Breakthroughs can be expected in multi-component ceramics by adjusting the phase assembly and the micro–nanostructure.Controlling the architecture of multi-materials at different scales is still challenging and provi...Breakthroughs can be expected in multi-component ceramics by adjusting the phase assembly and the micro–nanostructure.Controlling the architecture of multi-materials at different scales is still challenging and provides a great opportunity to broaden the range of functionalities in the field of ferroelectric-based ceramics.We used the potentialities of Spark Plasma Sintering(SPS)to control a number of key parameters regarding the properties:anisotropy,interfaces,grain size and strain effects.The flexibility of the wet and supercritical chemistry routes associated with the versatility of SPS allowed designing newferroelectric composite ceramics at different scales.These approaches are illustrated through various examples based on our work on ferroelectric/dielectric composites.展开更多
Three types of BaTiO3 core-amorphous nanoshell composite ceramics were processed from the same core-shell powder by standard sintering,spark-plasma sintering and two-step sintering techniques and characterized by XRD,...Three types of BaTiO3 core-amorphous nanoshell composite ceramics were processed from the same core-shell powder by standard sintering,spark-plasma sintering and two-step sintering techniques and characterized by XRD,HRSEM and broadband dielectric spectroscopy in the frequency range 10^(3)-10^(13)Hz including the THz and IR range.The samples differed by porosity and by the amount of interdiffusion from the cores to shells,in correlation with their increasing porosity.The dielectric spectra were also calculated using suitable models based on effective medium approximation.The measurements revealed a strong dielectric dispersion below the THz range,which cannot be explained by the modeling,and whose strength was in correlation with the degree of interdiffusion.It is assigned to an effect of the interdiffusion layers,giving rise to a strong interfacial polarization.It appears that the high-frequency dielectric spectroscopy is an extremely sensitive tool for detection of any gradient layers and sample inhomogeneities even in dielectric materials with negligible conductivity.展开更多
基金Financial support from the French National Center for Scientific Research(CNRS),the Conseil Regional d'Aquitaine,and the National Research Agency(ANR)(Projects NANO4F(ANR-05-JCJC-0169)ARCHIFUN(ANR-12-BS08–009)are gratefully acknowledged.
文摘Breakthroughs can be expected in multi-component ceramics by adjusting the phase assembly and the micro–nanostructure.Controlling the architecture of multi-materials at different scales is still challenging and provides a great opportunity to broaden the range of functionalities in the field of ferroelectric-based ceramics.We used the potentialities of Spark Plasma Sintering(SPS)to control a number of key parameters regarding the properties:anisotropy,interfaces,grain size and strain effects.The flexibility of the wet and supercritical chemistry routes associated with the versatility of SPS allowed designing newferroelectric composite ceramics at different scales.These approaches are illustrated through various examples based on our work on ferroelectric/dielectric composites.
基金supported by the Academy of Sci-ences of the Czech Republic(project AVOZ 10100520)the Czech Science Foundation(project 202/09/0430)by COST action MP904.
文摘Three types of BaTiO3 core-amorphous nanoshell composite ceramics were processed from the same core-shell powder by standard sintering,spark-plasma sintering and two-step sintering techniques and characterized by XRD,HRSEM and broadband dielectric spectroscopy in the frequency range 10^(3)-10^(13)Hz including the THz and IR range.The samples differed by porosity and by the amount of interdiffusion from the cores to shells,in correlation with their increasing porosity.The dielectric spectra were also calculated using suitable models based on effective medium approximation.The measurements revealed a strong dielectric dispersion below the THz range,which cannot be explained by the modeling,and whose strength was in correlation with the degree of interdiffusion.It is assigned to an effect of the interdiffusion layers,giving rise to a strong interfacial polarization.It appears that the high-frequency dielectric spectroscopy is an extremely sensitive tool for detection of any gradient layers and sample inhomogeneities even in dielectric materials with negligible conductivity.
