US2484242A - Coating ferrous metal sheets with an insulating film - Google Patents

Coating ferrous metal sheets with an insulating film Download PDF

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Publication number
US2484242A
US2484242A US659415A US65941546A US2484242A US 2484242 A US2484242 A US 2484242A US 659415 A US659415 A US 659415A US 65941546 A US65941546 A US 65941546A US 2484242 A US2484242 A US 2484242A
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United States
Prior art keywords
phosphoric acid
film
resistance
silicate
ferrous metal
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Expired - Lifetime
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US659415A
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English (en)
Inventor
Fritz J Nagel
Clifford C Horstman
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CBS Corp
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Westinghouse Electric Corp
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Publication date
Priority to NL66964D priority Critical patent/NL66964C/xx
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US659415A priority patent/US2484242A/en
Priority to GB9011/47A priority patent/GB639844A/en
Priority to CH265313D priority patent/CH265313A/de
Priority to FR946474D priority patent/FR946474A/fr
Application granted granted Critical
Publication of US2484242A publication Critical patent/US2484242A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
    • 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
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/73—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process
    • C23C22/74—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process for obtaining burned-in conversion coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/147—Alloys characterised by their composition
    • H01F1/14766—Fe-Si based alloys
    • H01F1/14775—Fe-Si based alloys in the form of sheets
    • H01F1/14783—Fe-Si based alloys in the form of sheets with insulating coating

