CeF3 and CeF3：Tb3＋ nanocrystals were successfully synthesized by the ultrasound assisted ionic liquid （IL） method at room temperature. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission ...CeF3 and CeF3：Tb3＋ nanocrystals were successfully synthesized by the ultrasound assisted ionic liquid （IL） method at room temperature. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, selected area electron diffraction （SAED）, high-resolution transmission electron micrographs （HRTEM） and photoluminescence （PL） spectra were employed to characterize the nanocrystals. The results of XRD indicated that the obtained samples crystallized well with a hexagonal phase crystal structure. SEM and TEM images demonstrated that the obtained CeF3：Tb3＋ nanocrystals had a discoid shapein the presence of ultrasound and IL, whereas only granular nanoparticles were obtained by magnetic stirring. The possible formation mechanisms of the crystal growth were proposed. The PL spectra of the CeF3：Tb3＋ nanodisks exhibited a strong green emission when excited at 254 nm. Furthermore, the photoluminescence intensity of CeF3：Tb3＋ of the discoid particles was largely improved com-pared with that of the granular nanoparticles.展开更多
The corrosion behavior of plasma sprayed 8YSZ （ZrO2 stabilized by 8 wt.% Y2O3） coating on the surface of carbon steel in seawater was investigated. The electrochemical impedance spectroscopy was used as a non-destru...The corrosion behavior of plasma sprayed 8YSZ （ZrO2 stabilized by 8 wt.% Y2O3） coating on the surface of carbon steel in seawater was investigated. The electrochemical impedance spectroscopy was used as a non-destructive evaluation technique to monitor the protection properties of the coating when it was immersed in seawater, and corrosion products were characterized by scanning electron microscopy, energy dispersive spectrometry and X-ray photoelectron spectroscopy. The results indicated that three time constants were obtained dur ing the initial immersion period, and then a new time constant appeared due to the formation of rust layer, which was corresponding to the corrosion process. Corrosion products were formed on the coating surface as well as inside the coating, and the crystalline composition of the rust layer mainly consisted of γ-FeOOH.展开更多
基金Project supported by National Natural Science Foundation of China(21001017,21171160,21376031)the Lotus Scholars Program of Hunan+1 种基金the Natural Science Foundation of Hunan Province(13JJ3068)Hunan Provincial Key Laboratory of Materials Protection for Electric Power and Transportation(2014CL03,2014CL05)
文摘CeF3 and CeF3：Tb3＋ nanocrystals were successfully synthesized by the ultrasound assisted ionic liquid （IL） method at room temperature. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, selected area electron diffraction （SAED）, high-resolution transmission electron micrographs （HRTEM） and photoluminescence （PL） spectra were employed to characterize the nanocrystals. The results of XRD indicated that the obtained samples crystallized well with a hexagonal phase crystal structure. SEM and TEM images demonstrated that the obtained CeF3：Tb3＋ nanocrystals had a discoid shapein the presence of ultrasound and IL, whereas only granular nanoparticles were obtained by magnetic stirring. The possible formation mechanisms of the crystal growth were proposed. The PL spectra of the CeF3：Tb3＋ nanodisks exhibited a strong green emission when excited at 254 nm. Furthermore, the photoluminescence intensity of CeF3：Tb3＋ of the discoid particles was largely improved com-pared with that of the granular nanoparticles.
基金Project supported by Lotus Scholars Program of Hunan (50825204) National Natural Science Foundation of China (21001017)
文摘The corrosion behavior of plasma sprayed 8YSZ （ZrO2 stabilized by 8 wt.% Y2O3） coating on the surface of carbon steel in seawater was investigated. The electrochemical impedance spectroscopy was used as a non-destructive evaluation technique to monitor the protection properties of the coating when it was immersed in seawater, and corrosion products were characterized by scanning electron microscopy, energy dispersive spectrometry and X-ray photoelectron spectroscopy. The results indicated that three time constants were obtained dur ing the initial immersion period, and then a new time constant appeared due to the formation of rust layer, which was corresponding to the corrosion process. Corrosion products were formed on the coating surface as well as inside the coating, and the crystalline composition of the rust layer mainly consisted of γ-FeOOH.
