Abstract: The invention provides: a glass composition comprising about 20 to about 85% of SiO.sub.2, about 2 to about 75% of B.sub.2 O.sub.3, about 15% or less of Al.sub.2 O.sub.3, about 30% or less of at least one of Li.sub.2 O, Na.sub.2 O, K.sub.2 O, Rb.sub.2 O and Cs.sub.2 O, about 0.1 to about 10% of ZnO, about 10% or less, calculated as total amount in combination with ZnO, of at least one of MgO, CaO, BaO, SrO and PbO, about 10% or less of at least one of ZrO.sub.2, La.sub.2 O.sub.3, Y.sub.2 O.sub.3, Ta.sub.2 O.sub.3 and Gd.sub.2 O.sub.3, and about 0.05 to about 15% of at least one copper halide.

Abstract: An optical glass which is a SiO.sub.2 --Nb.sub.2 O.sub.5 --R'.sub.2 O (R' being an alkali metal element)-F system of a specific composition range exhibits optical constants of a refractive index (Nd) of about 1.60 or below and an Abbe number (.nu.d) of about 57-40, is free of PbO and has an improved light transmissivity.

Abstract: Suitable starting materials for the manufacture of a heavy metal fluoride glass composition are mixed with solid xenon fluoride as the fluoridizing reagent, after which the mixture is heated to temperatures between 200.degree. and 400.degree. C. in an inert atmosphere for a time which suffices to bring about fluoridation of the starting materials. The intermediate product thus obtained is melted thereby forming a stable glass composition of a high purity and a high transparency. The method can be carried out in a simple manner in a furnace which need not be gastight.

Abstract: A glass powder crystallizable to yield a sintered glass ceramic containing hexagonal cordierite as the principal crystal phase is of the composition, in mol % on an oxide basis, of 48-61 SiO.sub.2 ; 10-16 Al.sub.2 O.sub.3 ; 23-35 MgO; 0-4 B.sub.2 O.sub.3 ; 0-2.5 P.sub.2 O.sub.5 ; 0.5-5 .SIGMA. B.sub.2 O.sub.3 +P.sub.2 O.sub.5 ; 0-3 ZnO; 0-3 CaO; 0-1.5 BaO and as an essential component 0.5-12 F as a substitute for O. The glass powder may also contain a total of up to 3 mol % of one or more of the oxides PbO, SrO and SnO.sub.2. The glass powder can be crystallized at sintering temperatures below 970.degree. C. in a relatively broad sintering temperature range to yield a sintered glass ceramic having excellent and constant properties. It is particularly suitable for the production of electrotechnical and electronic components since it has very good electrical, dielectrical and mechanical properties.

Abstract: Hollow glass spheres having average densities of approximately 0.10 grams/cc to approximately 2.0 grams/cc are prepared by heating solid glass particles. The glass spheres consist essentially of the following ingredients in the following amounts stated as weight percentages: SiO.sub.2 (50 to 57%); R.sub.2 0(2 to 15%); B.sub.2 O.sub.3 (0 to 20%); S(0.05 to 1.5%); RO(2 to 25%); RO.sub.2 (other than SiO.sub.2) (0 to 5%); R.sub.2 O.sub.3 (other than B.sub.2 O.sub.3) (0 to 10%); R.sub.2 O.sub.5 (0 to 5%); and F(0 to 5%). R represents a metal or an element like phosphorous which combines with oxygen in glass. The sizes of the hollow glass spheres are selected to produce a maximum average strength for a desired average density.

