Abstract: The porcelain of the present invention comprises 5 to 70% by weight of a non-oxide ceramic filler and 30 to 95% by weight of a borosilicate glass having a glass transition temperature of 800° C. or lower, wherein a weight loss per unit surface area of said non-oxide ceramics is not more than 0.15 g/cm2 after dipping said non-oxide ceramic having purity of not less than 96% by weight for five minutes in a glass melt obtained by melting said borosilicate glass with heating at 1200° C. Since the porcelain composition can be fired at a low temperature together with a low-resistance metal, the resulting porcelain has a high thermal conductivity, a low dielectric constant, a high heat dissipation property and a reduced apparent signal delay in a high frequency signal and is suited for use as an insulating board in a wiring board.

Abstract: Crystallized glasses for data recording media such as magnetic disks are provided, comprising 42-65 mol % SiO2, 11-25 mol % Al2O3, 15-33 mol % MgO and 5.5-13 mol % TiO2 or 58-80 mol % SiO2+Al2O3 with MgO/(SiO2+Al2O3) being in the range of 0.125-0.55, wherein major crystals or crystals present at 50% by volume or more comprise &agr;-quartz solid solution or quartz-based crystals and enstatite and/or enstatite solid solution, or quartz-based crystals having a diffraction pattern almost comparable to that unique to quartz in the X-ray diffraction pattern and enstatite and/or enstatite solid solution and wherein the specific gravity is 2.9 g/cm3 or more. Said glass substrates have high Young's modulus, strength and heat resistance and excellent surface smoothness and surface homogeneity, and can be easily prepared.

Abstract: Provided is a substrate for information recording medium composed of such a crystallized glass as having high Young's modulus, strength and heat resistance, being excellent in surface smoothness, surface homogeneity and surface processability, as well as having a relatively low temperature of glass liquid phase and being capable of producing cheaply, and an information recording medium using this substrate. The crystallized glass substrate for information recording medium comprising 35-65 mol % of SiO2, 5-25 mol % of Al2O3, 10-40 mol % of MgO and 5-15 mol % of TiO2, in which the total amount of aforementioned composition is at least equal to or higher than 92 mol % and the main crystals are enstatite and/or its solid solution. The information recording medium having this substrate and a recording layer formed on said substrate.

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: Glass powder for a dielectric material has a nature that, when fired, diopside (CaMgSi2O6) and at least one of titanite (CaTi(SiO4)O) and titania (TiO2) are precipitated. Preferably, the glass powder has a composition including SiO2, CaO, MgO, and TiO2 and the total content of these components is 80 mass % or more. Preferably, the glass powder comprises, by mass percent, 35-65% SiO2, 10-30% CaO, 10-20% MgO, and 12-30% TiO2.

Abstract: A glass ceramics composition for recording disk substrate contains, essentially, expressed in terms of weight percent on the oxide basis, from 48 to 54.8 wt % of SiO2, from 10 to 30 wt % of Al2O3, from 10 to 30 wt % of MgO, and from 2.4 to 10 wt % of Li2O.

Abstract: Disclosed is a process for preparation of crystallized glass obtained by making a glass containing TiO2 subjected to a phase separation step and a crystallization step, where the phase separation step has heat treatment of the glass at a temperature in a range from a temperature of the glass transition temperature Tg (Tg−30° C.) to a temperature 60° C. higher than the glass transition temperature Tg (Tg+60° C.). There are also disclosed a crystallized glass for information recording disk composed of the crystallized glass obtained by the preparation process, where a mean particle size of the crystal particles is in a range of equal to or less than 100 nm, or where a transparency at a wavelength of 600 nm is 40% or higher; and an information recording disk, composed of the glass, having a polished surface with a surface roughness Ra (JIS B0601) in a range from 0.1 to 0.5 nm.

