Abstract: ZrO2-toughened glass ceramics having high molar fractions of tetragonal ZrO2 and fracture toughness value of greater than 1.8 MPa·m1/2. The glass ceramic may also include also contain other secondary phases, including lithium silicates, that may be beneficial for toughening or for strengthening through an ion exchange process. Additional second phases may also decrease the coefficient of thermal expansion of the glass ceramic. A method of making such glass ceramics is also provided.

Abstract: Lithium silicate materials are described which can be easily processed by machining to dental products without undue wear of the tools.

Abstract: The process for producing a transparent lithium aluminosilicate glass ceramic plate includes ceramicizing a green glass body of the Li2O—Al2O—SiO2 system using a ceramization program, which includes heating it, for the purpose of nucleation, to a temperature of 750° C.±20° C. and maintaining the temperature for 20±15 minutes, further heating the green glass body, for the purpose of ceramization, to a temperature of 900±20° C. and maintaining the to temperature for 20±15 minutes and then cooling to room temperature. The transparent plate has a thermal expansion coefficient (CTE) from ?0.15×10?6/K to +0.15×10?6/K at 30 to 700° C. and a brightness value observed at an angle of 2° of ?80 for a 4-mm thick plate for transmitted normal light.

Abstract: Exemplary embodiments of the present disclosure provide a lithium silicate crystalline or amorphous glass overlaying the top surfaces of zirconia and the manufacturing process thereof. More specifically, exemplary embodiments of the present disclosure provide a lithium silicate glass or lithium silicate crystalline glass with high light transmittance and good coloring characteristics and the manufacturing process thereof, which overlays the top surface of zirconia with high mechanical strength, frameworks, or copings. The lithium silicate crystalline or amorphous glass may include 10-15 wt % Li2O, 71.1-85.0 wt % SiO2, 2-5 wt % P2O5 working as nuclear formation agent, 1-5 wt % Al2O3 to increase glass transition temperature and softening temperature, as well as chemical durability of the glass, and 0.01-1.0 wt % ZrO2 which increases the binding strength of the zirconia substructure.

Abstract: Glass-ceramics exhibiting a Vickers indentation crack initiation threshold of at least 15 kgf are disclosed. These glass-ceramics may be ion exchangeable or ion exchanged. The glass-ceramics include a crystalline and amorphous phases generated by subjecting a thin precursor glass article to ceramming cycle having an average cooling rate in the range from about 10° C./minute to about 25° C./minute. In one or more embodiments, the crystalline phase may comprise at least 20 wt % of the glass-ceramics. The glass-ceramics may include ?-spodumene ss as the predominant crystalline phase and may exhibit an opacity ?about 85% over the wavelength range of 400-700 nm for an about 0.8 mm thickness and colors an observer angle of 10° and a CIE illuminant F02 determined with specular reflectance included of a* between ?3 and +3, b* between ?6 and +6, and L* between 88 and 97.

Abstract: The invention relates to glass-ceramics based on the lithium disilicate system which can be mechanically machined easily in an intermediate step of crystallization and, after complete crystallization, represent a very strong, highly-translucent and chemically-stable glass-ceramic. Likewise, the invention relates to a method for the production of these glass-ceramics. The glass-ceramics according to the invention are used as dental material.

Abstract: The invention relates to a lithium silicate glass ceramic, which contains at least 8.5 wt.-% transition metal oxide selected from the group consisting of oxides of yttrium, oxides of transition metals with an atomic number from 41 to 79 and mixtures of these oxides. The invention also relates to a corresponding lithium silicate glass, a process for the preparation of the glass ceramic and of the glass as well as their use.

Abstract: The invention relates to a lithium silicate glass ceramic comprising CsO2 in an amount from about 6 to about 30 wt.-%. The invention also relates to a three-dimensional article comprising at least two layers (I) and (II), each layer (I) and (II) comprising a lithium silicate glass ceramic, the lithium silicate glass ceramics of layer (I) having a different translucency than the lithium silicate glass ceramic of layer (II).