Abstract: Cerium-doped radiation-shielding glasses in the system of SiO.sub.2 -PbO-alkali metal oxides, with a high absorption coefficient for high-energy X-ray and/or gamma- and, respectively, neutron radiation which are resistant to discoloration and exhibit a discharge stability of >5.times.10.sup.8 rad, consist essentially of (in % by weight)______________________________________ SiO.sub.2 35-56 Na.sub.2 O K.sub.2 O 12-21 Cs.sub.2 O PbO.sub.2 24-46 CeO.sub.2 0.5-2.5 CuO + Fe.sub.2 0-0.05; ______________________________________for absorption of neutrons, the isotope Li.sup.6 can furthermore be onctained therein, and SiO.sub.2 can be substituted by B.sub.2 O.sub.3 and/or Gd.sub.2 O.sub.3 in an amount of up to 10% by weight and Gd.sub.2 O.sub.3 is present.

Abstract: Glass having ultrafine particles of CuCl and/or CuBr precipitated therein, which consists essentially of:from 10 to 70 mol % of SiO.sub.2,from 30 to 90 mol % of B.sub.2 O.sub.3,from 0.1 to 50 mol % of Li.sub.2 O+Na.sub.2 O+K.sub.2 O, andfrom 0.01 to 10 mol % of CuCl+CuBr.The glass may further contain from 0.01 to 40 mol % of Al.sub.2 O.sub.3.

Abstract: Hollow glass spheres having average densities of approximately 0.10 grams/cc to approximately 2.0 grams/cc are prepared by heating solid glass particles. The glass spheres consist essentially of the following ingredients in the following amounts state as weight percentages: SiO.sub.2 (50 to 57%); R.sub.2 O(2 to 15%); B.sub.2 O.sub.3 (0 to 20%); S(0.05 to 1.5%); RO(2 to 25%); RO.sub.2 (other than SiO.sub.2) (0 to 5%); R.sub.2 O.sub.3 (other than B.sub.2 O.sub.3) (0 to 10%); R.sub.2 O.sub.5 (0 to 5%); and F(0 to 5%). R represents a metal or an element like phosphorous which combines with oxygen in glass. The sizes of the hollow glass spheres are selected to produce a maximum average strength for a desired average density.

Abstract: This invention relates to the production of opaque, beige-tinted glass-ceramic articles consisting essentially, in weight percent, of______________________________________ SiO.sub.2 66-70 TiO.sub.2 3.5-5.5 Al.sub.2 O.sub.3 16.5-19.5 CeO.sub.2 1.5-2.75 Li.sub.2 O 2-4 As.sub.2 O.sub.3 0-1.5 MgO 1-5 F 0-1.2 ZnO 0.5-2 ZrO.sub.2 0-2.5 Na.sub.

Abstract: There are disclosed fluoroborosilicate glasses that are particularly adapted to being drawn with lead silicate core glasses to produce clad glass fibers useful in forming fiber optic bundles to be incorporated in night vision equipment. The cladding glass has a refractive index not over about 1.465 and a coefficient of thermal expansion not over about 80.times.10.sup.-7 /.degree.C. The clad fiber has a numerical aperture approximating or equal to one.

Abstract: An inorganic glass having high water repellence produced by irradiating and/or implanting ions upon or into a surface of the inorganic glass, the ions are those of at least one element selected from the group consisting of(a) halogen elements selected from F, Cl, and Br, group 3A, 3B, 4A and 5B elements of the International Periodic Table selected from Al, Ti, Y, In and Bi,(b) rare gas elements selected from He, Ne, Ar, Kr and Xe, group 3A, 4A, 1B, 2B, 3B, 4B and 5B elements of the International Periodic Table selected from Sc, Cu, Zn, Ag, Cd, Sn, Sb, Au, Hg, Tl and Pb, alkali metal or alkaline earth metal elements selected from Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr and Ba, and(c) Ce, the dose of th (a), (b) and (c) ions being 5.times.10.sup.14 to 1.times.10.sup.20 ion/cm.sup.2, 5.times.10.sup.14 to 1.times.10.sup.17 ion/cm.sup.2 and 1.times.10.sup.17 to 1.times.10.sup.20 ion/cm.sup.2, respectively.

