Research On Aluminate Phosphors And Its Water-based Coating

SrAl2O4:Eu2+,Dy3+ which stand for rare earth aluminate phosphor has superior luminescence properties, but the biggest disadvantage of rare earth aluminate phosphor is that it is poor against moist, very unstable in water, vulnerable to hydrolysis in aqueous system, even if moisture in the air can make its brightness and afterglow time greatly reduced. The sensitivity of water for phosphor limits severely the applications in a variety of water-based system and demanding acid-base system.The sol-gel process of preparing the high performance long afterglow luminescent thin films and powders of SrAl2O4:Eu2+,Dy3+ were studied systematically in this paper. The stable transparent sol of SrAl2O4 was successfully prepared for the first time by using aluminum nitrate and strontium nitrate as precursors. The crystal forming process and structures were checked by means of X-ray diffraction. The uniform and crackless photo of luminescent thin films was observed by the scanning electron microscopy (SEM). And the optical properties were studied by the fluorescence spectrophotometer. The experimental results show that the luminescent features of samples in the proper condition is similar to those by solid-state reaction process. The phosphor of The uniform distribution, high crystal, perfect crystal growth was prepared, the grain size is about 41nm. But the hydrolysis of phosphor occurs to generate a white precipitate Al(OH)3 and white film at the solid surface layer in water and light conditions.In the paper,sol-gel method was adopted to encapsulate phosphor with TEOS as silicon coating reagent. Because phosphor is sensitive to water,the two steps of hydrolyzation and encapsulation should be performed separately. The conditions of hydrolyzation process were discussed. After the analysis of the sample the experimental results show that the optimum conditions is :the molar ratio of water to TEOS is 15, pH is 9 ~ 10, gelation temperature is about 60℃. In order to test its water resistance of the rare earth aluminate phosphors, a water-based test would be carried on.PH curves of two liquids respectively immersed with uncoated and coated phosphor indicate that the water-resistance of coated phosphor is improved greatly.The aim of this paper is to develop into a decoration, signage, and other environmental-type water-based luminescent coating functions with acrylic acid emulsion. put luminous powder and calcium carbonateas the main pigment and filling,then study emulsion,dispersing agent,thickener, anti-bubbling agent factors on the affect of the performance of good luminous paint. And achieve good performance optimization of luminous paint by adjusting the dosage of emulsion,thickener and other aids. Thus non-toxic, non-radioactive, long light-induced luminescent time, energy-saving green-luminous paint is produced.In the course of experiments, we use a combination of theoretical analysis and experimental research methods. Carry hardness, adhesive strength and alkali-resistant capacity test on samples for laboratory.And on this basis, the usage of all recipes in the decentralized system of the rare earth luminous coating is studied. The rare earth luminous coating produced by the laboratory has performance outstanding, non-toxic, small smell and such advantages. After integrating, luminous powder consumption for around 10%, Acrylic acid emulsion 30%, calcium carbonate 15%, thickener 2%, dispersant 0.4%, anti-bubbling agent 0.6% are prepared for luminous coating on better performance. The adhesion of the coat with zirconia ceramic based is better than that with tin or glass matrix.