Abstract: The present invention is directed to the production of glass-ceramic coatings capable of being fired repeatedly to temperatures in excess of 950.degree. C. without thermal deformation and being especially suitable for application to titanium-stabilized stainless steels. The coatings are highly crystalline, substantially free from alkali metal oxides, and consist essentially, by weight, of:______________________________________ MgO 5-35 CaO 0-35 ZnO 0-25 CaO + ZnO 10-35 Al.sub.2 O.sub.3 0-10 B.sub.2 O.sub.3 0-25 P.sub.2 O.sub.5 0-10 B.sub.2 O.sub.3 + P.sub.2 O.sub.5 4-25 SiO.sub.

Abstract: This invention is directed to means for producing strengthened, transparent glass-ceramic, partially body-crystallized, and surface-crystallized glass articles wherein beta-quartz solid solution constitutes the predominant crystal phase. The inventive method comprises subjecting a glass article consisting essentially, expressed in terms of weight percent, of about 2.5-6% Li.sub.2 O, 0.5-5% RO, wherein RO consists of ZnO and the alkaline earth metal oxides BaO, CaO, MgO, and SrO, 16-25% Al.sub.2 O.sub.3, 64-73% SiO.sub.2, and 3.0-6% RO.sub.2, wherein RO.sub.2 consists of 0-6% TiO.sub.2 and 0-3.5% ZrO.sub.2, to vapors of SO.sub.2 and thereafter heat treating the glass article to cause crystallization in situ thereof.

Abstract: This invention is concerned with the production of glasses in the Li.sub.2 O-PbO-Al.sub.2 O.sub.3 -SiO.sub.2 system which resist the development of devitrification at temperatures approaching the softening point of the glass, which resist surface wrinkling, haze, devitrification, spalling, and cracking when held for several hours at temperatures above the annealing point of the glass but below the softening point thereof, which can be chemically strengthened to demonstrate modulus of rupture values in excess of 60,000 psi, which display excellent chemical durability, and which, in the most preferred embodiment, exhibit a refractive index of 1.523. Such glasses consist essentially, expressed in terms of weight percent on the oxide basis as calculated from the batch, of______________________________________ SiO.sub.2 59-71% Al.sub.2 O.sub.3 20-28 Li.sub.2 O 4.5-7.5 PbO 3-9 ______________________________________wherein the mole ratio Al.sub.2 O.sub.3 :Li.sub.2 O+PbO ranges about 0.95-1.05.

Abstract: This invention is directed to the production of frits useful in decorating glazes and enamels for glass, glass-ceramic, and ceramic food service ware which exhibit coefficients of thermal expansion (20.degree.-300.degree. C.) between about 50-110.times.10.sup.-7 /.degree.C., a viscosity suitable for firing at about 650.degree.-775.degree. C., good glass stability, high gloss, and excellent resistance to attack by acids and bases, especially detergents such as are used in commercial dishwashers. The frits consist essentially, expressed in weight percent on the oxide basis as calculated from the batch, of:SiO.sub.2 :29-55B.sub.2 O.sub.3 :7-31Al.sub.2 O.sub.3 :2-8ZrO.sub.2 :5-16Na.sub.2 O:4- 20Li.sub.2 O:0-7Na.sub.2 O+Li.sub.2 O:6-24F:0.75-4.

Abstract: The subject invention is drawn to the production of composite glass articles having base compositions within the Li.sub.2 O and/or Na.sub.2 O-FeO-CoO and/or NiO-Al.sub.2 O.sub.3 SiO.sub.2 system and glass-ceramic articles having base compositions within the Li.sub.2 O-FeO-CoO and/or NiO-Al.sub.2 O.sub.3 -SiO.sub.2 system wherein the articles have a thin, integral, tightly-bonded surface layer containing crystals of nickel-iron, cobalt-iron, or cobalt-nickel-iron alloy.

Abstract: This invention is concerned with the production of transparent glass articles having compositions in the Li.sub.2 O and/or Na.sub.2 O-FeO-Al.sub.2 O.sub.3 -SiO.sub.2 field which additionally contain NiO and/or CoO. Upon exposure to a specifically-defined heat treatment in an oxidizing atmosphere, very fine-grained crystallites of NiFe.sub.2 O.sub.4, CoFe.sub.2 O.sub.4, or (Co,Ni)Fe.sub.2 O.sub.4 are formed spontaneously at the surface of the glass article to produce an integral surface layer thereon having a thickness of not more than about several thousand angstroms. These ferrite surfaces can be magnetized in a strong magnetic field and are relatively easily demagnetized. Such capabilities recommend these surface-crystallized glasses for applications in the storing, recording, retrieving, and erasing of information.

