Abstract: A process is described for the preparation of shaped translucent lithium disilicate glass ceramic products which are characterized by high strength and good chemical stability and may be processed by pressing in the plastic state or milling to finished glass ceramic products which may be used in particular as dental restorations.

Abstract: The invention provides a method to transform large quantities of waste glass into useful ceramic products by a low-cost manufacturing process. The major steps of the method consist of dry preparation of glass powder, granulation with a non-aqueous organic binder system, dry pressing with adequate green strength, and firing at low temperatures. Water and clay are not required in the processing, which eliminates problems that were encountered in the past. Only one firing step is needed with a low peak firing temperature of about 750° C. The method conserves energy and natural resources compared to clay-based traditional ceramic manufacturing. High-quality impervious ceramic products with only a small amount of porosity can be produced by the invention.

Abstract: A living tissue replacement of crystallized glass having bioaffinity and mechanical strength is briefly obtained simply by pressure molding or machining without using a special equipment. A glass material having a softening point below its crystallization temperature and exhibiting viscous flow at temperatures below its melting point is heated at a temperature above its Tg and pressed at the temperature to mold to a desired shape, thereby manufacturing a living tissue replacement such as a dental crown. Molding can be done under a pressure of up to 20 MPa.

Abstract: A glass-ceramic which is substantially and desirably totally transparent, and which contains a willemite predominant crystal phase within the ternary Mg2SiO4—Zn2SiO4—Li4SiO4 system. The glass-ceramic is formed from precursor glasses having the following compositions, in weight percent on an oxide basis, of 25-60 SiO2, 4-20 Al2O3, 20-55 ZnO, 0-12 MgO, 0-18 K2O, 0-12 Na2O, 0-30 GeO2, with the condition that &Sgr;K2O+Na2O≧5. The glass-ceramic may be doped with up to 1 wt. % Cr2O3 to impart optical activity thereto.

Abstract: A glass-ceramic which is substantially and desirably totally transparent, and which contains a predominant crystal phase of forsterite. The glass-ceramic is formed from precursor glasses having the following compositions, in weight percent on an oxide basis: SiO2 30-60; Al2O3 10-25; MgO 13-30; K2O 8-20; TiO2 0-10; and GeO2 0-25. The glass-ceramic may be doped with up to 1 wt. % chromium oxide to impart optical activity thereto.

Abstract: A gain medium for use in optical amplifiers or laser oscillators is disclosed. The gain medium includes a transition-metal doped glass-ceramic material having a crystal phase and a glass phase. The crystal phase is formed in situ in the glass phase, with the transition metal ions preferentially partitioning into the crystals from the glass phase. The crystals so formed have a size of less than 50 nm, and the transition metal ions within them are capable of lasing at a wavelength within the range of about 900 to 3000 nm. Also disclosed are amplifier and laser oscillator configurations, where the glass-ceramic gain medium is applied in a variety of configurations. Also disclosed is a method of amplifying a signal of light wherein the glass-ceramic gain medium is pumped with light energy so as to excite the transition metal ions, and the signal of light is transmitted through the gain medium while the transition metal ions are excited, whereby the signal of light is amplified.

Abstract: Enclosed are crystallized glasses suitable for a substrate for an information recording medium such as a magnetic disc, optical disc, or optomagnetic disc, a substrate for information recording medium using such a crystallized glass substrate, and an information recording medium using such a substrate for information recording medium. The crystallized glasses are capable of providing a glass substrate having a high Young's modulus, as well as excellent mechanical strength, surface flatness, and heat resistance and having an excellent surface smoothness upon polishing. Glass substrate having an excellent surface smoothness using such a crystallized glass are also disclosed.

Abstract: Long-lasting phosphorescent glasses and glass-ceramics have a composition containing 30-65 mol % SiO2 and 20-50 mol % ZnO as basic ingredients and may also contain, as an activator or an auxiliary activator, 0-5 mol % LnxOy where L n is an element or elements selected from the group consisting of Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Mn. In one aspect of the invention, long-lasting phosphorescent glass-ceramics have a composition containing 30-70 mol % SiO2, 5-40 mol % MgO and 10-55 mol % MO where M is an element or elements selected from the group consisting of Ca, Sr and Ba as basic ingredients. The composition further includes 0.0001-5 mol % Eu2O3 as an activator and 0.0001-6 mol % Ln2O3 as an auxiliary activator where Ln is an element or elements selected from the group consisting of Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.