Abstract: Methods, compositions, and articles provide for LAS-type glass-ceramics having specific thermo-mechanical, optical and coloration characteristics to yield generally brown-grey products. The glass-ceramic materials may include as colorants iron oxide, vanadium oxide, chromium oxide, cobalt oxide, nickel oxide and/or cerium oxide.

Abstract: A down-drawable glass ceramic. The glass ceramic has a composition which yields a liquidus viscosity that enables formation of the parent glass by down-draw techniques such as fusion-draw and slot-draw methods. The resulting glass ceramic is white or translucent in appearance with high strength achieved through heat treatment of the fusion-formed glass.

Abstract: Lithium silicate glass ceramics and glasses containing specific oxides of divalent elements are described which crystallize at low temperatures and are suitable in particular as dental materials.

Abstract: This invention relates to a glass-ceramic material and its production method wherein glass ceramics having low expansion coefficient are produced ecologically and whereby said method comprises the steps of raw material batch preparation (101), melting (102), batch compensation to final composition (103), refining of the gas bubbles (104), shaping process (105) and ceramization (106). Preferably, the glass-ceramic comprises in wt %: 60-70 SiO2, 15-25 AI2O3, 0.5-5 B2O3, 3-8 Li2O, 0.5-2 Na2O, 0.1-0.8 K2O, 0.1-1.5 BaO, 0-0.5 CaO, 1-2.5 ZnO, 1-4 TiO2, 1-4 ZrO2, 0.1-2.5 P2O5, 0-0.5 MgO. The batch compensation step (103) consists in adding 0.5-5 wt % B2O3 and 0.1-2.5 wt % P2O5 during the melting process (102). Instead of oxide raw materials, carbonates (e.g. Li2CO3), nitrates (e.g. KNO3), or sulphates are used.

Abstract: The invention relates to glass ceramics, which show high strength, high translucency, high chemical stability and which are still mechanically processible. The invention further refers to a method for producing a dental restoration comprising such glass or glass ceramic as well as the dental restoration itself.

Abstract: A glass-ceramic plate of lithium aluminosilicate free of arsenic and antimony, the optical transmission of which, for a thickness of 4 mm, is between 0.2 and 4% for at least one wavelength between 400 and 500 nm.

Abstract: Transparent, essentially colorless ?-quartz glass-ceramic materials, the composition of which is free of As2O3 and of Sb2O3, where said composition contains a specific combination of three nucleating agents: TiO2, ZrO2 and SnO2; TiO2 being present in low quantity.

Abstract: The process for producing a transparent lithium aluminosilicate glass ceramic plate includes ceramicizing a green glass body of the Li2O—Al2O—SiO2 system using a ceramization program, which includes heating it, for the purpose of nucleation, to a temperature of 750° C.±20° C. and maintaining the temperature for 20±15 minutes, further heating the green glass body, for the purpose of ceramization, to a temperature of 900±20° C. and maintaining the to temperature for 20±15 minutes and then cooling to room temperature. The transparent plate has a thermal expansion coefficient (CTE) from ?0.15×10?6/K to +0.15×10?6/K at 30 to 700° C. and a brightness value observed at an angle of 2° of ?80 for a 4-mm thick plate for transmitted normal light.

Abstract: A crystallized glass with negative coefficient of thermal expansion includes 38 wt % to 64 wt % of silica (SiO2); 30 wt % to 40 wt % of alumina (Al2O3); and 5 wt % to 12 wt % of lithium oxide (Li2O) as a basic component, and further includes more than one component selected from the group consisting of 0.5 wt % to 15 wt % of zirconia (ZrO2), 0.5 wt % to 6.5 wt % of titanium dioxide (TiO2), 0.5 wt % to 4 wt % of phosphorus pentoxide (P2O5), 2 wt % to 5 wt % of magnesium oxide (MgO), and 0 wt % to 5 wt % of magnesium fluoride (MgF2) in addition to the basic components. The crystallized glass may have a high negative coefficient of thermal expansion so that it has an advantage that it can be used as a thermal expansion compensation material according to the temperatures of all kinds of glasses and similar products thereof.

