Pure and superstoichiometric modified by 2 wt.%Bi_(2)O_(3) and 2 wt.%manganese oxide(Mn_(2)O_(3))ceramic samples of the binary system 0.71BiFeO_(3)-0.29BaTiO_(3) were fabricated using conventional ceramic technology b...Pure and superstoichiometric modified by 2 wt.%Bi_(2)O_(3) and 2 wt.%manganese oxide(Mn_(2)O_(3))ceramic samples of the binary system 0.71BiFeO_(3)-0.29BaTiO_(3) were fabricated using conventional ceramic technology by double solid-phase synthesis with following sintering.Mechanical activation of synthesized powders was carried out at the stage of manufacturing press powders prepared for sintering.X-ray analysis at room temperature showed that all studied ceramics have pseudo-cubic symmetry.Grain morphology,dielectric and piezoelectric properties of selected solid solutions were investigated.The modification increased the homogeneity of the material,dielectric constant and piezomodulus d_(33) and also resulted in a decrease in the dielectric loss tangent.The highest piezoelectric coefficient d_(33)=105 pC/N was obtained.Dielectric characteristics of ceramics revealed feroelectric relaxor behavior and region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 740-770 K.展开更多
In this report,the processes of texture formation in grain-oriented ferroelectric ceramics based on layer-structured ferroelectric Bi_(4)Ti_(3)O_(12)(LSBT)prepared by hot forging method are considered.The microstructu...In this report,the processes of texture formation in grain-oriented ferroelectric ceramics based on layer-structured ferroelectric Bi_(4)Ti_(3)O_(12)(LSBT)prepared by hot forging method are considered.The microstructural and X-ray methods revealed the axial textured formation in ferroelectric ceramic that are used to estimate the orientation factor of ceramics.For the first time,the domain structure changes when poling the anisotropic ferroelectric ceramics are investigated.The anisotropy of electromechanical,piezoelectric and ferroelectric properties of ferroelectric ceramics due to the crystal texture existence in it is studied.The aim of this study is to study the processes of crystalline texture formation in polycrystalline BLSF and to establish the dependence of the electrophysical properties of ceramics on the degree of texturing.Ceramics were textured using the hot stamping(HS)method developed at the Research Institute of Physics.The mechanism of the method is that the workpiece is subjected to uniaxial pressure and free radial deformation occurs due to the plastic flow of the material until the workpiece fills the free volume of the mold,which is created by placing the workpiece in the mold with a gap.The study of the microstructure of ceramics showed that an increase in the firing temperature in the range 950-1050℃ causes a sharp decrease in porosity and increases the density to 7.95 g/cm^(3),which is 98%of theoretical.An X-ray analysis was performed and microstructural studies were carried out,which revealed the formation of an axial texture in ceramics.The features of the switching processes of textured ceramics are revealed.The characteristics of the polarization switching of ceramics in the directions parallel and perpendicular(⊥)of the pressure axis during hot processing were obtained from the dielectric hysteresis P(E)loops,i.e.,axis axial texture.The⊥-cut ceramics are characterized by a more complete polarization switching,which is associated with the additional orientation of the(001)crystallographic planes in the textured material,as well as the presence of a threshold switching field.In the temperature range from-196 to+600℃,the anisotropy of the electro physical properties of ceramics due to the presence of a crystalline texture in it was studied.The dielectric constant,electrical conductivity,piezoelectric and elastic coefficients were measured for sections of ceramics of different orientations relative to the axis of the texture.The anisotropy of the dielectric constant and electrical conductivity manifests itself weakly at room temperature and increases sharply when approaching the Curie temperature.In the temperature range+20-400℃,the high thermal stability of the piezoelectric module d_(33),measured by the quasistatic method,was established.展开更多