Abstract: A fluoroaluminosilicate glass powder for dental glass ionomer cements has a specific gravity of 2.4 to 3.5 and a mean particle size of 0.02 to 10 .mu.m, contains in its components 20 to 50% by weight of SiO.sub.2, 20 to 40% by weight of Al.sub.2 O.sub.3, 15 to 40% by weight of SrO, 1 to 20% by weight of F.sub.2 and 0 to 15% by weight of P.sub.2 O.sub.5 on the converted oxide basis, and is substantially free from alkali metal ions such as Li, Na, K, Rb and Cs ions, and Be, Mg (and Ca) and Ba ions of alkali earth metal ions. For further improvements in physical properties, 100 parts by weight of the glass powder are surface-treated with 0.01 to 5 parts by weight of an acid and/or a fluoride.

Abstract: A material having superior that insulating qualities which may be formed in flat sheets or any other desired configuration. The material in its basic form is produced by mixing an alkali metal halide or nitrate into an alkali metal silicate solution to form a polymerized silicate gel. The gel may be heated to cause intumescence and the formation of a dry cellular ceramic, or may be used in gel form, e.g., as a fireproof barrier which will expand upon exposure to heat. Physical properties of the end product are altered by the inclusion of one or more additives prior to the polymerization reaction. These additives may be any of a number of materials that do not significantly react with the alkali metal silicate solution or otherwise inhibit the formation of the gel.

Abstract: A matrix of a glass or a plastic is mixed with 1% to 10% of a niobium substance, 1% to 10% of a magnesium compound, 1% to 10% of barium fluoride, and 5% to 30% of lead, the percentages indicating the weight of these substances the matrix. The mixture is heat-molded to form an anti-fogging material.

Abstract: A mold additive for use in continuous casting, which includes a base material having a chemical composition of CaO--BaO--SiO.sub.2 --F system, and contains 2-15% by weight in total of at least one carbonate of alkali and alkaline earth metals, 2-30% by weight in total of at least one fluoride of alkali and alkaline earth metals and 0.2-10% by weight of carbon, and, if necessary, 2-10% by weight in total of at least one oxide of Fe, Mn and Ni, and has a solidification temperature of not more than 900.degree. C. and a viscosity at 1,300.degree. C. of not more than 3 poises. The base material has a weight ratio of (CaO+BaO)/SiO.sub.2 of 0.6-2.5 and contains not less than 2% by weight of BaO and 2-15% by weight of F.

Abstract: A dental crown is prepared from a dental crown material including 7 to 11% by weight of Li.sub.2 CO.sub.3, 18 to 28% by weight of MgO, 9 to 15% by weight of Al.sub.2 O.sub.3, 38 to 48% by weight of SiO.sub.2 and 10 to 15% by weight of Na.sub.2 SiF.sub.6. The dental crown material is melted and the molten material is molded in a lost wax mold. The molded material is crystallized to form the dental crown.

Abstract: This invention relates to the preparation of glass-ceramic articles in which potassium fluorrichterite and/or a related fluormica constitutes the predominant crystal phase(s). The precursor glasses can be crystallized in situ very rapidly and exhibit very little thermal deformation during the crystallization heat treatment. The base glasses are essentially free of Li.sub.2 O and consist essentially, expressed in terms of weight percent on the oxide basis, of:______________________________________ SiO.sub.2 61-70 Na.sub.2 O 0.5-3 BaO 0-3.5 Al.sub.2 O.sub.3 2.75-7 K.sub.2 O 2.5-5.5 P.sub.2 O.sub.5 0-2.5 MgO 11-16 Na.sub.2 O + K.sub.2 O <6.8 CaO 4.75-9 F 2-3.

