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Preparation And Token Of Long-after Mica Covering Strontium Aluminates: Eu, Dy

Posted on:2008-08-22Degree:MasterType:Thesis
Country:ChinaCandidate:Z Q JingFull Text:PDF
GTID:2121360242968080Subject:Mineral processing engineering
Abstract/Summary:PDF Full Text Request
As new kind of non-infectant luminescent material, the long-after luminescent powders is not oly applied in writing Traffic directional signs, Numbers, equipment nameplate, public places security doors, security access, fire equipment directional signs etc, but also due to its unique artistic effect obtains the multitudinous decoration public figure to favour, displaying the good application prospect in the decorating market. But there are some problem such as high cost , low covering rate, bad suspending index. They would be solved by introducing mica into the luminescent material.Strontium aluminates was prepared by coprecipitation-calcination synthesis and combustion sythesis in the areticle, and the effects of them were studied by the numbers. The effects of coprecipitatio-calcination include kinds and dosage of precipitator ,active temperature, pH, Sr/Al, dosage of activation and assistant activation, dosage of boric acid, calcinations temperature and times etc. Base on the study, the best prepared conditions have been obtained. And then the other effects of combustion synthesis have been studied, such as dosage of urea, combusting-environment and ignition temperature, the best prepared process was fixed.Base on studies of preparation phosphors, the method of preparation phosphors were tried to applied in preparation luminescent mica. But they were defeated. Embellishing surface was introduced . And luminescent mica was successfully prepared on first time. The process is that ,covering luminescent powder with modifying agent (50%),then mixing it in mica ,lastly calcining at 600℃in reductive environment.Luminescent powders prepared by the coprecipitation-calcination synthesis and combustion sythesis was tested by Spectrofluorometer and XRD. It conclude that they are different matter ,although the stuff scale is same. luminescent powder prepared by the coprecipitation-calcination synthesis is Sr4Al14O25: Eu2+, Dy3+ ,but the powder prepared by combustion sythesis is SrAl2O4: Eu2+, Dy3+. And compared with the apex of eyes in dark, it indicates that luminescence property of Sr4Al14O25 is more adaptive than luminescence property of SrAl2O4The same testing method was applied in luminescent mica. The result is the same with luminescent powders, except emission apex. Emission apex of luminescent mica has blue-shift. Surface of luminescent mica has been tested by SEM, It indicates the luminescent powder can equably distribute on the surface .And the size of powder is between 50 and 1000nm. The luminescence theory of luminescent mica was discussed primarily. By calculated, the cost was reduce by 50%, the suspend index was increased by 50%, and the covering ratet was increase by 30% at least. So there is nice applying foreground.
Keywords/Search Tags:strontium aluminate, luminescent mica, preparation process, luminescent material
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