Abstract: The present invention is concerned with the preparation of glazes which are especially suitable for application to glass-ceramic articles containing potassium fluorrichterite as substantially the sole crystal phase. The glazes consist essentially, expressed in terms of weight percent on the oxide basis, ofSiO.sub.2 :46-50Al.sub.2 O.sub.3 :5-8ZrO.sub.2 :0.3-1Li.sub.2 O:1-2Na.sub.2 O:2-3.5K.sub.2 O:1-2CaO:1-4ZnO:2-6SrO:2-6B.sub.2 O.sub.3 :9-11PbO:20-25.

Abstract: This invention is directed to the production of glazes exhibiting an earthenware appearance which are particularly suitable for decorating ceramic dinnerware. The glaze composition consists essentially of about 4-8% by weight SnO.sub.2 and 4-8% by weight TiO.sub.2, the total SnO.sub.2 +TiO.sub.2 being about 10-14%, and about 0.025-0.04% by weight MnO.sub.2 incorporated into a base frit consisting essentially, as analyzed in weight percent on the oxide basis, of about______________________________________ SiO.sub.2 37-49 Al.sub.2 O.sub.3 4-7 B.sub.2 O.sub.3 6.5-11 ZrO.sub.2 0-1.75 Na.sub.2 O 1.75-3.5 K.sub.2 O 0.75-2.5 PbO 21-32 CdO 0-0.75 CaO 1-9 TiO.sub.2 0-0.35 F 0-0.6 ______________________________________The fired glaze contains crystallites of rutile and cassiterite.

Abstract: The present invention is concerned with a single-step process for hydrating alkali metal-containing silicate glasses starting with such fine-dimensioned forms as powders, granules, flakes, fibers, and thin sheets. The process, which contemplates hydration temperatures higher than 225.degree. C. and relative humidities less than 50%, permits the precise control of the quantity of water taken into the glass structure and, where the water content in the glass is held within about 1-25% by weight, the hydrated product of the above-cited powders, granules, etc., can be thermoplastically formed into sound bulk articles. A layer of the anhydrous powders can be applied to a substrate and then hydrated in situ to form glassy paints and coatings.

Abstract: Spontaneous sodium fluoride opal glassware is treated to improve surface durability against aqueous attack by controlled sodium depletion and subsequent heat consolidation of the glass surface. The method comprises extracting surface sodium ions using water or dilute aqueous acidic solutions and subsequently consolidating by heat the surface to produce a glossy surface without any migration of sodium ions.