Abstract: A biocompatible glass ceramic comprises, by weight, 7-16% MgO, 20-45% CaO, 41-50% SiO.sub.2, 8-30% P.sub.2 O.sub.5, 0-5% B.sub.2 O.sub.3, 0-5% F.sub.2, and 0-10% Al.sub.2 O.sub.3, and has a crystal structure where a number of fine crystals of apatite, wollastonite, and diopside are densely dispersed and interlace with one another in a glass phase. The glass ceramic is non-porous and has an increased mechanical strength of 2,000 Kg f/cm.sup.2 without degradation of the chemical bonding with the bone of the living body. The glass ceramic contains no alkali and is chemically stable in the living body. The glass ceramic is useful for replacement materials of tooth roots and crowns as well as bones.

Abstract: Disclosed is a glass-ceramic product having a chemical composition, as expressed in terms of oxides with the exception of F, in the weight range of 35 to 60% SiO.sub.2, 10 to 20% Al.sub.2 O.sub.3, 12 to 25% MgO, 5 to 15% K.sub.2 O and 4 to 15% F, containing no B.sub.2 O.sub.3, and containing 40 to 70% by weight of fluorophlogopite microcrystals. This glass-ceramic product has a flexural strength of not less than 1500 kgf/cm.sup.2, a heat resistance of about 1100.degree. C., excellent dielectric properties and good machinability, and is a material capable of extending the range of use of high performance ceramics.

Abstract: A fluoroaluminosilicate glass powder for dental glass ionomer cement, a surface of which is treated with a fluoride in an amount of from 0.01 to 5 parts by weight based on 100 parts by weight of the glass powder, is disclosed. The fluoroaluminosilicate glass powder of the invention is improved in not only physical properties such as crushing strength but also mixing workability without impairing the inherent characteristics thereof for the dental use.

Abstract: A fluoride-containing bioactive glass composition suitable for bulk implant prosthetic devices and coatings for prosthetic devices, the bioactive glass compositions selected from glass formulations containing, by mole 46.1% SiO.sub.2, 2.6% P.sub.2 O.sub.5, 26.9% CaO and 24.4% Na.sub.2 O and glass formulations containing, by mole, 52.1% SiO.sub.2, 23.8% CaO, 21.5% Na.sub.2 O, 2.6% P.sub.2 O.sub.5 wherein, respectively, 30 to 50 molar percent and 40 to 60 molar percent of the CaO is substituted with CaF.sub.2. These fluoride-containing bioactive glass materials demonstrate high resistance to demineralization in physiological fluids as well as extensive apatite formation which shows a predominance of crystalline apatite of mixed phase character.

Abstract: A dental crown formed of a dental crown material comprising crystallized glass containing 40 to 45% by weight of SiO.sub.2, 11 to 15% by weight of Al.sub.2 O.sub.3, 16 to 23% by weight of MgO, 6.5 to 8% by weight of F, 4.0 to 7.0% by weight of Na.sub.2 O, 5 to 9% by weight of Li.sub.2 O, not more than 1% by weight of TiO.sub.2, 2 to 4% by weight of ZrO.sub.2, and at least one oxide selected from the group consisting of Fe.sub.2 O.sub.3, MnO, CeO.sub.2 and NiO, and having a bending strength of at least 2000 Kg/cm.sup.2.

Abstract: This invention is directed to the production of inorganic crystalline fibers containing a minor amount of Mo0.sub.3 and/or W0.sub.3 and/or As.sub.2 0.sub.3 and wherein the predominant crystal phase is selected from the group of a fluormica, a fluoramphibole, canasite, potassium and/or sodium fluorrichterite, fluorapatite, and a lithium-containing, beta-spodumene-type crystal.

Abstract: High PbO-content glass in the optical range of flint and heavy flint glasses from the system SiO.sub.2 --PbO--M.sub.2 O wherein M.sub.2 O=alkali metal oxides, said glass having a minimum PbO content of 30 wt. % and a minimum M.sub.2 O content of 0.5 wt. %, are provided with enhanced chemical stability without loss of the desired optical position by replacing a portion of the SiO.sub.2 and PbO such that the glass contains 1.5-6 wt. % (TiO.sub.2 +ZrO.sub.2) and the ratio of TiO.sub.2 :ZrO.sub.2 is about 0.3-2.0.

