent/CH205653A/en unknown
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2445296A (en) * | 1942-10-20 | 1948-07-13 | Wejnarth Axel Richard | Process of manufacturing resistance elements durable at high temperature and proof against chemical action |
US2465672A (en) * | 1943-10-20 | 1949-03-29 | Selas Corp Of America | Refractory composition and method of making |
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