Hexaferrite materials
AssigneeThe University of Birmingham
InventorsAbolghasem Ataie, Ivor Rex Harris, Clive Brian Ponton
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Abstract
Barium, strontium and/or rare earth metal hexaferrite powder of low coercivity can be produced by subjecting a barium, strontium and/or rare earth metal hexaferrite powder to carburising, nitriding, carbonitriding, hydriding or carbohydriding conditions without undue loss of saturation magnetisation. High coercivity powder can be produced by calcining the low coercivity powder (FIG. 1). High remanence and high saturation magnetisation powder can be produced by mechanically alloying of a Sr--, Ba and/or rare earth metal hexaferrite powder with iron powder (FIG. 12).
Claims9
A method of producing a hexaferrite powder having high coercivity, said hexaferrite powder selected from barium hexaferrite powder, strontium hexaferrite powder and rare earth metal hexaferrite powder, comprising:
- a) heat treating one of a barium hexaferrite powder, strontium hexaferrite powder and rare earth metal hexaferrite powder under one of the following conditions:
- (i) carburising conditions in a gaseous atmosphere containing carbon:
- (ii) nitriding conditions in a gaseous atmosphere containing nitrogen;
- (iii) carbonitriding conditions in a gaseous atmosphere containing carbon and nitrogen:
- (iv) hydriding conditions in a gaseous atmosphere containing hydrogen:
- (v) carbohydriding conditions in a gaseous atmosphere containing carbon and hydrogen:
- and
- b) calcining the resultant powder.
Dependencies are inferred from the claim text.