Definitions

  • This invention relates to insulation, and in particular to tenaciously adherent films possessing high ohmic resistance for magnetic material.
  • the laminations In preparing magnetic materials, such, for example, as silicon iron, for the building of magnetic cores therefrom, it is necessary that the laminations be provided with electrical insulation between one another in order to minimize eddy currents and to achieve low losses.
  • the insulation should preferably be an extremely thin film to provide for a high space factor.
  • the insulating material applied to laminations should withstand the elevated temperatures which are encountered in strain annealing cores after assembly in order to improve their efficiency. Temperatures encountered in strain annealing occasionally reach 1200 C. and are rarely less than 600 C.
  • the insulation for the magnetic sheet material be capable of withstanding bending, scraping and other mechanical abuse or chemical treatment which may be encountered in forming the magnetic material to shape and assembling cores therefrom.
  • Magnetic material is usually cut or punched after the insulating material is applied thereto, and thereafter the cut or punched magnetic material may be bent or wound in order to produce a predetermined core structure.
  • the assembled cores may be subjected to machining or grinding, and, in some cases, etching with acids in order to remove burrs and the like.
  • the object of this invention is to provide a tenaciously adherent insulating film possessing high ohmic resistance on ferrous magnetic material.
  • a further object of the invention is to provide for producing an adherent film having high ohmic resistance on ferrous magnetic material by treating the material with a composition comprising phosphoric acid and an organic ester of silicic acid.
  • a further object of the invention is to provide a coating composition of phosphoric acid and a silicon compound capable of decomposing to produce microscropically fine silica for reaction with the phosphoric acid products when applied to ferrous material.
  • Figure 1 is a schematic view of a process for producing insulated magnetic strips and building a magnetic core in accordance with this invention
  • Fig. 2 is a greatly enlarged fragmentary crosssectional view of the insulated lamination of this invention applied thereto;
  • Fig. 3 is a view in elevation, partly broken, of an insulation tester.
  • insulating films of extraordinary ohmic insulation resistance which are tenaciously adherent and resistant to abrasion are produced on ferrous materials by applying to and chemically reacting therewith a solution having as its essential ingredients phosphoric acid and a silicon compound capable on decomposition of producing microscopically fine silica.
  • the insulating film is produced by applying to ferrous material, such, for example, as silicon iron laminations, a coating of a solution composed of a volatile solvent carrying substantial amounts of phosphoric acid and a silicon compound capable of liberating microscopically fine silica, such, for example, as tetraethyl silicate, and heat-treating the ferrous material and applied coating at a temperature of from 300 C. to 950 C. for a short period of time. A complex chemical reaction apparently takes place during the heat treatment.
  • the phosphoric acid is believed to react with the ferrous metal to produce iron phosphates. Simultaneously, the tetraethyl silicate decomposes to produce microscopically fine silica.
  • silicon compounds capable of producing on decomposition finely divided silica are employed.
  • Organic esters of silicic acid are particularly desirable for this purpose.
  • Typical esters are tetraethyl silicate, tetrabutyl silicate, methyl silicate, gylceryl silicate, diglycol silicate and ethylene glycol silicate, and condensed silicates such as hexa-ethyl sili cate, and mixtures of any of these.
  • tetraethyl silicate will be employed as exemplary of other silicon compounds as well.
  • Sufllcient water should be present with the tetraethyl silicate or other hydrolyzable silicates to produce a decomposition of the ester to silicic acid which may then be readily converted to silica, in the form of silica gel, or the like.
  • Ortho-phosphoric acid has been found the most satisfactory substance for use in the composition. Any strength phosphoric acid above about may be used. In practice 50% to 85% phosphoric acid is employed. In some cases, it has been found possible to substitute chromic acid up to an amount where it does not exceed 35% of the weight of the phosphoric acid. Furthermore, slight amounts of alkaline dihydrogen phosphates, such, for example, as monosodium dihydrogen phosphate, may be substituted for a small portion of the phosphoric acid. Considerations of cost and ease of preparation will render the ortho-phosphoric acid alone preferable in most instances.
  • the phosphoric 1 acid and tetraethyl silicate are preferably made into a solution.
  • a simple aliphatic alcohol may be employed as a solvent with good results.
  • the best results were obtained when a mixture of water and the alcohol were used as the solvent for the phosphoric acid and the silicon compound.
  • simple aliphatic alcohols suitable for the practice of this invention are ethanol, propanol, isopropanol,
  • the simple alcohol be present in an amount equal to at least about half the weight of the water. It will be appreciated that alcoholic solutions having substantial amounts of water, such, for example, as 70% ethanol or 60% isopropanol may be used alone without the addition of water. Denatured ethanol is satisfactory for use.
  • Fig. 1 of the drawing there is illustrated a schematic diagram of a suitable process for applying to ferrous magnetic material the composition of Example I, and building a wound core from the resulting insulated material.
  • Strip silicon iron Hi from a supply coil 8 is coated in a tank 12 containing the tetraethyl silicate-phosphoric acid solution H such as that of Example I.
  • the composition H may be applied in other ways as by spraying.
  • the strip I initially passes over a guide roll IO, thence into the solution where it passes under a submerged roller l8 and then passes over two rubber squeeze rolls and 22 maintained under a selected pressure for predeterminin the amount of the solution l4 to be rfatlained on the surfaces of the magnetic mater
  • the strip l0 coated with the solution is then heat-treated in the furnace 24 at a temperature of from about 300 C. to 950 C. for a brief period of time. It is preferred to maintain a relatively low oxidizing or inert atmosphere in the furnace in order to prevent undue oxidation and the formation of rust. In an oxidizing atmosphere, such as air, heating should not be conducted for longer than five minutes at a temperature of 550 C.