Abstract: This invention provides a novel apatite composite ceramic useful for implants such as artificial dental root, artificial bone or the like. The apatite composite ceramic comprises an interconnected structure of fluorapatite phase and an at least partially crystallized biologically active glass phase, which ceramic is obtained by reaction-sintering at a sintering temperature of 700.degree.-1100.degree. C. at a pressure of at least atmospheric pressure a powder mixture of a synthetic hydroxyapatite (A) and a biologically active glass (B) containing fluoride ions and having a crystallization temperature below the sintering temperature in a weight ratio of A/B ranging from 60/40 to 30/70. The reaction-sintered material has excellent biological affinity and high mechanical strength.

Abstract: This invention relates to the production of opal glasses having a creamy-white tint which are suitable for forming culinary articles. The opacity is obtained through precipitation of fluorides, preferably NaF. The creamy-white tint results from the association of Fe.sub.2 O.sub.3 with TiO.sub.2 and/or As.sub.2 O.sub.3 and/or CeO.sub.2, with the addition of nitrates. The preferred composition of the final glass consists essentially, in weight percent, of:______________________________________ SiO.sub.2 70-73 Fe.sub.2 O.sub.3 0.1-0.25 Na.sub.2 O 10.5-13 TiO.sub.2 0.1-0.7 Fluorine 4-5.5 As.sub.2 O.sub.3 0.05-0.4 Al.sub.2 O.sub.3 6-9 CeO.sub.2 0-0.2 CaO 0.2-1.7 B.sub.2 O.sub.3 0.5-3 BaO 1-3 ______________________________________The starting composition contains NaNO.sub.3 in a proportion of 0.2-2 by weight, counted as Na.sub.2 O with regard to the glass, or an equivalent quantity of another alkali metal or alkaline earth metal nitrate.

Abstract: A low expansion glass comprising, all by weight, from 55 to 65% of SiO.sub.2, from 10 to 20% of Al.sub.2 O.sub.3, from 2 to 10% of B.sub.2 O.sub.3, from 3 to 10% of MgO, from 1 to 8% of CaO, from 2 to 10% of ZnO, from 0 to 4% of R.sub.2 O where R is an alkali metal atom, and from 0 to 4% of ZrO.sub.2.

Abstract: Glass fibers having the following constituents in the ranges of proportions indicated: SiO.sub.2, 57-70 wt. %; Al.sub.2 O.sub.3, 2-7 wt. %; CaO, 5-10 wt. %; MgO, 0-4 wt. %; B.sub.2 O.sub.3, 0-4.5 wt. %; and F, 0.5-4 wt. %; and wherein B.sub.2 O.sub.3 and F are present in amounts according to the relationship:3.ltoreq.B.sub.2 O.sub.3 +1.5 F.ltoreq.6.5and wherein the fibers also contain the alkali oxides Na.sub.2 O and K.sub.2 O, in amounts according to the relationship:16 wt. %<Na.sub.2 O+K.sub.2 O<20 wt. %.The glass fibers are used advantageously in thermal and/or acoustic insulation.

Abstract: This invention is directed to the production of glass-ceramic articles exhibiting great toughness, a modulus of rupture of at least 20,000 psi, and, in the form of bars having dimensions 5".times.0.5".times.0.1", sagging during the crystallization heat treatment of no more than 0.2" over a 4" span, and wherein potassium fluorrichterite constitutes the predominant crystal phase but wherein cristobalite is also present in an amount of at least 10% by volume. The inventive articles having an overall composition consisting essentially, in weight percent on the oxide basis, of:______________________________________ SiO.sub.2 65-69 Na.sub.2 O 1.5-3.3 Al.sub.2 O.sub.3 0.75-3.5 K.sub.2 O 4.2-6.0 MgO 13.5-17.5 BaO 0-2.5 CaO 3-4.8 P.sub.2 O.sub.5 `0-2.5 Li.sub.2 O 0.5-2.0 F 3.3-5.

