156 results about "Lithium disilicate" patented technology

Glass and glass ceramic compositions having a combination of lithium disilicate and -spodumene 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 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.

For providing glass-ceramics having properties suitable for use as a substrate of an information storage medium of next generation such as one for the perpendicular magnetic recording system without employing arsenic and antimony components which adversely affect human beings and the environment, there are provided glass-ceramics comprising SiO2, Li2O and Al2O3 on oxide basis, comprising lithium disilicate as a crystal phase, and comprising one or more elements selected from the group consisting of Sn, Ce, Mn, W, Ta, Bi, Nb, S, Cl and F.

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 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 material 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. Once the glass-ceramic material is heated to its working temperature, the crucible is brought into contact with a mold having a preformed cavity therein, the cavity being in the shape of the desired dental restoration. As the distance between the heated glass-ceramic material and the mold is decreased, the crucible is deformed to form a seal with the mold, thereby facilitating the injection of the molten glass-ceramic material into the mold cavity. An interactive seal between the crucible and the mold may be provided for. The composite process may be carried out in a vacuum. The resulting dental restoration has superior optical esthetic and strength properties. The invention further includes the heat-pressure deformable crucible. The invention includes dental restorations which are formed from particular lithium-disilicate glass-ceramics. In addition to forming dental restorations by the process of this invention, the dental restorations may be milled.

Glass and glass ceramic compositions having a combination of lithium disilicate and β-spodumene 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 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.

The present invention provides an inorganic composition for use in information recording medium disc substrate and such, having an excellent surface property capable of sufficiently corresponding with a ramp load system for high density recording, a high degree of tolerability to high speed rotation, and high productivity at a low melting point. Specifically, this invention provides an inorganic composition containing one crystalline phase selected from the group consisting of α-quartz (α-SiO2), lithium disilicate (Li2Si2O5) and lithium monosilicate (Li2SiO3), or that contain at least a crystalline phase of lithium monosilicate (Li2SiO3), in which a mean particle diameter of a particle showing a crystalline phase contained in the inorganic composition is 1 μm or less, a ring flexural strength is 300 MPa or more, and a surface roughness (an arithmetic mean roughness) thereof after a polishing process is 10 Å or less.

The present invention describes a composition, method and article for a photomachinable glass having a coefficient of thermal expansion from less than 6×10−6 / ° C. in the temperature range of 0° C. to 300° C. The photomachinable glass composition is a low expansion glass having an amorphous glass phase and crystalline phases selected from the group consisting of spudomene and lithium disilicate.

The invention belongs to the field of medical materials and relates to a lithium disilicate glass ceramic, a preparation method thereof and application. The lithium disilicate glass ceramic is prepared from, by mass, SiO2 55%-65%, Li2O 16%-24%, P2O52 2%-5%, Al2O3 8%-12%, K2O 2%-5% and TbO2 1%-10%. According to the method, raw materials are subjected to pre-sintering, calcination, molding by casting and then are subjected to annealing, coring and crystallization to prepare a lithium metasilicate glass ceramic block, the lithium metasilicate glass ceramic block has very good machinability, and heat treatment is performed again after machining to obtain the lithium disilicate glass ceramic. The lithium disilicate glass ceramic prepared by the preparation method is doped with a specific content of rare earth element Tb, a glass grid structure can be destroyed, the viscosity can be reduced, crystallization is promoted, the hardness and bending strength of the glass ceramic are improved, and a novel method is provided for preparation of the lithium disilicate glass ceramic.

In all of an in-plane magnetic recording system and a perpendicular magnetic recording system, there is provided a crystallized glass for a disk substrate for information recording medium, etc., which has satisfactory surface properties capable of sufficiently adapting with a lamp loading system for high-density recording, has high strength such that it is able to withstand high-speed rotation and impact, has heat expansion properties and heat resistance in agreement with respective drive members, has a low melting temperature, has excellent productivity and is reduced in the elution amount of an alkali from the raw material, namely excellent in chemical durability. The crystallized glass of the invention is a crystallized glass containing an SiO2 component and an Li2O component; further containing at least one member selected from an SrO component and a BaO component in a total content of more than 3.5% and not more than 15% in terms of % by mass; and containing at least one member selected among lithium disilicate, lithium monosilicate, α-quartz, an α-quartz solid solution and a β-quartz solid solution as a main crystal phase on the oxide basis.