This paper studies the relaxation processes and electromechanical hysteresis in relaxor piezoceramics based on the PzT system.Measurements and analysis of the electric displacement and mechanical strain hysteresis loo...This paper studies the relaxation processes and electromechanical hysteresis in relaxor piezoceramics based on the PzT system.Measurements and analysis of the electric displacement and mechanical strain hysteresis loops recorded in bipolar AC electric fields in the frequency range 0.001-5 Hz were performed by means of the electromechanical response characterization system(STEPHV)and program(STEP).It was found that the coercive field,remnant and saturation electric displacement,area of hysteresis loops and relative mechanical strain values are strongly dependent on frequency.As a result of this study,complete sets of parameters characterizing the switching and ferroelectric hysteresis processes in relaxor piezoceramics were obtained.展开更多
This paper presents the results of an experimental study of the percolation behavior of the complex dielectric constant of ceramic matrix composites(CMC).Samples of piezoactive CMC were obtained by joint sintering of ...This paper presents the results of an experimental study of the percolation behavior of the complex dielectric constant of ceramic matrix composites(CMC).Samples of piezoactive CMC were obtained by joint sintering of synthesized PZT piezoceramic powder(matrix)and crushed particles of sintered PZT piezoceramics(filler)of different compositions.The experimental dependencies of real and imaginary parts of the complex dielectric constant of CMC on the porosity of piezoceramic matrix and volume content of ceramic filler particles were measured and analyzed.It was shown that the additional porosity of the ceramic matrix resulting from sintering of the CMC masks the dielectric percolation transition,that actually occurs at the volume concentration of ceramic filler close to percolation threshold(V~1/3).展开更多
In this paper,we present the experimental results of the comprehensive study of the microstructural features and complex dielectric,elastic and electromechanical properties of the ferroelectrically“hard”piezoceramic...In this paper,we present the experimental results of the comprehensive study of the microstructural features and complex dielectric,elastic and electromechanical properties of the ferroelectrically“hard”piezoceramics based on the lead zirconate titanate(PZT)composition.For the measurements and analysis of the real and imaginary parts of the complex parameters of the studied piezoceramics as well as their frequency dependences,we used precision impedance analyzer Agilent 4294A and Piezoelectric Resonance Analysis Program(PRAP)software.We have found that the studied piezoceramics demonstrate a unique combination of dielectric,elastic and electromechanical parameters along with very low elastic and electromechanical losses and dispersion over a wide frequency range and can be used in various high-power ultrasonic applications.展开更多
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 paper,the results of experimental study of dispersion characteristics of complex electromechanical parameters of ferroelectrically“hard”porous piezoceramics based on PZT composition were presented.Experiment...In this paper,the results of experimental study of dispersion characteristics of complex electromechanical parameters of ferroelectrically“hard”porous piezoceramics based on PZT composition were presented.Experimental samples of porous piezoceramics were fabricated using a modified method of burning-out a pore former.The complex constants of porous piezoceramics with relative porosity 16%and their frequency dependences were measured using the piezoelectric resonance analysis method.As a result of experimental studies,regions of elastic,piezoelectric and electromechanical dispersion,characterized by anomalies in the frequency dependences of the imaginary and real parts of the complex constants of porous piezoelectric ceramics were found.It was revealed also that the microstructural features of porous piezoceramics determine the character of frequency dependences of complex electromechanical parameters of porous piezoelectric ceramics.In conclu-sion,the microstructural and physical mechanisms of electromechanical losses and dispersion in porous piezoceramics were discussed.展开更多
In this paper,a comprehensive study of microstructure/properties interrelations for porous piezoceramics based on PZT composition was performed.Experimental samples of porous piezoceramics were fabricated using a modi...In this paper,a comprehensive study of microstructure/properties interrelations for porous piezoceramics based on PZT composition was performed.Experimental samples of porous piezoceramics were fabricated using a modified method of burningout a pore former.Porosity dependencies of elastic,dielectric,piezoelectric and electromechanical coefficients of the porous ceramics in the relative porosity range 0-50%were obtained and analyzed.As a result of microstructure analysis,it was found that at any connectivity type(3-0,3-3)and porosity up to 50%the real structures of porous piezoceramics were close to the matrix medium structure with continuous piezoceramic skeleton.It was also revealed that the microstructural features of porous piezoceramics define the character of the dependences of the dielectric,piezoelectric and electromechanical properties of porous piezoelectric ceramics on porosity.In conclusion,microstructure/properties interrelations,as well as new applications of porous piezoceramics were discussed.展开更多
基金financially supported by the Russian Science Foundation Grant No.24-22-00063,https:/rscf.ru/project/24-22-00063/at the Southern Federal University.