Abstract: New, PbO-free glasses for cathode ray tubes are composed of (in % by weight) 50-52 SiO.sub.2 ; 0-3 Al.sub.2 O.sub.3 ; 1-1.7 Li.sub.2 O; 6.5-10.7 Na.sub.2 O; 0-4.5 K.sub.2 O; 0.4-1.4 F; 0-0.5 TiO.sub.2 ; 0.2-1.2 CeO.sub.2 ; 0-5 ZnO; 0-7.0 BaO; 15-22 SrO; and 6.3-10.3 ZrO.sub.2, and are characterized by a high protective effect against X-rays while having at the same time good resistance to acid and stability to radiation.

Abstract: A high strength glass-ceramic containing apatite and alkaline earth metal silicate (diopside/forsterite/akermanite) crystals having an excellent affinity for a living body and a process for producing the same are disclosed. The glass-ceramic is useful as an implant material such as an artificial dental root and an artificial bone.

Abstract: This invention is related to the production of machinable glass-ceramic articles which are essentially free from crystals having a mica structure and consist essentially, in weight percent, ofSiO.sub.2 : 24-28Al.sub.2 O.sub.3 : 9-20MgO: 12-28SrO: 0-11BaO: 0-14CuO: 0-5Ag.sub.2 O: 0-3.5NiO: 0-1.5Cr.sub.2 O.sub.3 : 0.5-6.

Abstract: This invention relates to the production of sodium fluoride opal glasses tinted in a shade lying in the range from "cream-like" to "beige" by an iron-sulfur system, the analyzed quantities of sulfur (S), sulfide ions (S.sup.-2), iron (Fe), and ferric ions (Fe.sup.+3) conforming to the following expressions:S.sup.-2 /S.gtoreq.0.1570.ltoreq.Fe.ltoreq.300 ppm0.05.ltoreq.Fe.sup.+3 /Fe.sup.+2 .ltoreq.1and 3.ltoreq.S.sup.-2 .ltoreq.160 ppm when the ZnO content is below 0.1%. The glasses are especially applicable for use in culinary ware.

Abstract: A method of introducing fluorine into glasses characterized by high fluorine retention and low processing costs which involves introducing the fluorine into the glass batch as a fluorine-containing frit comprising an inorganic fluoride and containing from about 6 to about 10 weight percent fluorine.

Abstract: These objects have been attained by providing highly absorbent lead containing alkali metal silicate glasses for cathode ray tube image screens, having a linear absorption coefficient .mu. of >30 cm.sup.-1 (0.6 .ANG.) and with a high resistance to discoloration by X-ray and electron radiation, comprises, in weight percent:______________________________________ SiO.sub.2 20-65% P.sub.2 O.sub.5 + B.sub.2 O.sub.3 + Al.sub.2 O.sub.3 0-30% Li.sub.2 O 0-5% Na.sub.2 O 0-10% K.sub.2 O 0-15% MgO + CaO + ZnO 0-15% SrO 0-20% BaO 0-40% PbO 5-60% ZrO.sub.2 0-10% CeO.sub.2 0.1-5% Other Components 0-20%.

Abstract: Electrochemical devices use a vitreous material having a general formulaxAaR.sub.b --yNmRc--zN.sub.n Y.sub.pwherein A is Si, Ge, P, S, B, Nb, As, V, Cr or Mo; R is O, S or Se; N is Li, Na, K or Ag and Y is I, Br, Cl, F, ClO.sub.4, CF.sub.3, SO.sub.3, SCN or SO.sub.4 with the proviso that the material contain at least two salts NY. Such materials have increased cationic conductivity.

