US3607475A - Method of manufacturing electrical resistance elements and elements manufactured by the method - Google Patents

Method of manufacturing electrical resistance elements and elements manufactured by the method Download PDF

Info

Publication number
US3607475A
US3607475A US677569A US3607475DA US3607475A US 3607475 A US3607475 A US 3607475A US 677569 A US677569 A US 677569A US 3607475D A US3607475D A US 3607475DA US 3607475 A US3607475 A US 3607475A
Authority
US
United States
Prior art keywords
electrical resistance
chemical agent
incandescent
accordance
volume
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US677569A
Other languages
English (en)
Inventor
Nils Gustav Schrewelius
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kanthal AB
Original Assignee
Kanthal AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kanthal AB filed Critical Kanthal AB
Application granted granted Critical
Publication of US3607475A publication Critical patent/US3607475A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H05B3/14—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
    • H05B3/148—Silicon, e.g. silicon carbide, magnesium silicide, heating transistors or diodes
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • H01B1/14—Conductive material dispersed in non-conductive inorganic material
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
    • H05B2203/018—Heaters using heating elements comprising mosi2
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49082—Resistor making
    • Y10T29/49083—Heater type

Definitions

  • An electric resistance element of molybdenum disilicide has a thin incandescent zone whose dimensions are formed by chemical decomposition, dissolution or corrosion.
  • the present invention relates to a method of manufacturing electrical resistance elements substantially consisting of molybdenum disilicide and having an incandescent zone and at least one thicker terminal. Such electrical resistance elements have been known for a long time.
  • the natural brittleness of the material in cold condition has limited the use of molybdenum disilicide substantially to elements having a rather large cross sectional area.
  • molybdenum disilicide substantially to elements having a rather large cross sectional area.
  • the proven type of element sold under the registered trade mark of KANTHAL SUPER may be mentioned, said element consisting of an incandescent portion in U-shape and having straight terminals.
  • the incandescent portion may have a diameter of about 6 mm.
  • an the terminals which are generally connected to the incandescent portion by resistance butt welding may have a diameter of about 12 mm. ln these thick terminals the temperature will be low even though the incandescent portion has a temperature of about l,600 to l,700 C., and thereby it becomes possible to con nect them with contacts of aluminum, for instance.
  • the object of the present invention is to remedy the above difficulties in a simple and cheap way, and a thin molybdenum disilicide element with at least one thicker terminal is characterized, according to the invention, substantially in that at least the incandescent portion of the element has been given its final dimension by removing certain portions of an element blank by a chemical removal process such as chemical dissolution, decomposing or corrosion.
  • the simplest way of carrying out the method according to the invention is to submerge a U-shaped rod blank in an acid mixture for such a long period of time and to such depth that the acid corrodes away the amount of material required to give the incandescent portion the desired final diameter and length.
  • the chemically dissoluting, decomposing or corroding agent which has proven most useful in this connection is an acid mixture containing hydrofluoric acid, nitric acid and, if desired, water.
  • Resistance elements which are in the known way built up of a powder metallurgical composition of molybdenum disilicide and a glass rich in SiO are dissolved in said acid mixture as the molybdenum disilicide and the glass component are dissolved at approximately the same rate. Thereby a smooth surface and a controllable cross sectional area of the portion treated with acid are obtained.
  • resistance elements substantially consisting of molybdenum disilicide may also contain other substances as additions in order to modify different properties.
  • an addition is finely powdered silicon car bide which is then substituted for the glass component in the above example.
  • the glass as well as the silicon carbide prevents the grain growth of the molybdenum disilicide at high temperature and also gives the material other advantageous properties, such as plastic workability in heat, for instance.
  • the silicon carbide component in such an element is not dissolved at all or only dissolved very slowly in the acid mixture mentioned, but nevertheless it is possible according to the invention to produce elements with thin incandescent portions by chemical treatment provided that the molybdenum disilicide is the main component; unattacked silicon carbide present in rather insignificant amounts will automatically fall off from the goods dissolved.
  • other additions and modifications of the composition may be permitted according to the invention, such as a modification of the MoSi, component by adding as alloy components small amounts of other metals which do not influence the chemical solubility.
  • the interface between air and liquid in an acid bath for chemical dissolution as per above has proved to have a disadvantageous influence on the smoothness of the corroded portion. Therefore, it has proved convenient to keep the element in motion during the treatment to avoid a reduced diameter of the portion located at the interface.
  • Another way of avoiding the problems with the interface between air and liquid is to coat those portions of the element blank which are not to be corroded with a layer of an acidproof material, such as plastics, the element blank being submerged in the acid bath to such a depth that the interface air-liquid will be within the plastics-coated area.