文摘This paper studies the relaxation processes and electromechanical hysteresis in relaxor piezoceramics based on the PzT system.Measurements and analysis of the electric displacement and mechanical strain hysteresis loops recorded in bipolar AC electric fields in the frequency range 0.001-5 Hz were performed by means of the electromechanical response characterization system(STEPHV)and program(STEP).It was found that the coercive field,remnant and saturation electric displacement,area of hysteresis loops and relative mechanical strain values are strongly dependent on frequency.As a result of this study,complete sets of parameters characterizing the switching and ferroelectric hysteresis processes in relaxor piezoceramics were obtained.
基金supported by the Russian Science Foundation Grant No.24-22-00063。
文摘This paper presents the results of an experimental study of the percolation behavior of the complex dielectric constant of ceramic matrix composites(CMC).Samples of piezoactive CMC were obtained by joint sintering of synthesized PZT piezoceramic powder(matrix)and crushed particles of sintered PZT piezoceramics(filler)of different compositions.The experimental dependencies of real and imaginary parts of the complex dielectric constant of CMC on the porosity of piezoceramic matrix and volume content of ceramic filler particles were measured and analyzed.It was shown that the additional porosity of the ceramic matrix resulting from sintering of the CMC masks the dielectric percolation transition,that actually occurs at the volume concentration of ceramic filler close to percolation threshold(V~1/3).
基金financially supported by the Russian Science Foundation Grant No.24-22-00063,https:/rscf.ru/project/24-22-00063/at the Southern Federal University.
文摘In this paper,we present the experimental results of the comprehensive study of the microstructural features and complex dielectric,elastic and electromechanical properties of the ferroelectrically“hard”piezoceramics based on the lead zirconate titanate(PZT)composition.For the measurements and analysis of the real and imaginary parts of the complex parameters of the studied piezoceramics as well as their frequency dependences,we used precision impedance analyzer Agilent 4294A and Piezoelectric Resonance Analysis Program(PRAP)software.We have found that the studied piezoceramics demonstrate a unique combination of dielectric,elastic and electromechanical parameters along with very low elastic and electromechanical losses and dispersion over a wide frequency range and can be used in various high-power ultrasonic applications.
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The study was financially supported by 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(BAS0110/20-3-08IF)].
文摘In this paper,the results of experimental study of dispersion characteristics of complex electromechanical parameters of ferroelectrically“hard”porous piezoceramics based on PZT composition were presented.Experimental samples of porous piezoceramics were fabricated using a modified method of burning-out a pore former.The complex constants of porous piezoceramics with relative porosity 16%and their frequency dependences were measured using the piezoelectric resonance analysis method.As a result of experimental studies,regions of elastic,piezoelectric and electromechanical dispersion,characterized by anomalies in the frequency dependences of the imaginary and real parts of the complex constants of porous piezoelectric ceramics were found.It was revealed also that the microstructural features of porous piezoceramics determine the character of frequency dependences of complex electromechanical parameters of porous piezoelectric ceramics.In conclu-sion,the microstructural and physical mechanisms of electromechanical losses and dispersion in porous piezoceramics were discussed.
基金The study was financially supported by 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(BAS0110/20-3-08IF)].
文摘In this paper,a comprehensive study of microstructure/properties interrelations for porous piezoceramics based on PZT composition was performed.Experimental samples of porous piezoceramics were fabricated using a modified method of burningout a pore former.Porosity dependencies of elastic,dielectric,piezoelectric and electromechanical coefficients of the porous ceramics in the relative porosity range 0-50%were obtained and analyzed.As a result of microstructure analysis,it was found that at any connectivity type(3-0,3-3)and porosity up to 50%the real structures of porous piezoceramics were close to the matrix medium structure with continuous piezoceramic skeleton.It was also revealed that the microstructural features of porous piezoceramics define the character of the dependences of the dielectric,piezoelectric and electromechanical properties of porous piezoelectric ceramics on porosity.In conclusion,microstructure/properties interrelations,as well as new applications of porous piezoceramics were discussed.