Abstract: The instant invention is related to the production of highly refractory glass-ceramic articles having moderate coefficients of thermal expansion in the CaO-Al.sub.2 O.sub.3 -SiO.sub.2 -TiO.sub.2 field wherein anorthite comprises the predominant crystal phase with a minor amount of rutile also being present. The articles demonstrate very high D.C. volume resistivities and high dielectric constants with exceptionally low loss tangents and dielectric loss factors. Their refractoriness and moderate expansion suggests an application such as kiln furniture where high temperatures, but not severe temperature changes, are encountered. Their high D.C. resistivities and low A.C. dielectric losses suggest their utility as insulators and electronic substrate materials.

Abstract: The present invention relates to the preparation of essentially silica-free glasses which can be melted at low temperatures and which have compositions within the Li.sub.2 O--Al.sub.2 O.sub.3 and/or F--B.sub.2 O.sub.3 system. The glasses exhibit very high lithium ion mobility which, resulting in low electrical resistivity, has led to their consideration as solid membrane electrolyte-separators in such devices as the lithium metal-sulfur battery.

Abstract: The instant invention relates to the production of glass and glass-ceramic compositions containing a ferrimagnetic crystal phase throughout which respond thermally to fields generated by induction coils. Magnetite (Fe.sub.3 O.sub.4) is the preferred ferrimagnetic crystal phase because of its high permeability and low resistivity (.about.10.sup.-4 ohm-cm) at room temperature as well as the relative low cost of iron when compared with other ferrimagnetic species. Two general composition areas are of interest: Na.sub.2 O and/or K.sub.2 O-FeO-B.sub.2 O.sub.3 -SiO.sub.2 and Li.sub.2 O-Al.sub.2 O.sub.3 -B.sub.2 O.sub.3 -SiO.sub.2. Where the coefficient of thermal expansion is sufficiently low to impart good thermal shock resistance, the compositions can be considered for top-of-stove cooking vessels.

Abstract: This invention is directed to the production of glass-ceramic articles having compositions within the Li.sub.2 O-Al.sub.2 O.sub.3 -SiO.sub.2 field nucleated with a combination of TiO.sub.2 + ZrO.sub.2 wherein beta-spodumene solid solution constitutes the primary crystal phase. Mullite and/or corundum along with ZrTiO.sub.4 solid solution and, occasionally, ZrO.sub.2 solid solution are present as secondary crystal phases. Because of their low coefficients of thermal expansion and exceptional long time dimensional stability at temperatures up to 1000.degree. C., the compositions can be useful in applications where extreme changes in temperature are experienced; for example, the construction of honeycomb structures used in regenerative heat exhchangers for turbine engines.

Abstract: The instant invention relates to the production of crystal-free, transparent glass articles which emit a strong bluish luminescence when excited by either ultraviolet or cathode rays. Such glass articles are prepared from aluminosilicate compositions which consist essentially, in terms of mole percent on the oxide basis, of about 15-30% Al.sub.2 O.sub.3 and 45-70% SiO.sub.2, the sum of those two components constituting at least 75 mole percent, but no more than about 95 mole percent, of the total composition, and 0.025-2% europium, expressed as Eu.sub.2 O.sub.3. The remainder of the composition is generally made up of compatible monovalent, divalent, and/or trivalent modifying oxides. The desired high degree of luminescence is brought about by exposing the glass articles to a reducing atmosphere at a temperature below the softening point of the glass.

Abstract: The instant invention is concerned with the preparation of iron-containing glasses having compositions within the R.sub.2 O-Al.sub.2 O.sub.3 -SiO.sub.2 field, wherein R.sub.2 O consists of Li.sub.2 O, Na.sub.2 O, and/or K.sub.2 O, which spontaneously develop thin surface layers containing hematite (alpha-Fe.sub.2 O.sub.3) crystals when exposed to relatively low temperature heat treatments, viz., at least about 675.degree. C. but less than about 950.degree. C., in an oxidizing environment. Described visually, the resulting surfaces exhibit a variety of appearances, ranging from mirror-like through lustrous metallic to dull-earthen. In all surface layers, the hematite crystals may subsequently be chemically reduced to magnetite (Fe.sub.3 O.sub.4) or metallic iron crystals. Permanent magnetization can then be induced by means of the application of a strong magnetic force. The magnetite-containing surfaces can also demonstrate semiconductivity. The metallic iron surface can be highly electrically conductive.

Abstract: The present invention is concerned with the production of glass-ceramic articles, wherein the predominant crystal phase consists of beta-spodumene solid solution or nepheline, but which have integral surface films containing alpha-iron. The method for producing such articles comprises two general steps. First, a glass article having a composition within a particularly-defined area within the Li.sub.2 O-FeO-Al.sub.2 O.sub.3 -SiO.sub.2 -TiO.sub.2 field or within the Na.sub.2 O-FeO-Al.sub.2 O.sub.3 -SiO.sub.2 -TiO.sub.2 field is heat treated under oxidizing conditions at temperatures of at least about 1000.degree. C. to cause crystallization in situ of the glass to a glass-ceramic article wherein beta-spodumene solid solution or nepheline crystals constitute the predominant crystal phase in the interior of the article and, at the same time, an integral surface layer containing hematite crystals is developed.

