Raman Study of the Interface between Hot‐Pressed Silica Parts

Abstract

We present a Raman spectroscopy study of silica glasses prepared by hot-pressing of gels. Our particular interest is the structure at the interfaces formed during hot-pressing of small parts to obtain large pieces, such as silica tubes for opticalfiber preforms. A specific feature of the interface that distinguishes this layer from the bulk is its fractal structure. The parameters of the fractal units, including their maximum dimensions in real space, are determined by the pre-hotpressing mechanical processing. We attribute this structure to residual microcracks inherent in the surface layer of polished plates. There are no fractals at the interfaces sintered at temperatures higher than the glass transition temperature.

Reliability studies of gelcast fused silica between organic and inorganic binder systems

“…It also plays very important role in diversified fields such as refractory materials in metal processing and kiln furniture . In general, fused silica ceramics is fabricated by powder processing methods like cold and hot compaction techniques, slipcasting, injection molding, and gelcasting process . The fused silica raw material powder is obtained by grinding in ball milling using melt and quenched amorphous silica lumps .…”

Aqueous Gelcasting of Fused Silica Using Colloidal Silica Binder

“…Due to these properties, fused silica could find a wide range of strategic and industrial applications such as electromagnetic transparent materials, thermal protection systems as refractory materials in metal processing and kiln furniture etc . Fabrication of fused silica products is conventionally carried out by hot pressing, slip casting and recently gelcasting process also have been reported . Among these forming processes, the most suitable process is Gelcasting process to fabricate near‐net shape of ceramics having complex shapes.…”