  • the coatings may be heattreated at temperatures of 950 C. for 30 seconds as the upper limit and ten minutes or longer at temperatures of 300 C. with excellent results.
  • the heat treatment applied to the strip l0 coated with the solution l4 should be carried out in the light of the subsequent processing of the insulated strip.
  • the heat treatment in furnace 24 is preferably conducted at temperatures of the same order as the required subsequent reannealing temperatures.
  • the reannealing temperatures for wound cores range from about 650 C. to 1000 C. and accordingly the heat-treating of the strip carrying the phosphoric acid and ester of silicic acid solutions should be conducted at temperatures approximating the reannealing temperature of cores prepared therefrom.
  • the water and alcohol solvent of the solution i4 evaporates, the phosphoric acid reacts with the ferrous metal while the tetraethyl silicate decomposes simultaneously, whereby microscopically fine silica is precipitated during the reaction involving the phosphoric acid.
  • the smoothest films are secured when the heat treatment is not too rapid so that vapors are not evolved at too great a rate.
  • a refractory, homogeneous film characterized by good adherence and high electrical insulation is quickly produced.
  • the subsequent building of a wound core from the insulated strip I0 is illustrated. Building of wound cores is believed to bethe most severe test of the properties of integral insulation on laminations.
  • the insulated-strip l0 passes through the guide rolls 28 to a winding machine where it is wound on a rectangular mandrel 28 into a continuous rectangular or wound core 30.
  • a pressure roll 22 is applied to assure the formation of a tight core. It will be found that the strip may be bent about the mandrel without the insulating film being loosened, even though the radii at the corners of the mandrel 28 may be 4; inch or less.
  • the film does not powder or otherwise separate from the strip during the winding operation.
  • the wound core 30 is then subjected to a strain anneal in an annealing oven 34 at temperatures of from 700 C. to 950 C. without the insulating film on the laminations softening or fusing and sticking the laminations to one another.
  • This characteristic is quite important since fused insulation will give rise to strains when the core is cooled to room temperature. Insulating films produced by applying only phosphoric acid or phosphoric acid and an inert filler such as talc often results in adhesions being formed between laminations during the strain annealing, and it is necessary to apply physical force to separate the laminations. Application of the physical force is not only time-consuming and uneconomical, but may result in some damage to the core.
  • the atmosphere in the strain annealing oven is preferably one containing hydrogen.
  • the core 30 after strain annealing is then impregnated in the tank 36 containing an insulating resin 38. Thereafter the resin impregnated core 30 is baked in the oven 40 to harden and polymerize the resin. While the core may be used in this condition, for many applications it must be cut, the resin bonded core 30 is then mounted in a jig 42 and severed into predetermined sections by a cutter 44. It will be apparent that the resin bond strength cannot be better than the film adherence. It has been found that abrasive bonded wheels, metal cutting saws, milling cutters, and other machine tools may be employed in machining the core 30 to any desired shape and size without disruption of the insulating film of this invention.
  • the cut core 30 is mounted on a jig 46 for grinding the cut faces thereof by the grinding wheel 48 to render them smooth and plane.
  • the ground core may be subjected to acid etching in order to remove any burrs that may be present on the machined surfaces due to the grinding and machining operations.
  • wound core sections The building of wound core sections is believed to be the severest practical test of the adherence, heat and mechanical resistance, and durability of an insulating film on magnetic laminations known to the art today.
  • the insulating film on the laminations must withstand extremely elevated temperatures and mechanical and chemical reagents without losing its adherence to the ferrous metal or deteriorating unduly in insulation resistance.
  • wound cores using oriented silicon iron a minimum of one ohm per square centimeter is the least acceptable resistance, and preferably the resistance should be higher: 5 ohms per square centimeter and better.
  • the insulated strip l0 produced bythe heattreating furnace 24 obviously can be made into any predetermined type of lamination by punching or cutting,vor otherwise machining to shape.
  • the insulating film will withstand punching operation such as encountered in producing L- shaped or other shaped laminations for transformer cores and the like, ormotor and generator rotor and stator laminationsin which sheets are punched into complex shapes.
  • the insulating ed for vertical movement by cation of a predetermined tracted for the passing of has from a value of 0.1 ohm
  • a particularly desirable application of this invention is for preferentially oriented silicon iron containing from 2% to 5% silicon-usually about 3.25% silicon.
  • the preferentially oriented 'silicon iron is extremely sensitive to strains and the insulating films here disclosed cooperate successfully therewith to produce substantially strain free insulated laminations. Not only strips but wires, bars, straps and the like can be treated.
  • 'Other ferrous material containing any of the usual alloying elements, aluminum, nickel, cobalt and the like, capable of reacting with phosphoric acid may be treated with the composition of this v invention to produce the highly desirable electrical insulation disclosed.
  • Sheet silicon iron having up to 7% silicon, from '2 mils to mils in thickess is easily treated with the composition.
  • the ferrous material may be thereafter formed to shape by winding, bending or otherwise mechanically deforming without anyserious impairment of the insulating film.
  • the film i0 is composed of iron phosphate chemically reacted with the microscopically fine silica produced by the simultaneous decomposition of the tetraethyl silicate as described hereinbefore.
  • the thickness of the film 50 is approximately 2% of the thickness of the sheet l0.
  • the thickness of the film 50 may be varied considerably from this ratio to suit individual requirements.
  • the film thickness has been measured as approximately 0.25 mil.
