Study On Preparation Process Of Magnetic Fluids And Light Dispersed Particles In Magnetorheological Fluid

Magnetorheological Fluids is a class of suspension that is made up of um-grademagnetic partcles dispersed in carrier liquid. It mainly consists of base fluid (dispersionmedium), dispersion particles (dispersion) and additive (stabilizer), etc. The preparationand properties of base fluid and light magnetic dispersion are the two main investigationparts in this paper.As for the dispersion, Ni-Fe was electroless plated on polyurethane foam particles toget magnetorheological fluids with light magnetic dispersion. The surface andcross-section morphology of the particles after electroless plated were investigated, Theresults show that the plating is lack of flatness, and the distribution of elements on platingis uneven. The composition of Fe is over25%, which indicates a good magnetic property.Finally, according to the weight and radius of the magnetic particle along with thethickness of the plating,the density of magnetic particles and plating are calculated to be0.193g/c m3and1.994g/cm³, respectively.On the other side, the magnetic fluid will be used as the base fluid of themagnetorheological fluids. As a result, the preparation and properties of magnetic fluid ofFe₃O₄were researched. The four main aspects in this part are:1) the sequence of addingoleic acid and ammonia in the preparation of Fe₃O₄;2) the ratio of Fe²⁺0and Fe³⁺;3) thecontrol of reacting temperature in the preparation of Fe₃O₄magnetic particle;4) thequantity of the added oleic acid. The final results show that the optimal technique ofpreparation Fe₃O₄in nanometer is as follows: adding oleic acid and ammoniasimultaneously. In other words, drip ammonia firstly, and then drip oleic acid when thesolution shows brown opacity, but finish the dripping of oleic acid before that of ammonia.The ratio of Fe2+/Fe3+is1:1.65. the reacting temperature is65℃, and the adding amountof oleic acid is0.7ml.