Glass-ceramics and precursor glasses that are crystallizable to glass-ceramics are disclosed. The glass-ceramics of one or more embodiments include rutile, anatase, armalcolite or a combination thereof as the predominant crystalline phase. Such glasses and glass-ceramics may include compositions of, in mole %: SiO.sub.2 in the range from about 45 to about 75; Al.sub.2O.sub.3 in the range from about 4 to about 25; P.sub.2O.sub.5 in the range from about 0 to about 10; MgO in the range from about 0 to about 8; R.sub.2O in the range from about 0 to about 33; ZnO in the range from about 0 to about 8; ZrO.sub.2 in the range from about 0 to about 4; B.sub.2O.sub.3 in the range from about 0 to about 12, and one or more nucleating agents in the range from about 0.5 to about 12. In some glass-ceramic articles, the total crystalline phase includes up to 20% by weight of the glass-ceramic article.

A glass-ceramic, includes a silicate-containing glass comprising a first portion and a second portion. A plurality of crystalline precipitates comprising at least one of W and Mo. The crystalline precipitates are distributed within at least one of the first and second portions of the silicate-containing glass. The glass-ceramic comprises a difference in absorbance between the first and second portions of 0.04 optical density (OD)/mm or greater over a wavelength range of from 400 nm to 1500 nm.

Provided is a silicate glass, a method for preparing a silicate glass-ceramics by using the silicate glass, and a method for preparing a lithium disilicate glass-ceramics by using the silicate glass, and more particularly, to a method for preparing a glass-ceramics that has a nanosize of 0.2 to 0.5 μm and contains lithium disilicate and silicate crystalline phases. A nano lithium disilicate glass-ceramics containing a SiO.sub.2 crystalline phase includes: a glass composition including 70 to 85 wt % SiO.sub.2, 10 to 13 wt % Li.sub.2O, 3 to 7 wt % P.sub.2O.sub.5 working as a nuclei formation agent, 0 to 5 wt % Al.sub.2O.sub.3 for increasing a glass transition temperature and a softening point and enhancing chemical durability of glass, 0 to 2 wt % ZrO.sub.2, 0.5 to 3 wt % CaO for increasing a thermal expansion coefficient of the glass, 0.5 to 3 wt % Na.sub.2O, 0.5 to 3 wt % K.sub.2O, and 1 to 2 wt % colorants, and 0 to 2.0 wt % mixture of MgO, ZnO, F, and La.sub.2O.sub.3.

A glass ceramic contains the following components by wt %: 60 to 80% of SiO.sub.2; 4 to 20% of Al.sub.2O.sub.3; 0 to 15% of Li.sub.2O; more than 0 but less than or equal to 12% of Na.sub.2O; 0 to 5% of K.sub.2O; more than 0 but less than or equal to 5% of ZrO.sub.2; 0 to 5% of P.sub.2O.sub.5; and 0 to 10% of TiO.sub.2. A crystalline phase contains at least one of R.sub.2SiO.sub.3, R.sub.2Si.sub.2O.sub.5, R.sub.2TiO.sub.3, R.sub.4Ti.sub.5O.sub.12, R.sub.3PO.sub.3, RAlSi.sub.2O.sub.6, RAlSiO.sub.4O.sub.10, R.sub.2Al.sub.2Si.sub.2O.sub.5, R.sub.4Al.sub.4Si.sub.5O.sub.18, quartz and quartz solid solution. With a liquidus temperature below 1,450° C., a thermal conductivity above 2 w/m.Math.k, and a Vickers hardness above 600 kgf/mm2, the glass ceramic is applicable to portable electronic devices and optical devices.

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.

A method of manufacturing a lithium ion conductive glass ceramic, includes a step of forming granules using a material including an SiO.sub.2 source, a ZrO.sub.2 source, a P.sub.2O.sub.5 source and an Na.sub.2O source; a step of obtaining a powder including a glass ceramic by passing the granules under a heated gas phase atmosphere to melt the granules and solidifying the melted granules; a step of obtaining a target object including a glass ceramic by performing a heat treatment on the powder to precipitate crystals; and a step of obtaining a lithium ion conductive glass ceramic by performing an ion-exchange process on the target object in molten salt including lithium ions.

The present invention relates to inorganic fibres having a composition comprising: 65.7 to 70.8 wt % SiO.sub.2; 27.0 to 34.2 wt % CaO; 0.10 to 2.0 wt % MgO; and optional other components providing the balance up to 100 wt %,
wherein the sum of SiO.sub.2 and CaO is greater than or equal to 97.8 wt %; and the other components, when present, comprise no more than 0.80 wt % Al.sub.2O.sub.3; and wherein the amount of MgO and other components are configured to inhibit the formation of surface crystallite grains upon heat treatment at 1100° C. for 24 hours, wherein said surface crystallite grains comprise an average crystallite size in a range of from 0.0 to 0.90 μm.

The present application provides LAS type transparent glass-ceramics of β-quartz of composition containing a high content of zinc, articles constituted at least in part of said glass-ceramics, glasses precursors of said glass-ceramics (with a low viscosity at high temperature), and also a method of preparing said articles. Said glass-ceramics present a composition, free of arsenic oxide and antimony oxide, except for inevitable traces, expressed as percentages by weight of oxides, containing: 64.5% to 66.5% of SiO.sub.2; 19.0% to 20.6% of Al.sub.2O.sub.3; 3.0% to 3.6% of Li.sub.2O; 0 to 1% of MgO; 1.7% to 3.4% of ZnO; 2% to 3% of BaO; 0 to 3% of SrO; 0 to 1% of CaO; 2% to 4% of TiO.sub.2; 1% to 2% of ZrO.sub.2; 0 to 1% of Na.sub.2O; 0 to 1% of K.sub.2O; with Na.sub.2O+K.sub.2O+BaO+SrO+CaO≤6%; optionally up to 2% of at least one fining agent comprising SnO.sub.2; and optionally up to 2% of at least one coloring agent.

Methods for processing and or removing organic residuals and or impurities from a solgel-derived bioactive glass-ceramic and compositions comprising solgel-derived bioactive glass-ceramics processed using these methods, are described.

Lithium disilicate apatite glass-ceramics are described which are characterized by a high chemical stability and can therefore be used in particular as restoration material in dentistry.