Experimental Study On Synthesis Of Silica Coated Iron Nanoparticles By Detonation Method

With the development of nano magnetic materials,silica coated ironnanoparticles have attracted more and more attention due to their excellent magnetic properties and microwave absorbing properties.At present,it could be synthesized by physical vapor evaporation and chemical hydrolysis.Compared with other methods of detonation synthesis process was relatively simple and fast,and did not require sophisticated instruments and strict experimental conditions only need to experiment with very low cost can synthesize our required target material.Then the composition,morphology and magnetic properties of detonation products were tested by XRD,TEM and VSM.This paper used two kinds of explosives that emulsion explosive and RDX detonation synthesis process and used the control variable method and inverse method to design the experimental formula,and studied the emulsion explosive and RDX formula of different effects on the synthesis and comparison of two kinds of explosives.On the other hand,contrasted with the two kinds of explosives.The synthetic products were studied by changing the iron source(ferric nitrate,Er Maotie),carbon source(urea,petroleum jelly)and silicon source(silicone oil and sodium silicate)in the emulsion explosive formula.Through the analysis of XRD spectra revealed nuclei containing ferrite coated particles,TEM experiments show that it has obvious core-shell structure particles but the poor dispersion,the particle size is between 30~60nm,and calculated its theory of detonation velocity found its ideal detonation velocity in 4800m/s when the particle morphology was better.The analysis of VSM hysteresis loop showed that it exhibits ferromagnetism and has weak ferromagnetic properties,which had wide application prospect in magnetic storage.The experimental formula of RDX was used the RDX and detonation precursor of iron(ferric nitrate)and silicon source(sodium silicate)and adding carbon source(ethanol)mixed the formation of plastic explosives,experimental steps with emulsion explosive.The change of carbon source(Naphthalene,Urea and Ethanol)on the detonation ash analysis.By compared and analyzed with the products of the emulsion explosive,it was found that the dispersion of the particles was very good and showed regular spherical shape.At this point,the optimum theoretical detonation velocity wasabout 6200m/s.But its magnetism was very weak,almost without magnetism.Finally,the magnetic properties of the detonation products were treated at 600 degrees for 4hours.The magnetic properties of these products were greatly increased and showed a weak ferromagnetism.The above research showed that detonation method can be used to synthesize iron oxide coated nano magnetic material.By changing the experimental formula can control the crystal nuclear component(or ferrous iron oxide),changed the type of explosive and detonation velocity can control the morphology and magnetism,reasonable regulation of the formula can be obtained in different magnetic materials.In summary,magnetic materials of emulsion explosive synthesis but strong particle morphology and poor dispersion,and the morphology of RDX material used a regular spherical and well dispersed,but had a poor magnetic.The lack of magnetism can be compensated by heat treatment.