Inelastische Neutronenstreuung bei hohen Temperaturen und Drücken zur Aufklärung der Lösungs- und Transportmechanismen von Wasser in wasserhaltigen Silikatschmelzen

高温高压下的非弹性中子散射阐明水在含水硅酸盐熔体中的溶解和传输机制

• 批准号: 5446993
• 负责人: Professor Dr. Winfried Petry
• 金额: --
• 依托单位: Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5446993?language=en
• 关键词: Inelastische; Neutronenstreuung; bei; hohen; Temperaturen

We have successfully constructed a high temperature/pressure cell for the application on neutron scattering spectrometers provides temperatures up to 1250 K and pressures up to 2 kbar at the sample position. This has been achieved with an internally heated NbZr autoclave. So far experiments on hydrous Na2O•3SiO2 melts with 10 mol% water have been performed on the time-of-flight spectrometer TOFTOF at FRM II. The measured density correlation functions exhibit the incoherent dynamics of the proton. The quasielastic line width is used to derived the self diffusion coefficient. The Q2 dependence even holds up to 1.5 A−1. This might be an indication of the diffusion mechanism via channel structures, similar to the alkali ions in anhydrous alkali silicate melts. A contrast variation with H2O/D2O allows to measure pure hydrogen dynamics since the total scattering cross-section for H is much larger than for D. With this analysis we expect to gain new insight of rotational dynamics of the water species and of the influence of the water addition on the Na dynamics. For the hydrous SiO2 and Al2O3•Na2O•6SiO2 systems, the water diffusion is not fast enough to be resolved within the instrument energy resolution of TOFTOF at the working temperature range of the pressure cell. However, experiments scheduled on the neutron backscattering spectrometer with higher resolutions should allow to study diffusive dynamics and diffusion mechanisms of the water species.

我们已经成功地构建了一个高温/高压单元的中子散射谱仪上的应用程序提供的温度高达1250 K和压力高达2 kbar的样品位置。这已经通过内部加热的NbZr高压釜实现。到目前为止，在FRM II的飞行时间谱仪TOFTOF上对含水量为10mol%的Na 2 O·3SiO 2熔体进行了实验。测量的密度相关函数显示了质子的非相干动力学。利用准弹性线宽导出了自扩散系数。Q2依赖性甚至高达1.5 A−1。这可能是通过通道结构的扩散机制的指示，类似于无水碱金属硅酸盐熔体中的碱金属离子。H2O/D2 O的对比度变化允许测量纯氢动力学，因为H的总散射截面远大于D。通过这种分析，我们希望获得新的见解的旋转动力学的水物种和水的影响，除了对钠动力学。对于含水SiO_2和Al_2O_3·Na_2O·6SiO_2体系，在压力池工作温度范围内，水的扩散速度不足以在TOFTOF仪器能量分辨率内分辨。然而，实验上安排的中子背散射光谱仪具有更高的分辨率应允许研究扩散动力学和扩散机制的水物种。