Classifications

• • 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
  • H01F1/40—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials of magnetic semiconductor materials, e.g. CdCr2S4
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/02—Making non-ferrous alloys by melting
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/047—Making non-ferrous alloys by powder metallurgy comprising intermetallic compounds
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C28/00—Alloys based on a metal not provided for in groups C22C5/00 - C22C27/00
• • 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
  • H01F1/0302—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity characterised by unspecified or heterogeneous hardness or specially adapted for magnetic hardness transitions
  • H01F1/0306—Metals or alloys, e.g. LAVES phase alloys of the MgCu2-type
• • 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
  • H01F1/032—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 hard-magnetic materials
  • H01F1/04—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 hard-magnetic materials metals or alloys
  • H01F1/047—Alloys characterised by their composition
  • H01F1/053—Alloys characterised by their composition containing rare earth metals

Definitions

• the new rare earth compounds Gd Bi, Gd Sb and Dy Sb and their solid solutions: Gd (Bi Sb and (Gd Dy (Sb Bi are prepared.
• the constituent elements are powdered, mixed and heated in an airtight crucible to a temperature of 1300 C. and then cooled to room temperature.
• the new compounds and their solid solutions are ferromagnetic and exhibit varying Curie temperatures.
• the members of the class can be used in thermal control and safety devices.
• This invention relates to new rare earth compounds and, more particularly, to those compounds having the formula: Gd Bi, Gd Sb and Dy Sb and solid solutions thereof. These new compounds either When pure or in solid solutions are ferromagnetic.
• the rare earth metals and their compounds are important magnetic materials because they exhibit higher magnetic moments than the iron group metals (e.g., Fe, Co, and Ni) and their compounds.
• the magnetic moment of the rare earth elements is either the sum or difference of the spin and orbital moments of theunpaired electrons in the 4f shell, the difference resulting for the lighter and the sum for the heavier elements.
• the outer bonding orbitals effectively shield the 4f shell so that chemical bond formation has little effect on the total magnetic moment.
• the unpaired 3d electrons of the iron group metals are directly involved in bond formation and magnetic c upling so that'compounds and alloys of these elements generally have different moments.
• Still another object of the invention is to prepare rare earth solid solution systems which are ferromagnetic.
• Another object of the invention is to prepare a ferromagnetic compound having the formula Gd Bi.
• Still another object of the invention is to prepare a ferromagnetic compound having the formula Gd Sb.
• Still another object of the invention is to prepare a ferromagnetic compound having the formula Dy Sb.
• the rare earth compounds of the invention have the formula Gd Bi, Gd Sb and Dy Sb and crystallize with a hexagonal structure.
• Pure rare earth metal ingots (99.9 percent pure) of Gd and Dy are filed into powders in a dry oxygen free atmosphere (e.g., He, Ar, N). Rare earth metal filings are then mixed with antimony or bismuth metal (99.9 percent pure) and pressed into pellets which are then placed in a crucible which is made of a material which does n t enter into the reaction (e.g., tantalum or molybdenum). The size of the pellet is such that the pellet provides a piston fit to the crucible. A tapered plug of crucible material is forced into the crucible so that it presses 0n the surface of the pellets in order to exclude as much dead (i.e., empty) volume as possible.
• a dry oxygen free atmosphere e.g., He, Ar, N
• Rare earth metal filings are then mixed with antimony or bismuth metal (99.9 percent pure) and pressed into pellets which are then placed in a crucible which is made of a material which does
• the tight fit and small particle size are necessary because if there is dead (or empty) space in the crucible the Sb or Bi vapor will condense out on cooling and result in inhomogenous 'products. If the particles are too large, the high reaction temperature will vaporize the Sb or Bi before the reaction is completed and force the vapor out of the crucible. The excess tantalum above the plug is then peened over to form a tight closure so that Bi or Sb vapor pressure produced during the reaction can be contained within the crucible. The crucible is then placed on a pedestal in a quartz vacuum system centered in a radio frequency induction heating coil. An ambient atmosphere of helium is often used in place of the vacuum.
• Power is delivered to the coil at a rate such that the crucible temperature rises to 1300" C. within approximately 10-30 seconds.
• the temperature is maintained at 1300 C. for 15 minutes and the sample is then cooled to room temperature.
