Hexagonal Ba Ferrite magnetic powder and its manufacturing method

摘要

PROBLEM TO BE SOLVED: To provide hexagonal ferrite powder, provided that fine magnetic particles which make up the powder and the individual magnetic particles are small in the variation in coercive force.SOLUTION: In hexagonal crystal Ba ferrite magnetic powder, Fe-site valence Xis 3.005-3.030; R/M mole ratio (M represents Fe and its substitute element) is 0.001-0.020; and Dx volume is 1150-1450 nm, provided that X=(3+2×[M(II)/Fe]+4×[M(IV)/Fe])/(1+[M(II)/Fe]+[M(IV)/Fe]), and Dx volume (nm)=Dxc×π×(Dxa/2). In the above formulas, M(II) and M(IV) are divalent and quadrivalent substitute elements respectively, Dxc and Dxa are crystallite diameters (nm) in hexagonal crystal c-axial and a-axial directions respectively and π is the circular constant.SELECTED DRAWING: Figure 1