Abstract: A glass ceramics composition for recording disk substrate consists essentially, expressed in terms of weight percent on the oxide basis, of from 65 to 80 wt % of SiO2, from 3 to 15 wt % of Al2O3, from 3 to 15 wt % of Li2O, from 0.2 to 5 wt % of P2O5, and from 0.1 to 15 wt % of ZrO2, wherein a value of ZrO2/P2O5 is within a range from 1.1 to 8.5, expressed in terms of weight percent on the oxide basis.

Abstract: A glass ceramics composition for recording disk substrate consists essentially, expressed in terms of weight percent on the oxide basis, of from 65 to 80 wt % of SiO2, from 3 to 15 wt % of Al2O3, from 3 to 15 wt % of Li2O, from 0.2 to 5 wt % of P2O5, and from 0.1 to 0.8 wt % of ZrO2.

Abstract: The present invention provides the sanitary ware for which it is possible to accurately design the shapes and dimensions of the products after being subjected to firing while maintaining the mechanical strength required to sanitary ware, degradation of the process yield caused by shrinkage and deformation scarcely occurs, and the setting efficiency and productivity are improved as compared to the prior art. The sanitary Ware of the present invention is the sanitary ware which includes a ceramic body and a glaze layer formed on the desired portions of the body surface, and is characterized in that the CaO component segregation portions in which portions the CaO component is segregated are dispersed in the body.

Abstract: High-frequency ceramics containing SiO2, Al2O3, MgO, ZnO and B2O3 as constituent components, said ceramics comprising: 30 to 50% by weight of a crystal phase containing ZnO and Al2O3; 5 to 15% by weight of a crystal phase containing SiO2 and MgO; and 40 to 60% by weight of an amorphous phase comprising substantially SiO2 or SiO2 and B2O3; wherein the content of the SiO2 crystal phase is suppressed to be not larger than 6% by weight. The ceramics has a dielectric loss at 60 GHz of not larger than 15×10−4, exhibiting excellent high-frequency characteristics, and is very useful as an insulating substrate for the wiring boards that deal with high-frequency signals.

Abstract: A glass ceramics composition for recording disk substrate contains, essentially, expressed in terms of weight percent on the oxide basis, from 52 to 56 wt % of SiO2, from 10 to 30 wt % of Al2O3, from 10 to 30 wt % of MgO, and from 7 to 12 wt % of TiO2.

Abstract: A glass ceramics composition for recording disk substrate contains, essentially, expressed in terms of weight percent on the oxide basis, from 54 to 60 wt % of SiO2, from 10 to 30 wt % of Al2O3, from 10 to 30 wt % of MgO, and from 0.1 to 2.7 wt % of Li2O.

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: This invention is directed to lithium disilicate (Li2Si2O5) based glass-ceramics comprising silica, lithium oxide, alumina, potassium oxide and phosphorus pentoxide. The glass-ceramics are useful in the fabrication of single and multi-unit dental restorations (e.g. anterior bridges) made by heat pressing into refractory investment molds produced using lost wax techniques. The glass-ceramics have good pressability, i.e., the ability to be formed into dental articles by heat-pressing using commercially available equipment. In accordance with one embodiment directed to the process of making the glass-ceramics, the compositions herein are melted at about 1200° to about 1600° C., thereafter quenched (e.g., water quenched or roller quenched) or cast into steel molds, or alternately, cooled to the crystallization temperature. The resulting glass is heat-treated to form a glass-ceramic via a one or two step heat-treatment cycle preferably in the temperature range of about 400° to about 1100° C.

Abstract: A method of producing alumina-silica ceramic with mullite whisker structure has been produced as armor materials for protecting high velocity projectile. The mixing composition of starting powders consists of alumina, quartz, kaoline, feldspar and talc, and the green compacts were sintered at the temperature range from 1200 to 1450° C. for 0.5 to 3 hours. Mullite whisker structure in the ceramic was fabricated and grown in the period of liquid phase sintering. The whisker phase of mullite is homogeneously distributed in the ceramic.

