Sodium europium double tungstate [NaEu(WO4)2] phosphor was prepared by the solid-state reaction method. Its crystal structure, photoluminescence properties and thermal quenching characteristics were investigated aiming at the potential application in the field of white light-emitting diodes (LEDs). The influences of Sm doping on the photoluminescence properties of this phosphor were also studied. It is found that this phosphor can be effectively excited by 394 or 464 nm light, which nicely match the output wavelengths of near-ultraviolet (UV) or blue LED chips. Under 394 or 464 nm light excitation, this phosphor exhibits stronger emission intensity than the Y2O2S:Eu3+ or Eu2+-activated sulfide phosphor. The introduction of Sm3+ ions can broaden the excitation peaks at 394 and 464 nm of the NaEu(WO4)2 phosphor and significantly enhance its relative luminance under 400 and 460 nm LEDs excitation. Furthermore, the relative luminance of NaEu(WO4)2 phosphor shows a superior thermal stability compared with the commercially used sulfide or oxysulfide phosphor, and make it a promising red phosphor for solid-state lighting devices based on near-UV or blue LED chips.

The microstructure, mechanical properties and seawater corrosion resistance of annealed Cu–30Ni alloy tube were investigated using mechanical test, optical microscope, scanning electronic microscope and electrochemical measurement system, respectively. The recrystallizations gradually increased with the increase of annealing temperature and holding time. The hardness and tensile strength, which maintained invariability with annealing temperature at 680–720 °C, dramatically decreased with annealing temperature at 720–770 °C. As annealing temperature and holding time increase, corrosion potential (EC) increased while corrosion rate (iC) decreased at the beginning of seawater immersion. But after 15 days’ seawater immersion, as annealing temperature and holding time increase, EC firstly increased and then decreased, on the contrary, iC firstly decreased and then increased. The Ni-rich surface film and the Ni-rich sub-grains were responsible for the initial and extended immersion, respectively. It was found that the Cu–30Ni alloy tube annealed at 720 °C for 30 min exhibited favorable comprehensive mechanical properties and seawater corrosion resistance.