| Strontium aluminate is an excellent long-lasting light-emitting material exhibit excellent properties, such as high quantum efficiency, long persistence of phosphorescence, chemicacally stable and no radiation. The novel copper matrix composite materials were successfully prepared with strontium aluminate phosphor powder and high aluminum bronze powder. It not only has excellent wear ability and corrosion-resistance of aluminum bronze alloy powder, but also has fine luminous property of phosphorescent materials. This composite material is prepared by a thermal spray process, used in industrial large parts mold surface, can be easily and quickly achieve the purpose of detecting the wear condition. However, the activator Eu2+of SrAl2O4:Eu2+,Dy3+ can easily be oxidized to Eu3+ at high temperature and afterglow phosphor powder loss of performance durying our previous studies. Furthermore phosphorescent particles contact with the metal powder will generating contact quenching. Electronic transition process is too active to make it escape or loss a large number of electronic in the process of composite and release, results in the decrease of strength of excited electrons transition and even part of the phosphor luminescence reduce and even lost at high temperatures.To prevent thermal quenching and luminescence intensity decreasing by contacting metal ions during thermal spraying, the surface of luminescence phosphor SrAl2O4:Eu2+,Dy3+ was coated with SiO2 by Sol-gel process, in the presence of tetraethyl orthosilicate (TEOS) as silicon source.The influence of pH value and the solution component ratio etc were researched,confirming the optimum process. The luminous and friction properties of phosphorescence copper-matrix composite samples which fabricated by vacuum hot pressing sintering. For examination and assessment of temperature and contact with the metal particles of the influence of the phosphor powder before and after coating. By analyzing the phosphorescence mechanical properties and corrosion resistance of composite,studying the influence of coated phosphors. By analyzing the mechanical properties and fluorescence of composite materials which fabricated by vacuum hot pressing sintering, exploring the effect of coated phosphors applied to composite coating.The tests revealed that the molar ratio of tetraethoxysilane,ethanol and water was 1:3:5,the solution PH value was 4,the stirring time was 15 25min under the temperature 60℃, in order to get cladding coating SiO2 phosphor powder with better effect,the amount of SiO2 coated was 5% 20%.The SiO2-coating improved the compatibility of the phosphor powder, the fluorescence and crystal structure of the phosphors was affected so little.Luminescent composite coating doped with the phosphors with different ratio and the high aluminum bronze phosphorescence were fabricated by vacuum hot pressing sintering.The surface of composite were leveling and dense, the fluorescence of composite with coating phosphors much higher then the composite without coated, the fluorescence were better With the increase of coating ratio.The coated phosphors may act as enhancements to hardness, effective reduction of wear loss of the composite 。 The composite had very stable friction coefficient, the SiO2-coating could repair the wear surface. When the coating ratio was 10%,the luminescent properties and friction property of composite was optimal. The SiO2-coating avoided corrosion in H2SO4、NaOH、NaCl systems,improving the corrosion resistance of the composite.Luminescent composite coating doped with the phosphors with 10% coating ratio and the high aluminum bronze phosphorescence were fabricated by supersonic plasma spray. The surface and interface of the composite coated phosphors were leveling and dense, effective reduction of wear loss of the composite, low friction coefficient under the lower loads. The SiO2-coating could prevent quenching of phosphors,increase the area of luminescence. |
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