| 摘要 |
1,243,378. Magnetic materials. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 19 Dec., 1968 [21 Dec., 1967], No. 60378/68. Heading H1H. [Also in Division C7] Magnetic material consists of magnetic particles (diameter <30Á) coated with metal. The magnetic particles consist of an alloy of the system M-R within the region of homogeneity which includes M-R and in which all alloys have the same hexagonal crystal structure as M 5 R where M is Co, or Co and one or more of Fe, Ni, Cu, and R is one or more of Y, Th or rare earth elements (see Specification 1,187,853). When M 5 R is Co 5 Sm, the metal coating may be NiŒP or B; CoŒP or B, SnŒZn or Cd; or Cu. The coated particles may be made by melting, casting and pulverizing the core materials and forming the metallic layer by sputtering, or by electroless or electrolytic deposition. In examples, SmCo 5 particles are etched in an ultrasonically vibrated vessel containing INH 2 SO 4 at 20-50‹ C. for 60 seconds before being electrolessly coated with Ni-P, Co-P, or Ni-Co-P and electrolytically coated with Cu. In further examples, SmCo 4 . 9 is coated with Cu or Ag by cathode sputtering, and Ni-P coatings are applied to particles of YCo 5 , GdCo 5 , PrCo 5 , LaCo 5 and Mischmetall Co 5 . The IHc of the coated particles ranges from 1700 Oe. to 26,000 Oe. Permanent magnets made from the particles are anisotropic. |
