Precipitation Concentration Test and Type Inspection Performance Test of Nano-Fe₃O₄ Water-Based Magnetic Fluids

Fe₃O₄ magnetic fluids of two different shapes of sphere and sheet were prepared by chemical method. The samples were characterized by XRD, TEM, SEM. Studies on the concentration by precipitation and type inspection performance of nano-Fe₃O₄ water-based magnetic fluid were made, and the results showed that no obviously precipitation was found in the pear shaped sedimentation tube after stabling 30min. The type inspection performance was consistent with JB/T6063-2006 Non-destructive testing-Materials for magnetic particle testing. Test result showed the current method of measuring the concentration by precipitation needed further improvement.