Glass and glass ceramic compositions having a combination of lithium silicate and petalite crystalline phases along with methods of making the glass and glass ceramic compositions are described. The compositions are compatible with conventional rolling and float processes, are transparent or translucent, and have high mechanical strength and fracture resistance. Further, the compositions are able to be chemically tempered to even higher strength glass ceramics that are useful as large substrates in multiple applications.

A glass ceramic substrate made of a transparent, colored LAS glass ceramic is provided. The glass ceramic has a gradient layer with keatite solid solution and an underlying core with high-quartz solid solution as predominant crystal phase. The keatite solid solution in a depth of 10 m or greater exceeds 50% of the sum of the high-quartz solid solution proportion and keatite solid solution proportion. The ceramization includes a crystal transformation step, in which the high-quartz solid solution is transformed at a maximum temperature in the range of 910 to 980 and a time period of between 1 and 25 minutes in part into the keatite solid solution.

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.

An LAS-glass for producing a transparent glass-ceramic and an LAS-glass-ceramic having a predetermined chroma C* and a predetermined visually determinable scatter value (S) are provided. The LAS-glass and LAS-glass-ceramic has a process window as large as possible during the nucleus formation process with respect to the residence time in the relevant temperature range for the formation of nuclei.

The present invention relates to glass-ceramic compositions, as well as methods for forming such composition. In particular, the compositions include various polymorphs of silica that provide beneficial thermal expansion characteristics (e.g., a near linear thermal strain). Also described are methods of forming such compositions, as well as connectors including hermetic seals containing such compositions.

Provided is a Li.sub.2OAl.sub.2O.sub.3SiO.sub.2-based crystallized glass in which a yellowish tint due to TiO.sub.2, Fe.sub.2O.sub.3 or so on is reduced. The Li.sub.2OAl.sub.2O.sub.3SiO.sub.2-based crystallized glass contains, in terms of % by mass, 40 to 90% SiO.sub.2, 5 to 30% Al.sub.2O.sub.3, 1 to 10% Li.sub.2O, 0 to 20% SnO.sub.2, 1 to 20% ZrO.sub.2, 0 to 10% MgO, 0 to 10% P.sub.2O.sub.5, and 0 to below 2% TiO.sub.2.

A process allowing to obtain ceramic glass material in the form of sheets of large dimensions usable in constructions for panelling or for flooring is described.

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.

A multilayer ceramic electronic component includes a plurality of dielectric layers; and internal electrodes disposed on the dielectric layers and containing an additive. The additive contains lithium (Li) and a dielectric material.

A glass ceramic precursor glass and a glass ceramic having low levels of rhodium and a method of controlling the amount of rhodium in such glasses and glass ceramics. The precursor glass and glass ceramic contain from about 1 ppm to about 10 ppm and, in certain embodiments, from about 1 ppm to about 6 ppm rhodium. The method of controlling of reducing rhodium dissolution from a rhodium-containing material such as, for example, an alloy into a glass melt comprises controlling and/or lowering the partial pressure of oxygen at the rhodium-containing vessel/glass interface by imposing a high humidity condition around the external (non-glass-contact) surface of the rhodium-containing material. The lower concentration of rhodium minimizes its coloring effect on the white color of the glass ceramic.