Abstract: ?-quartz lithium aluminosilicate (LAS) glass-ceramics contain neither arsenic oxide nor antimony oxide, are fined with tin oxide and include vanadium oxide, chromium oxide and a high iron oxide content (>950 ppm), and have a controlled transmission curve. Articles such as cook-tops can be made from such glass-ceramics.

Abstract: ?-quartz lithium aluminosilicate (LAS) glass-ceramics contain neither arsenic oxide nor antimony oxide, are fined with tin oxide and include vanadium oxide, chromium oxide and a high iron oxide content (>1500 ppm), and have a controlled transmission curve. Articles such as cook-tops can be made from such glass-ceramics.

Abstract: Process for preparing glass-ceramic body including the steps of providing a basic glass body and subjecting the basic glass body to a thermal treatment whereby a crystalline phase embedded in a glass matrix is formed. The basic glass body is made of a composition comprising 65 to 72 wt-% SiO2, at least 10.1 wt-% Li2O and at least 10.1 wt-% Al2O3 based on the total weight of the composition, the proportion of Li2O to Al2O3 being from 1:1 to 1.5:1. The thermal treatment involves a nucleation step followed by several crystallization steps at different temperatures, whereby at least two different crystalline phases are formed.

Abstract: Transparent, essentially colorless and non-diffusing ?-quartz glass-ceramics and glass compositions for forming the same have a composition, free of arsenic oxide, antimony oxide and rare earth oxides except for inevitable trace amounts, which contains, expressed as percentages by weight of oxides 62-72% of SiO2, 20-23% of Al2O3, 2.8-5% of Li2O, 0.1-0.6% of SnO2, 1.9-4% of TiO2, 1.6-3% of ZrO2, less than 0.4% of MgO, 2.5-6% of ZnO and/or BaO and/or SrO, less than 250 ppm of Fe2O3; and their crystallites present in the ?-quartz solid solution have an average size of less than 35 nm. The glass-ceramics exhibit low thermal expansion and are easily obtained at an industrial scale.

Abstract: A glass substrate for information recording medium, said glass substrate being composed of an aluminosilicate glass containing 60-75% by mass of SiO2, 5-18% by mass of Al2O3, 3-10% by mass of Li2O, 3-15% by mass of Na2O and 0.5-8% by mass of ZrO2 relative to the entire glass components. The glass substrate for information recording medium contains neither As (arsenic) nor Sb (antimony), while containing at least one substance selected from the group consisting of SO3 (sulfurous acid), F (fluorine), Cl (chlorine), Br (bromine) and I (iodine), as a refining agent. The molar ratio of the total amount of the refining agent to the amount of ZrO2 is within the range of 0.05-0.50.

Abstract: Crystallizable glasses, glass-ceramics, IXable glass-ceramics, and IX glass-ceramics are disclosed. The glass-ceramics exhibit ?-spodumene ss as the predominant crystalline phase. These glasses and glass-ceramics, in mole %, include: 62-75 SiO2; 10.5-17 Al2O3; 5-13 Li2O; 0-4 ZnO; 0-8 MgO; 2-5 TiO2; 0-4 B2O3; 0-5 Na2O; 0-4 K2O; 0-2 ZrO2; 0-7 P2O5; 0-0.3 Fe2O3; 0-2 MnOx; and 0.05-0.2 SnO2. Additionally, these glasses and glass-ceramics exhibit the following criteria: a. a ratio: [ Li 2 ? O + Na 2 ? O + K 2 ? O + MgO + ZnO ] [ Al 2 ? O 3 + B 2 ? O 3 ] between 0.7 to 1.5; b. a ? ? ratio ? : ? [ TiO 2 + SnO 2 ] [ SiO 2 + B 2 ? O 3 ] greater than 0.04. Furthermore, the glass-ceramics exhibit an opacity ?about 85% over the wavelength range of 400-700 nm for an about 0.

Abstract: The invention relates to glass ceramics based on the lithium metasilicate system (Li2O SiO2 (Li2SiO3)), which are mechanically processible in a simple manner in an intermediate stage of the crystallization and, after complete crystallization, represent a high- strength, highly translucent and chemically stable glass ceramic.