  • the method according to the invention presupposes that there is no intercrystalline corrosion or any other type of attack interiorly of the element. Therefore, it is important that the bodies containing molybdenum disilicide are free of pores.
  • the porosity should be less than 2 percent, preferably below 0.5-1 percent. To obtain such low porosity it is convenient to use low melting glass as binding agent for the molybdenum disilicide.
  • a straight homogenous rod of 4.6 mm. diameter and having a porosity less than 1 percent consisting of a fine-grained powder metallurgical dense body containing 90 percent by weight of MoSi and 10 percent by weight of a glass rich in SiO, which has been produced by pressing and sintering MoSi and bentonite was bent in heat into U-shape, the legs having a length of 50 mm., and the space between the legs being 15 mm.
  • This U-shaped blank was half submerged in a cold mixture of 50 parts of volume of concentrated nitric acid, 50 parts by volume of concentrated hydrofluoric acid and l0 parts by volume of water.
  • the element was kept submerged in this mixture for 2 minutes, while being slightly moved, and was then carefully rinsed in water. After the treatment, an incandescent zone having the diameter 2.3 mm., had been formed.
  • the element was provided with sprayed-on contact layers of aluminum, whereupon it was connected in a current circuit and permitted operating temperatures of 1,600 C. and more in the incandescent zone, while the thicker, uncorroded terminals had a temperature of less than 200 C. in the contact layers.
  • the method offers, possibilities of automatizing the production, as it is easy to make such arrangements that the resistance of the element blank may be caused, during the acid treatment, to control the moment at which the blank is removed from the acid bath.
  • the method may also be applied such that a blank of molybdenum disilicide in the form of a tube or a plate, for instance,
  • a material resistant to the acid mixture such as plastics, for instance, and that a desired pattern is drawn on the surface so that a selective dissolution of the material can then take place in accordance with particular wishes.
  • a material resistant to the acid mixture such as plastics, for instance
  • a desired pattern is drawn on the surface so that a selective dissolution of the material can then take place in accordance with particular wishes.
  • Such flat elements may be used in cigarette lighters, for instance.
  • FIG. 1 is a perspective view of a hairpin-shaped element and FIG. 2 is a plan view of an element formed as a flat spiral.
  • the elements in FIG. 1 which consists essentially of MoSi has two terminals 11, 12 with flame sprayed aluminiumcontacts 11A, 12A and of a diameter of about 1 mm. and a length of about 60 mm. each.
  • the terminals 11, 12 are parallel to each other and spaced apart about 3-10 mm.
  • the bent incandescent zone 13 which is formed from the same rodshaped blank as the terminals 11, 12 has had its diameter reduced down to about 0.4 mm. by chemical corrosion as discussed above.
  • the element 14 in FIG. 2 has been formed with an incandescent zone 15 and two wider terminal portions 16, 17 by corroding away a spiral shaped portion to form a spiral slot 18 in a flat, plate-shaped blank, essentially of MoSi in the above-described manner.
  • a method in accordance with claim 2 in which said step of bringing a chemical agent into contact with said incandescent portion comprises the step of bringing an acid mixture consisting essentially of 50 parts by volume of concentrated nitric acid and 50 parts by volume of concentrated hydrofluoric acid into contact with said incandescent ortion.
  • step of bringing said chemical agent into contact with said incandescent portion comprises the step of submerging said incandescent portion into said chemical agent while maintaining said electrode portion free from said chemical agent.
  • step of forming said electrical resistance blank comprises the step of coating said electrode portion with a masking substance that is not affected by said chemical agent, whereby the interface between the chemical agent and the atmosphere is prevented from creating a discontinuity in said electrical resistance element.
  • step of forming said electrical resistance blank includes the step of forming said electrical resistance blank from a material consisting of at least 60 percent by volume of molybdenum disilicide and at most 40 percent by volume of ceramic additions.
  • said step of forming said electrical resistance blank includes the step of forming a straight rod of approximately 5 millimeters in diameter with a porosity less than 1 percent of a fine-grained powder metallurgical body containing percent by weight of molybdenum disilicide and 10 percent by weight of a glass rich in silicone dioxide which has been produced by sintering molybdenum disilicide and bentonite and the step of bending said rod while heated into a U-shape with the legs of the U having a length of approximately 50 millimeters and with a space between the legs of approximately 15 millimeters; said step of bringing a chemical agent into contact with said incandescent portion includes the step of submerging the U-shaped blank half way into a cold mixture of 50'parts by volume of concentrated nitric acid, 50 parts by volume of concentrated hydrofluoric acid and [0 parts by volume of water.
  • An electrical resistance element formed in accordance with the method of claim 1 and having a rodlike cross section in which the diameter of the incandescent zone is less than i millimeter and the diameter of the electrode portion is more than 1 millimeter.
US677569A 1966-10-24 1967-10-24 Method of manufacturing electrical resistance elements and elements manufactured by the method Expired - Lifetime US3607475A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE14564/66A SE301519B (de) 1966-10-24 1966-10-24