Abstract: A crystallized glass has a main crystal phase of petalite (Li2O.Al2O3.8SiO2) phase and lithium disilicate (Li2O.2SiO2) phase and an auxiliary crystal phase of &agr;-quartz phase. In the crystallized glass, a crystal phase composition measured by Rietvelt method is as follows: 20 wt %≦petalite phase≦40 wt %, 25 wt %≦lithium disilicate phase≦45 wt %, and 10 wt %≦&agr;-quartz phase≦25 wt %.

Abstract: Provided is a crystalline glass composition for use in a circuit board that can be sintered at a temperature of 1100° C. and is endowed with favorable characteristics such as a relative dielectric constant of as low as ½ and a thermal expansion coefficient of as high as 12 ppm/° C. as an electrical insulating insulator for use in a circuit board. The crystalline glass composition contains SiO2, MgO and CaO, the composition ratio of SiO2, MgO and CaO in % by weight falling within an area surrounded by the lines connecting the points A (25, 45, 30), B (25, 0, 75), C (44, 0, 56), D (44, 22, 34), E (40, 19, 41) and F (29, 40, 31) in a ternary phase diagram wherein at least one melwinite, monticellite or calcium silicate crystalline phase is deposited by heat-treating the composition. A ceramic powder having a thermal expansion coefficient of about 6.0 ppm/C or more is sometimes added in the powder comprising the glass composition.

Abstract: A crystallized glass has a main crystal phase of &agr;-quartz (SiO2) and lithium disilicate (Li2·2SiO2) and has a thermal expansion coefficient of (90˜130)×10−7/K at −50° C.˜70° C. The crystallized glass mentioned above, has a following chemical composition; 70 wt %≦SiO2≦80 wt %, 5 wt %≦Al2O3≦9 wt %, 7 wt %≦Li2O≦10 wt %, 1 wt %≦P2O5≦3 wt %, 0 wt %≦K2O≦3 wt %, 0 wt %≦CaO≦3 wt %, 0 wt %≦BaO≦4 wt %, 0 wt %≦ZnO≦4 wt %, 0 wt %≦Sb2O3≦1 wt %, 0 wt %≦ZrO2≦6 wt %, 0 wt %≦Nb2O5≦6 wt %, 0 wt %≦SnO2≦4 wt %, 0 wt %≦MoO3≦3 wt %, 0.7 wt %≦(Nb2O5+SnO2+MoO3)≦6 wt %.

Abstract: Dielectric ceramics comprising a diopside oxide crystal phase, at least one kind of crystal phase selected from the group consisting of a quartz crystal phase and a composite oxide crystal phase containing Ti and Mg or Zn, and a glass phase of an amount of not larger than 30% by weight, said dielectric ceramics having a coefficient of thermal expansion of not smaller than 5.5 ppm/° C. at room temperature to 400° C. and a dielectric loss of not larger than 30×10−4 at 60 to 77 GHz. The ceramics can be obtained by the co-firing with a low-resistance metal such as copper or silver, and can be advantageously used for the production of wiring boards to which the signals of particularly high frequencies are applied. The ceramics has a large coefficient of thermal expansion which can be brought close to the coefficient of thermal expansion of the semiconductor element such as of GaAs or of the printed board.

Abstract: A glass-ceramic substrate for a magnetic disk suitable for use as a contact recording type magnetic disk includes alpha-cristobalite (alpha-SiO2) and lithium disilicate (Li2O·2SiO2) as main crystal phases. The ratio of alpha-cristobalite/lithium disilicate is within a range from 0.20 to less than 0.25, a grain diameter of crystal grains is within a range from 0.1 &mgr;m to 1.0 &mgr;m, surface roughness (Ra) of the substrate after polishing is within a range from 2 Å to 9 Å.

Abstract: A glass-ceramic substrate for an information storage medium includes, as a predominant crystal phase, lithium disilicate (Li2O·2SiO2) or a combination of lithium disilicate and at least one crystal phase selected from the group consisting of &agr;-quartz (&agr;-SiO2), &agr;-quartz solid solution (&agr;-SiO2 solid solution), &agr;-cristobalite (&agr;-SiO2) and &agr;-cristobalite solid solution (&agr;-SiO2 solid solution). This substrate has Young's modulus (GPa)/specific gravity of 37 or over, surface roughness Ra (arithmetic mean roughness) of 5.0 Å or below, a coefficient of thermal expansion within a temperature range from −50° C. to +70° C. which ranges from +65×10−7/° C. to +130×10−7/° C. and bending strength of 400 MPa or over.

