Measurements of the deformation stress of molten mold fluxes

为了确定F离子在熔融碱硅酸盐体系中的作用，利用拉曼光谱和分子动力学模拟研究了淬火na_2o - sio_2 - naf体系。在硅酸盐熔体的拉曼光谱中，随着F被O取代，谱带强度系统增加了1100 cm^<-1>，这为熔体的伴随聚合提供了证据。从分子动力学模拟中证实，取代的F大部分主要与Na^+离子配位，而不是与Si^<4+>离子配位，至少高达10 mol%的F。从MD模拟中发现少量F与Si作为非桥接离子配位，尽管拉曼光谱没有可识别的证据。这些结果与F与其他修饰网络的Na而不是与形成网络的Si相关联的机制一致。由于F与Na^+离子结合，两个F离子取代O离子促进了硅酸盐熔体的聚合。2003年，利用新研制的超微应力测量系统，研究了1673K下不同Al_2O_3含量和压缩速度下CaO-Al_2O_3-SiO_2熔融体系的变形行为。变形应力随Al_2O_3含量的增加而增大。已知铝离子具有构建三维网络结构的偏好。这是添加Al_2O_3后变形应力增大的原因之一。

To determine the effect of F ions in the molten alkali silicate systems, quenched Na__2O-SiO__2-NaF systems were investigated by Raman spectroscopy and molecular dynamics simulation in 2002 term. The systematic increase of 1100 cm^<-1> band intensity in the Raman spectra of the silicate melts accompanying the replacement of F for O provides the evidence for concomitant polymerization of melts. From the molecular dynamics simulation, it was confirmed that most of substituted F was mainly coordinated to Na^+ ions but not Si^<4+> ions at least up to 10 mol% of F. A small amount of F was found to be coordinated to Si as a non-bridging ion from the MD simulation, although there was no recognizable evidence from Raman spectroscopy. These results are consistent with the mechanism in which F associated with otherwise network-modifying Na rather than with network-forming Si. Since F was associated to Na^+ ions, the replace of O ion by two F ions promote the polymerization of silicate melts.In 2003 term, by using a newly developed ultra micro stress measurement system, the deformation behavior of molten CaO-Al_2O_3-SiO_2 system at 1673K with varying Al_2O_3 content and compress speed was investigated. It was found that the deformation stress was increased with increase of Al_2O_3 content. Al ion is know to have a preference to construct three-dimensional network structure. This is the one of the reason of increase of deformation stress with Al_2O_3.