Well-defined Fe

3

O

4

/MnOOH nanoparticles with 61.1 emu·g

-1

in magnetization intensity and 90.53 m

2

·g

-1

in surface area have been synthesized by a new-style of high-frequency impinging stream (HFIS) reactor. In this reactor

two streams first collided together to form nano Fe

3

O

4

suspension

which subsequently flew through an S-shaped main channel to generate high-frequency reversing high-gravity fields. At the same time

24 thin liquid sheets impinged into the main channel at the frequencies higher than 100 Hz to create nano Fe

3

O

4

/ MnOOH colloids. The obtained powders were characterized by transmission electron microscopy/energy dispersive spectrometer (TEM/EDS)

X-ray diffraction (XRD)

Brunner-Emmet-Teller (BET) and vibrating sample magnetometer (VSM). Experimental results indicated that low coating ratio prolonged the induction period of heterogeneous nucleation. The high-frequency impingements of 24 thin liquid sheets greatly accelerated the macro-mixing and the initial dispersion. The high-frequency reversing high-gravity fields promoted the mesoand micro-mixing. As a result

nano Fe

3

O

4

cores were fleet

ly and uniformly covered by MnOOH precursor. As a continuously operated and static high-gravity reactor

the high-frequency impinging stream (HFIS) reactor is being developed to the large-scaled and low-cost production of various nanocomposites.