The thermodynamic properties of Fe_(2)Ti_(3)O_(9) and Fe_(2)TiO_(5) were measured by means of the following solid state electrolyte cells:Pt,Fe+"FeO"||ZrO_(2)(CaO)||FeTiO_(3)+Fe_(2)Ti_(3)O_(9)+Fe_(2)O_(3),Pt...The thermodynamic properties of Fe_(2)Ti_(3)O_(9) and Fe_(2)TiO_(5) were measured by means of the following solid state electrolyte cells:Pt,Fe+"FeO"||ZrO_(2)(CaO)||FeTiO_(3)+Fe_(2)Ti_(3)O_(9)+Fe_(2)O_(3),Pt Pt,Fe+"FeOM"||ZrO_(2)(CaO)||FeTiO_(3)+Fe_(2)TiO_(5)+TiO_(2),Pt From the experimental data,the Gibbs energies of formation of Fe_(2)Ti_(3)O_(9) and Fe_(2)TiO_(5) were obtained:△G^(0)_(pr)(kJ·mol^(-1))=3459.7-0.847T,(1053K<T<1153K) △G^(0)_(pb)(kJ·mol^(-1))=-1700.2-0.465T,(1173K<T<1273K) Experimental results fit approximately to those of estimation.展开更多
The effects of different x values on the dielectric properties in the Ba6-3xSm8+2xTi18O54 microwave dielectric ceramics(0.3≤x≤0.7) were studied. The results showed that the major crystal phase was BaSm2Ti4O12 and th...The effects of different x values on the dielectric properties in the Ba6-3xSm8+2xTi18O54 microwave dielectric ceramics(0.3≤x≤0.7) were studied. The results showed that the major crystal phase was BaSm2Ti4O12 and the sintering temperature of the ceramics was 1340 ℃ when the x value was 0.67. The dielectric properties were better: εr≈79, tanδ≈1×10-4(1 MHz); εr≈80, Q·f=9230 GHz(3.97 GHz), τf=-17 ppm·℃-1.展开更多
采用传统的高温固相法制备一种新型的红色荧光粉Ba_(6)Gd_(2)Ti_(4)O_(17):Sm^(3+),并通过X射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscope,SEM)、荧光(photoluminescence,PL)光谱及色坐标表征系列样...采用传统的高温固相法制备一种新型的红色荧光粉Ba_(6)Gd_(2)Ti_(4)O_(17):Sm^(3+),并通过X射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscope,SEM)、荧光(photoluminescence,PL)光谱及色坐标表征系列样品的物相、形貌和发光性能.PL光谱表明该荧光粉可以被近紫外光有效激发,在407 nm近紫外光激发下,发射光谱由四个发射峰组成,最强发射峰位于616 nm处,归结为Sm^(3+)的^(4)G_(5/2)→^(6)H_(7/2)跃迁.随着Sm^(3+)掺杂量的增加,荧光粉的发光强度先增大后减小,最佳掺杂比例(物质的量分数)为3%.系列掺杂比例荧光粉的色坐标基本不变,均位于红光区.研究结果表明,该荧光粉是一种具有应用前景的新型白光发光二极管(light-emitting diode,LED)用红色荧光粉.展开更多
We present an efficient strategy,that is the co-substitution of Fe^(3+)and Ta^(5+)ions with large radius for Ti^(4+)ion,to enhance energy storage performance of Ba_(2)Bi_(4)Ti_(5)O_(18) film.For the films co-doped wit...We present an efficient strategy,that is the co-substitution of Fe^(3+)and Ta^(5+)ions with large radius for Ti^(4+)ion,to enhance energy storage performance of Ba_(2)Bi_(4)Ti_(5)O_(18) film.For the films co-doped with Fe^(3+)and Ta^(5+)ions,the maximum polarization under the same external electric field is improved because the radius of Fe^(3+)and Ta^(5+)ions is larger than that of Ti^(4+)ion.Moreover,due to the composition and chemical disorder,the relaxor properties are also slightly improved,which can not be achieved by the film doped with Fe^(3+)ions only.What is more,for the films doped with Fe^(3+)ion only,the leakage current density increases greatly due to the charge imbalance,resulting in a significant decrease in breakdown strength.It is worth mentioning that the breakdown strength of Fe^(3+)and Ta^(5+)ions co-doped film does not decrease due to the charge balance.Another important point is the recoverable energy storage density of the films co-doped with Fe^(3+)and Ta^(5+)ions has been greatly improved based on the fact that the maximum external electric field does not decrease and the maximum polarization under the same external electric field increases.On top of that,the hysteresis of the polarization has also been improved.Finally,the co-doped films with Fe^(3+)and Ta^(5+)ions have good frequency and temperature stability.展开更多
