It is well-known that the performance of BiFeO3eBaTiO3(BF-BT)ceramics is sensitive to composition,calcining and sintering temperature(Tcal and Tsint)due to the formation of Bi25FeO39 and/or Bi2Fe4O9 impurities and/or ...It is well-known that the performance of BiFeO3eBaTiO3(BF-BT)ceramics is sensitive to composition,calcining and sintering temperature(Tcal and Tsint)due to the formation of Bi25FeO39 and/or Bi2Fe4O9 impurities and/or the volatilization of Bi_(2)O_(3).We report remarkably stable electrical properties over the range of0.03≤x≤0.05 and 930℃≤Tsint≤970C in 0.7Bi(1þx)FeO_(3)-0.3BaTiO_(3)ceramics prepared by one-step process.This method avoids the thermodynamically unstable region of BiFeO_(3)and prevents the formation of Bi25FeO39 and/or Bi_(2)Fe_(4)O_(9)impurities even when the addition of a-Bi_(2)O_(3)raw material is intentionally deficient or rich to make off-stoichiometric BF-BT,thus greatly improving the robustness of compositional and processing.Rhombohedral-pseudocubic phase coexists in all ceramics,and their CR/CPC fraction are 48.0/52.0e50.6/49.4 and 55.9/44.1e56.6/43.4 when x increases from0.05≤x≤0 to 0.01≤x≤0.05.The stable electrical properties of d33¼180e205 pC/N,Pr¼17.9e23.8 mC/cm^(2),and TC¼485e518℃are achieved.The maximum d_(33T)/d_(33RT)of BF-BT is twice that of soft PZT,superior to most the-state-of-art lead-free ceramics.Our results provide a synthesis strategy for designing high performance piezoelectric materials with good stability and easy industrialization.展开更多
NaNbO_(3)-based ceramics usually show ferroelectric-like P-E loops at room temperature due to the irreversible transformation of the antiferroelectric orthorhombic phase to ferroelectric orthorhombic phase,which is no...NaNbO_(3)-based ceramics usually show ferroelectric-like P-E loops at room temperature due to the irreversible transformation of the antiferroelectric orthorhombic phase to ferroelectric orthorhombic phase,which is not conducive to energy storage applications.Our previous work found that incorporating CaHfO_(3) into NaNbO_(3) can stabilize its antiferroelectric phase by reducing the tolerance factor(t),as indicated by the appearance of characteristic double P-E loops.Furthermore,a small amount of MnO_(2) addition effectively regulate the phase structure and tolerance factor of 0.94NaNbO_(3)-0.06CaHfO_(3)(0.94NN-0.06CH),which can further improve the stability of antiferroelectricity.The XRD and XPS results reveal that the Mn ions preferentially replace A-sites and then B-sites as increasing MnO_(2).The antiferroelectric orthorhombic phase first increases and then decreases,while the t shows the reversed trend,thus an enhanced antiferroelectricity and the energy storage density Wrec of 1.69 J/cm^(3) at 240 kV/cm are obtained for 0.94NN-0.06CH-0.5%MnO_(2)(in mass fraction).With the increase of Mn content to 1.0%from 0.5%,the efficiency increases to 81% from 45%,although the energy storage density decreases to 1.31 J/cm^(3) due to both increased tolerance factor and non-polar phase.展开更多
基金supported by the National Natural Science Foundation of China(52072028 and 52032007).
文摘It is well-known that the performance of BiFeO3eBaTiO3(BF-BT)ceramics is sensitive to composition,calcining and sintering temperature(Tcal and Tsint)due to the formation of Bi25FeO39 and/or Bi2Fe4O9 impurities and/or the volatilization of Bi_(2)O_(3).We report remarkably stable electrical properties over the range of0.03≤x≤0.05 and 930℃≤Tsint≤970C in 0.7Bi(1þx)FeO_(3)-0.3BaTiO_(3)ceramics prepared by one-step process.This method avoids the thermodynamically unstable region of BiFeO_(3)and prevents the formation of Bi25FeO39 and/or Bi_(2)Fe_(4)O_(9)impurities even when the addition of a-Bi_(2)O_(3)raw material is intentionally deficient or rich to make off-stoichiometric BF-BT,thus greatly improving the robustness of compositional and processing.Rhombohedral-pseudocubic phase coexists in all ceramics,and their CR/CPC fraction are 48.0/52.0e50.6/49.4 and 55.9/44.1e56.6/43.4 when x increases from0.05≤x≤0 to 0.01≤x≤0.05.The stable electrical properties of d33¼180e205 pC/N,Pr¼17.9e23.8 mC/cm^(2),and TC¼485e518℃are achieved.The maximum d_(33T)/d_(33RT)of BF-BT is twice that of soft PZT,superior to most the-state-of-art lead-free ceramics.Our results provide a synthesis strategy for designing high performance piezoelectric materials with good stability and easy industrialization.
基金This work was supported by the National Natural Science Foundation of China(52072028 and 52032007).
文摘NaNbO_(3)-based ceramics usually show ferroelectric-like P-E loops at room temperature due to the irreversible transformation of the antiferroelectric orthorhombic phase to ferroelectric orthorhombic phase,which is not conducive to energy storage applications.Our previous work found that incorporating CaHfO_(3) into NaNbO_(3) can stabilize its antiferroelectric phase by reducing the tolerance factor(t),as indicated by the appearance of characteristic double P-E loops.Furthermore,a small amount of MnO_(2) addition effectively regulate the phase structure and tolerance factor of 0.94NaNbO_(3)-0.06CaHfO_(3)(0.94NN-0.06CH),which can further improve the stability of antiferroelectricity.The XRD and XPS results reveal that the Mn ions preferentially replace A-sites and then B-sites as increasing MnO_(2).The antiferroelectric orthorhombic phase first increases and then decreases,while the t shows the reversed trend,thus an enhanced antiferroelectricity and the energy storage density Wrec of 1.69 J/cm^(3) at 240 kV/cm are obtained for 0.94NN-0.06CH-0.5%MnO_(2)(in mass fraction).With the increase of Mn content to 1.0%from 0.5%,the efficiency increases to 81% from 45%,although the energy storage density decreases to 1.31 J/cm^(3) due to both increased tolerance factor and non-polar phase.
