Surface organic modification of Fe₃O₄ nanoparticles by silane-coupling agents

Fe₃O₄ nanoparticles were prepared by chemistry co-precipitation and the mean crystal size was 17.9 nm measured by XRD. After it had been treated by silane-coupling agents KH570, magnetic microspheres dispersed in organic medium glycol were gained and the mean size of Fe₃O₄ nanopowders was 33.7 nm. So it can be concluded that magnetic micro-sphere is made of a few Fe₃O₄ crystals. Many factors of modification were researched, such as the time of ball milling, the content of Fe₃O₄ and the content of KH570.The modification of Fe₃O₄ is relative to the time of ball milling, but the dominant function is affected by the content of Fe₃O₄and KH570.When the content of Fe₃O₄ is known, there is a suitable content of KH570.Different content of Fe₃O₄ will make the different suitable content of KH570, but the range of latter is less than former, which is relative to the distribution of KH570 on Fe₃O₄ surface or in the solution.