Publications (1)

Publication Number Publication Date
US3607475A true US3607475A (en) 1971-09-21

Family

ID=20299306

Family Applications (1)

Application Number Title Priority Date Filing Date
US677569A Expired - Lifetime US3607475A (en) 1966-10-24 1967-10-24 Method of manufacturing electrical resistance elements and elements manufactured by the method

Country Status (5)

Country Link
US (1) US3607475A (de)
DE (1) DE1615121B2 (de)
GB (1) GB1135138A (de)
NL (1) NL6714427A (de)
SE (1) SE301519B (de)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3742601A (en) * 1972-06-19 1973-07-03 Itt Method of making an electrical apparatus
US3875476A (en) * 1974-01-10 1975-04-01 Honeywell Inc Igniter element
US4158744A (en) * 1976-07-05 1979-06-19 Elektroschmelzwerk Kempten Gmbh Electrical resistance furnace for the production of silicon carbide
US4263470A (en) * 1978-08-30 1981-04-21 Bulten-Kanthal Ab Holding device for electrical resistance elements in furnaces
US4295033A (en) * 1977-06-20 1981-10-13 Bulten-Kanthal Aktiebolag Annealing oven
US6323465B1 (en) * 1998-01-13 2001-11-27 Mold-Masters Limited Externally heated hot-runner nozzle with resistance wire
US6464918B1 (en) * 1998-08-29 2002-10-15 Heraeus Noblelight Gmbh Method for production of a spiral-shaped heating element
US20040021548A1 (en) * 2000-01-25 2004-02-05 Albrecht Geissinger Passive, high-temperature-resistant resistor element for measuring temperature in passenger and commercial vehicles
US20050236399A1 (en) * 2002-04-05 2005-10-27 Sandvik Ab Method of marking a heating element of the molybdenum silicide type and a heating element
US20050252909A1 (en) * 2002-04-05 2005-11-17 Jan Andersson Electrical heating resistance element
FR2957746A1 (fr) * 2010-03-22 2011-09-23 Valeo Systemes Thermiques Element resistif pour un radiateur electrique et procede de realisation d'un tel element resistif
US20120193343A1 (en) * 2010-07-13 2012-08-02 Tyler Johnson Portable Rechargeable Battery Powered Flameless Cigar Lighter
US11123791B2 (en) 2017-10-16 2021-09-21 General Electric Company Method for casting a mold
US11123790B2 (en) 2017-10-16 2021-09-21 General Electric Company Apparatus for casting a mold

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1091812B (de) * 1958-04-17 1960-10-27 Mann & Hummel Filter Ansaugluftfilter
US4704514A (en) * 1985-01-11 1987-11-03 Egmond Cor F Van Heating rate variant elongated electrical resistance heater

