尖晶石型γ-AlON透明陶瓷的紫外辐照及光学性能研究
发布时间：2018-10-16 18:53
【摘要】：氮氧化铝(γ-AlON)透明陶瓷是一种重要的尖晶石结构材料,由于非化学计量比特点,γ-AlON晶体中包含大量的缺陷微结构,对材料性能产生显著影响。目前,人们对γ-AlON缺陷微结构的研究较少,对于γ-AlON材料性能的报导存在较大差异。本课题采用紫外辐照和退火处理等方法,利用光催化反应仪、荧光分光光度计和热释光光谱仪等检测设备,对γ-AlON材料中的缺陷微结构及其形成机理进行了详细的研究,具体内容和主要结论如下：(1)γ-AlON粉体为纯净的尖晶石结构,尺寸分布300-900 nm,平均粒经约580nm,无团聚现象,禁带宽度5.2 eV,内含大量的铝空位等缺陷。γ-A10N粉体在2h内,对甲基橙溶液(10mg/L)紫外降解率达到92%。分析表明：γ-AlON晶体中缺陷能级电子跃迁形成的电子-空穴对,在大量缺陷阱辅助作用下有效分离,与甲基橙分子反应并将其降解；(2)γ-AlON透明陶瓷紫外(汞灯)辐照15mmin后,样品由无色变为蓝紫色；其透过光谱中550 nm处出现明显光吸收,与辐照样品呈现蓝紫色相一致。样品中铝空位等缺陷产生的诱导色心,随退火过程表现出一定的迁移性,250℃低温退火即可将其“漂白”；(3)γ-AlON晶体缺陷形成机理为：[Al24O24N8]+3/202→[Al23027N5]+3[ON']+ [VA1],主要缺陷结构为VAl"'和ON·,理论浓度1/56。VAl"'和ON·在静电作用下形成[VAl-ON].[ON'-VAl"-ON']'和[VAl-30N]等缺陷簇,它们是样品出现辐照诱导着色的根源；(4)y-A1ON透明陶瓷在紫外(371 nm)和可见光范围(707 nm)内均表现出明显的荧光特性,起源于[VAl-ON'].[ON'-VAl一ON]'口[VAl-3ON]等缺陷能级。分析表明：γ-AlON晶体结构稳定,高温退火处理只影响缺陷扩散运动,表述为：[VAl-3ON] (?)[ON-VAl-ON]'+ON'(?)[VAl-ONr+20N'(?)VAl+30N',从而引起缺陷簇的结合形式或相对浓度改变；紫外辐照对缺陷结构无影响,不会改变荧光特性。
[Abstract]:Alumina nitride (纬-AlON) transparent ceramics is an important spinel structure material. Due to the non-stoichiometric characteristics, 纬-AlON crystal contains a large number of defective microstructures, which have a significant impact on the properties of the materials. At present, there are few studies on the microstructure of 纬-AlON defects, and there are great differences in the reports of the properties of 纬-AlON materials. In this paper, the defect microstructure and formation mechanism of 纬-AlON materials were studied by means of ultraviolet irradiation and annealing, using photocatalytic reaction apparatus, fluorescence spectrophotometer and thermoluminescence spectrometer. The specific contents and main conclusions are as follows: (1) 纬-AlON powder is pure spinel structure, the size distribution of 300-900 nm, average particle size is about 580nm, there is no agglomeration, the gap width 5.2 eV, contains a lot of aluminum vacancies and so on. 纬 -A10N powder contains a lot of aluminum vacancies within 2 hours. The UV degradation rate of p-methyl orange solution (10mg/L) was 92%. The results show that the electron-hole pair formed by the electron transition of defect level in 纬-AlON crystal is effectively separated by a large number of traps and reacted with methyl orange molecule and degraded. (2) 纬-AlON transparent ceramics irradiated by UV (mercury lamp), The sample changed from colorless to blue purple, and there was obvious light absorption at 550 nm through the spectrum, which was consistent with that of irradiated sample. The induced color center produced by the defects such as aluminum vacancy in the sample shows a certain migration with the annealing process, and it can be "bleached" after low temperature annealing at 250 鈩，
本文编号：2275318
[Abstract]:Alumina nitride (纬-AlON) transparent ceramics is an important spinel structure material. Due to the non-stoichiometric characteristics, 纬-AlON crystal contains a large number of defective microstructures, which have a significant impact on the properties of the materials. At present, there are few studies on the microstructure of 纬-AlON defects, and there are great differences in the reports of the properties of 纬-AlON materials. In this paper, the defect microstructure and formation mechanism of 纬-AlON materials were studied by means of ultraviolet irradiation and annealing, using photocatalytic reaction apparatus, fluorescence spectrophotometer and thermoluminescence spectrometer. The specific contents and main conclusions are as follows: (1) 纬-AlON powder is pure spinel structure, the size distribution of 300-900 nm, average particle size is about 580nm, there is no agglomeration, the gap width 5.2 eV, contains a lot of aluminum vacancies and so on. 纬 -A10N powder contains a lot of aluminum vacancies within 2 hours. The UV degradation rate of p-methyl orange solution (10mg/L) was 92%. The results show that the electron-hole pair formed by the electron transition of defect level in 纬-AlON crystal is effectively separated by a large number of traps and reacted with methyl orange molecule and degraded. (2) 纬-AlON transparent ceramics irradiated by UV (mercury lamp), The sample changed from colorless to blue purple, and there was obvious light absorption at 550 nm through the spectrum, which was consistent with that of irradiated sample. The induced color center produced by the defects such as aluminum vacancy in the sample shows a certain migration with the annealing process, and it can be "bleached" after low temperature annealing at 250 鈩，
本文编号：2275318
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