Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
• • 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
  • H01F1/153—Amorphous metallic alloys, e.g. glassy metals
  • H01F1/15308—Amorphous metallic alloys, e.g. glassy metals based on Fe/Ni
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D6/00—Heat treatment of ferrous alloys
  • C21D6/008—Heat treatment of ferrous alloys containing Si
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C45/00—Amorphous alloys
  • C22C45/02—Amorphous alloys with iron as the major constituent

Definitions

• the invention relates to amorphous metal alloy compositions and, in particular, to amorphous alloys containing iron, silicon and boron having enhanced A.C. magnetic properties.
• An amorphous material substantially lacks any long range atomic order and is characterized by an X-ray diffraction profile consisting of broad intensity maxima. Such a profile is qualitatively similar to the diffraction profile of a liquid or ordinary window glass. This is in contrast to a crystalline material which produces a diffraction profile consisting of sharp, narrow intensity maxima.
• amorphous materials exist in a metastable state. Upon heating to a sufficiently high temperature, they crystallize with evolution of the heat of crystallization, and the X-ray diffraction profile changes from one having amorphous characteristics to one having crystalline characteristics.
• Novel amorphous metal alloys have been disclosed by H. S. Chen and D. E. Polk in U.S. Pat. No. 3,856,513, issued Dec. 24, 1974. These amorphous alloys have the formula MaY bZc where M is at least one metal selected from the group of iron, nickel, cobalt, chromium and vanadium, Y is at least one element selected from the group consisting of phosphorus, boron and carbon, Z is at least one element selected from the group consisting of aluminum, antimony, beryllium, germanium, indium, tin and silicon, "a” ranges from about 60 to 90 atom percent, "b” ranges from about 10 to 30 atom percent and "c” ranges from about 0.1 to 15 atom percent.
• amorphous alloys have been found suitable for a wide variety of applications in the form of ribbon, sheet, wire, powder, etc.
• the Chen and Polk patent also discloses amorphous alloys having the formula T i X j , where T is at least one transition metal, X is at least one element selected from the group consisting of aluminum, antimony, beryllium, boron, germanium, carbon, indium, phosphorus, silicon and tin, "i” ranges from about 70 to 87 atom percent and "j" ranges from about 13 to 30 atom percent.
• T is at least one transition metal
• X is at least one element selected from the group consisting of aluminum, antimony, beryllium, boron, germanium, carbon, indium, phosphorus, silicon and tin
• "i” ranges from about 70 to 87 atom percent
• "j" ranges from about 13 to 30 atom percent.
• US ⁇ A ⁇ 4 219 355 discloses amorphous alloys consisting of iron, boron, silicon and carbon, the atomic percentages of iron and carbon being in the range of 80.0 to 82.0 and 1.5 to 2.5, respectively.
• the document also discloses that the magnetic properties can be enhanced by heating them to a temperature sufficient to achieve stress relief, cooling and applying a magnetic field during heating and cooling.
• a metal alloy which is at least 90% amorphous containing apart from incidental impurities iron, silicon and boron and is producible by a process comprising the steps of heating said amorphous alloy to a temperature in the range of about 340 to 440°C and sufficient to achieve stress relief but less than that required to initiate crystallization; cooling said alloy at a rate of about 0.5°C/min to 7°C/min; and applying a magnetic field to said alloy during said heating and cooling, and which is characterized in that it consists of a composition having the formula Fe.,Sit,Bc wherein "a", "b” and “c” are atomic percentages ranging from about 75 to 78.5, 4 to 10.5 and 11 to 21, respectively, with the proviso that the sum of "a", "b” and “c” equals 100.
• the invention provides a magnetic core comprising a metal alloy identified above.
• the alloys of this invention exhibit improved A.C. magnetic properties at temperatures up to about 150°C.
• the alloys are particularly suited for use in power transformers, aircraft transformers, current transformers, high frequency transformers (e.g. transformers having operating frequencies ranging from about 400 Hz to 100 kHz), switch cores, high gain magnetic amplifiers and low frequency inverters.
• composition of the new amorphous Fe-Si-B alloy in accordance with the invention, consists of 75 to 78.5 atom percent iron, 4 to 10.5 atom percent silicon and 11 to 21 atom percent boron.
• Such compositions exhibit enhanced A.C. magnetic properties.
• the improved magnetic properties are evidenced by high magnetization, low core loss and low volt-ampere demand which remain constant and stable at temperatures up to 125°C.
• a further composition consists of 78 atom percent iron, 6 to 10 atom percent silicon, the balance being boron.
• the alloys of the present invention are preferably at least about 97% amorphous and most preferably 100% amorphous. Magnetic properties are improved in alloys possessing a greater volume percent of amorphous material. The volume percent of amorphous material is conveniently determined by X-ray diffraction.
• the amorphous metal alloys from which those according to the invention are producible are formed by cooling a melt at a rate of about 10 5 °C to 10 6 °C/sec.
• the purity of all materials is that found in normal commercial practice.
• a variety of techniques is available for fabricating splat-quenched foils and rapid- quenched continuous ribbons, wire, sheet, etc.
• a particular composition is selected, powders or granules of the requisite elements (or of materials that decompose to form the elements, such as ferroboron, ferrosilicon, etc.) in the desired proportions are melted and homogenized, and the molten alloy is rapidly quenched on a chill surface, such as a rotating cylinder.
