Preparation Of Diesel Fuel Based Magnetic Fluid

Magnetic fluid has been widely used in seal, sensors and shock absorbers and made remarkable progress because of its unique performance. In order to expand the scope of its application, in this paper diesel oil which is cheap and has low viscosity and volatility was chosen as carrier liquid and diesel fuel based magnetic fluid was prepared. Then a variety of test means have been used for characterization of the structure and properties of magnetic fluid. Finally, the paper summarized the influence factors that had bearing on magnetic fluid properties during the preparation.Firstly, Fe3O4nano-magnetic particles were prepared by the improved Massart hydrolysis method and the improved titering hydrolysis process which all based on the principle of chemical precipitation. By making experiments that Fe3O4nano-magnetic particles were prepared by the improved Massart hydrolysis method, optional technological conditions were determined. It was that concentration of the reactors was0.6mol/L, reaction temperature was70℃, reaction time was1h. Moreover, the coating experiment was conducted using oleic acid as the surface active agent to the sample which had the best performance. The results indicated that the best coating time was4h and the average size of the coated particles was about12nm. By making experiments that Fe3O4nano-magnetic particles were prepared by the improved titering hydrolysis process, it was found that the best time for adding surfactants was the moment that the brown precipitation began to appear in the reaction solution. The particles prepared under this process had the smallest size and preferable dispersibility.By the disperse way of ultrasonic oscillating combining with mechanical raking, diesel fuel based Fe3O4magnetic fluid was prepared. The influence of technological condition of magnetic particles and its content in the fluid on the performance of the fluid were observed. The results showed that the size and dispersibility of magnetic particles were key factors to magnetic property and stability of the fluid. Within a certain range, the smaller the particle size was, the more magnetic particles can suspend in the fliud and the higher saturation magnetization strength of magnetic fluid had.Diesel fuel based Fe3O4magnetic fluid which has high saturation magnetization strength and low viscosity has been prepared. Its saturation magnetization strength was as high as625Gs while its viscosity was only34mPa· s at room temperature.In order to enhance saturation magnetization strength of the fluid, diesel fuel based magnetic fluid was prepared. The nano-Co particles were firstly prepared in aqueous solution by chemical method using zinc dust as reducing agent and cobalt chloride as cobalt source. ZnO impurities were removed and relatively pure schistic nano-Co particles with size of123nm were obtained by taking measures of changing reactants ratio and making the particle suspension react with NaOH solution. Nano-Co particles and Fe3O4nano-magnetic particles were dispersed in the diesel fuel at the same time by the disperse way of ultrasonic oscillating combined with mechanical raking so that diesel fuel based Co-Fe3O4magnetic fluid was attained. But for the reason of size and shape of nano-Co particles, saturation magnetization strength of diesel fuel based Co-Fe3O4magnetic fluid was less than the diesel fuel based Fe3O4magnetic fluid which had same ratio of magnetic particles and carrier liquid. Theoretical analysis showed that, the spherical rather than flake cobalt particles were more suitable for the preparation of diesel fuel based Co-Fe3O4magnetic fluid. The author put forward preparation scheme in theory for spherical nano-Co particles using chemical method.