Abstract: The present invention provides a method for preparing a glass-ceramic containing leucite crystals, comprising the steps of: mixing (1) a glassy material comprising 53 to 65 wt. % of SiO2, 13 to 23 wt. % of Al2O3, 9 to 20 wt. % of K2O and 6 to 12 wt. % of Na2O and (2) synthetic leucite seed crystals comprising 53 to 64 wt. % of SiO2, 19 to 27 wt. % of Al2O3 and 17 to 25 wt. % of K20, and heat-treating the mixture at 750 to 950° C. for 1 to 5 hours; and a dental porcelain powder and a metal-ceramic restoration both comprising a glass-ceramic prepared by the method. The porcelain comprising the glass-ceramic prepared by the method is substantially free of opacification and decrease in the coefficient of thermal expansion, during fusion-bonding to a metal frame.

Abstract: A glass-ceramic which is substantially and desirably totally transparent, and which contains a predominant, orthosilicate crystal phase whose composition lies 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: 35-72 SiO2, 0-20 Al2O3, 0-40 ZnO, 0-18 MgO, 1-15 Li2O, 0-18 K2O, 0-8 Na2O, 0-8 P2O5, with the condition that &Sgr;ZnO+MgO≧7. The glass-ceramic may be doped with up to 1 wt. % chromium, oxide to impart optical activity thereto.

Abstract: The invention relates to a glass-ceramic material for dental restoration having a high crystalline leucite content. The leucite crystals are needle- or rod-shaped, have a thickness of between 0.3 and 1.5 micrometers and are between 7.5 and 20 micrometers in length. Said glass-ceramic material is substantially semi-transparent and contains, in% by weight: between 67 and 71% SiO2, between 8 and 12% Al2O3, between 3 and 5% Na2O, between 8 and 10% K2O, between 1 and 3% CaO, between 0.2 and 2% BaO, between 0.5 and 2% CeO2, between 0.2 and 1% TiO2 and between 0.5 and 2% B2O3. The above glass-ceramic material presents improved fracture strength and offers new indications for the use of full ceramic materials in dental technology, notably metal-free dental restoration.

Abstract: This invention is directed to lithium disilicate (Li2Si2O5) based glass-ceramics comprising silica, lithium oxide, alumina, potassium oxide and phosphorus pentoxide. The glass-ceramics are useful in the fabrication of single and multi-unit dental restorations (e.g. anterior bridges) made by heat pressing into refractory investment molds produced using lost wax techniques. The glass-ceramics have good pressability, i.e., the ability to be formed into dental articles by heat-pressing using commercially available equipment. In accordance with one embodiment directed to the process of making the glass-ceramics, the compositions herein are melted at about 1200° to about 1600° C., thereafter quenched (e.g., water quenched or roller quenched) or cast into steel molds, or alternately, cooled to the crystallization temperature. The resulting glass is heat-treated to form a glass-ceramic via a one or two step heat-treatment cycle preferably in the temperature range of about 400° to about 1100° C.

Abstract: A glass ceramics composition for recording disk substrate consists essentially, expressed in terms of weight percent on the oxide basis, of from 65 to 80 wt % of SiO2, from 3 to 15 wt % of Al2O3, from 3 to 15 wt % of Li2O, from 0.2 to 5 wt % of P2O5, and from 0.1 to 0.8 wt % of ZrO2.

Abstract: High-strength sinterable lithium disilicate glass ceramics are described which can be further processed in particular by pressing in the viscous state to shaped dental products.

Abstract: A glass-ceramic substrate for an information storage medium made of a glass-ceramics having a crystal phase dispersed in a glass matrix has a ratio of crystal phase (the amount of crystal) in the glass-ceramics is within a range from 50 wt % to 70 wt % and crystal grains having an average crystal grain diameter within a range from 0.10 &mgr;m to 0.50 &mgr;m are exposed on the surface of the substrate. The glass-ceramics substrate has Young's modulus within a range from 95 GPa to 160 GPa, specific gravity within a range from 2.40 to 2.80, and a ratio of Young's modulus to specific gravity within a range from 39 GPa to 57 GPa. The glass-ceramic substrate has a surface microstructure in which respective crystal grains present in a surface portion of the substrate are fixed to the surface portion with half or more in volume of the respective crystal grains being exposed above the surface of the glass matrix.

