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Li 2 SrSiO 4 :Eu 2+ /Ce 3+ phosphors have been synthesized by solid state reaction. Eu 2+ and/or Ce 3+ doped Li 2 SrSiO 4 have the hexagonal crystal structure, indicating the doped Eu 2+ and/or Ce 3+ ions have no influence on the crystal structure of Li 2 SrSiO 4 . Under the excitation at 365 nm, Eu 2+ or Ce 3+ doped Li 2 SrSiO 4 phosphors give characteristic emission bands of Eu 2+ or Ce 3+ , respectively. For Li 2 SrSiO 4 :Eu 2+ /Ce 3+ phosphors with the fixed Ce 3+ concentration, two emission bands originating from Eu 2+ and Ce 3+ can be observed. On the basis of luminescent properties of Li 2 SrSiO 4 :Eu 2+ /Ce 3+ phosphors, we can conclude that energy transfer from Ce 3+ to Eu 2+ occurs in Li 2 SrSiO 4 .

NaBaPO 4 :Eu 2+ /Tb 3+ phosphors were synthesized by the hydrothermal process. The phase structure of obtained samples was characterized by powder X-ray diffraction. The morphology and size were obtained by field emission scanning electron microscope. Under the excitation at 346 nm, NaBaPO 4 :Eu 2+ /Tb 3+ phosphors exhibited the emission band originating from the 4f 6 5d 1 → 4f 7 transitions of Eu 2+ and the emission bands originating from the 5 D 4 → 7 F j transitions of Tb 3+ . The intensities and lifetimes of Eu 2+ decrease with increasing Tb 3+ concentrations. On the basis of luminescence properties of NaBaPO 4 :Eu 2+ /Tb 3+ phosphors, we can conclude the energy transfer occurs between Eu 2+ and Tb 3+ in NaBaPO 4 host.

The effects of aging precipitates on microstructure, mechanical properties and damping capacities of Mg–Zn–Y–Nd alloy were investigated in this study. The structure results indicate that the as-cast alloys consist of α-Mg and W-phase when Zn/RE (rare earth element) weight ratio is about 1.7. After solution-aging treatment, the dissolved W-phase precipitates in the form of large amount of nano-scaled MgZn 2 and Mg 12 Nd phases. The tensile strengths of aged Mg–Zn–Y–Nd alloys are continuously enhanced with the precipitation of MgZn 2 and Mg 12 Nd phase particles, the highest ultimate tensile strength, yield strength and elongation reach up to 257 MPa, 152 MPa and 13.9%. The aging precipitates inhibit deformation twin from growing up and decrease its size, this favors homogeneous deformation and reduces the source of crack initiation, which results in the high elongation of aged Mg–Zn–Y–Nd alloys. The damping capacities of aged Mg–Zn–Y–Nd alloys decrease dramatically at high strain–amplitude stage compared with that of as-cast alloy. The appearance of aging twins and movement or slippage of thin twin boundaries can explain the better damping and unusual damping growth in aged Mg–3.0%–0.9%Y–0.9%Nd (wt%) alloy and Mg–4.0%Zn–1.2%Y–1.2%Nd (wt%) alloys (alloys 2 and 3). The formation of aging twin relates closely to the amount of aging precipitates, no aging twin occurs in the aged Mg–2.0%Zn–0.6%Y–0.6%Nd (wt%) alloy (alloy 1) due to lower precipitates content. The aged Mg–4.0%Zn–1.2%Y–1.2%Nd (wt%) alloy (alloy 3) with more precipitates shows lower damping values than Mg–3.0%Zn–0.9%Y–0.9%Nd (wt%) alloy (alloy 2) because of the stronger pinning effect of precipitates on dislocation.

The effect of long-period stacking ordered (LPSO) structure on mechanical and damping properties of as-cast Mg–Zn–Y–Zr alloy were investigated. Obtained results indicate that the Mg– x %Zn–2 x %Y–0.6%Zr alloys are mainly comprised of α-Mg and LPSO phase. The grain sizes of the Mg–Zn–Y–Zr alloys are obviously refined and the mechanical properties are improved continuously with the formation of LPSO phase, with a maximum value of 222.5 MPa in ultimate tensile strength and 18.9% in elongation. The fracture mechanism of alloys transforms from cleavage fracture to quasi-cleavage fracture with increasing amount of LPSO phase. The damping capacities of Mg–Zn–Y–Zr alloys increase continuously with the increasing LPSO phase and the damping behavior can be explained by the moving model of Shockley partial dislocation. Due to the stacking fault probability, the LPSO phase in the Mg–Zn–Y–Zr alloys could be new damping source to dissipate energy so as to contribute to the improvement of damping capacities.

