Preparation And Properties Of Pb(Mg_1/3Nb_2/3)O₃ And Pb(Mg_1/3Nb_2/3)O₃-CoFe₂O₄ Materials Via Liquor-Complexation Process

The Pb(Mg_1/3Nb_2/3)O₃ multilayer ceramic capacitors (MLCCs) are more and more widely used in the circuits of the latest electronic products, such as mobile phones, personal computers-television hybrid,because of their compact size, low manufacturing cost, good temperature and voltage characteristics.Magnetoelectric materials, which can display a spontaneous dielectric polarization as a response to an applied magnetic field, or an induced magnetization by an external electric field, are widely used in microwave domain, current measurement of high-tension transmission line, broadband magnetic detect, magnetic field inductor. The Pb(Mg_1/3Nb_2/3)O₃ exhibits excellent dielectric and electrostrictive properties and CoFe2O4 exhibits magnetostrictive properties, thus the Pb(Mg_1/3Nb_2/3)O₃-CoFe2O4 composite maybe exihibits unique advantage as the magnetoelectric materials.The purpose of this work is to prepare high purity Pb(Mg_1/3Nb_2/3)O₃ dielectric ceramic powder and Pb(Mg_1/3Nb_2/3)O₃-CoFe2O4 composite powder by liquid complexation process. The study includes:(1) Pb(Mg_1/3Nb_2/3)O₃ ceramic powder is prepared via liquid complexation method. The phase development of the precursor is analysed via X-ray diffraction spectrometry(XRD).(2) MgNb2O6-CoFe2O4 precursor is prepared via liquid complexation method, pure MgNb2O6-CoFe2O4 ceramic powder is obtained when calcining at 1000℃for 1h.(3) Pb(Mg_1/3Nb_2/3)O₃-CoFe2O4 precursor is prepared via core-shell method, the organic ligands'burnout and phase development of solid solution is analysed via X-ray diffraction spectrometry(XRD), Fourier Transform Infrared Spectroscopy (FTIR)and Thermogravimetric/Differential Thermal Analysis (TG/DTA). With the excess 10% mol of PbO, pure Pb(Mg_1/3Nb_2/3)O₃-CoFe2O4 powder is obtained when the precursor is calcined at 700℃for 5hs.(4)The mechanism of the core-shell method is discussed, theoretical module of the core-shell method is provided. (5)The microstructure of Pb(Mg_1/3Nb_2/3)O₃-CoFe2O4 ceramic is observed by Scanning Electron Microscope (SEM) and the phase separation of is investigated via Energy Dispersive X-ray Analysis (EDX).