Zeolites are hydrated alumino-silicates. crystallize in framework structures. Zeolites are used in the catalysis, adsorption, drying and separation technologies. Glass-ceramics are polycrystalline solids prepared by controlled crystallization of glasses, with interesting properties. A new field of application can be opened by combination of the properties of zeolites and glass-ceramics. It is possible to design glass-ceramics with a zeolite as crystal phase. In this stuudy further investigations of the phase distribution and the interface between the crystal phases will be presented. Glasses with a composition similar to the stoichiometric composition of a zeolite were melted with partial substitution of NaF for Na_2CO_3. Samples of these glasses were crystallized at various temperatures. The zeolitic phase Na_6[AlSiO_4]_6 and the nepheline were precipitated in two of the glass compositions at all crystallization temperatures. Na_6[AlSiO_4]_6 is a zeolite of the sodalite type. The interface between the zeolite and the nepheline will be shown. The nepheline seems to grow radially (epitaxially) on the zeolite. The obtained zeolite does not correspond to the synthesis compositions of the glasses.
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