Abstract: There is disclosed a highly crystalline glass-ceramic article exhibiting superior toughness against fracture propagation, a modulus of rupture in excess of 20,000 psi, a predominant crystal phase of potassium fluorrichterite, and having an overall composition consisting essentially ofSiO.sub.2 : 50-70CaO: 4-15MgO: 8-25F: 3-8Na.sub.2 O: 2-9K.sub.2 O: 2-12Li.sub.2 O: 0-3Al.sub.2 O.sub.3 : 0-7Canasite may be a secondary phase, but a crystal phase composed essentially of potassium fluorrichterite is preferred for dinnerware.

Abstract: The present invention is directed to the production of spontaneous opal glasses exhibiting softening points in excess of 750.degree. C., a coefficient of thermal expansion between about 60-90.times.10.sup.-7 /.degree.C., a crystal liquidus temperature below 1350.degree. C., a liquidus viscosity of at least 200 poises, and excellent resistance to attack by alkalies. Spherically-shaped glassy droplets constitute the opal phase in the glasses which consist essentially, in weight percent, of______________________________________ SiO.sub.2 50-72 Na.sub.2 O 0-8 CaO 10-40 Al.sub.2 O.sub.

Abstract: An alkali-free glass composition for a photoetching mask is described, which comprises, all by mol, 55 to 65% SiO.sub.2, 7 to 11% Al.sub.2 O.sub.3, 1 to 11% PbO, 7 to 20% CaO, 3 to 13% MgO, 3 to 13% ZnO, 0 to 3% ZrO.sub.2, 0 to 3% F.sub.2, 0 to 5% As.sub.2 O.sub.3, and 0 to 5% Sb.sub.2 O.sub.3. This glass is free from defects such as pinholes, has a relatively low coefficient of thermal expansion and contains no air bubbles, and a photoetching mask composed of the glass composition.

Abstract: The instant invention is directed to the production of highly crystalline glass-ceramic articles demonstrating high intrinsic mechanical strength and toughness containing crystals of canasite and/or agrellite and/or fedorite as the predominant crystal phase. The articles have overall compositions consisting essentially, expressed in terms of weight percent on the oxide basis, of about______________________________________ SiO.sub.2 45-75 CaO 8-30 F 3.5-12 Na.sub.2 O 3-15 K.sub.2 O 0-20 Na.sub.2 O + K.sub.2 O 5-25 B.sub.2 O.sub.3 0-6 Al.sub.2 O.sub.3 0-7 ZrO.sub.

Abstract: The bonding of smooth dental porcelain using glass-ionomer cement has hitherto been difficult. The present invention incorporates particles of an ion-leachable glass, particularly a calcium fluoroaluminosilicate glass, in the dental porcelain and improves the bonding properties.

Abstract: A calcium aluminum fluorosilicate glass powder is disclosed which has average particle size of at least 0.5 microns, and is characterized in that the calcium in the surface of the powder's particles is depleted so that the quotient of the atomic ratio Si/Ca at the surface of the particles and the atomic ratio Si/Ca in the core region of the particles is at least 2.0, more preferably at least 3.0 and most preferably at least 4.0. The glass powder may be prepared by surface treating calcium aluminum fluorosilicate glass powder particles with an acid which forms calcium salts, washing the calcium salts off the treated particles and drying the washed particles.The glass powder has utility in self-hardening glass ionomer cements, such as dental or bone cements. Cements formed from the glass powder exhibit reduced periods of water sensitivity, while permitting sufficient time for processing.

