The BaAl2Si2O8:Eu2+blue emitting phosphor was obtained through the one-step calcination process of precursors prepared bychemical co-precipitation method. The phase structure and luminescence propertied of the phospho...The BaAl2Si2O8:Eu2+blue emitting phosphor was obtained through the one-step calcination process of precursors prepared bychemical co-precipitation method. The phase structure and luminescence propertied of the phosphor were investigated usingX-ray diffraction (XRD) and a fluorescence spectrophotometer. The excitation spectrum exhibited a broad band between 230nm and 400 nm and the emission peaking at about 470 nm was observed, which originated from the allowed f-d transition ofEu2+ions at Ba2+sites. Owing to the different optimal concentrations under different excitation wavelengths (254 nm and 365nm), the energy-transfer mechanism in this phosphor has changed from the dipole-dipole interaction to the exchange interac-tion of Eu2+ions.展开更多
Silicon carbide (SiC) composites were prepared by hot-press sintering from α-SiC starting powders with BaAl2Si2O8 (BAS). The effects of additives on densification, microstructure, flexural strength, and fracture beha...Silicon carbide (SiC) composites were prepared by hot-press sintering from α-SiC starting powders with BaAl2Si2O8 (BAS). The effects of additives on densification, microstructure, flexural strength, and fracture behavior of the liquid phase sintered (LPS) SiC composites were investigated. The results show that the served BAS effectively promotes the densification of SiC composites. The flexural strength and fracture toughness of the SiC composites can reach a maximum value of 454 MPa and 5.1 MPa·m1/2, respectively, for 40% (w/w) BAS/SiC composites. SiC grain pullout, crack deflection, and crack bridging were main toughening mechanisms for the sintered composites.展开更多
基金supported by the Scientific and Technological Project of Chongqing, China (Grant No. CSTC, 2009AB4171)the Innovation Foundation for Technology Based Firms of Ministry of Science and Technology, China (Grant No. 04C26225100807)
文摘The BaAl2Si2O8:Eu2+blue emitting phosphor was obtained through the one-step calcination process of precursors prepared bychemical co-precipitation method. The phase structure and luminescence propertied of the phosphor were investigated usingX-ray diffraction (XRD) and a fluorescence spectrophotometer. The excitation spectrum exhibited a broad band between 230nm and 400 nm and the emission peaking at about 470 nm was observed, which originated from the allowed f-d transition ofEu2+ions at Ba2+sites. Owing to the different optimal concentrations under different excitation wavelengths (254 nm and 365nm), the energy-transfer mechanism in this phosphor has changed from the dipole-dipole interaction to the exchange interac-tion of Eu2+ions.
文摘Silicon carbide (SiC) composites were prepared by hot-press sintering from α-SiC starting powders with BaAl2Si2O8 (BAS). The effects of additives on densification, microstructure, flexural strength, and fracture behavior of the liquid phase sintered (LPS) SiC composites were investigated. The results show that the served BAS effectively promotes the densification of SiC composites. The flexural strength and fracture toughness of the SiC composites can reach a maximum value of 454 MPa and 5.1 MPa·m1/2, respectively, for 40% (w/w) BAS/SiC composites. SiC grain pullout, crack deflection, and crack bridging were main toughening mechanisms for the sintered composites.
