The mineral transition, microstructure and self-pulverization as well as the Al2O3 leaching performance of calcium aluminate clinkers with different P additions in CaO-Al2O3-SiO2 system during high-temperature sinteri...The mineral transition, microstructure and self-pulverization as well as the Al2O3 leaching performance of calcium aluminate clinkers with different P additions in CaO-Al2O3-SiO2 system during high-temperature sintering were systematically studied by XRF, XRD, SEM-EDS and DSC-TG technologies. The clinkers sintered at 1350 °C mainly contain 12CaO·7Al2O3, CaO·Al2O3,β-2CaO·SiO2 and γ-2CaO·SiO2. The content of β-2CaO·SiO2 increases while the content of γ-2CaO·SiO2 decreases as the P addition increases. The self-pulverization property of clinkers deteriorates with increasing P addition. P distributes evenly in the clinkers, and inhibits the transformation of β-2CaO·SiO2 to γ-2CaO·SiO2. The cell volumes of 12CaO·7Al2O3 and CaO·Al2O3 decrease and increase respectively as the P addition increases, and P decreases their formation temperatures. The Al2O3 leaching rate of calcium aluminate clinkers decreases obviously with increasing P addition, which decreases form 95.01% to 83.84% as the P addition increases from 0 to 0.85%.展开更多
Yellow-green-emitting Sr Si2O2N2:Eu2+phosphors were synthesized with Sr2Si O4:Eu2+as precursor.The effects of flux and the concentration of Eu2+on the crystal structure and luminescent properties of the phosphors were...Yellow-green-emitting Sr Si2O2N2:Eu2+phosphors were synthesized with Sr2Si O4:Eu2+as precursor.The effects of flux and the concentration of Eu2+on the crystal structure and luminescent properties of the phosphors were investigated.Results suggested that the optimal content of flux Na2CO3 was 1 wt%and the optimal doping concentration of Eu2+was 0.05 mol.The emission spectra showed the most intense peaks located at 535 nm which corresponded to the 4f65d→4f7 transition of Eu2+.The excitation spectra showed that these phosphors could be effectively excited by near-ultraviolet and blue light,whichwas consistent with the widely applied output wavelengths of near-ultraviolet and blue-white light-emitting diode(LED)chips.When the influence of flux on the luminescent properties of Sr Si2O2N2:Eu2+phosphor was analyzed,the X-ray diffraction(XRD)patterns indicated that the flux could help the crystallization of the phosphors.No other phases except the triclinic structure of Sr Si2O2N2 were formed.The thermal stability and the emission intensity of synthesized Sr Si2O2N2:Eu2+phosphor were examined and compared with commercial YAG yellow phosphors.All results indicate that the yellow-green-emitting phosphor is a suitable candidate for the fabrication of white LEDs.展开更多
基金Projects(51674075,51774079) supported by the National Natural Science Foundation of China
文摘The mineral transition, microstructure and self-pulverization as well as the Al2O3 leaching performance of calcium aluminate clinkers with different P additions in CaO-Al2O3-SiO2 system during high-temperature sintering were systematically studied by XRF, XRD, SEM-EDS and DSC-TG technologies. The clinkers sintered at 1350 °C mainly contain 12CaO·7Al2O3, CaO·Al2O3,β-2CaO·SiO2 and γ-2CaO·SiO2. The content of β-2CaO·SiO2 increases while the content of γ-2CaO·SiO2 decreases as the P addition increases. The self-pulverization property of clinkers deteriorates with increasing P addition. P distributes evenly in the clinkers, and inhibits the transformation of β-2CaO·SiO2 to γ-2CaO·SiO2. The cell volumes of 12CaO·7Al2O3 and CaO·Al2O3 decrease and increase respectively as the P addition increases, and P decreases their formation temperatures. The Al2O3 leaching rate of calcium aluminate clinkers decreases obviously with increasing P addition, which decreases form 95.01% to 83.84% as the P addition increases from 0 to 0.85%.
基金supported by the National Natural Science Foundation of China(Grant No.11204258)the National Science Foundation for Distinguished Young Scholars of Fujian Province(Grant No.2012J06024)+3 种基金the Program for New Century Excellent Talents in University of Fujian Province(Grant No.ZA14228)the Outstanding Young Scientific Research Personnel Training Plan in Colleges and Universities of Fujian Province(Grant No.JA13229)the Science and Technology Plan of Xiamen City(Grant No.3502Z20123040)the Ministry of Education in China Project of Humanities and Social Sciences(Grant No.11YJC820135)
文摘Yellow-green-emitting Sr Si2O2N2:Eu2+phosphors were synthesized with Sr2Si O4:Eu2+as precursor.The effects of flux and the concentration of Eu2+on the crystal structure and luminescent properties of the phosphors were investigated.Results suggested that the optimal content of flux Na2CO3 was 1 wt%and the optimal doping concentration of Eu2+was 0.05 mol.The emission spectra showed the most intense peaks located at 535 nm which corresponded to the 4f65d→4f7 transition of Eu2+.The excitation spectra showed that these phosphors could be effectively excited by near-ultraviolet and blue light,whichwas consistent with the widely applied output wavelengths of near-ultraviolet and blue-white light-emitting diode(LED)chips.When the influence of flux on the luminescent properties of Sr Si2O2N2:Eu2+phosphor was analyzed,the X-ray diffraction(XRD)patterns indicated that the flux could help the crystallization of the phosphors.No other phases except the triclinic structure of Sr Si2O2N2 were formed.The thermal stability and the emission intensity of synthesized Sr Si2O2N2:Eu2+phosphor were examined and compared with commercial YAG yellow phosphors.All results indicate that the yellow-green-emitting phosphor is a suitable candidate for the fabrication of white LEDs.
