（Y0.87La0.1Zr0.03）2O3 nanopowders doped with various concentrations of Tm^3＋ and Ho^3＋ were prepared by the citrate method. The standard cubic Y2O3 phase can be matched in the Tm^3＋/Ho^3＋ co-doped（Y0.87La0.1Zr0...（Y0.87La0.1Zr0.03）2O3 nanopowders doped with various concentrations of Tm^3＋ and Ho^3＋ were prepared by the citrate method. The standard cubic Y2O3 phase can be matched in the Tm^3＋/Ho^3＋ co-doped（Y0.87La0.1Zr0.03）2 O3 nanopowders. The nanopowders exhibit average particle sizes of 40,60, 80 and 100 nm after calcinated at 900,1000,1100 and 1200℃,respectively. The energy transfer from Tm^3＋ to Ho^3＋ and the optimum fluorescence emission around 2 μm were investigated. Results indicate that the emission bands at around 1.86 and 1.95 μm correspond to 3 F4→3 H6 transition of Tm^3＋ and 5 I7→5 I8 transition of Ho^3＋, respectively.Better spectral properties were achieved in Tm^3＋/Ho^3＋ co-doped（Y0.87La0.1Zr0.03）2O3 nanopowders with the average size of 100 nm obtained at the conditions of the treatment of precursors calcinated at 1200 ℃ for 2 h doped with 1.5 mol% Tm^3＋ and 1 mol% Ho^3＋.展开更多
Dry sliding wear tests on as-cast and T6-treated Mg-3Gd-1Zn-0.4Zr（wt%, GZ31K） and Mg-6Gd-1Zn-0.4Zr（wt%, GZ61K） alloys were performed using a ball-on-disk configuration at room temperature. Friction coefficient and...Dry sliding wear tests on as-cast and T6-treated Mg-3Gd-1Zn-0.4Zr（wt%, GZ31K） and Mg-6Gd-1Zn-0.4Zr（wt%, GZ61K） alloys were performed using a ball-on-disk configuration at room temperature. Friction coefficient and wear rate of the alloys were measured under three different applied loads（50 N, 100 N, and 200 N, respectively）. Worn surface morphologies were analyzed using a scanning electron microscope（SEM） coupled with an energy dispersive spectrometer（EDS）. It is found that the friction coefficient of the alloys decreases with increasing load, except the as-cast GZ61 K. The wear rates of the as-cast Mg-Gd-Zn-Zr alloys increase with the increase of the load. However, the wear rates of the T6-treated Mg-Gd-Zn-Zr alloys first increase because of the participation of a large amount of needle-like precipitates, but then decline due to obvious work hardening. The wear mechanisms of abrasion, plastic deformation, oxidation, adhesion and delamination are detected. Abrasion dominates the wear mechanism under the low load; whereas, adhesion is the main wear mechanism under intermediate load, and plastic deformation has great effect on the wear rate under high applied load.展开更多
基金Project supported by Zhejiang Provincial Natural Science Foundation of China(LZ14B010001)
文摘（Y0.87La0.1Zr0.03）2O3 nanopowders doped with various concentrations of Tm^3＋ and Ho^3＋ were prepared by the citrate method. The standard cubic Y2O3 phase can be matched in the Tm^3＋/Ho^3＋ co-doped（Y0.87La0.1Zr0.03）2 O3 nanopowders. The nanopowders exhibit average particle sizes of 40,60, 80 and 100 nm after calcinated at 900,1000,1100 and 1200℃,respectively. The energy transfer from Tm^3＋ to Ho^3＋ and the optimum fluorescence emission around 2 μm were investigated. Results indicate that the emission bands at around 1.86 and 1.95 μm correspond to 3 F4→3 H6 transition of Tm^3＋ and 5 I7→5 I8 transition of Ho^3＋, respectively.Better spectral properties were achieved in Tm^3＋/Ho^3＋ co-doped（Y0.87La0.1Zr0.03）2O3 nanopowders with the average size of 100 nm obtained at the conditions of the treatment of precursors calcinated at 1200 ℃ for 2 h doped with 1.5 mol% Tm^3＋ and 1 mol% Ho^3＋.
基金supported by the National Natural Science Foundation of China (No. 51301089)the Natural Science Foundation of Jiangsu Province for Outstanding Youth (No. BK20160081)+3 种基金the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology (No. ASMA201503)the Innovative Foundation Project for Students of Nanjing Institute of Technology (No. TB20160233 and No. TZ20160004)the Six Talent Peaks (No. 2015-XCL-025)the Qing Lan Project of Jiangsu Province
文摘Dry sliding wear tests on as-cast and T6-treated Mg-3Gd-1Zn-0.4Zr（wt%, GZ31K） and Mg-6Gd-1Zn-0.4Zr（wt%, GZ61K） alloys were performed using a ball-on-disk configuration at room temperature. Friction coefficient and wear rate of the alloys were measured under three different applied loads（50 N, 100 N, and 200 N, respectively）. Worn surface morphologies were analyzed using a scanning electron microscope（SEM） coupled with an energy dispersive spectrometer（EDS）. It is found that the friction coefficient of the alloys decreases with increasing load, except the as-cast GZ61 K. The wear rates of the as-cast Mg-Gd-Zn-Zr alloys increase with the increase of the load. However, the wear rates of the T6-treated Mg-Gd-Zn-Zr alloys first increase because of the participation of a large amount of needle-like precipitates, but then decline due to obvious work hardening. The wear mechanisms of abrasion, plastic deformation, oxidation, adhesion and delamination are detected. Abrasion dominates the wear mechanism under the low load; whereas, adhesion is the main wear mechanism under intermediate load, and plastic deformation has great effect on the wear rate under high applied load.