• the most preferred process for fabricating continuous metal strip containing the alloys of the invention is that set forth in U.S.P. 4,142,571 to Narasimhan.
• the Narasimhan patent sets forth a method of forming a continuous metal strip by depositing molten metal onto the surface of a moving chill body.
• the method comprises the steps of (a) moving the surface of a chill body in a longitudinal direction at a constant predetermined velocity of from about 100 to about 2000 meters per minute past the orifice of a slotted nozzle defined by a pair of generally parallel lips located proximate to the surface such that the gap between the lips and the surface is from about 0.03 to about 1 millimeter, the orifice being arranged generally perpendicular to the direction of movement of the chill body, and (b) forcing a stream of molten metal through the orifice of the nozzle into contact with the surface of the moving chill body to permit the metal to solidify thereon to form a continuous strip.
• the nozzle slot has a width of from about 0.34 to 1 millimeter
• the first lip has a width at least equal to the width of the slot
• the second lip has a width of from about 1.5 to 3 times the width of the slot
• amorphous metal strip produced in accordance with the Narasimhan process has a width of at least about 7 millimeters, preferably at least about 1 centimeter and, more preferably yet, a width of at least about 3 centimeters.
• the strip is at least 0.02 millimeter thick but may be as thick as about 0.14 millimeter, or thicker, depending on the melting point, solidification and crystallization characteristics of the alloy employed.
• the alloys of the present invention have an improved processability as compared to other iron-based metallic glasses, since the subject alloys demonstrate a minimized melting point and maximized undercooling.
• the method of annealing comprises heating the alloy to a temperature sufficient to achieve stress relief but less than that required to initiate crystallization, cooling the alloy, and applying a magnetic field to the alloy during the heating and cooling.
• a rate of cooling range of about 1°C/min to 16°C/min is employed.
• the alloys of the present invention exhibit improved magnetic properties that are stable at temperatures up to about 150°C, rather than a maximum of 125°C as evidenced by prior art alloys.
• the increased temperature stability of the present alloys allows utilization thereof in high temperature applications, such as cores in transformers for distributing electrical power to residential and commercial consumers.
• cores comprising the subject alloys When cores comprising the subject alloys are utilized in electromagnetic devices, such as transformers, they evidence high magnetization, low core loss and low volt-ampere demand, thus resulting in more efficient operation of the electromagnetic device.
• Cores made from the subject alloys require less electrical energy for operation and produce less heat.
• cooling apparatus is required to cool the transformer cores, such as transformers in aircraft and large power transformers, an additional savings is realized since less cooling apparatus is required to remove the smaller amount of heat generated by cores made from the subject alloys.
• the high magnetization and high efficiency of cores made from the subject alloys result in cores of reduced weight for a given capacity rating.
• Toroidal test samples were prepared by winding approximately 0.030 kg of 0.0254 m wide alloy ribbon of various compositions containing iron, silicon and boron on a steatite core having inside and outside diameters of 0.0397 m and 0.0445 m, respectively.
• One hundred and fifty turns of high temperature magnetic wire were wound on the toroid to provide a D.C. circumferential field of 795.8 ampere/meter for annealing purposes.
• the samples were annealed in an inert gas atmosphere for 2 hours at a temperature ranging from 340°C to 440°C with the 795.8 A/m field applied during heating and cooling to determine the optimum field annealing conditions for each composition.
• the optimum field annealing condition for each composition is that at which the exciting power of the core is lowest.
• the samples were cooled at a rate of approximately 10°C/min.
• the A.C. magnetic properties i.e., power loss (watts/kilogram) and exciting power (RMS Volt-amperes/ kilogram), of the samples were measured at a frequency of 60 Hz and a magnetic intensity of 1.4 Tesla by the sine-flux method.
• compositions of some amorphous metal alloys lying outside the scope of the invention and their field annealed A.C. measurements are listed in Table II. These alloys, in contrast to those within the scope of the present invention, have higher core loss and higher volt-ampere demand at room temperature and at 100°C.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Organic Chemistry (AREA)
• Metallurgy (AREA)
• Materials Engineering (AREA)
• Physics & Mathematics (AREA)
• Dispersion Chemistry (AREA)
• Crystallography & Structural Chemistry (AREA)
• Thermal Sciences (AREA)
• Power Engineering (AREA)
• Electromagnetism (AREA)
• Soft Magnetic Materials (AREA)
• Manufacture Of Alloys Or Alloy Compounds (AREA)
• Hard Magnetic Materials (AREA)

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• 1981
  • 1981-09-23 AT AT81107559T patent/ATE8914T1/de not_active IP Right Cessation
  • 1981-09-23 EP EP81107559A patent/EP0055327B2/en not_active Expired - Lifetime
  • 1981-09-23 DE DE8181107559T patent/DE3165416D1/de not_active Expired
  • 1981-10-20 CA CA000388318A patent/CA1215253A/en not_active Expired
  • 1981-11-02 AU AU77031/81A patent/AU550157B2/en not_active Ceased
  • 1981-11-24 JP JP56188291A patent/JPS57116750A/ja active Granted
  • 1981-12-28 KR KR1019810005175A patent/KR860000832B1/ko active

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