Crystallization processes in the silicate phase during the sintering of metal-glass materials

Conclusions

• 1. The formation of a crystalline phase in metal-glass materials may take place even in the early stages of sintering, at 600–700°C. During heating to temperatures exceeding that of primary crystalline phases, intensified impregnation of the glass with ions of the metallic matrix may result in recrystallization.

• 2. The extent of crystallization of glass particles in metal-glass materials is controlled by a variety of factors: glass particle size, presence of defects in the starting glass, impregnations of the glass with ions of the metallic matrix, presence of gas blisters in the glass and of interfaces between mutually insoluble glasses, position of the glass particle in the compact, compact porosity, and so forth.

• 3. Cyclic heating during the sintering of metal-glass materials and also low glass viscosity promote intensified growth of the crystalline phase. It is probably for these reasons that the micro-structure of Pyrex glass in metal-glass materials is more finegrained than that of window-grade glass, as a result of which the former has a stronger propensity to form Sitall-like structures.