| Mn2+-doped barium hexaaluminate with the p-Al2O3 type structure ofBaAl12O19:Mn has been investigated extensively as the green component of tricolor luminescence materials. Especially with the development of plasma display panel (PDP), the green-emitting BaAl12O19:Mn phosphor has been paid more attention because it has a good efficiency under vacuum ultraviolet (VUV) excitation. Conventionally, the aluminates phosphors were prepared by solid state reaction required firing temperature in the range of 1600-1 800 C because of the refractory nature of the oxide precursors. The resulting large size phosphors were ground to obtain fine powder that caused the decreasing of the luminescent efficiency. Recently, phosphors of hexaaluminates were prepared by sol-gel technique, hydrothermal processing, combustion syntheses and microwave heating method. Sol-gel method as a solution-based method, which allows mixing of precursors at the molecular and atom level, has an advantage in the preparation of aluminates phosphors. In this dissertation we prepared the phosphor BaAl12O19:Mn which has the -Al2O3 type structure by Sol-gel method for the first time. We also conducted a series of experiments researching with the aids of the measure methods such as XRD, DTA, IR spectra, TEM and so on. The major work is summarized as the following:(1) We selected citric acid as a chelate to prepare BaAl2O19:Mn phosphor by sol-gel. According to the experiments, some factors in the preparation process such as concentration of metal-cations and precipitators, the ratio between the citric acid and the total number of the metal-ion ,pH value ,and sintering temperature, sintering time , reaction temperature , the pH value of the system, were discussed. It was found that the pH value is the critical factor that affects the preparation process.It can completely chelate between metal-ion and citric acid by controlling the pH value in 8-9.(2) The influence on gel formation with the varying dosage of the citric acid was discussed. When the citric acid chelated with the metal-ion such as Al3+,Ba2+,Mn2+ ,the molar ratio was 1:1. So it can ensure that the metal-ions completely were cheated as the ratio (M) between the citric acid and the total molar number of the metal-ion was 1 at least.It was advantaged when M was 1.2 in the expeiments,it's also good to the amount of water.(3) The influence on the preparation of BaAluOjgiMn with the firing temperature was discussed.Because the product had formed partly before sintering and gel's big apperance-area was advantage of the product formation,these all can decrease the sintering temperature.Selectiing citric acid as a chelate,and citric acid contained amount of carbon.It was found that BaAl12O19-.Mn powder can be obtained in the temperature 1100C without any assist of the flux in the sintering process.lt decreaesed the firing temperature about 500 C contrasted with the conventional solid-state reaction.lt provided reliable experimental basis for the preparation the congeneric materials.(4) With the expression of BayMno.osAln.gsOig+g, the correlation between host structure and the ratio of barium oxide and alumina was investigated in detail It was at the range of 1.2 to 1.4 not of 0.82 to 1.32 according to the literatures to obtain the BaAl12O19:Mn phase. Investigation on XRD and IR spectrum revealed that there are uncrystled materials that caused the y value change in the products.In this dissertation, our creative research in the preparation of BaAl12O19:Mn gives some significant results, we hope that will give some elicitation for the further investigation of the preparation of aluminates for luminescence.
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