  • the thickness has been varied 0.5 mil for 13-mil thick sheets and in all cases, the insulation resistance and adherence of the film has been at a high level.
  • an insulation tester 60 known as the v c-clamp spot tester, which has been found to be extremely useful in evaluating'the properties magnetic material.
  • the insulatingmaterial of this invention will almost invariably withstand three or four successive twists without the resistance dropping below the range of 10 to 100 ohms per square centimeter, and usually the insulationresistanee remains at approximately infinity. Therefore it will be obvious that the nature of the insulation is entirely different, both in properties and performance, over any magnetic sheet insulating material known heretofore.
  • compositions in accordance with this invention, and have been able to produce therewith on magnetic material insulating films having the unexpected properties set forth.
  • the applied compositions have been varied within the range of 100 parts of solvent, 5 to parts by weight of phosphoric acid, and from 1 to parts by weight of tetraethyl silicate or its equivalent. Since the organic silicates vary a silicon dioxide equal to from 1% to 100% of the 1 weight of the phosphoric way, the compositions comprise 30 partsbyweight' from 0.1 to
  • provides for the applipressure of 50 pounds per'square inch at the face of the contact.
  • a manually operated lever 12 connected to the shaft 08 enables the upper contact 06' to be rea sheet between the contacts 84 and 66.
  • An insulated conductor .”
  • the measuring device 84 is capable of determining'ohmic resistance of coatper square centimeter up to infinity on .a scale.
  • an organic ester of silicic acid in an amount sufiicient to produce on decomposition silicon dioxide-in an amount equaltofrom 1 to 100% of the weight of the phosphoric acid, and from 50 to 400 parts by weight of a solvent for the phosphoric acid and the silicic 'acid ester, the solvent containing sufiicient water to hydrolyze the silicic acidester.
  • suflicient organic silicate ester to provide silica equal to from 4% to 20% of the weight of the phosphoric acid.
  • Example I a Parts 95% ethanol 80 Water 120 Phosphoric acid 60 Tetraethyl orthosilicate solution --e 20 trample III 95% ethanol 50 Distilled water H3P04 i. 80
  • Ethyl silicate solution 30 obtained when the com- Excellent results have been ob-
  • Example 17 Parts 95% ethanol 50 Distilled water 50 HaPO4 (85%) 60 (210: Ethyl silicate solution so
  • Example V Parts 95% ethanol 100 HsPO4 80 Ethyl silicate solution 70
  • Example V1 Parts 95% ethanol 50 Water 50 11:104 l Ethyl silicate solution.
  • the steps comprising applying to the sheets a coating composition composed of 30 parts by weight of phosphoric acid, an organic ester of silicic acid in an amount sufilcient on decomposition to produce silicon dioxide equal to from 1% to of the weight of the phosphoric acid, and about from 50 to 400 parts of a solvent for the phosphoric acid and organic ester of silicic acid, the solvent composed of water and a simple compatible aliphatic alcohol, the alcohol being at least half the weight of the water, the water being present in an amount suflicient to hydrolyze the organic ester, the composition applied in an amount of from 1 to 10 gallons per ton of 13 mil thick sheet, and heat-treating the ferrous metal sheets and applied composition at a temperature of from about 300 C.
  • a coating composition composed of 30 parts by weight of phosphoric acid, an organic ester of silicic acid in an amount sufilcient on decomposition to produce silicon dioxide equal to from 1% to of the weight of the phosphoric acid, and about from 50 to 400 parts of a solvent
  • the steps comprising applying to the surfaces of the sheets a coating composition composed of from 5 to 60 parts by weight of phosphoric acid, from about 1 to 65 parts by weight of the tetraethyl silicate, and 100 parts by weight of a solvent, the solvent composed of water and a compatible simple aliphatic alcohol, the alcohol being at least half the weight of the water, the water being present in an amount sufflcient to hydrolyze the tetraethyl silicate, the composition being applied in an amount of from 1 to 10 amounts of solid refractories may be inc rpo gallons per ton of 13 mil thick sheets, and heattreating the ferrous metal sheets and applied composition at a temperature of from 300 C.
  • a coating composition composed of from 5 to 60 parts by weight of phosphoric acid, from about 1 to 65 parts by weight of the tetraethyl silicate, and 100 parts by weight of a solvent, the solvent composed of water and a compatible simple aliphatic alcohol, the alcohol being at least half the
  • the steps comprising applying to the surfaces of the sheets a coating composition composed of from 5 to 60 parts by weight of phosphoric acid, from about 1 to 65 parts by weight of the ethylene glycol silicate, and 100 parts by weight of a solvent, the solvent composed of water and a, compatible simple aliphatic alcohol, the alcohol being at least half the weight of the water, the water being present in an amount sumcient to hydrolyze the ethylene glycol silicate, the composition being applied in an amount of from 1 to gallons per ton of 13 mil thick sheets,'and heat-treating the ferrous metal sheets and applied composition at a temperature of from 300 C.
  • a coating composition composed of from 5 to 60 parts by weight of phosphoric acid, from about 1 to 65 parts by weight of the ethylene glycol silicate, and 100 parts by weight of a solvent, the solvent composed of water and a, compatible simple aliphatic alcohol, the alcohol being at least half the weight of the water, the water being present in an amount sumcient to hydrolyze the ethylene glycol silicate, the
  • the steps comprising applying to the surfaces of the sheet a coating composition composed of Etc 60 parts by weight of a organic ester, but not mixture of phosphoric acid and chromic acid, the chromic acid not exceeding 35% 01 the weight of the phosphoric acid, from 1 to parts by weight of an organic ester of silicic acid, parts by weight of a solvent composed of water and a compatible simple aliphatic alcohol, the water being present in an amount sufliclent to hydrolyze the exceeding half the weight of the solvent, and heat-treating the sheet and the applied coating composition to provide for simultaneously reacting the phosphoric and chromic acids with the ferrous metal and liberating microscopically fine silica from the organic ester of silicic acid.
  • a coating composition composed of Etc 60 parts by weight of a organic ester, but not mixture of phosphoric acid and chromic acid, the chromic acid not exceeding 35% 01 the weight of the phosphoric acid, from 1 to parts by weight of an organic ester of silicic acid, parts by weight of