Abstract: The present invention is directed at a glass-ceramic having high strength and toughness and containing miserite as a predominant crystal phase. The glass-ceramic has a composition calculated in terms of a weight percent on the oxide basis comprising 40-68% SiO.sub.2, 12-35% CaO, 8-20% CaF.sub.2, 4-10.5% K.sub.2 O, 0-5% Al.sub.2 O.sub.3, 0-5% B.sub.2 O.sub.3, 0-15% P.sub.2 O.sub.5, 0-4% R.sub.2 O.sub.3, wherein R represents Y.sup.3+ and rare earth metals in the lanthanide series, and 0-5% of optional constituents selected from the group consisting of MgO, SrO, BaO, Na.sub.2 O, Nb.sub.2 O.sub.5, ZrO.sub.2, and ZnO, and 0-10% of optional constituents selected from the group consisting of Nb.sub.2 O.sub.5 and TiO.sub.2 and 0-2% Li.sub.2 O as an optional constituent. The glass-ceramic may contain secondary phases of cristobalite (SiO.sub.2), fluorite (CaF.sub.2), xonotlite (Ca.sub.6 Si.sub.6 O.sub.17 F.sub.2), and fluorapatite (Ca.sub.5 (PO.sub.4).sub.

Abstract: Nanocrystalline glass-ceramic materials based on .beta.-quartz solid solution Mg-rich phases formed in the system SiO.sub.2 --Al.sub.2 O.sub.3 --MgO--Li.sub.2 O--TiO.sub.2 (ZnO, BaO, ZrO.sub.2, P.sub.2 O.sub.5). Articles made from the glass-ceramic materials exhibit a crystal phase assemblage of a fine-grained, microstructure which is predominantly .beta.-quartz, and at least one additional phase selected from enstatite and spinel, and having a composition which consists essentially of, in weight percent on the oxide basis, 40-65% SiO.sub.2, 10-14% Al.sub.2 O.sub.3, 5-25% MgO, 0.5-4% Li.sub.2 O, 5-15% TiO.sub.2, and up to 5% ZrO.sub.2, such that the sum of (TiO.sub.2 +ZrO.sub.2) is at least 9% The glass-ceramide article is particularly useful for memory disk applications.

Abstract: The insulated board of this invention is a sintered body of a complex oxide containing Si, Al, Mg, Zn and B as constituent elements. This sintered body contains a spinel crystal phase containing at least ZnO and Al.sub.2 O.sub.3 and a quartz crystal phase. Since the amorphous phase does not substantially contain ZnO, Al.sub.2 O.sub.3 or MgO, the sintered body has a low dielectric loss of 30.times.10.sup.-4 or below and a dielectric constant of 30 or below at a frequency of 15 to 20 GHz. As a result, by forming a wiring layer on the surface or the inside of the insulated board of this invention, the insulated board can transmit high frequency signals at a low loss as the wiring layer.

Abstract: An electrochemical device for separating oxygen from an oxygen-containing gas comprises a plurality of planar ion-conductive solid electrolyte plates and electrically-conductive gas-impermeable interconnects assembled in a multi-cell stack. Electrically-conductive anode and cathode material is applied to opposite sides of each electrolyte plate. A gas-tight anode seal is bonded between the anode side of each electrolyte plate and the anode side of the adjacent interconnect. A biasing electrode, applied to the anode side of each electrolyte plate between the anode seal and the edge of the anode, eliminates anode seal failure by minimizing the electrical potential across the seal. The seal potential is maintained below about 40 mV and preferably below about 25 mV. A gas-tight seal is applied between the cathode sides of each electrolyte plate and the adjacent interconnect such that the anode and cathode seals are radially offset on opposite sides of the plate.

