Preparation Of Fe-Co Based Alloy Magnetic Fluid

Magnetic fluids have been widely used in aerospace,sealing materials,medical science and many other fields due to outstanding performance.Nevertheless,its applications in pressure resistance and sealing are limited by their poor magnetic and thermal stability of the magnetic fluid,which is mainly related to the performance of magnetic particles in the magnetic fluid.Therefore,it is very necessary to the preparation of magnetic fluids with high saturation magnetization and thermal stability of Fe-Co-based soft magnetic alloy magnetic particles.Fe-Co based soft magnetic alloy particles were prepared by a melt spinning technique,and the influence of B and Si addition on magnetic particles were discussed.The results shows that the saturation magnetization,remanence,and coercive force of the magnetic particles gradually increase as the content of the B element decreases in the soft magnetic alloy of(Fe_0.8Co_0.2)_98-XB_XSi₂.Among them,Fe₆₈Co₂₂B₁₀0 has best performance of a maximum saturation magnetization of 245.39A·m²/kg,a coercive force of 5.10kA/m,and a residual magnetization of 0.67A·m²/kg.After dealing with the surface of the magnetic particles,the maximum saturation magnetization reduced to183.19A·m²/kg,and the coercive force and residual magnetization increased to8.42kA/m and 0.95A·m²/kg,respectively.The degree of agglomeration of the modified magnetic particles is reduced.The average particle size of the initial alloy particles is about 500nm,and the average particle size after modification is about 580nm.The magnetic fluid is prepared by constant temperature and stirring,Through the test that the viscosity of the Fe-Co-based magnetic fluid is affected by the mass fraction,particle size,temperature,and time.The higher magnetic particle mass fraction leads to more serious the reunion and greater the viscosity of the magnetic fluid.As the temperature rises,the viscosity of the Fe-Co-based magnetic fluid tends to decrease,and the viscosity decreases more slowly after the temperature exceeds 65?,so temperature stability is good.At the same time,the viscosity will decrease with time,but it will be slower.The highest viscosity of the Fe₆₈Co₂₂B₁₀0 magnetic fluid with a mass fraction of35wt%is 4.63×10⁴mPa·s.The particles in the magnetic fluid tend to aggregate,and the block size is about 2⁵?m.The magnetic fluid was prepared by 35wt%of Fe₆₈Co₂₂B₁₀the magnetic particle,the maximum saturation magnetization and remanencea reached to 47.08A·m²/kg and 3.96A·m²/kg respectively.