A Raman spectral investigation of structural variations in thin silicate glass fibers
Raman spectroscopy has been used to characterize the structure of glass fibers with diameters as small as 3 μm. A special sample holder, which enables the laser beam to strike the transverse surface of the fiber bundles and to probe structural variations along the longitudinal direction, was designed. Structural variations in multi-component silicate glass fibers were studied as a function of fiber drawing conditions and different annealing temperatures.
A finite 3D element model coupled with a 2D finite volume one has been developed obatained in order to study the miscrostruture evolution during the desification of a green compact obtained by powder metturgy [1]. The simulation of the process was performed on to grains considering surface diffusion of the grains, grain boundary diffusion and volume diffusion in the grains, with as source terms the radii of curvature. The stress gradients are the driving forces of sintering. The mechanical behaviour of the grains is considered as elastic in the whole temperature range of the sintering cycle.