Abstract: A magnetic disc substrate is provided, which includes a magnetic disc substrate body made of glass and is characterized in that a metal element capable of absorbing light is present in at least a surface portion of the magnetic disc substrate body, and a texture is formed on a surface of the magnetic disc substrate body. Ions of the metal element are dispersed in the surface portion of the magnetic disc substrate, or the metal element is contained in a composition of the glass constituting the magnetic disc substrate in the form of an oxide. The glass is preferably a crystallized glass a Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 based crystallized glass, which particularly preferably contains 65 to 85 wt % of SiO.sub.2, 8 to 15 wt % of Li.sub.2 O, 2 to 8 wt % of Al.sub.2 O.sub.3, 1 to 5 wt % of P.sub.2 O.sub.5 and 1 to 10 wt % of ZrO.sub.2 and has lithium disilicate (Li.sub.2 O.multidot.2SiO.sub.2) as a main crystalline phase.

Abstract: A glass-ceramic substrate for a magnetic head has as its predominant crystal phase a mixed crystal of lithium disilicate (Li.sub.2 O.2SiO.sub.2) and either or both of .alpha.-quartz (.alpha.-SiO.sub.2) and .alpha.-cristobalite (.alpha.-SiO.sub.2), the .alpha.-quartz has a globular grain structure each globular crystral grain being made of aggregated particles and having a grain diameter within a range from 0.1 .mu.m to 3.0 .mu.m, the .alpha.-cristobalite has a globular grain structure each globular grain having a grain diamter within a range from 0.1 .mu.m to 1.0 .mu.m, and surface roughness (Ra) of the glass-ceramic substrate after polishing is within a range from 5 .ANG. to 50 .ANG..

Abstract: There are provided glass-ceramics having a high lithium ion conductivity which include in mol %:______________________________________ P.sub.2 O.sub.5 35-40% SiO.sub.2 0-15% GeO.sub.2 + TiO.sub.2 25-50% in which GeO.sub.2 0 <-50% and TiO.sub.2 0-<50% ZrO.sub.2 0-10% M.sub.2 O.sub.3 (where M is one or 0.5-15% two selected from the group consisting of Al and Ga) Li.sub.2 O 10-25% ______________________________________and containing Li.sub.1+X M.sub.X (Ge.sub.1-Y Ti.sub.Y).sub.2-X (PO.sub.4).sub.3 (where 0<X<0.8 and 0<Y<1.0) as a main crystal phase. There are also provided glass-ceramics having a high lithium ion conductivity which include in mol % ______________________________________ P.sub.2 O.sub.5 32-40% SiO.sub.2 7-14% TiO.sub.2 38-45% Li.sub.2 O 10-18% ______________________________________and containing Li.sub.1+X Ti.sub.2 Si.sub.X P.sub.3-X O .sub.12 (where X>0) as a main crystal phase.

Abstract: High magnesium-content magnesium aluminosilicate glasses are used to form green tape compositions that are fired stepwise, i.e., first to about 500.degree. C. to remove organic materials, then to a temperature 10-30.degree. C. above the glass transition temperature for a time sufficient to nucleate the glass, and finally to a higher temperature near but below the softening temperature to complete crystallization of the glass. The resultant glass-ceramic may include substantial amounts of the forsterite crystalline phase. Multilayer ceramic printed circuit boards are made that are useful for high frequency, microwave applications. The fired high magnesium oxide content glasses have low dielectric constant and low dissipation loss factors, and they have a thermal coefficient of expansion that is compatible with metal or ceramic support substrates that impart mechanical strength to the printed circuit boards and that are thermally conductive. The boards are compatible with gallium arsenide devices.

Abstract: A glass-ceramic substrate for a magnetic disk suitable for use as a contact recording type magnetic disk includes alpha-cristobalite (alpha-SiO.sub.2) and lithium disilicate (Li.sub.2.SiO.sub.2) as main crystal phases. The ratio of alpha-cristobalite/lithium disilicate is within a range from 0.25 to 0.35, a grain diameter of crystal grains is within a range from 0.1 .mu.m to 1.0 .mu.m, surface roughness (Ra) of the substrate after polishing is within a range from 2 .ANG. to 10 .ANG. and abrasion resistance index (Aa) of the substrate is within a range from 5 to 15.

Abstract: A bioactive ceramic composition including 47 to 51% SiO.sub.2, 23 to 25% CaO, 23 to 25% Na.sub.2 O and 0 to 6% P.sub.2 O.sub.5, the bioactive ceramic having a bioacitivity level such that the composition forms at least a thin layer of HCA within about 30 hours of implantation into a patient. The bioactive ceramic composition having a crystallinity of 34 to 60 volume percent and a crystalline phase of 1Na.sub.2 O.2CaO.3SiO.sub.2.