Abstract: The present invention is concerned with a process for the formation of dental restorations from glass-ceramic materials and the resulting dental restorations. A dental restoration is prepared by placing a glass-ceramic material in a heat-pressure deformable crucible. Heat is applied to the crucible to bring the glass-ceramic to a working range at temperatures above its liquidus temperature. The crucible has heat-pressure deformation properties which are matched to the working temperature of the glass-ceramic. Once the glass-ceramic is heated to its working temperature, the crucible is brought into contract with a mold having a cavity therein. As the distance between the heated crucible and the mold is decreased, the crucible is deformed to form a seal with the mold facilitating the injection of the molten glass-ceramic into the cavity. The resulting dental restoration has superior optical, esthetic and strength properties.

Abstract: The present invention describes an extrusion process for manufacturing a titanium-containing silicate glass honeycomb structure, having a variety of shapes and sizes depending on its ultimate application. The titanium-containing glass honeycomb has a very low coefficient of thermal expansion (CTE) and the CTE can be varied by adjusting the titanium level to match the CTE of members that are bonded to the honeycomb. Furthermore, the inventive honeycomb structure is lightweight, yet able to support heavy loads on its end faces. Therefore, the inventive honeycomb can be advantageously used as a light-weight support for such objects as mirrors. Especially contemplated is using these inventive honeycomb supports for mirrors used in extraterresial environments where temperature extremes are present. These honeycombs can be used singularly or in aggregates to provide such support.

Abstract: The present invention relates to glass ceramic material and its use as means for joining different types of material and as support. Said glass ceramic material comprising, on a weight percent basis, 10-35% MgO, 10-55% BaO and 25-50% SiO2 and is formed by the following steps: a) melting of glass raw material at a temperature in excess of 1450 ° C. and that the thereby formed melt is cooled rapidly to a temperature below 900° C. and thereafter to ambient temperature to form a precursor glass, b) milling of the precursor glass into a sinterable glass powder with an average particle size in the range of 1 micron to 100 microns, c) forming of the glass powder into a green body of suitable shape, with or without organic processing aids, and subjecting said green body to a thermal treatment comprising a heating stage of average heating rate not exceeding 100 ° C./minute between the temperatures of 750 ° C. and 900 ° C.

Abstract: This invention deals with dental abstract restorations which are formed from glass-ceramic materials. In this invention the dental restorations may be formed by pressing. The resulting dental restorations have superior optical esthetic and strength properties. The invention includes dental restorations which are formed from particular lithium-disilicate glass-ceramics. In addition to forming dental restorations by pressing, the dental restorations may be milled. After forming the dental restorations are altered by applying one or more layers of a porcelain material to said dental restorations, and fusing said layers.

Abstract: A glass ceramics composition for recording disk substrate consists essentially, expressed in terms of weight percent on the oxide basis, of from 65 to 80 wt % of SiO2, from 3 to 15 wt % of Al2O3, from 3 to 15 wt % of Li2O, from 0.2 to 5 wt % of P2O5, and from 0.1 to 0.8 wt % of TiO2.

Abstract: This invention is directed to lithium disilicate (Li2Si2O5) based glass-ceramics comprising silica, lithium oxide, alumina, potassium oxide and phosphorus pentoxide. The glass-ceramics are useful in the fabrication of single and multi-unit dental restorations (e.g. anterior bridges) made by heat pressing into refractory investment molds produced using lost wax techniques. The glass-ceramics have good pressability, i.e., the ability to be formed into dental articles by heat-pressing using commercially available equipment. In accordance with one embodiment directed to the process of making the glass-ceramics, the compositions herein are melted at about 1200° to about 1600° C., thereafter quenched (e.g., water quenched or roller quenched) or cast into steel molds, or alternately, cooled to the crystallization temperature. The resulting glass is heat-treated to form a glass-ceramic via a one or two step heat-treatment cycle preferably in the temperature range of about 400° to about 1100° C.