Abstract: Provided is a Li2O—Al2O3—SiO2-based crystallizable glass characterized by comprising, as a glass composition in terms of mass %, 55 to 75% of SiO2, 19 to 24% of Al2O3, 3 to 4% of Li2O, 1.5 to 2.8% of TiO2, 3.8 to 4.8% of TiO2+ZrO2, and 0.1 to 0.5% of SnO2, and satisfying a relationship of 4?Li2O+0.741MgO+0.367ZnO?4.5.

Abstract: Lithium silicate materials are described which can be easily processed by machining to dental products without undue wear of the tools.

Abstract: Described herein are glass ceramic compositions with bulk scattering properties that have improved light extraction properties due to high levels of diffuse transmission, and methods of making such glass ceramic compositions. The compositions are based on Li2O—Al2O3—SiO2 glass ceramics and with the proper crystal size, exhibit good volume scattering characteristic for visible light and enhance the outcoupling from the substrate to the air in optical devices, such as light emitting diodes.

Abstract: Provided is a Li2O—Al2O3—SiO2-based crystallized glass, comprising, as a composition in terms of mass %, 55 to 75% of SiO2, 20.5 to 27% of Al2O3, 2% or more of Li2O, 1.5 to 3% of TiO2, 3.8 to 5% of TiO2+ZrO2, and 0.1 to 0.5% of SnO2, and satisfying the relationships of 3.7?Li2O+0.741MgO+0.367ZnO?4.5 and SrO+1.847CaO?0.5.

Abstract: Antiballistic armor is provided that includes a glass-ceramic component having 50 to 70 weight percent SiO2, 15 to 25 weight percent Al2O3, 0.5 to 5 weight percent ZrO2, 0.1 to 10 weight percent Li2O, 1 to 5 weight percent TiO2. The glass ceramic component has a main crystalline phase that comprises keatite mixed crystal in a compositional range of LiAlSi2O6 to LiAlSi4O10.

Abstract: The invention relates to glass-ceramics based on the lithium disilicate system which can be mechanically machined easily in an intermediate step of crystallisation and, after complete crystallisation, represent a very strong, highly-translucent and chemically-stable glass-ceramic. Likewise, the invention relates to a method for the production of these glass-ceramics. The glass-ceramics according to the invention are used as dental material.

Abstract: Transparent ?-quartz glass-ceramics containing vanadium oxide. Such glass-ceramics have advantageous optical properties including good transmission in the infrared range, low transmission in the visible range, and significant transmission in the blue range for thicknesses of 3 mm. They can be used as materials for cooking top plates.

Abstract: A glass-ceramic plate of lithium aluminosilicate free of arsenic and antimony, the optical transmission of which, for a thickness of 4 mm, is between 0.2 and 4% for at least one wavelength between 400 and 500 nm.

Abstract: The present invention discloses a blue transparent glass-ceramic material comprising ?-quartz solid solution as a predominant crystalline phase and process for making same. The glass-ceramic comprises TiO2 as a nucleating agent, sulphur and at least one metal oxide, advantageously MgO and/or ZnO. The process for making the glass-ceramic material comprises including a metal sulphide, such as ZnS and/or MgS, as a reducing agent in melting the precursor glass of the glass-ceramic material.

Abstract: The invention relates to a transparent and essentially colorless ?-quartz glass-ceramic material which is free of TiO2, As2O3, Sb2O3 and phosphates; articles formed from said glass-ceramic material; lithium aluminosilicate glasses, precursors for said glass-ceramic material; and methods of producing said glass-ceramic material and said articles formed from said glass-ceramic material.

Abstract: A crystallized glass with negative coefficient of thermal expansion includes 38 wt % to 64 wt % of silica (SiO2); 30 wt % to 40 wt % of alumina (Al2O3); and 5 wt % to 12 wt % of lithium oxide (Li2O) as a basic component, and further includes more than one component selected from the group consisting of 0.5 wt % to 15 wt % of zirconia (ZrO2), 0.5 wt % to 6.5 wt % of titanium dioxide (TiO2), 0.5 wt % to 4 wt % of phosphorus pentoxide (P2O5), 2 wt % to 5 wt % of magnesium oxide (MgO), and 0 wt % to 5 wt % of magnesium fluoride (MgF2) in addition to the basic components. The crystallized glass may have a high negative coefficient of thermal expansion so that it has an advantage that it can be used as a thermal expansion compensation material according to the temperatures of all kinds of glasses and similar products thereof.

