To prepare the composite materials by the mechanical mixing
method, commercial sub-micron powders of LSF731 and iron oxide
were mixed in two different mass ratios: 7:3 and 8.9:1.1. Pellets of
2 g were formed from these mixtures by applying 1500 kgf/cm2 for
30 s with a hydraulic press, followed by sintering at 1250 C in air
for 4 h in a tubular furnace