Abstract: High magnesium-content magnesium aluminosilicate glasses are used to form green tape compositions that are fired stepwise, i.e., first to about 500.degree. C. to remove organic materials, then to a temperature 10-30.degree. C. above the glass transition temperature for a time sufficient to nucleate the glass, and finally to a higher temperature near but below the softening temperature to complete crystallization of the glass. The resultant glass-ceramic may include substantial amounts of the forsterite crystalline phase. Multilayer ceramic printed circuit boards are made that are useful for high frequency, microwave applications. The fired high magnesium oxide content glasses have low dielectric constant and low dissipation loss factors, and they have a thermal coefficient of expansion that is compatible with metal or ceramic support substrates that impart mechanical strength to the printed circuit boards and that are thermally conductive. The boards are compatible with gallium arsenide devices.

Abstract: The present invention relates to a transparent glass-ceramic article which includes a glass matrix and a crystalline phase of apatite crystals in the glass matrix. The present invention further relates to a method of producing the transparent glass-ceramic article.

Abstract: A method of calcining kaolin, comprising the steps of:a) producing a clay slurry comprised of water and kaolin clay of a specific particle size;b) mixing a water insoluble potassium containing glass forming compound into the clay slurry in an amount wherein the potassium content of the slurry is equal to about 1% by weight of the kaolin clay in the slurry;c) removing sufficient water from the slurry to form a material having an extrudable consistency;d) extruding the material into elongated shapes;e) heating the shapes by continuously moving them through a furnace having a zone, wherein the material is exposed to temperatures of at least 2700.degree. C. for at least 30 minutes.

Abstract: A method of preparing a membrane is disclosed, which includes the step of impregnating an inorganic proton-conductive material into matrices of porous ceramic membranes. The inorganic proton-conductive material may include an inorganic poly-acid, such as polyphosphates or poly-antimonic acids. The inorganic proton conducting material may include Zr (zirconium).The invention further provides a porous ceramic membrane, which includes an inorganic proton-conductive material impregnated into a porous ceramic membrane matrix.The ceramic membrane may be a tubular ceramic membrane, which includes pores with a diameter of at least 0.3 .mu.m, and depositions of electroconductive coatings onto its surface on which externally applied potential can be applied as a driving force for hydrogen separation.

Abstract: A ZrO.sub.2 -containing glass ceramic is described, the main crystalline phase of which is formed by ZrO.sub.2 and which has at least one further crystalline phase, and which can be used in particular in dentistry.

Abstract: A low temperature firing glass-ceramic substrate comprising a borosilicate glass, .alpha.-alumina, .gamma.-alumina, and mullite crystals crystallized out in a dispersed form from the borosilicate glass and the .gamma.-alumina, and a production process of the substrate. It is an object of this invention to provide a glass-ceramic substrate, which is low in dielectric constant and dielectric loss and high in strength and is useful for multilayer wiring.

Abstract: A glass-ceramic composite which has forsterite in an amount of 40 to 60% by weight is included in crystallized glass having a coefficient of thermal expansion of 100.degree. to 200.times.10.sup.-7 /.degree.C. is used to configure a package, to the electrode pads of which a quartz crystal is directly soldered, without any supporting material. A quartz crystal piece is included within a flat package that use a glass-ceramic composite according to the present invention, thereby greatly limiting the variation in resonance characteristics with respect to heat treating done when the package is sealed, as compared to previous packages.

Abstract: A glass composition for magnetic disk substrates comprising as oxides: from 66 to 80% by weight of SiO.sub.2, from 5 to 15% by weight of Al.sub.2 O.sub.3, from 3 to 8.5% by weight of Li.sub.2 O, from 0 to 3% by weight of Na.sub.2 O, from 0 to 3% by weight of K.sub.2 O, from 0.5 to 8% by weight of TiO.sub.2, from 3.5 to 8% by weight of ZrO.sub.2, from 0.5 to 3% by weight of P.sub.2 O.sub.5, from 0 to 2% by weight of Sb.sub.2 O.sub.3, and from 0 to 2% by weight of As.sub.2 O.sub.3, and having a theoretical optical basicity of 0.548 or less; a magnetic disk substrate which is prepared by forming and polishing the above glass composition, followed by chemically strengthening the polished substrate by ion exchange or by forming, heat treating, and polishing the above composition and contains Li.sub.2 O.2SiO.sub.2 and/or spodumene as the main crystalline phase.