NaGd(WO4)2:RE3+ (RE = Eu, Tb, Tm) phosphors were synthesized by a hydrothermal process. The XRD and FTIR results show that the hydrothermal time has obvious influence on the crystallization of samples. The longer hydrothermal time benefits to the higher crystallization of NaGd(WO4)2:RE3+ samples. All of the excitation spectra of NaGd(WO4)2:RE3+ samples show the charge transfer bands, which suggests the effective energy transfer between the WO4 2− group and RE3+ ions. Under the excitation of 288 nm, NaGd(WO4)2:RE3+ (RE = Eu, Tb, Tm) phosphors show emissions in red, green, and blue regions, respectively. The results of this work indicate that NaGd(WO4)2:RE3+ (RE = Eu, Tb, Tm) phosphors have potentials to be used as red, green, and blue emitting phosphors.

We synthesized Sr2SiO4:Eu3+ phosphors with spherical morphology by a spray-drying process. The obtained samples were characterized by XRD, SEM, and spectrophotometer. The XRD results show that samples have good crystallinity after the heat-treatment at 1150 °C. The higher temperature has no obvious influence on the crystallinity and will destroy the spherical morphology. The SEM results show that the phosphors are microspheres with size in the range of 0.8–2.1 μm when they were heat treated at 1050 °C and 1150 °C. The excitation and emission spectra of the samples indicate that Eu3+ ions doped into Sr2SiO4 host successfully. The Sr2SiO4:Eu3+ sample heat-treated at 1150 °C has the highest emission intensity and the longest decay times. The results of this work indicate that the optimized heat-treatment temperature should be at 1150 °C for Sr2SiO4:Eu3+ micro-spherical phosphors synthesized by the spray-drying process.

The effects of solution treatment and aging on microstructure, mechanical properties and damping capacity of as-cast Mg–3%Zn–0.9%Y–0.6%Nd–0.6%Zr (wt%) (ZW30N) magnesium alloy were investigated. The as-cast alloy is comprised of α-Mg matrix and W-phase. After solution treatment at 540 °C for 8 h, the net-like interdendritic W-phase dissolves into the matrix and small Zr-containing particles precipitate at grain interiors. Due to the precipitation of fine W, β1′ and β2′ phases during the subsequent aging treatment, the ultimate tensile strength, yield strength and elongation of the alloy significantly improved from 180 MPa, 119 MPa and 12.3% in as-cast alloy to 262 MPa, 161 MPa and 15.2%, respectively. The damping capacity of heat-treated Mg–Zn–Y–Nd–Zr alloys decreases dramatically with respect to that of as-cast condition. In the solution-treated alloy, increasing number of Zr-containing particles and solute atoms in the matrix is responsible for the damping decline. For the peaked-aged alloy, the favorable damping and unusual damping growth at high strain amplitude stage are believed to be closely related to the formation of a twin dislocation, which produces new energy-dissipation source besides dislocation damping.

Sr3Al2O6:Ce3+ powders were synthesized using a solid state reaction method in air with addition of H3BO3. The effects of Ce3+ dopant concentrations and the weight ratio (wt) of H3BO3 to total raw materials weight on the formation of Sr3Al2O6:Ce3+ samples were investigated. Single-phase and well-crystallized Sr3Al2O6:Ce3+ samples can be obtained when the addition of H3BO3 is lower than 7 wt%. The excitation spectrum indicates that Sr3Al2O6:Ce3+ phosphor powders exhibit two excitation bands centered at 345 and 462 nm. The emission spectrum shows that Sr3Al2O6:Ce3+ phosphor powders exhibit an emission band peaked at 536 nm when excited at 462 nm. Sr3Al2O6:Ce3+ sample at the Ce3+ concentration of 5 mol% shows the strongest emission intensity. The addition of H3BO3 has obvious influence on phase and emission intensity of Sr3Al2O6:Ce3+ phosphors. The results show that the Sr2.95Ce0.05Al2O6 sample with the 7 wt% addition of H3BO3 has the highest emission intensity and the longest lifetime.