Abstract:

Strontium aluminate (SrAl2O4) co-doped with Eu2+and Dy3+ ions has been considered one of the best long-lasting phosphorescent materials. Due to this propertie it shows a largest potential of applications, such as, electronic displays, detecting high energy rays (UV, X-rays and rays), digital radiography, optical memories and image storage. Frequently, the boron has been used as an excellent flux agent in order to optimize the long-lasting phosphorescence (SrAl2O4). By replacing B in Al site can be possible accelerate the grain growth, improve the mass diffusion, increases the relative density and decreases the pores amount. In this work the SrBxAl2-xO4:Eu;Dy powders were synthesized by the polymeric precursor method and sintered using a new method. In this method a CO2 laser is used as the main heating source for sintering. To sintering, the powders were uniaxially pressed in discs of 4 mm in diameter by 1 mm thick and the laser radiation was focused on the sample providing very high heating and cooling rates, which are estimated at 2000 °C/min. The characterization was done by Differential Thermal Analysis, Thermogravimetry, X-rays diffraction, Scanning Electron Microscopy and Photoluminescent techniques. The synthesized powders were calcined at 600 °C for 5 h using a heating rate of 10 °C/min under open atmosphere, at concentrations of 0.1/0.1, 0.5/0.5, and 2.0/1.0 mol% of Eu and Dy respectively, and 3.0 mol% of boron. The structural characterization was made by the Rietveld method in some samples. Finally, the laser sintered ceramics presented long-lasting phosphorescence visible to “naked eye” for 2h with emission band centred at 513 nm.