Abstract: A crystallized glass comprises, in term of mass %, 55 to 73% of SiO2, 17 to 25% of Al2O3, 2 to 5% of Li2O, 4 to 5.5% of TiO2, 0.05 to less than 0.2% of SnO2, and 0.02 to 0.1% of V2O5. The crystallized glass has a ratio V2O5/(SnO2+V2O5) of 0.2 to 0.4 and is substantially free of As2O3 and Sb2O3.

Abstract: An optically detectable, floatable arsenic- and antimony-free, glazable lithium-aluminosilicate glass that can be prestressed and the glass ceramic converted therefrom are described. The glass or the glass ceramic has a composition (in % by weight based on oxide) of essentially SiO2 55-69, Al2O3 19-25, Li2O 3.2-5, Na2O 0-1.5, K2O 0-1.5, MgO 0-2.2, CaO 0-2.0, SrO 0-2.0, BaO 0-2.5, ZnO 0-<1.5, TiO2 1-3, ZrO2 1-2.5, SnO2 0.1-<1, ?TiO2+ZrO2+SnO2 2.5-5, P2O5 0-3, Nd2O3 0.01-0.6, CoO 0-0.005, F 0-1, B2O3 0-2.

Abstract: Lithium silicate materials are described which can be easily processed by machining to dental products without undue wear of the tools and which subsequently can be converted into lithium silicate products showing high strength.

Abstract: Lithium silicate materials are described which can be easily processed by machining to dental products without undue wear of the tools and which subsequently can be converted into lithium silicate products showing high strength.

Abstract: Antiballistic armor is provided that includes a glass-ceramic component having 50 to 70 weight percent SiO2, 15 to 25 weight percent Al2O3, 0.5 to 5 weight percent ZrO2, 0.1 to 10 weight percent Li2O, 1 to 5 weight percent TiO2. The glass ceramic component has a main crystalline phase that comprises keatite mixed crystal in a compositional range of LiAlSi2O6 to LiAlSi4O10.

Abstract: Glass-ceramics includes Li2O, Al2O3 and SiO2, have an average crystal grain diameter of a predominant crystal phase of 90 nm or below and have crystal grain diameter distribution of 20 nm or below. The glass-ceramics can be manufactured by heat treating glass comprising Li2O, Al2O3 and SiO2 under a temperature within a range from 650° C. to 750° C. and then further heat treating the glass under a temperature within a range from 700° C. to 800° C. for 100-200 hours.

Abstract: The present invention relates to glass-ceramic materials, processes for making the same and articles comprising the same. The glass-ceramic material has a composition, by weight of the total composition, comprising 55-68% SiO2; 18-24% Al2O3; 3.3-4.1% Li2O; 1.5-4.0% ZnO; 1.5-5.0% MgO; 2-5% TiO2; 0-2% ZrO2; 0-5% B2O3; 0-8% P2O5; 0-2% Na2O, 0-2% K2O; and at least one component resulting from an effective amount of at least one fining agent; wherein: the total of B2O3 and P2O5 is at least 1.5% by weight, the total of MgO and ZnO is at least about 3.5% by weight, the total of Na2O and K2O is less than about 3.0% by weight, the total of P2O5, B2O3, Na2O and K2O is less than about 11% by weight, the weight ratio of the sum total of Na2O+K2O to the sum total of P2O5+B2O3 ( Na 2 ? O + K 2 ? O B 2 ? O 3 + P 2 ? O 5 ) is less than about 0.