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  • Inorganic Chemistry (AREA)
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  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
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US659415A 1946-04-03 1946-04-03 Coating ferrous metal sheets with an insulating film Expired - Lifetime US2484242A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
NL66964D NL66964C (ro) 1946-04-03
US659415A US2484242A (en) 1946-04-03 1946-04-03 Coating ferrous metal sheets with an insulating film
GB9011/47A GB639844A (en) 1946-04-03 1947-04-02 Improvements in or relating to electrical insulation
CH265313D CH265313A (de) 1946-04-03 1947-04-03 Verfahren zur Herstellung eines gut haftenden Films von hohem elektrischem Widerstand auf der Oberfläche eines eisenhaltigen Metallerzeugnisses sowie nach diesem Verfahren erhaltener Film.
FR946474D FR946474A (fr) 1946-04-03 1947-05-09 Revêtement isolant et méthode d'obtention

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US659415A US2484242A (en) 1946-04-03 1946-04-03 Coating ferrous metal sheets with an insulating film

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CH (1) CH265313A (ro)
FR (1) FR946474A (ro)
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Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2645716A (en) * 1948-08-24 1953-07-14 Westinghouse Air Brake Co Electron tube circuits
US2743203A (en) * 1951-08-29 1956-04-24 Westinghouse Electric Corp Phosphate coating for electrical steel
US2835618A (en) * 1954-03-09 1958-05-20 Parker Rust Proof Co Solution and method for producing heat resistant electrical insulation coatings on ferrous surfaces
US2879183A (en) * 1955-12-15 1959-03-24 Bell Telephone Labor Inc Insulating coatings and a method for their production
US2909454A (en) * 1957-12-04 1959-10-20 United States Steel Corp Process for producing core-plated electrical steel strip
US2920296A (en) * 1955-01-07 1960-01-05 Gen Electric Reduction of transformer noise due to magnetostrictive effects
US2935422A (en) * 1955-10-28 1960-05-03 Poor & Co Corrosion preventing coatings and coating compositions
US2978349A (en) * 1957-07-03 1961-04-04 Eastern Prod Corp Soil proofing
US3104993A (en) * 1960-09-20 1963-09-24 Inland Steel Co Galvanizing process
US3138492A (en) * 1961-10-11 1964-06-23 Allegheny Ludlum Steel Insulating coating for magnetic steel
US3207636A (en) * 1962-06-26 1965-09-21 Yawata Iron & Steel Co Method for coating silicon steel transformer sheets and composition
US3276923A (en) * 1961-04-17 1966-10-04 Gen Electric Reduction in magnetic losses in electrical induction apparatus
US3421949A (en) * 1964-08-12 1969-01-14 Hooker Chemical Corp Composition and process for producing an electrically resistant coating on ferrous surfaces
US3477881A (en) * 1964-02-24 1969-11-11 Yawata Seitetsu Kk Process for the formation of electric insulating coating on electric iron sheet
US3819427A (en) * 1971-09-11 1974-06-25 Ludwig Ofag Indugas Gmbh Method of making an electromagnetic-sheet stack
US3985583A (en) * 1973-11-17 1976-10-12 Kawasaki Steel Corporation Method for forming an insulating coating on an oriented silicon steel sheet
EP4133571B1 (de) * 2020-07-08 2024-01-10 Siemens Aktiengesellschaft Materiallage für ein blechpaket einer elektrischen maschine

