【作者】 安丽娟；

【导师】 张密林；

【作者基本信息】 哈尔滨工程大学 ， 应用化学， 2004， 硕士

【摘要】 具有β-Al₂O₃结构的铝酸盐BaAl₁₂O₁₉：Mn作为三基色发光材料的绿色组分，一直是人们研究的重点。随着等离子显示器的出现和广泛应用，BaAl₁₂O₁₉：Mn优异的真空紫外激发特性更为人们所关注。但是通常制备铝酸盐体系的荧光粉，是在1600～1800℃的高温下进行固相合成，焙烧后需要粉碎，而使得荧光粉的发光效率有一定的下降。近些年来，人们尝试用溶胶-凝胶法、水热合成法、燃烧法、微波热效应法等来制备铝酸盐发光材料取得了一定的成果。溶胶-凝胶法较之其它方法的一大特点是制品均匀性好，尤其是多组分制品，其均匀度可以达到分子或原子尺度，因此在铝酸盐荧光粉制备中具有一定的优势。本文探索用溶胶凝胶法制备出铝酸钡发光体，通过焙烧得到β-Al₂O₃结构的BaAl₁₂O₁₉∶Mn粉体，运用X射线衍射（XRD）、透射电子显微镜（TEM）、红外光谱（IR spectra）等多种表征手段进行了深入的研究。主要内容如下： （1）选取柠檬酸作为螯合剂，利用溶胶-凝胶法合成了BaAl₁₂O₁₉：Mn。通过实验，确定了制备过程中金属盐浓度、柠檬酸与金属离子总摩尔数的比值、反应温度、溶液pH值、焙烧温度、焙烧时间等工艺条件，发现体系pH值是影响溶胶形成的关键因素，控制其在8～9就可以使各个金属离子与柠檬酸充分的整合。 （2）研究了柠檬酸用量对凝胶形成的影响。由于柠檬酸与所需用的Al³⁺、Ba²⁺、Mn²⁺相络合时，摩尔比均是1：1，因此，柠檬酸与金属离子总摩尔比（M）至少是1，才能保证金属离子的完全螯合。实验中，我们确定当M=1.2时，能保证金属离子发生较好的螯合，并且对加水量有好的影响。 （3）研究了焙烧温度对BaAl₁₂O₁₉：Mn合成的影响。用溶胶-凝胶法，由于所需的生成物在烧成前已部分形成，而且凝胶所具有的大表面积利于产物生成，使得烧结温度降低。而且由于选取柠檬酸作为螯合剂，而柠檬酸中含有大量的碳，使得在焙烧过程中，不用任何助熔剂的情况下，在1100℃就可以合成出BaAl₁₂O₁₉∶Mn粉体，比传统的高温固相合成法降低了约500℃。这对合成同类材料提供了可靠的实验依据。 （4）按照组成Ba_yMn_0.005Al_11.95O_19+δ，详细考察了氧化钡和氧化铝的含量与基质结构的相关性，发现控制y在1.2～1.4的范围内，可以得到BaAl₁₂O₁₉。根哈尔滨工程大学硕士学位论文据X射线衍射和红外分析，发现增加氧化钡将导致体系中非晶态物质的含量增加，非晶态物质的存在是导致y值偏移的主要因素。 通过本文的研究表明，溶胶一凝胶法可以作为制备铝酸盐BaAI、:O、，:Mn的一种有效的方法，这为该类荧光粉的制备研究提供了成功的经验。并且为铝酸盐体系的发光材料的制备提供了一些通用性方法，对这一类功能材料生产有较大的现实意义。更多还原

【Abstract】 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.更多还原