Abstract: A glass ceramic which is especially suitable as a resistor (5) or a gas-tight glass ceramic solder (9) in a spark plug (1) is described. The glass ceramic here is a fused seal of a starting glass which is fused from a starting mixture containing SiO2, Al2O3, TiO2 and CaO. The fused seal also has crystalline phases in at least some areas. In addition, a method is described for producing such a glass ceramic, the starting glass being processed in a first method step to form a starting material. This starting material is then heated for a first period of time in a second method step from a starting temperature, which is below the softening temperature (Tg) of the starting glass, to a fusion temperature, which is above the softening temperature (Tg) of the starting glass, and is kept at that temperature for a second period of time and finally is cooled again.

Abstract: Systems and methods are described for coated glass work, compositions and multilayer coatings. A multilayer coated glass work includes: a substrate; and a composition coupled to the substrate, the composition defining a multilayer coating coupled to the substrate. Each of a plurality of sublayers that compose the multilayer coating includes, when initially coupled to the substrate, glass powder, water and methyl cellulose. Multi-layer coated colored printed glass panels based on the invention do not break during firing. The composition as prepared is acid-free, non-toxic, odorless, and colorless. The composition has a long shelf life, a good consistency similar to a screen printing ink and offers an adhesive surface on which to apply additional colored glass powder evenly. The invention results in clear, detailed, dense and brilliant colored images. The invention makes it possible to produce editioned fine art pieces with a printed design inside of glass.

Abstract: A high rigidity glass-ceramic substrate is provided which contains, as a predominant crystal phase or phases, at least one crystal phase selected from the group consisting of enstatite (MgSiO3), enstatite solid solution (MgSiO3 solid solution), magnesium titanate (MgTi2O) and magnesium titanate solid solution (MgTi2O5 solid solution), has fine crystal grains (preferably globular crystal grains) of precipitated crystal phases, has excellent melting property of a base glass, high resistivity to devitrification, easiness in polishing, excellent smoothness in the surface after polishing and has high Young's modulus capable of coping with a high speed rotation.

Abstract: Glass-ceramics fo a light filter capable of preventing variation of refractive index in a band-pass filter have a coefficient of thermal expansion within a range from 95×10−7/° C. to 140×10−7/° C. within a temperature range from −20° C. to +70° C. and, preferably, Young's modulus of 85 GPa and bending strength of 10 kg/mm2, and light transmittance for plate thickness of 10 mm of 60% or over within a wavelength range from 950 nm to 1600 nm. Predominant crystal phases of these glass-ceramics should preferably be (a) lithium disilicate and (b) one selected from the group consisting of &agr;-quartz, &agr;-quartz solid solution, &agr;-cristobalite and &agr;-cristobalite solid solution.

Abstract: Ceramics containing a diopside crystal phase and a cordierite phase, the remainder being a glass phase and/or other ceramic crystal phases, and having an open porosity of not larger than 1%. The ceramics is obtained by firing at from 800 to 1050° C., and exhibits a dielectric constant of not larger than 7 and a small dielectric loss in a high-frequency region, a ceramic strength of not smaller than 250 MPa, and a coefficient of thermal expansion close to those of the chips such as of Si and Ga—As and of the printed board.

Abstract: A glass-ceramic suitable for use as a light filter 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: 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 present invention provides a glass ceramics dielectric material, comprising: a crystallizable glass powder in an amount of from 40% to 100% by mass; and a ceramics powder in an amount of from 0% to 60% by mass, wherein the crystallizable glass powder comprises: SiO2 in an amount of from 35% to 65% by mass; CaO in an amount of from 10% to 30% by mass; MgO in an amount of from 10% to 20% by mass; and ZnO in an amount of from 0.5% to 35% by mass, and wherein the material is capable of forming: diopside, CaMgSi2O6, as crystals; and at least one of hardestnite, Ca2ZnSiO7, and willemite, Zn2SiO4, as crystals; and a sintered glass ceramics, comprising: diopside, CaMgSi2O6, as crystals; and at least one of hardestnite, Ca2ZnSiO7, and willemite, Zn2SiO4, as crystals.