The purpose of this work is to study the processes of interfacial interactions,their influence on the piezoelectric properties in highly elastic composite structures,to establish the patterns that determine the volume...The purpose of this work is to study the processes of interfacial interactions,their influence on the piezoelectric properties in highly elastic composite structures,to establish the patterns that determine the volume-sensitive piezoelectric characteristics of composites and to create effective piezoelectric materials for hydroacoustic receiving devices.In the process of this work,the development of a method for obtaining anisotropic ferropiezoelectric ceramics,the development of methods for the preparation of perfect ceramic powders and composite materials based on thermoplastic fluoropolymers and the study of composite materials based on lead-calcium titanate were carried out.As a result of the study,the dependences of the hydrostatic parameters of the composites on the degree of filling,particle size distribution,piezoelectric anisotropy of the active phase and the elastic properties of the polymer matrix were established.Composite materials were based on ceramics of the PT-CT system and thermoplastic fluoropolymers F-2ME,F-62,F-2N with a degree of filling with a ceramic phase from 30 to 60%vol.The dependences of the hydrostatic piezoelectric moduli gh and dh,and the quality factor gh·dh on the degree of filling of the composite for polymers F-62 and F-2ME with different average sizes of ceramic particles are plotted.It has been established that the maximum values gh=119.1·10^(−3)V·m/N and the quality factor g_(h)·d_(h)=6074·10^(−15)m^(2)/N are achieved for a polymer with a higher elastic compliance(F-62)at a degree of filling of 60%vol.and the use of granular filler.展开更多
Ceramics of quasi-binary concentration section(x=0.50,0.1≤y≤0.2,Δy=0.025)of the ternary solid solution system(1−x−y)BiFeO_(3)-xPbFe_(0.5)Nb_(0.5)O_(3)-yPbTiO_(3)were prepared by the conventional solid-phase reactio...Ceramics of quasi-binary concentration section(x=0.50,0.1≤y≤0.2,Δy=0.025)of the ternary solid solution system(1−x−y)BiFeO_(3)-xPbFe_(0.5)Nb_(0.5)O_(3)-yPbTiO_(3)were prepared by the conventional solid-phase reaction method.By using X-ray diffraction technique,the phase diagram of the system was constructed,which was shown to contain the regions of cubic and tetragonal symmetry and the morphotropic phase boundary between them.Grain morphology,dielectric and piezoelectric properties of the selected solid solutions were investigated.The highest piezoelectric coefficient d_(33)=260 pC/N was obtained.Dielectric characteristics of ceramics revealed ferroelectric relaxor behavior,a region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 350-500 K.展开更多
基金financial support of the Ministry of Science and Higher Education of the Russian Federation(State task in the field of scientific activity.Project No.FENW-2023-0010/GZ0110/23-11-IF)。
文摘Pure and superstoichiometric modified by 2 wt.%Bi_(2)O_(3) and 2 wt.%manganese oxide(Mn_(2)O_(3))ceramic samples of the binary system 0.71BiFeO_(3)-0.29BaTiO_(3) were fabricated using conventional ceramic technology by double solid-phase synthesis with following sintering.Mechanical activation of synthesized powders was carried out at the stage of manufacturing press powders prepared for sintering.X-ray analysis at room temperature showed that all studied ceramics have pseudo-cubic symmetry.Grain morphology,dielectric and piezoelectric properties of selected solid solutions were investigated.The modification increased the homogeneity of the material,dielectric constant and piezomodulus d_(33) and also resulted in a decrease in the dielectric loss tangent.The highest piezoelectric coefficient d_(33)=105 pC/N was obtained.Dielectric characteristics of ceramics revealed feroelectric relaxor behavior and region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 740-770 K.
基金supported by the Ministry of Science and Higher Education of the Russian Federationthe state task in the field of scientific activity No.FENW-2022-0001.