• the tantalum crucible is opened, the compound appears as a dense metallic ingot.
• the new rare earth compounds are brittle metallic materials which oxidize slowly when exposed to air and are pyrophoric in finely powdered form.
• Example IGd Bi 3.1454 grams of Gd is filed into a fine powder in a dry box and the filings mixed with 2.0900 grams of powdered bismuth metal. The mixture is then pressed into pellets in a nitrogen purged dry box. These pellets are then placed in an out-gassed tantalum crucible. The tapered tantalum plug is forced into the crucible so that it presses on the surface of the pellet in order to exclude as much dead volume as possible. The excess tantalum above the plug is then peened over to form a gas-tight closure. This crucible is now placed on a pedestal in a Example II-Gd Sb The procedure of Example I is repeated except that 1.217 5 grams of antimony are substituted for the bismuth. The resultant product is Gd Sb.
• Example lIl-Dy Sb 3.2500 grams of Dy is filed into a fine powder in a dry box and the filings mixed with 1.2175 grams of powdered antimony. This mixture is then pressed into pellets in a nitrogen purged dry box. These pellets are then placed in an out-gassed tantalum crucible. The tapered tantalum plug is forced into the crucible so that it presses on the surface of the pellet in order to exclude as much dead volume as possible. The excess tantalum above the plug is then peened to form a gas-tight closure.
• This crucible is now placed on a pedestal in a quartz vacuum system centered in a RF. induction coil. The temperature of the crucible is raised to 1400 C. and held there for 15 minutes. Then the crucible is rapidly cooled to room temperature. The resultant product is Dy Sb.
• Dy Sb has a positive paramagnetic Curie Temperature (0 of 110 K. which indicates at least a partial ferromagnetic interaction.
• Solid solution systems of the rare earth compounds of the invention have the formulas:
• These rare earth solid solution systems are ferromagnetic and since their Curie temperatures are a rapidly varying function of composition they can be used to prepare a series of materials with Curie temperatures rarbitrarily selected from a continuous range of Curie temperatures and thus find application in thermal control and safety devices.
• the solid solution systems are prepared in much the same manner as the rare earth compounds.
• the initial mixture is prepared by weighting and thoroughly mixing the component materials (i.e., rare earths and metalloids) in finely divided form as specified for any of the examples set forth in Table I.
• the mixture is then pressed into pellets and heated in a sealed tantalum crucible as in the procedure set forth for the pure compounds as prepared in Example I.
• Example I The procedure of Example I is followed except that the quantities indicated for each example in Table I are used, intimately mixed and then pressed into pellets. The resulting products is a solid solution system having the formula indicated for each example.
• the solid solutions show a linear variation of lattice constant with z which can be used to determine the ratio of Gd to Dy.
• the Curie temperature varies as a function of concentration of the rare earth atom.
• the magnetic moments of the solid solutions are an average of the individual rare earth moments Weighted on the basis of their concentrations.
• the solid solutions Gd (Bi Sb (Gd Dy Sb, and (Gd Dy Sb Bi have the average physical properties of the above solid solutions, i.e., the average moment of the rare earth part of the solid solution will vary rapidly as a function of the Sb and Bi concentration or conversely given a ratio of Sb to Bi the moment is the average of the moments of Gd and Dy according to their concentr-ations.
• the invention herein described results in new rare earth compounds having the formulas, Gd Bi, Gd Sb, Dy Sb, z( 1 X X), 1z yz) 2 and 1 z yz) 2 1-x x and their preparation. As has been shown, these compounds either in their pure state or in solid solution systems are ferromagnetic.
• a rare earth compound selected from the group consisting of Gd Bi, Gd Sb and Dy Sb.
• a rare earth solid solution system having a formula (Gd Dy (Sb Bi where 1 z 0 and l x 0.
• the rare earth solid solution system having the formulaGd Bi Sb 10.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Power Engineering (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)
• Powder Metallurgy (AREA)
• Crystals, And After-Treatments Of Crystals (AREA)
• Magnetic Ceramics (AREA)

Priority Applications (6)

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Cited By (5)

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Citations (3)

• 1964
  • 1964-08-31 US US393388A patent/US3342591A/en not_active Expired - Lifetime
• 1965
  • 1965-05-24 GB GB21808/65A patent/GB1089746A/en not_active Expired
  • 1965-08-25 NL NL6511066A patent/NL6511066A/xx unknown
  • 1965-08-27 CH CH1207665A patent/CH449271A/de unknown
  • 1965-08-27 DE DE19651483245 patent/DE1483245A1/de active Pending
  • 1965-08-30 AT AT794965A patent/AT261239B/de active

Patent Citations (3)

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