Abstract: A glass-ceramic substrate for a magnetic information storage medium includes, as predominant crystal phases, lithium disilicate (Li2O.2SiO2) and at least one selected from a 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) and has a coefficient of thermal expansion of +65 to +130×10−7/° C. at a temperature within a range from −50° C. to +70° C. and surface roughness (Ra) after polishing of 3 Å-9 Å.

Abstract: Glass-ceramics of a light filter capable of preventing variation of refractive index in a band-pass filter have a coefficient of thermal expansion within a range from 95×10−7/° C. to 140×10−7/° C. within a temperature range from −20° C. to +70° C. and, preferably, Young's modulus of 85 GPa and bending strength of 10 kg/mm2, and light transmittance for plate thickness of 10 mm of 60% or over within a wavelength range from 950 nm to 1600 nm. Predominant crystal phases of these glass-ceramics should preferably be (a) lithium disilicate and (b) one selected from the group consisting of &agr;-quartz, &agr;-quartz solid solution, &agr;-cristobalite and &agr;-cristobalite solid solution.

Abstract: Resistors can be screen printed onto a green tape stack from a resistor ink comprising ruthenium oxide and a sufficient amount of a low melting temperature glass so that the resultant mixture fires at a temperature of 850-900° C. A conductive layer, as of silver, terminates the screen printed resistor layer and one or two green tapes are applied over the resistor layer to embed the resistors during firing. A final conductive layer is applied after firing.

Abstract: The cooking panel is made from an opaque glass-ceramic material uniformly colored throughout and having keatite mixed crystals as the predominant crystalline phase, which is ceramicized with a ceramicizable glass or a transparent glass-ceramic with high quartz mixed crystals as the predominant crystalline phase in a definite color location range according to its later service and wear pattern. The cooking panel makes deposited material, such as dirt and the like, less conspicuous.

Abstract: A glass-ceramics having a high elastic modulus, processes for producing the same, and an information recording medium substrate effectively inhibited from bending or vibrating are disclosed. The glass-ceramics has a major crystalline phase which has a Mohs' hardness of 6 or higher and is constituted of crystals containing manganese (Mn).

Abstract: The glass or glass-ceramic has the following composition (in % by weight based on oxide content): SiO2, 25 to 50; B2O3, >5 to 16; Al2O3, 10 to 17; P2O5, 0 to 8; Li2O,5 to 15; Na2O, 0 to 10; K2O, 0 to 10; MgO, 10 to 30; CaO, 0 to 10; SrO, 0 to 8; ZnO, 0 to 8; TiO2, 0.1 to 10; ZrO2, 0 to 8; and at least one refining agent, in an amount as needed according to its purpose. The sum total amount of divalent metal oxides (RO) present is less or equal to than 45% by weight based on oxide content and the sum total amount of alkali metal oxides (R2O) present is less than or equal to 30% by weight based on oxide content. The glass or glass-ceramic material generally has elasticity modulus values (E)>90×103 N/mm2 and <125×103 N/mm2, specific elasticity modulus values (E/&rgr;)>30×105 N cm/g and <45×105 N cm/g and thermal expansion coefficient values (&agr;20/300)>7.0×10−6/K and <11.0×10−6/K.

Abstract: The present invention is concerned with a process for the formation of dental restorations from glass-ceramic materials and the resulting dental restorations. In this invention, a dental restoration is prepared by placing a glass-ceramic material in a heat-pressure deformable crucible. Heat is then applied to the crucible in order to bring the glass-ceramic material to a working range at temperatures above its liquidus temperature. The crucible in which the glass-ceramic material is placed has heat-pressure deformation properties which are matched to the working temperature of the glass-ceramic materials being heated. The heat deformation properties of the crucible must be such that when the glass-ceramic material in the crucible is in the working range the crucible is heat-pressure deformable without rupturing.