文摘In this report,the processes of texture formation in grain-oriented ferroelectric ceramics based on layer-structured ferroelectric Bi_(4)Ti_(3)O_(12)(LSBT)prepared by hot forging method are considered.The microstructural and X-ray methods revealed the axial textured formation in ferroelectric ceramic that are used to estimate the orientation factor of ceramics.For the first time,the domain structure changes when poling the anisotropic ferroelectric ceramics are investigated.The anisotropy of electromechanical,piezoelectric and ferroelectric properties of ferroelectric ceramics due to the crystal texture existence in it is studied.The aim of this study is to study the processes of crystalline texture formation in polycrystalline BLSF and to establish the dependence of the electrophysical properties of ceramics on the degree of texturing.Ceramics were textured using the hot stamping(HS)method developed at the Research Institute of Physics.The mechanism of the method is that the workpiece is subjected to uniaxial pressure and free radial deformation occurs due to the plastic flow of the material until the workpiece fills the free volume of the mold,which is created by placing the workpiece in the mold with a gap.The study of the microstructure of ceramics showed that an increase in the firing temperature in the range 950-1050℃ causes a sharp decrease in porosity and increases the density to 7.95 g/cm^(3),which is 98%of theoretical.An X-ray analysis was performed and microstructural studies were carried out,which revealed the formation of an axial texture in ceramics.The features of the switching processes of textured ceramics are revealed.The characteristics of the polarization switching of ceramics in the directions parallel and perpendicular(⊥)of the pressure axis during hot processing were obtained from the dielectric hysteresis P(E)loops,i.e.,axis axial texture.The⊥-cut ceramics are characterized by a more complete polarization switching,which is associated with the additional orientation of the(001)crystallographic planes in the textured material,as well as the presence of a threshold switching field.In the temperature range from-196 to+600℃,the anisotropy of the electro physical properties of ceramics due to the presence of a crystalline texture in it was studied.The dielectric constant,electrical conductivity,piezoelectric and elastic coefficients were measured for sections of ceramics of different orientations relative to the axis of the texture.The anisotropy of the dielectric constant and electrical conductivity manifests itself weakly at room temperature and increases sharply when approaching the Curie temperature.In the temperature range+20-400℃,the high thermal stability of the piezoelectric module d_(33),measured by the quasistatic method,was established.
基金supported by the Ministry of Science and Higher Education of the Russian Federationthe state task in the field of scientific activity No.FENW-2022-0001.
文摘The purpose of this work is to study the processes of interfacial interactions,their influence on the piezoelectric properties in highly elastic composite structures,to establish the patterns that determine the volume-sensitive piezoelectric characteristics of composites and to create effective piezoelectric materials for hydroacoustic receiving devices.In the process of this work,the development of a method for obtaining anisotropic ferropiezoelectric ceramics,the development of methods for the preparation of perfect ceramic powders and composite materials based on thermoplastic fluoropolymers and the study of composite materials based on lead-calcium titanate were carried out.As a result of the study,the dependences of the hydrostatic parameters of the composites on the degree of filling,particle size distribution,piezoelectric anisotropy of the active phase and the elastic properties of the polymer matrix were established.Composite materials were based on ceramics of the PT-CT system and thermoplastic fluoropolymers F-2ME,F-62,F-2N with a degree of filling with a ceramic phase from 30 to 60%vol.The dependences of the hydrostatic piezoelectric moduli gh and dh,and the quality factor gh·dh on the degree of filling of the composite for polymers F-62 and F-2ME with different average sizes of ceramic particles are plotted.It has been established that the maximum values gh=119.1·10^(−3)V·m/N and the quality factor g_(h)·d_(h)=6074·10^(−15)m^(2)/N are achieved for a polymer with a higher elastic compliance(F-62)at a degree of filling of 60%vol.and the use of granular filler.
基金The study was carried out with the financial support of the Ministry of Science and Higher Education of the Russian Federation(State task in the field of scientific activity,scientific project No.0852-2020-0032)(BAZ0110/20-3-07IF)Work was performed using the equipment of the Center for Collective Use“Electromagnetic,Electromechanical and Thermal Properties of Solids”,Research Institute of Physics,Southern Federal University and Center for Collective Use of the Southern Scientific Center of the Russian Academy of Science(Rostov-on-Don,Russia).
文摘Ceramics of quasi-binary concentration section(x=0.50,0.1≤y≤0.2,Δy=0.025)of the ternary solid solution system(1−x−y)BiFeO_(3)-xPbFe_(0.5)Nb_(0.5)O_(3)-yPbTiO_(3)were prepared by the conventional solid-phase reaction method.By using X-ray diffraction technique,the phase diagram of the system was constructed,which was shown to contain the regions of cubic and tetragonal symmetry and the morphotropic phase boundary between them.Grain morphology,dielectric and piezoelectric properties of the selected solid solutions were investigated.The highest piezoelectric coefficient d_(33)=260 pC/N was obtained.Dielectric characteristics of ceramics revealed ferroelectric relaxor behavior,a region of diffuse phase transition from the paraelectric to ferroelectric phase in the temperature range of 350-500 K.
