Fe³⁺ Magnetic Doping Of Tetragonal Barium Titanate And Its Electromagnetic Synergistic Response Performance

In the excellent electrorheological and magnetorheological materials of inorganic compounds,the dielectric properties,magnetic permeability,and polarization state of the materials are important factors affecting the electromagnetic rheological effect.A typical electrorheological material,barium titanate(BaTiO3),has almost the highest rank in the selection of electrorheological particles due to its extremely high dielectric constant and low dielectric loss.According to polarization and dielectric mismatch theory,it should have very strong ER activity under external electric field,but experiments show that dry BaTiO3 has almost no electrorheological effect under DC electric field,and there is no magnetic field response.For this reason,in this dissertation,Fe3+ magnetically doped tetragonal barium titanate was used to obtain a composite particle Ba1-xFexTiO3 with quadrangular pyramidal morphology and spherical shape,where x=n(Fe)/n(Ti),1-x=n(Ba)/n(Ti),and study the electromagnetic response of composite particles.The main contents are as follows:1.In this paper,a simple one-step hydrothermal synthesis method is adopted.By optimizing the reaction time and the input ratio of the reaction materials,a composite particle Ba1-xFexTiO3 with a certain morphology and a certain gradient molar ratio is obtained.2.The obtained composite particle Ba1-xFexTiO3 is characterized by field emission scanning electron microscopy(FE-SEM)and transmission electron microscopy(TEM)and X-ray diffractometer(XRD).The results show that the obtained composite particle Ba1-xFexTiO3 is a quadrangular pyramidal morphology;the tetragonal phase content of the series of composite particles are all high and increase with the increasing of the proportion of Fe3+ input.Through comprehensive ICP spectroscopic characterization,the measurement ratio of the elements in the product is consistent with the input ratio,indicating that Fe3+ substituting part of Ba2+in BaTiO3,the x value of Ba1-xFexTiO3 was determined,ie x = 0.04,0.10,0.16.The Ba1-xFexTiO3 particles were found to have good compatibility with aqueous media as measured by a video optical contact angle meter.3.Using hydrothermal synthesis method to optimize the reaction conditions and changing the titanium source,a spherical Ba1-xFexTiO3(x=0.10)composite particle was prepared,and two types of Ba1-xFexTiO3(x=0.10)composite particles were synthesized.By comparison,the results show that the tetragonal pyramidal composite particles have a higher tetragonal phase content.4.The resulting composite particles,Ba1-xFexTiO3 were dispersed in a gelatin hydrogel system at 65 ?,with no field,field(E=0.80 kV/mm),magnetic field(H=0.04 T),and double field(E=0.80 kV/mm,H=0.04 T),respectively.Gelification was performed to obtain four aqueous composite elastomers.The elastic storage modulus of the elastomer was measured by a dynamic viscoelasticity spectrometer.The results showed that the response ability of the composite particle to double fields was greater than that to a single field;the Ba1-xFexTiO3(x=0.10)composite particle applied electric field(E=0.80 kV/mm),magnetic field(H=0.04 T),double field(E=0.80 kV/mm,H=0.04 T)have the largest response;the composite particles with quadrangular pyramidal shape have better response to electric and magnetic fields.