Abstract: A novel Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 series glass-ceramics for magnetic disc substrate use, which can prevent deformation of the substrate at a large temperature change and provide a strong, small and compact magnetic disc substrate without trouble and much reading and/or writing informations on the smoothened surface of the substrate, is provided. The glass-ceramics has a main crystal phase of lithium disilicate (Li.sub.2 O.2SiO.sub.2) phase, the peak intensity I of cristobalite phase (CRI) of at least 20 but not more than 50 when the peak intensity of I of lithium disilicate (L2S) phase measured by an X-ray diffraction analysis is taken as 100, and containing 1.0-3.0 parts by weight of Cr.sub.2 O.sub.3 and 1.0-3.0 parts by weight of MnO when the sum of metal oxides other than Cr.sub.2 O.sub.3 and MnO is taken as 100 parts by weight.

Abstract: A glass-ceramic substrate for a magnetic disk suitable for use as a contact recording type magnetic disk includes alpha-cristobalite (alpha-SiO.sub.2) and lithium disilicate (Li.sub.2 O . 2SiO.sub.2) as main crystal phases. The ratio of alpha-cristobalite/lithium disilicate is within a range from 0.25 to 0.35, a grain diameter of crystal grains is within a range from 0.1 .mu.m to 1.0 .mu.m, surface roughness (Ra) of the substrate after polishing is within a range from 2 .ANG. to 10 .ANG. and abrasion resistance index (Aa) of the substrate is within a range from 5 to 15.

Abstract: The present invention relates to a process of forming ceramic tiles having the appearance of tiles produced from clays. The process includes melting a material to form a glass melt, treating the glass melt to produce a solid glass product, grinding the solid glass product to produce glass particles having a particle size of less than 200 microns, mixing the glass particles with a first additive to form a glass powder mixture having a composition of 55 to 99 wt. % glass particles and 45-1 wt. % first additive, forming the glass powder mixture into tiles by dry pressing, where the tiles have a primary crystalline phase selected from the group consisting of nepheline, diopside, anorthite, wollastonite, melilite, merwinite, spinel, akermanite, gehlenite, crystalline phases based on iron substitutions in the crystalline phase, and mixtures thereof.

Abstract: A colored ceramic composition comprising, as inorganic components, from 5 to 40 wt % of a colored heat resistant pigment powder, from 60 to 95 wt % of a powder of zinc-containing glass and from 0 to 10 wt % of a refractory filler powder, wherein said glass consists essentially of the following components:______________________________________ SiO.sub.2 30 to 60 wt % ZnO 8 to 60 wt % B.sub.2 O.sub.3 0 to 5 wt % Li.sub.2 O 0 to 20 wt % Na.sub.2 O 0 to 20 wt % K.sub.2 O 0 to 20 wt % Li.sub.2 O + Na.sub.2 O + K.sub.2 O 0.1 to 20 wt % MgO + CaO + SrO + BaO 0 to 20 wt % Bi.sub.2 O.sub.3 0 to 40 wt % TiO.sub.2 0 to 10 wt % F 0 to 5 wt %.

Abstract: A crystallized glass for a substrate of an information-recording disk, which has been obtained by melting a glass forming material consisting essentially of, in wt. % as oxide, 55 to 85% of SiO.sub.2, 5 to 20% of Li.sub.2 O, 0 to 10% of K.sub.2 O+Na.sub.2 O, 0 to 10% of MgO, 0 to 20% of CaO, 0 to 10% of SrO, 0 to 10% of BaO, 0 to 10% of ZnO, 0 to 10% of Al.sub.2 O.sub.3, 0 to 15% of B.sub.2 O.sub.3, 0 to 6% of P.sub.2 O.sub.5, 0 to 3% of TiO.sub.2, 0 to 3% of ZrO.sub.2, 0 to 3% of SnO.sub.2 and 0 to 1% of As.sub.2 O.sub.3 +Sb.sub.2 O.sub.3, 0.1 to 10 wt. % of F and 0.1 to 20 wt. % of Cl, molding, vitrifying and crystallizing the material, and which contains at least 0.05% by weight of chlorine after crystallization. The glass forming material may further contain 0 to 10% of Fe.sub.2 O.sub.3, 0 to 10% of Cr.sub.2 O.sub.3, 0 to 10% of NiO, 0 to 10% of V.sub.2 O.sub.5, 0 to 10% of CuO, 0 to 10% of MnO.sub.2, 0 to 10% of MoO.sub.3, the total of Fe.sub.2 O.sub.3 +Cr.sub.2 O.sub.3 +NiO+V.sub.2 O.sub.5 +CuO+MnO.sub.

