The LiMn2O4 spinel was prepared by wet method using Li2CO3, Mn(CH3COO)2·4H2O and CO2 as raw materials. The products were measured by TG/DTA, XRD, IR. The results Showed that the sample calcined at 800℃for 10h was well crystallized monophase product. The contents of Mn?and Mn?of LiMn2O4 spinel were determined simultaneously by spectrophotometric analysis with pyrophosphoric acid.
The paper first reported the preparation of ultrafine Fe3O4 powder about 8～ 10nm by improved chemical precipitation method, then turned it into magnetic fluid. The phase analysis, morphology, ultrafine powder size and magnetic property were measured by XRD, TEM and vibrating sample magnetometer(VSM),respectively. In addition, a new method , by analyzed the suspending percentage of Fe3O4 powder, was introduced to study the effects of concentration, pH value, centrifugal rate and time on the stability of the magnetic fluid.