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3742601A (en) * 1972-06-19 1973-07-03 Itt Method of making an electrical apparatus
US3875476A (en) * 1974-01-10 1975-04-01 Honeywell Inc Igniter element
US4158744A (en) * 1976-07-05 1979-06-19 Elektroschmelzwerk Kempten Gmbh Electrical resistance furnace for the production of silicon carbide
US4295033A (en) * 1977-06-20 1981-10-13 Bulten-Kanthal Aktiebolag Annealing oven
US4263470A (en) * 1978-08-30 1981-04-21 Bulten-Kanthal Ab Holding device for electrical resistance elements in furnaces
US6323465B1 (en) * 1998-01-13 2001-11-27 Mold-Masters Limited Externally heated hot-runner nozzle with resistance wire
US6464918B1 (en) * 1998-08-29 2002-10-15 Heraeus Noblelight Gmbh Method for production of a spiral-shaped heating element
US7061363B2 (en) * 2000-01-25 2006-06-13 Robert Bosch Gmbh Passive, high-temperature-resistant resistor element for measuring temperature in passenger and commercial vehicles
US20040021548A1 (en) * 2000-01-25 2004-02-05 Albrecht Geissinger Passive, high-temperature-resistant resistor element for measuring temperature in passenger and commercial vehicles
US20050236399A1 (en) * 2002-04-05 2005-10-27 Sandvik Ab Method of marking a heating element of the molybdenum silicide type and a heating element
US20050252909A1 (en) * 2002-04-05 2005-11-17 Jan Andersson Electrical heating resistance element
US7164103B2 (en) * 2002-04-05 2007-01-16 Sandvik Intellectual Property Aktiebolag Electrical heating resistance element
US8053710B2 (en) * 2002-04-05 2011-11-08 Sandvik Intellectual Property Aktiebolag Method of making a heating element of the molybdenum silicide type and a heating element
FR2957746A1 (fr) * 2010-03-22 2011-09-23 Valeo Systemes Thermiques Element resistif pour un radiateur electrique et procede de realisation d'un tel element resistif
US20120193343A1 (en) * 2010-07-13 2012-08-02 Tyler Johnson Portable Rechargeable Battery Powered Flameless Cigar Lighter
US11123791B2 (en) 2017-10-16 2021-09-21 General Electric Company Method for casting a mold
US11123790B2 (en) 2017-10-16 2021-09-21 General Electric Company Apparatus for casting a mold

Also Published As

Publication number Publication date
NL6714427A (de) 1968-04-25
DE1615121B2 (de) 1971-04-15
SE301519B (de) 1968-06-10
GB1135138A (en) 1968-11-27
DE1615121A1 (de) 1969-12-11

Similar Documents

Publication Publication Date Title
US3607475A (en) Method of manufacturing electrical resistance elements and elements manufactured by the method
Vermilyea The oxidation of tantalum at 50–300 C
US4064914A (en) Porous metallic layer and formation
JP2019502825A5 (de)
US3147547A (en) Coating refractory metals
US2576405A (en) Protector for electric circuits
US2445858A (en) Laminated structure
US2918392A (en) Method of depositing metal in the pores of a porous body
US2261412A (en) Fabrication of duplex metal bodies
US3372471A (en) Method of manufacturing microwave components
US3132928A (en) Simultaneous brazing and corrosion protecting refractory metals
US3104167A (en) Method and solution for selectively stripping electroless nickel from a substrate
US3508894A (en) Method for metailizing a glass surface
US2891881A (en) Recovery of metals
US3748729A (en) Traveling wave tube interaction circuit manufacture
US2547536A (en) Formation of a surface easily
US3345225A (en) Method of chemically polishing copper and copper alloys
US2043307A (en) Metal glass seal
US2472786A (en) Method of pickling metal contact surfaces
CN110814449B (zh) 梯度材料电极及其制备方法
US3351726A (en) Low power mercury switch
US4374901A (en) Very fine diameter uniform wires
US1268647A (en) Leading-in conductor.
US2640020A (en) Formation of a surface easily wettable by mercury
KR102568034B1 (ko) 감탕을 이용한 은기물 제조방법