Abstract: A glass composition which is essentially free of lead and cadmium includes 30 to 70 wt % SiO.sub.2, 1 to 25 wt % B.sub.2 O.sub.3, 0 to 10 wt % Al.sub.2 O.sub.3, 0 to 5 wt % Bi.sub.2 O.sub.3, 0.1 to 30 wt % CoO, 0.1 to 20 wt % ZnO, 1 to 30 wt % total of at least one of Li.sub.2 O, Na.sub.2 O or K.sub.2 O, up to 10 wt % ZrO.sub.2 and other optional ingredients. The glass composition can be used as a blue colored on-glaze enamel which relies upon the presence of Co.sup.2+ in a network-forming position in the glass to produce the blue color, with oxygen donors such as ZnO.sub.2, alkaline earth oxides and alkali oxides increasing the amount of cobalt occupying network-forming positions, and ZrO.sub.2 to provide chemical durability.

Abstract: This invention is directed at the makings of glass-ceramic which is uniquely suited for use as a disc substrate for utilization in a magnetic memory storage device. The glass ceramic material exhibits a crystal phase assemblage comprised predominately of a mixture of lithium disilicate and tridymite which are uniformly interspersed with a residual glass phase and form an interlocked microstructure with the glass. The composition consists essentially, expressed in terms of weight percent on the oxide basis, of 75-95% SiO.sub.2, 3-15% Li.sub.2 O, 0-6% Al.sub.2 O.sub.3, and 0-6% K.sub.2 O. The nucleating agent for this glass-ceramic is selected from the group consisting of 0-0.1% Pd and 0-5% P.sub.2 O.sub.5 ; however if Pd is absent the P.sub.2 O.sub.5 amount is at least 0.5% and if P.sub.2 O.sub.5 is absent then the Pd amount is at least 0.005%. Additionally, up to 15% of optional ingredients may be added, including, B.sub.2 O.sub.3, Na.sub.2 O, ZnO, MgO, CaO, SrO, ZrO.sub.2, TiO.sub.2, F, Sb.sub.2 O.sub.3, As.

Abstract: A glass-ceramic magnetic disk substrate which is prepared by forming, then heat treating, and then polishing a crystallizable glass composition comprising, expressed in terms of weight percent on the oxide basis: from 20 to 45% SiO.sub.2 ; from 25 to 45% Al.sub.2 O.sub.3 ; from 10 to 25% B.sub.2 O.sub.3 ; from 2 to 12% MgO; from 0.5 to 8% TiO.sub.2 ; from 0.5 to 5% P.sub.2 O.sub.5 ; from 0 to 2% Li.sub.2 O; from 0 to 2% Na.sub.2 O; from 0 to 3% K.sub.2 O; wherein, the total of the contents of Li.sub.2 O, Na.sub.2 O and K.sub.2 O is from 0 to 5%; and wherein the magnetic disk substrate comprises a main crystalline phase consisting of at least one member selected from the group consisting of mullite and aluminum borate crystals. The glass composition can easily be formed and the disk substrate can easily be polished, has excellent mechanical strength, surface flatness, surface smoothness, chemical durability, and heat resistance, and shows no deterioration of magnetic film characteristics by alkali migration.

Abstract: A ceramic mixture of a crystallizable ZnO--MgO--B.sub.2 O.sub.3 --SiO.sub.2 glass mixed with a non-crystallizing lead-based glass and one or more oxide fillers forms a fired ceramic that has a TCE compatible with that of kovar. Green tapes made from the ceramic mixture aligned with a kovar support substrate when fired have excellent dielectric and low loss properties.

Abstract: A ZrO.sub.2 -containing glass ceramic is described, the main crystalline phase of which is formed by ZrO.sub.2 and which has at least one further crystalline phase, and which can be used in particular in dentistry.

