Nano-crystalline Fe*O* particles with high absorption capacity and preparation method thereof

The invention relates to nano-crystalline Fe3O4 particles with high absorption capacity and a preparation method thereof which belong to the field of material science. The microstructure of the particles comprises equiaxed nano-grains, and the particle size of the nano-grains is 5-100nm; the average particle size is 8-25nm, and the saturated magnetization MS is 6.7-7.2 multiplied by 10 A/m. The preparation method is as follows: solution containing ferric ions and ferrous ions is prepared, ammonia solution is added under nitrogen atmosphere, ultrasonic waves are transmitted to carry out the ultrasonic dispersion, and heating, stirring and reaction are carried out; solids are washed till neutral by water under the condition of a magnetic field; water is removed by drying after the centrifugal separation. The invention utilizes the simple chemical reaction co-precipitation technology and combines the ultrasonic stirring, the centrifugal separation, the vacuum drying and other technologies to obtain the Fe3O4 powder materials with the average particle size of 8-25nm and the higher saturated magnetization.