Abstract: The invention relates to: a method of preparing glass-ceramics of ?-quartz and/or of ?-spodumene; a method of preparing articles made from said glass-ceramics; novel glass-ceramics of ?-quartz and/or of ?-spodumene; articles made from said novel glass-ceramics; and lithium aluminosilicate glasses, which are precursors of such novel glass-ceramics. The present invention relates to the use, as agent for fining the glass-ceramic glass precursor, of fluorine and at least one oxide of a multivalent element.

Abstract: The present invention relates to: novel glass-ceramics of ?-quartz and/or of ?-spodumene; articles made from said novel glass-ceramics; and ithium alumino-silicate glasses, which are precursors of said novel glass-ceramics; methods of preparing said novel glass-ceramics and articles made from said novel glass-ceramics. The present invention relates to the use of SnO2 and of Br, as an agent for fining the glass-ceramic glass precursor.

Abstract: Provided are SiO2—Al2O3-based or Li2O—Al2O3—SiO2-based crystallized glass that solves the cause of cracking and fracture in forming it into large-size shaped articles, that has homogeneous inner quality and that may be produced stably at high efficiency; and a method for producing it. The crystallized glass contains components of SiO2 and Al2O3, wherein the crystal precipitation peak temperature width obtained in differential thermal analysis of amorphous glass, a precursor thereof, is at least 22° C. Preferably, the total amount of the TiO2 component and the ZrO2 component in the crystallized glass is within a range of from 3.0 to less than 4.3%. FIG. 1 is referred to.

Abstract: The present invention relates to glass, glass-ceramic materials, lamp reflectors and processes for making them. The glass material has a composition, by weight of the total composition, comprising 56-67% SiO2; 9-22% Al2O3; 3.4-3.8% Li2O; 1.8-2.6% ZnO; 1.5-2.5% MgO; 3.3-5% TiO2; 0-2.5% ZrO2; 1.5-3% B2O3; 0-6% P2O5; 0-0.6% F; less than 500 ppm Fe; and components resulting from effective amount of at least one refining agent. The glass-ceramic material of the present invention contains ?-spodumene solid solution as the predominant crystalline phase, and can be obtained by proper thermal treatment of the glass-ceramic material.

Abstract: The method produces a glass-ceramic article substantially in the form of a plate with improved high temperature difference resistance or strength. The glass-ceramic article contains keatite mixed crystals (KMK) or high quartz mixed crystals (HQMK) as well as the keatite mixed crystals (KMK). The method includes heating a glass-ceramic in a high quartz mixed crystal state to form the keatite mixed crystals with a heating rate of 20 K/min to 150 K/min, preferably more than 15 K/min, especially preferably more than 20 K/min. These high heating rates increase the temperature difference resistance.

Abstract: The present invention relates to glass, glass-ceramic materials, lamp reflectors and processes for making them. The glass material has a composition, by weight of the total composition, comprising 56-67% SiO2; 9-22% Al2O3; 3.4-3.8% Li2O; 1.8-2.6% ZnO; 1.5-2.5% MgO; 3.3-5% TiO2; 0-2.5% ZrO2; 1.5-3% B2O3; 0-6% P2O5; 0-0.6% F; less than 500 ppm Fe; and components resulting from effective amount of at least one refining agent. The glass-ceramic material of the present invention contains &bgr;-quartz solid solution as the predominant crystalline phase, and can be obtained by proper thermal treatment of the glass-ceramic material. The glass-ceramic material is particularly suitable for heat-resistant lamp reflectors which require a high surface smoothness Ra of lower than 75 nm, a low CTE between 25 and 300° C. of less than 10×10−7 K−1, and IR transmission at about 1050 nm of over 80% at a thickness of 3 mm.

Abstract: Crystallized glass is formed by precipitating &bgr;-spodumene solid solution or &bgr;-quartz solid solution, and contains, by mass percent, 55-72% SiO2, 14-30% Al2O3, 2.9-6.0% Li2O, and 1.0-10.0% K2O, wherein a mass ratio between Li2O and K2O (Li2O/K2O) is 2.2 or less.

Abstract: A ceramic structure which is pollucite-based and has high refractoriness and high resistance to thermal shock. The inventive structure is suitable in high temperature applications such as a filtering particulates from diesel engine exhaust.