Abstract: A process is described for making a doped-silica ingot useful in the manufacture of optical fibers. At least a silicon compound and a titanium compound are decomposed in the flame of the induction plasma burner in the presence of a determined supply of hydrogen and are reacted with the oxygen contained in the burner feed gas and/or in the vector gas to form SiO.sub.2 and H.sub.2 O against a heat-stable support. As a result silica and titanium oxide are deposited on the support in the form of a homogeneous vitreous mass exhibiting a selected concentration of hydroxyl groups between 10 and 50 parts per million. Fluorine-doped silica is deposited radially in the same way on the resulting ingot. The resulting semifinished product is a cylinder consisting of a titanium-doped silica core, whose TiO.sub.2 concentration by weight is about 0.1 to 8%, covered by a sheath of fluorine-doped silica, whose fluorine concentration is about 0.1 to 3%.

Abstract: Alkali-resistant glass fibres for use as reinforcement in cementitious products are formed from a composition comprising, in weight percentages:______________________________________ SiO.sub.2 55 to 75% R.sub.2 O 11 to 23% ZrO.sub.2 6 to 22% Cr.sub.2 O.sub.3 0.1 to 1% Al.sub.2 O.sub.3 0.1 to 7% Rare earth oxides + TiO.sub.2 0.5 to 16% ______________________________________where R.sub.2 O is any one or more of Na.sub.2 O, K.sub.2 O or Li.sub.2 O, the content of TiO.sub.2 does not exceed 10%, and the total of the components recited above amounts to at least 88% by weight of the glass, the glass having been melted under non-oxidizing conditions such that all or a substantial proportion of the chromium in the glass is in the trivalent state.Cementitious products incorporating such fibres, e.g. in a proportion of 3 to 6 weight %, can be made using a Magnani-type asbestos cement machine or by a "spray-up" method.

Abstract: The instant invention is directed to faceplate glasses for television picture tubes which, because they are essentially free from MgO, have liquidus temperatures below 800.degree. C. Such glasses consist essentially, in weight percent on the oxide basis, of:______________________________________ SiO.sub.2 58-65 Al.sub.2 O.sub.3 1-3 CaO 1-4 SrO 6-12 BaO 2-9 PbO 1-3 Na.sub.2 O 5-9 K.sub.2 O 5-12 Na.sub.2 O + K.sub.2 O 14-18 TiO.sub.2 0.3-1 CeO.sub.2 0.05-0.

Abstract: Alkali-resistant glass fibres, in the form of continuous-filament for use as reinforcement in cementitious products, or in the form of glass wool, are given enhanced alkali resistance by the incorporation of ThO.sub.2. The fibres are formed from a glass composition comprising, in weight percentages:______________________________________ SiO.sub.2 50 to 75% ThO.sub.2 + ZrO.sub.2 5 to 30% with ThO.sub.2 at least 0.4% R.sub.2 O 0 to 25% R'O 0 to 40% R.sub.2 O + R'O 10 to 40% Rare earth oxides 0 to 20% ______________________________________the content of ThO.sub.2 being at least 1% when the content of ZrO.sub.2 is less than 6% but not exceeding 9.5% when ZrO.sub.2 exceeds 8%, where R.sub.2 O represents Na.sub.2 O, K.sub.2 O or LiO.sub.2, with K.sub.2 O not exceeding 10% and Li.sub.2 O not exceeding 5% and R'O represents one or more of MgO, CaO, SrO, BaO, ZnO and MnO.

Abstract: A flux composition for ceramic color, containing no harmful heavy metal such as lead, cadmium, chromium, etc. is provided.The flux composition consists mainly of 30 to 45% of SiO.sub.2, 0 to 5% of TiO.sub.2, 4 to 10% of ZrO.sub.2, 13 to 18% of B.sub.2 O.sub.3, 18 to 23% of ZnO, 0 to 3% of CaO, 12 to 15% of the total of two or three kinds of R.sub.2 O selected from Na.sub.2 O, K.sub.2 O and Li.sub.2 O, 4 to 10% of fluorine and 0 to 5% of tin oxide (% being all by weight).The composition uses no lead which has been indispensable for lower melting glasses, and exhibits superior performances difficult to afford according to conventional lower melting lead-free fluxes.