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2811473A (en) * 1953-12-07 1957-10-29 United States Steel Corp Composition and method for increasing surface resistivity of silicon steel

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US1750270A (en) * 1927-06-13 1930-03-11 Parker Rust Proof Co Coated iron and steel articles and method of making the same
FR679083A (fr) * 1928-12-03 1930-04-08 Parker Ste Continentale Procédé de revêtement superficiel des objets en fer ou acier
US1889654A (en) * 1928-01-14 1932-11-29 Ohio Sanitary Engineering Corp Fertilizer
DE570990C (de) * 1928-12-18 1933-02-22 Mij Tot Exploitatie Van De Par Verfahren zum UEberziehen von eisernen Gegenstaenden mit Rostschutzschichten
US2144425A (en) * 1936-12-09 1939-01-17 Sterling Varnish Company Insulating composition
US2161319A (en) * 1935-04-29 1939-06-06 Ig Farbenindustrie Ag Well-covering coating composition
US2413949A (en) * 1942-12-23 1947-01-07 Gen Electric Treating silicon steel strip

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1750270A (en) * 1927-06-13 1930-03-11 Parker Rust Proof Co Coated iron and steel articles and method of making the same
US1889654A (en) * 1928-01-14 1932-11-29 Ohio Sanitary Engineering Corp Fertilizer
FR679083A (fr) * 1928-12-03 1930-04-08 Parker Ste Continentale Procédé de revêtement superficiel des objets en fer ou acier
DE570990C (de) * 1928-12-18 1933-02-22 Mij Tot Exploitatie Van De Par Verfahren zum UEberziehen von eisernen Gegenstaenden mit Rostschutzschichten
US2161319A (en) * 1935-04-29 1939-06-06 Ig Farbenindustrie Ag Well-covering coating composition
US2144425A (en) * 1936-12-09 1939-01-17 Sterling Varnish Company Insulating composition
US2413949A (en) * 1942-12-23 1947-01-07 Gen Electric Treating silicon steel strip

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2645716A (en) * 1948-08-24 1953-07-14 Westinghouse Air Brake Co Electron tube circuits
US2743203A (en) * 1951-08-29 1956-04-24 Westinghouse Electric Corp Phosphate coating for electrical steel
US2835618A (en) * 1954-03-09 1958-05-20 Parker Rust Proof Co Solution and method for producing heat resistant electrical insulation coatings on ferrous surfaces
US2920296A (en) * 1955-01-07 1960-01-05 Gen Electric Reduction of transformer noise due to magnetostrictive effects
US2935422A (en) * 1955-10-28 1960-05-03 Poor & Co Corrosion preventing coatings and coating compositions
US2879183A (en) * 1955-12-15 1959-03-24 Bell Telephone Labor Inc Insulating coatings and a method for their production
US2978349A (en) * 1957-07-03 1961-04-04 Eastern Prod Corp Soil proofing
US2909454A (en) * 1957-12-04 1959-10-20 United States Steel Corp Process for producing core-plated electrical steel strip
US3104993A (en) * 1960-09-20 1963-09-24 Inland Steel Co Galvanizing process
US3276923A (en) * 1961-04-17 1966-10-04 Gen Electric Reduction in magnetic losses in electrical induction apparatus
US3138492A (en) * 1961-10-11 1964-06-23 Allegheny Ludlum Steel Insulating coating for magnetic steel
US3207636A (en) * 1962-06-26 1965-09-21 Yawata Iron & Steel Co Method for coating silicon steel transformer sheets and composition
US3477881A (en) * 1964-02-24 1969-11-11 Yawata Seitetsu Kk Process for the formation of electric insulating coating on electric iron sheet
US3421949A (en) * 1964-08-12 1969-01-14 Hooker Chemical Corp Composition and process for producing an electrically resistant coating on ferrous surfaces
US3819427A (en) * 1971-09-11 1974-06-25 Ludwig Ofag Indugas Gmbh Method of making an electromagnetic-sheet stack
US3985583A (en) * 1973-11-17 1976-10-12 Kawasaki Steel Corporation Method for forming an insulating coating on an oriented silicon steel sheet
EP4133571B1 (de) * 2020-07-08 2024-01-10 Siemens Aktiengesellschaft Materiallage für ein blechpaket einer elektrischen maschine

Also Published As

Publication number Publication date
GB639844A (en) 1950-07-05
CH265313A (de) 1949-11-30
NL66964C (ro)
FR946474A (fr) 1949-06-03

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