Abstract: A glass composition for magnetic disk substrates comprising as oxides: from 66 to 80% by weight of SiO.sub.2, from 5 to 15% by weight of Al.sub.2 O.sub.3, from 3 to 8.5% by weight of Li.sub.2 O, from 0 to 3% by weight of Na.sub.2 O, from 0 to 3% by weight of K.sub.2 O, from 0.5 to 8% by weight of TiO.sub.2, from 3.5 to 8% by weight of ZrO.sub.2, from 0.5 to 3% by weight of P.sub.2 O.sub.5, from 0 to 2% by weight of Sb.sub.2 O.sub.3, and from 0 to 2% by weight of As.sub.2 O.sub.3, and having a theoretical optical basicity of 0.548 or less; a magnetic disk substrate which is prepared by forming and polishing the above glass composition, followed by chemically strengthening the polished substrate by ion exchange or by forming, heat treating, and polishing the above composition and contains Li.sub.2 O.multidot.2SiO.sub.2 and/or spodumene as the main crystalline phase.

Abstract: Alkali-zinc-silicate glass ceramics and glasses are described which have a linear thermal expansion coefficient in the range from 8.0 to 18.7.times.10.sup.-6 K.sup.-1, an excellent chemical resistance and other advantageous optical properties and can be used in particular as dental material.

Abstract: The invention relates to a porcelain with a transparency and strength properties of a hard porcelain, characterized by a phosphate-containing glass phase as well as the predominance of unreacted quartz bodies [sic; grains] in the matrix. The invention relates to a porcelain batch composition as well as to a method for the manufacture of the porcelain.

Abstract: A ceramic circuit board comprises a ceramic substrate having a glaze film formed thereon, the glaze film being overlaid with a functional thin film such as a ferromagnetic film serving as a magnetic sensor, for example. The ceramic substrate is made of a low-firing ceramic material such as a glass ceramic material which can be sintered at a temperature below 1000.degree. C. by co-firing with the glaze film. Preferably, the ceramic substrate has a recess on its top surface, and the glaze film is embedded in the recess such that the difference in level between the ceramic substrate and the glaze film is 20 .mu.m or less.

Abstract: A magnetic disk substrate is made of a glass-ceramic having crystal phases of lithium disilicate (Li.sub.2 O.2SiO.sub.2) and alpha-quartz (SiO.sub.2). The crystal phase of alpha-quartz is formed of grown crystal grains each having a globular grain structure made of aggregated particles. Each globular grain has a size within a range from 0.3 .mu.m to 3 .mu.m. Surface roughness (Ra) of a polished surface of the magnetic disk substrate is within a range from 15 .ANG. to 50 .ANG. which is an optimum range of surface roughness for the magnetic disk.

Abstract: A glass-ceramic article, such as an information disk substrate, and a method of making the article. The glass-ceramic has Mg-rich pyroxene and spinel-type predominate crystal phases and a composition at least 92% of which consists essentially of 35-60% SiO.sub.2, 10-30% Al.sub.2 O.sub.3, 12-30% MgO, 0-10% ZnO, 5-20% TiO.sub.2, and 0-8% NiO.

Abstract: A novel crystallizable glass composition for producing a novel low temperature co-fired glass-ceramic substrate having patterns of a low electrical-resistance conductor such as Ag, Ag-Pd, Au, and/or Cu is obtained. Being subjected to a firing process, the novel crystallizable glass can precipitate mullite as main crystalline phase, and at least one subordinate crystalline phase among forsterite, spinel, sapphirine, and similar crystalline phases. And also, the novel crystallizable glass powder composition with a inorganic filler as external additive having a minimum of 1.4 m.sup.2 /g. of mean specific surface area can precipitate both mullite phase and cordierite phase. The mixing weight ratio of the filler to the crystallizable glass powder is from 0.1/99.9 to 20/80. The crystallizable glass composition comprises following oxide components expressed in terms of percent by weight on the oxide basis; 45-58% of Al.sub.2 O.sub.3, 20-35% of SiO.sub.2, 5-15% of B.sub.2 O.sub.

Abstract: Novel oxide coatings which can be conveniently applied to reinforcing fibers such as silicon carbide fibers, and which when introduced as a fiber coating into fiber reinforced ceramic matrix composites provide composites exhibiting improved resistance to embrittlement at high temperatures, are described. Oxides effective to provide the improved composites in accordance with the invention include CeO.sub.2 and ZrO.sub.2.