基金Supported by the National Natural Science Foundation of Chinathe Committee of Science and Technology of Liaoning Province and the State Education Committee of China。
文摘The thermodynamic properties of Fe_(2)Ti_(3)O_(9) and Fe_(2)TiO_(5) were measured by means of the following solid state electrolyte cells:Pt,Fe+"FeO"||ZrO_(2)(CaO)||FeTiO_(3)+Fe_(2)Ti_(3)O_(9)+Fe_(2)O_(3),Pt Pt,Fe+"FeOM"||ZrO_(2)(CaO)||FeTiO_(3)+Fe_(2)TiO_(5)+TiO_(2),Pt From the experimental data,the Gibbs energies of formation of Fe_(2)Ti_(3)O_(9) and Fe_(2)TiO_(5) were obtained:△G^(0)_(pr)(kJ·mol^(-1))=3459.7-0.847T,(1053K<T<1153K) △G^(0)_(pb)(kJ·mol^(-1))=-1700.2-0.465T,(1173K<T<1273K) Experimental results fit approximately to those of estimation.
文摘The effects of different x values on the dielectric properties in the Ba6-3xSm8+2xTi18O54 microwave dielectric ceramics(0.3≤x≤0.7) were studied. The results showed that the major crystal phase was BaSm2Ti4O12 and the sintering temperature of the ceramics was 1340 ℃ when the x value was 0.67. The dielectric properties were better: εr≈79, tanδ≈1×10-4(1 MHz); εr≈80, Q·f=9230 GHz(3.97 GHz), τf=-17 ppm·℃-1.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.12074204,11864028,and 11904054)the Natural Science Foundation of Inner Mongolia,China(Grant No.2022ZD06).
文摘We present an efficient strategy,that is the co-substitution of Fe^(3+)and Ta^(5+)ions with large radius for Ti^(4+)ion,to enhance energy storage performance of Ba_(2)Bi_(4)Ti_(5)O_(18) film.For the films co-doped with Fe^(3+)and Ta^(5+)ions,the maximum polarization under the same external electric field is improved because the radius of Fe^(3+)and Ta^(5+)ions is larger than that of Ti^(4+)ion.Moreover,due to the composition and chemical disorder,the relaxor properties are also slightly improved,which can not be achieved by the film doped with Fe^(3+)ions only.What is more,for the films doped with Fe^(3+)ion only,the leakage current density increases greatly due to the charge imbalance,resulting in a significant decrease in breakdown strength.It is worth mentioning that the breakdown strength of Fe^(3+)and Ta^(5+)ions co-doped film does not decrease due to the charge balance.Another important point is the recoverable energy storage density of the films co-doped with Fe^(3+)and Ta^(5+)ions has been greatly improved based on the fact that the maximum external electric field does not decrease and the maximum polarization under the same external electric field increases.On top of that,the hysteresis of the polarization has also been improved.Finally,the co-doped films with Fe^(3+)and Ta^(5+)ions have good frequency and temperature stability.
基金The Science and Technology Innovative Research Team of Zhejiang Province(2009R50010)The Zhejiang Science and Technology Innovation Projects for students(2009R409014)
