(Mg²⁺+M⁵⁺) (M=V, Nb, Ta) Doped TiO₂ Preparation And Electrical Properties The Study

With the development of miniaturization and integration of electronic products,giant dielectric materials have been received extensive attention.In recent years,a large number of studies on the doping of TiO2-based ceramics have found that doped TiO2-based ceramics have high dielectric constant(>104),good temperature stability and frequency stability,and low dielectric loss(<5%),it has broad application prospects in the field of capacitors and the like.This paper is based on the idea of different ionic radius doping of the same family dements(V,Nb,Ta),(Mg1/3NbZ/3)xTi1-xO2(abbreviated as MNTO,x=0.005,0.01,0.02,0.03,0.04,0.05)ceramics by introducing Mg2+/Nb5+ co-doped TiO2;(Mg1/3Ta2/3)xTi1-xO2(abbreviated as MTTO,x=0.005,0.01,0.02,0.03,0.04,0.05)ceramics by introducing Mg2?/Ta5+ co-doped TiO2;(Mg1/3V2/3)xTi1-xO2(abbreviated as MNTO,x=0.005,0.01)ceramics by introducing Mg2+/V5+ co-doped TiO2.By changing the doping amount of the co-doped element,it is desirable to change the concentration of the defect composite inside the ceramic material,thereby obtaining a ceramic sample excellent in dielectric properties.At the same time,the effect of different sintering processes on the dielectric properties of TiO2-based ceramics was studied by using the plasma sintering technique of Mg2+/V5+ co-doped TiO2-based dielectric ceramics.The main conclusions are as follows:1.The sintering process of MNTO,MTTO and MVTO ceramics was systematically studied.The conclusion is:MNTO,MTTO ceramic pre-sintering temperature is 1100?,holding 3 h,sintering temperature is 1400?,holding 20 h;The pre-burning temperature of MVTO ceramics is 1050?,the temperature is kept for 3 h,the sintering temperature is 1400?,and the temperature is kept for 10 h.2.The MNTO,MTTO and MVTO ceramic materials were successfully prepared by the traditional solid phase method.The samples showed high dielectric constant.With the increase of doping amount,the dielectric constant of the sample increased,the dielectric loss decreased,and the frequency stability was enhanced.When the doping amount is x=0.01,MNTO ceramic materials for optimum dielectric properties:at 10 kHz,the relative dielectric constant of the material is ?r=12961,and the dielectric loss is tan?=0.076.The ceramic material has a ?C/C25? of about-1.3%to 8.1%in the temperature range of-150? to 150?,and has excellent temperature stability.When the doping amount is x=0.01,the relative dielectric properties of the MTTO ceramic material are optimal:at 10 kHz,the relative dielectric constant of the material is ?r=1 7286,and the dielectric loss is tan?=0.029.The MTTO ceramic material has a AC/C25Oe of about-1.3%to 8.0%in the temperature range of-150? to 150?,and has excellent temperature stability.When the doping amount is x=0.01,the relative dielectric properties of the MVTO ceramic material are optimal:at 10 kHz,the relative dielectric constant ?r-6301,and the dielectric loss tan?=0.029.3.(Mg1/3M2/3)0.01Ti0.99O2(M=V,Nb,Ta)ceramic materials were successfully prepared,and the samples all exhibited giant dielectric properties(>5000),and the low frequency of the material increased with the ionic radius(<100 kHz)dielectric loss is reduced and frequency stability is enhanced.(Mg1/3Ta2/3)0.01Ti0.99O2 ceramic material has the best dielectric properties:at 10 kHz,the dielectric constant ?r=17286,and the dielectric loss tan?=0.029.At the same time,according to the XPS analysis of the material,the doping of different ionic radius elements did not significantly change the ratio of Ti4+/Ti3+,Therefore,the difference in dielectric properties of(Mg1/3M2/3)0.01Ti0.99O2(M=V,Nb,Ta)ceramics may change the lattice of ceramic materials due to the increase of doping ionic radius,resulting in extrinsic defects,which in turn affects the dielectric properties of the material.Further analysis of XPS results show that there may be defect complexes in different ionic radius(Mg1/3M2/3)0.01/Ti0.99O2(M=V,Nb,Ta)ceramic materials:MgTi?TaTi?MgTi?Vo?TiTi etc.Therefore,it can be inferred that the mechanism of the giant dielectric response of(Mg1/3M2/3)0.01Ti0.99O2(M=V,Nb.Ta)ceramic materials is mainly the defect dipole effect(EPDD)of electron pinning.4.The Mg2+/50 co-doped(Mg1/3V2/3)xTi1-xO2(x=0.005.0.01)ceramic materials were successfully prepared by spark plasma sintering technique,and the breakdown strength(>100kV/cm)was obtained,and better residual polarization.(Mg1/3V2/3)0.01Ti0.99O2 ceramic material is obtained by spark plasma sintering.The dielectric constant of the material is above 1000 at 10 kHz,and the dielectric loss is less than 5‰,while retaining the giant dielectric properties of the material,the breakdown strength of the MVTO ceramic material is increased to 110 kV/cm.