Abstract: A ceramic substrate composition includes about 26 to 48% by weight of a CaO—Al2O3—B2O3—SiO2 type glass, about 35 to 68% by weight of at least one of alumina, mullite, cordierite and forsterite, and about 3 to 24% by weight of quartz, said glass being capable of being crystallized to wollastonite by firing of the composition at a temperature of about 800 to 1000° C. A ceramic circuit component contains a circuit formed on the ceramic substrate obtained by firing the composition.

Abstract: A composition for a glass-ceramic material that contains a crystallinity of at least about 30% by weight of forsterite components at a liquidus temperature of about 1525° C. or below. The glass-ceramic has a composition, in weight percent on an oxide basis, consisting essentially of about: 40-60% SiO2; 10-25% Al2O3; 18-30% MgO; 3-10% Na2O; 0-10% K2O; >5-15% TiO2. The invention further comprises a method for achieving high crystalline yield at such a low liquidus with increased solubility of high levels of chromium ions. The glass-ceramics can be used in drawing optical fibers and as gain media in amplifier and laser devices for near infrared wavelengths.

Abstract: The present invention provides a glass-ceramic glaze composition for use in the production of ceramic tile. The glaze composition comprises a glass composition from which diopside crystals can be formed, a diopside crystallization rate controller, a surface texture controller, and other optional fillers, pigments and additives. Preferably, the glass composition comprises one or more glass frits containing precursors from which diopside crystals can be formed. The diopside crystallization rate controller comprises mill added sodium feldspar, potassium feldspar, nepheline, and/or spodumene, with sodium feldspar being preferred. The surface texture controller preferably comprises zinc oxide and calcined alumina. When fired on a ceramic tile, the glaze composition of the present invention provides a semi-transparent to translucent, smooth matte finish that displays excellent chemical durability and abrasion resistance.

Abstract: A glass having an oxide-converted composition of 35 to 65 wt % of SiO2, 5 to 35 wt % of B2O3, 2 to 20 wt % of CaO, 5 to 25 wt % of Al2O3 where the ratio of CaO to Al2O3 is 1/1 to 1/2.5, 0.5 to 5 wt % of TiO2, 0.5 to 5 wt % of ZrO2, 0.5 to 5 wt % of ZnO, 0 to 5 wt % of MgO, 0 to 5 wt % of SrO, 0 to 5 wt % of BaO and 0 to 1 wt % of the total of group 1A element oxides such as Na2O, K2O and Li2O, or a glass having an oxide-converted composition of 10 to 45 wt % of SiO2, 20 to 50 wt % of CaO, 20 to 45 wt % of Al2O3, 0.1 to 5 wt % of MgO, 0.1 to 5 wt % of SrO, 0.1 to 5 wt % of BaO, 0.1 to 5 wt % of TiO2, 0.1 to 5 wt % of ZnO, 0.1 to 5 wt % of ZrO2 and 0 to 3 wt % of a group 1A element oxide has a low glass softening point, can be calcined as a composite with a variety of ceramics at a temperature below 1000° C., precipitates crystals during the calcination process, and can provide a glass ceramic exhibiting a low dielectric constant and a low dielectric loss.

Abstract: A high rigidity glass-ceramic substrate for a magnetic information storage medium has a ratio of Young's modulus to specific gravity within a range from 37 to 63 and comprises Al2O3 within a range from 10% to less than 20%. A predominant crystal phase of the glass-ceramic substrate consists of one or more crystals selected from the group consisting of &bgr;-quartz, &bgr;-quartz solid solution, enstatite, enstatite solid solution, forsterite and forsterite solid solution.

Abstract: High-strength sinterable lithium disilicate glass ceramics are described which can be further processed in particular by pressing in the viscous state to shaped dental products.