Abstract: This invention relates to the manufacture of glass-ceramic articles having integral surface layers exhibiting ferrimagnetic behavior. More specifically, this invention is directed to glass bodies having compositions within the Li.sub.2 O-Al.sub.2 O.sub.3 -Fe.sub.2 O.sub.3 -SiO.sub.2 -TiO.sub.2 base system, and that additionally contain NiO and/or CoO, which, when heat treated under oxidizing conditions to effect crystallization in situ to glass-ceramic articles, spontaneously develop crystallites of NiFe.sub.2 O.sub.4 and/or CoFe.sub.2 O.sub.4 in the surfaces thereof. The ferrite surfaces can be magnetized in a strong magnetic field and demonstrate magnetic properties eminently suitable for the recording, storage, and erasing of information.

Abstract: The instant invention relates to the production of glass-ceramic articles, wherein the predominant crystal phase is beta-quartz solid solution and/or beta-spodumene solid solution, but which have a thin, integral, tightly-bonded surface film containing crystals exhibiting the structure of magnetite. The preferred method of production for such articles requires three general steps. First, a glass article having a particular composition within the Li.sub.2 O--FeO--Al.sub.2 O.sub.3 --SiO.sub.2 field nucleated with TiO.sub.2 is heat treated in air or other oxidizing atmosphere to yield a glass-ceramic article through the crystallization in situ of beta-quartz solid solution and/or beta-spodumene solid solution crystals. Simultaneously during this heat treatment, a surface layer containing hematite is developed. Second, the glass-ceramic article is subjected to a hot acid bath. Third, the acid-washed article is heat treated in a H.sub.

Abstract: The present invention is related to the production of glasses in the Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 or Na.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 composition systems containing NiO and TiO.sub.2. Such glasses exhibit a brown coloration when first melted but the color is converted to a green hue after exposure to a particularly-defined heat treatment. The green coloration results from the growth of a small amount of very fine-grained crystallites of nickel spinel (NiO.Al.sub.2 O.sub.3). The crystallized articles can be chemically strengthened utilizing a low temperature ion exchange reaction.

Abstract: This invention is concerned with the manufacture of refractory articles of a partially crystalline nature, i.e., materials having a substantial crystal content within a glassy matrix, but wherein the crystal phase normally comprises less than about 50% by volume of the materials. The bodies are produced through the heat treatment of glass articles having compositions within the Al.sub.2 O.sub.3 --SiO.sub.2 --TiO.sub.2 --Nb.sub.2 O.sub.5 and/or Ta.sub.2 O.sub.5 system at elevated temperatures, but not in excess of about 1150.degree. C., to cause the in situ growth of crystals. The materials, containing aluminum niobate, aluminum tantalate, or an aluminum niobate-tantalate solid solution as the predominant crystal phase, exhibit a high degree of transparency to visible light, and retain that transparency even after very extended exposures to temperatures up to in excess of 1000.degree. C. That capability has recommended their utility as arc-tubes or as envelopes for high temperature lamps.

Abstract: This invention relates to the production of glass-ceramic articles in the Li.sub.2 O--MgO--Al.sub.2 O.sub.3 --SiO.sub.2 system nucleated with TiO.sub.2, and, optionally, ZrO.sub.2 which, containing beta-spodumene solid solution as the predominant crystal phase, exhibit average coefficients of thermal expansion over the range of 25.degree.-1000.degree. C. of less than about 15 .times. 10.sup.-.sup.7 /.degree. C. and total elongations after 2000 hours at 950.degree. C. of less than about 1000 PPM. The compositions are especially useful in the manufacture of honeycomb structures which are to be subjected to extreme changes in temperature, such as are experienced in regenerative heat exchangers for use in turbine engines.

Abstract: The present invention relates to the production of glasses which will emit a yellow-to-orange luminescence when subjected to bombardment by high energy electrons. Glasses demonstrating good efficiency and resistance to aging can be formed from a very narrowly-defined range of compositions within the alkaline earth aluminosilicate field, wherein the alkaline earth oxide is MgO, CaO, and/or SrO, which are activated by manganese.

Abstract: Clear alkali aluminosilicate glasses free of boron but exhibiting good stability against copper and silver reduction, resistance to opalization, reduced temperature melting characteristics, and good photochromic properties after heat treatment are described. The use of P.sub.2 O.sub.5 and Li.sub.2 O in combination with fluorine in these compositions facilitates the manufacture of strongly photochromic glasses at reduced halide concentrations.