Patents Assigned to Ugimag S.A.
  • Method for making m- type hexaferrite powders or wafers
    Patent number: 6761830
    Abstract: A method for manufacturing type M hexaferrite powders fo the formula AFe12O19 where A is Ba, Sr, Ca, Pb or a mixture thereof. An iron oxide Fe2O3 and a compound A are mixed with a molar ratio n=Fe2O3/AO, formed and calcined, and the agglomerates which result from the calcining are ground to obtain a fine ferrite powder. The mixture is formed with a ratio n ranging between 5.7 and 6.1, and with a predetermined degree of homogeneity, and before or during the grinding process, an agent controlling the microstructure is introduced.
    Type: Grant
    Filed: February 15, 2002
    Date of Patent: July 13, 2004
    Assignee: Ugimag S.A.
    Inventors: Antoine Morel, Eric Brando, Philippe Tenaud