Controllable Preparation And Microwave Absorption Properties Of BaTiO₃ Nanoparticles Based On Solvothermal Method

Barium titanate?BaTiO₃?nanoparticles are very promising as microwave absorption materials.However,the microwave absorption properties of BaTiO₃ nanoparticles are unsatisfied in high-frequency band,which hinders its wide application in the field of electromagnetic wave absorption.In this work,using low-cost titanium tetrachloride?TiCl₄?and barium hydroxide octahydrate?Ba?OH?₂·8H₂O?as raw materials,the BaTiO₃ nanoparticles with different morphologies were prepared by solvothermal method.And then combining as-prepared BaTiO₃ nanoparticles with GO which has large complex permittivity,the barium titanate/reduced graphene oxide?BaTiO₃/RGO?nanocomposites were finally obtained after calcining the mixtue in Argon.The effects of experimental parameters on the complex permittivity and microwave absorption properties of BaTiO₃/RGO nanocomposites were systematically investigated.The major research contents as follows:?1?TiCl₄ was dissolved in ethanol while Ba?OH?₂·8H₂O was dissolved in deionized water,and then the alcoholic solution of TiCl₄ were dropped slowly into the aqueous solution of Ba?OH?2.The mixed solution was transferred to a teflon vessel and subjected to hydrothermal treatment at 240? for 24 h after adjusting the pH value by NaOH.The structures of as-prepared BaTiO₃ nanoparticles were cubic,and BaTiO₃ nanoparticles had high purity,narrow size distribution and good regularity.By changing the volume ratio of deionized water and ethanol as 1.0,1.4,2.0 and 3.0,the particle diameter of BaTiO₃ nanoparticles were controlled at 70 nm,90 nm,130 nm and 180 nm.?2?Using ethanediamine and cetyltrimethyl ammonium bromide?CTAB?as surfactants and mixing as-prepared BaTiO₃ nanoparticles with graphene oxide?GO?,BaTiO₃/RGO nanocomposites with different mass ratio were prepared by solvothermal method.This research had three synthetic parameters including the mass ratio of BaTiO₃ and GO,BaTiO₃ nanoparticles' size and annealing temperature.The effects of experimental parameters on the complex permittivity and microwave absorption properties of BaTiO₃/RGO nanocomposites were systematically investigated by vector network analyzer?VNA?.When the mass ratio of BaTiO₃ with the particles' diameter of 70 nm and GO was 7:3 in raw materials and annealing temperature at 600 ?,BaTiO₃/RGO nanocomposites performed the excellent microwave absorption properties.The minimum reflection loss of BaTiO₃/RGO nanocomposites was-33.43 dB at 10.48 GHz with the thickness of 2.0 mm and the reflection loss bandwidth less than-10 dB was from 9.2 to 11.6 GHz.With the introduction of RGO,the impedance matching had been improved.The microwave absorption properties of BaTiO₃/RGO nanocomposites were farther enhanced due to the coefficient effect of interfacial polarization and synergistic effect.