Glass phases in ceramics

On the equilibrium thickness of intergranular glass phases in ceramic materials. J. Amer. Ceramic Soc., 70, 15-22. 

As shown later in this chapter, the presence of glass phase in structural ceramics appears to enhance the propensity for subcritical creep crack... 

Glass-ceramics are processed in the same way as glasses, but are then given a further heat treatment to nucleate and grow a crystalline phase, such that the final microstructure is composed of crystals with a glass phase in between. The possibility of tailoring both the initial composition and size and the volume fraction of the crystalline phase allows for precise tailoring of properties. 

Basis and Applications of Convergent Beam Electron Diffraction (CBED) for the Investigation of Phases in Ceramics and Glass-Ceramics... 

In most cases, controlled crystal growth produces various types of crystals, rather than Just one crystal phase, giving the glass-ceramic product special properties. The crystals must also demonstrate a specific arrangement in the microstructure of the glass matrix. Furthermore, certain glass-ceramics contain glass phases in addition to several crystal phases. 

Let us consider two hypothetical phases in our composite, A and B, without specifying their physical state. They conld be a polymer melt and a glass fiber reinforcement during melt infiltration processing, a metal powder and ceramic powder that are being snbjected to consolidation at elevated temperatnre and pressure, or two immiscible polymer melts that will be co-extruded and solidified into a two-phase, three-dimensional object. In any case, the surface that forms between the two phases is designated AB, and their individual surfaces that are exposed to their own vapor, air, or inert gas (we make no distinction here) are labeled either A or B. The following three processes are defined as these surfaces interact and form ... 

Based on dissolved ions only, the titanate waste showed an overall leach rate of x 10 5 g/cm day and a rate of 5 3 x 10 7 g/cm day for the fission waste oxides only. The results indicate that the leaching which is occurring is associated with the silicate phases in the ceramic, i.e., the Si02 formed from the silicon and the zeolite. The glass samples showed overall leach rates of 6-15 x 10 5 g/cm day and fission waste oxide leach rates of 1.8-2.7 x 10 g/cm day, where the higher rates in both cases were observed in the phosphate-containing glass. 

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