Development of Optimum Preparation Conditions of Fe-Deficient M-Type Ca–Sr–La System Hexagonal Ferrite Magnet

In this work, an experiment was carried out to investigate the preparation condition of anisotropic Fe-deficient M-type Ca–Sr–La system ferrite with optimum magnetic and physical properties using the raw material Fe
₂
O
₃
from steel industrial iron oxide waste. The compositions of the calcined ferrites were chosen according to the stoichiometry
${\mathrm {Ca}}_{1-x-y}$
La
_x
Sr
_y
Fe
_10.9
Co
_z
O
₁₉
, where M-type single-phase calcined powder was synthesized with a composition of
$x = 0.45$
,
$y = 0.18$
, and
$z= 0$
. The effect of CaO, SiO
₂
, and Co
₃
O
₄
inter-additives on the Ca–Sr–La system ferrite was also discussed in order to obtain low-temperature sintered magnets. The magnetic properties of
$B_{r} = 4570$
Gauss,
$_{b}H_{c} = 4320$
Oe,
$_{i}H_{c} = 5260$
Oe, and (
$BH$
)
$_{\mathrm {max}}= 5.16$
MGOe were obtained for Ca–Sr–La system hard magnets with low cobalt content at 1.85 wt%. The magnetic properties of the prepared magnets really good compared to that of the traditional Sr–La–cobalt (Co) M-type ferrite, which has been the highest grade M-type hard ferrite. The remarkable steel industrial iron oxide waste Fe
₂
O
₃
is recycled to produce high-end permanent magnets under an output power of < 1 kW, which will eventually be used in high-efficiency motors.