Cristobalite Phase Formation in Glass/Ceramic Composites

Abstract

The effect of several different aluminum‐containing ceramic additions to borosilicate glass on suppressing cris‐tobalite precipitation has been examined. The results showed that mullite or aluminum nitride suppresses cristo‐balite formation more effectively than alumina or spinel. Although both follow a simple rule of mixtures, glass/mullite composites can be fabricated with lower dielectric constants than glass/alumina composites, while maintaining a thermal expansion coefficient close to Si. Electron micro‐analysis using X‐ray energy dispersive spectroscope showed that the measured interdiffusion coefficient between alumina and glass is in good agreement with the data which have already been published.

Amorphous Si(Al)OC ceramic from polysiloxanes: bulk ceramic processing, crystallization behavior and applications

“…Past studies on borosilicate glasses which undergoes devitrification have shown that addition of alumina, aluminum nitride, cordierite and mullite can suppress the formation of cristobalite. 18,19 This finding coincides with our results supporting a strong influence of Al-cations on the crystallization of silica. Moreover, the literature data indicate that mullite most effectively suppresses the formation of cristobalite.…”

Effects of multiple firings on the mechanical properties and microstructure of veneering ceramics for zirconia frameworks

“…34 Cristobalite precipitation in the composite takes place during firing, but it can be prevented by the presence of Al ions. 35 The size and number of the fluorapatite crystals were influenced by ripening and dissolving effects, and the X-ray intensity of the apatite phase depended on the heat treatment temperature. 36 In addition, SEM observation showed that there were fewer pores in some materials as the number of firings increased.…”

The mechanism of foaming and thermal conductivity of glasses foamed with MnO 2

“…7). Cristobalite is a polymorph of SiO 2 formed at 1048-1373 K in float glass and borosilicate glass [39,40]. Since the foam glasses are prepared at 1063 and 1083 K, the Si rich particles are likely cristobalite.…”

“…To avoid sticking of the glass melt to the mould, the steel was coated with a kaolin suspension. The samples were then heated in air at 10 K/min to 1063 or 1083 K for different durations (5,10,20,40,80 and 160 min). The foams were cooled to 803 K (T g ) at 5 K/min and then to room temperature at~1 K/min.…”