A red-emitting phosphor GdNbO4：Eu3＋,Bi3＋ was prepared by a high temperature solid-state reaction technique. The phosphor was characterized by X-ray diffraction （XRD）, particle size analyzer and fluorescence spect...A red-emitting phosphor GdNbO4：Eu3＋,Bi3＋ was prepared by a high temperature solid-state reaction technique. The phosphor was characterized by X-ray diffraction （XRD）, particle size analyzer and fluorescence spectrometer. The single phase of GdNbO4：Eu3＋,Bi3＋ was obtained at 1150~C and the average particle diameter was about 2.30 μm. Excitation and emission spectra reveal that the phosphor can be ef- ficiently excited by ultraviolet （UV） light （394 nm） and emit the strong red light of 612 nm due to the Eu3＋ transition of SD0~TF2. The opti- mum content of Eu3＋ doped in the phosphor GdNbOn：Eu3＋ is 20mo1%. The phosphor Gdo.80NbO4：0.20Eu3＋,0.03Bi3＋ shows much stronger photoluminescence intensity and better chromaticity coordinates （x=0.642, 0.352） than GdNbO4：Eu3＋. It is confirmed that Gdo.80NbO4：0.20Eu3＋,0.03Bi3＋ is a potential candidate for near-UV chip-based white light emitting diodes.展开更多
The corrosion behavior of nickel-based 718 alloy at seven partial pressures of H2 S(PH2 S)was investigated using electrochemical impedance spectroscopy(EIS)and polarization methods in 25 wt% NaCl solution at150℃ for ...The corrosion behavior of nickel-based 718 alloy at seven partial pressures of H2 S(PH2 S)was investigated using electrochemical impedance spectroscopy(EIS)and polarization methods in 25 wt% NaCl solution at150℃ for 168 h.The tested results show that anodic reactions are controlled alternately by the diffusion mostly,then both charge transfer and diffusion and finally charge transfer mainly with the increment of PH2 S.The corrosive products are composed of sulfides and oxides of Ni,Cr and Fe with double layers for PH2 S of 5.1 and 13.0 MPa and three layers for PH2 S of 10.4 MPa according to microstructures and compositions of corrosion products characterized by the scanning electron microscope(SEM)and electron probe microanalysis(EPMA)methods.The inner oxides layer plays a critical role in anti-corrosion in a wet H2 S environment at high temperature and pressure.展开更多
基金the National"12th Five-year"Science and Technology Support Program of China(No.2011BAE22B03-3)the Project of Chong qing Scientific and Technological Commission(No.CSTC2010AA4048)
文摘A red-emitting phosphor GdNbO4：Eu3＋,Bi3＋ was prepared by a high temperature solid-state reaction technique. The phosphor was characterized by X-ray diffraction （XRD）, particle size analyzer and fluorescence spectrometer. The single phase of GdNbO4：Eu3＋,Bi3＋ was obtained at 1150~C and the average particle diameter was about 2.30 μm. Excitation and emission spectra reveal that the phosphor can be ef- ficiently excited by ultraviolet （UV） light （394 nm） and emit the strong red light of 612 nm due to the Eu3＋ transition of SD0~TF2. The opti- mum content of Eu3＋ doped in the phosphor GdNbOn：Eu3＋ is 20mo1%. The phosphor Gdo.80NbO4：0.20Eu3＋,0.03Bi3＋ shows much stronger photoluminescence intensity and better chromaticity coordinates （x=0.642, 0.352） than GdNbO4：Eu3＋. It is confirmed that Gdo.80NbO4：0.20Eu3＋,0.03Bi3＋ is a potential candidate for near-UV chip-based white light emitting diodes.
基金financially supported by the Science and Technology Open Cooperation Project of Henan Province (No. 172106000062)the Science and Technology Development Project of Henan Province (No. 182102310837)the HighSchool Science and Technology Innovation Team Support Plan of Henan Province (No. 18IRTSTHN005)
文摘The corrosion behavior of nickel-based 718 alloy at seven partial pressures of H2 S(PH2 S)was investigated using electrochemical impedance spectroscopy(EIS)and polarization methods in 25 wt% NaCl solution at150℃ for 168 h.The tested results show that anodic reactions are controlled alternately by the diffusion mostly,then both charge transfer and diffusion and finally charge transfer mainly with the increment of PH2 S.The corrosive products are composed of sulfides and oxides of Ni,Cr and Fe with double layers for PH2 S of 5.1 and 13.0 MPa and three layers for PH2 S of 10.4 MPa according to microstructures and compositions of corrosion products characterized by the scanning electron microscope(SEM)and electron probe microanalysis(EPMA)methods.The inner oxides layer plays a critical role in anti-corrosion in a wet H2 S environment at high temperature and pressure.
