Provided in the present invention is a rare earth-doped reinforced glass-ceramic, and a preparation method and a use therefor. Raw materials rare earth-doped reinforced glass-ceramic comprise at least one of the following rare earth oxides: Ta.sub.2O.sub.5, La.sub.2O.sub.3, Y.sub.2O.sub.3, Tm.sub.2O.sub.3, or Nb.sub.2O.sub.5. In the present invention, a glass article doped with at least one rare earth oxide from among Ta.sub.2O.sub.5, La.sub.2O.sub.3, Y.sub.2O.sub.3, Tm.sub.2O.sub.3, or Nb.sub.2O.sub.5 is subjected to thermal treatment and ion exchange to produce the rare-earth doped reinforced glass-ceramic. In the rare earth-doped reinforced glass-ceramic, due to the high field strength and high accumulation effects of the rear earth element, the crystal size of the glass-ceramic is caused to low, and the crystal ratio thereof to be high, thus being able to effectively improve the mechanical performance and visible light transmittance of the glass-ceramic, and effectively controlling uniform devitrification of the glass. The invention is suitable for use in cover panels of electronic devices.

A silicate-based composition includes: 40-80 mol % SiO.sub.2, >0-25 mol % MO, 15-40 mol % R.sub.2O, >0-10 mol % Al.sub.2O.sub.3, >0-10 mol % P.sub.2O.sub.5, and >0-5 mol % ZrO.sub.2, such that MO is a sum of BeO, MgO, CaO, SrO, and BaO; and R.sub.2O is a sum of Li.sub.2O, Na.sub.2O, K.sub.2O, Rb.sub.2O, Cs.sub.2O.

A ceramic glass for cooktop includes a glass material having an uneven layer formed on an upper surface of the glass material. A color difference meter value L of the ceramic glass ranges from 90 to 100. The glass material includes Li.sub.2O, Al.sub.2O.sub.3, and SiO.sub.2. A heat shock temperature of the ceramic glass ranges from 525° C. to 575° C. The ceramic glass implements a surface roughness Ra of 0.1 μm or less and surface roughness Rz of 0.8 μm or less through a polishing operation. The surface roughness Ra corresponds to an average length between at least one peak of the uneven layer and at least one valley of the uneven layer. The surface roughness Rz corresponds to a vertical distance between the at least one peak of the uneven layer and the at least one valley of the uneven layer.

A process for the preparation of multi-coloured dental restorations is described, in which glasses and glass ceramics with various compositions are given the shapes of dental restorations and colour changes are effected in the glasses and glass ceramics by irradiating them with artificial electromagnetic radiation and subjecting them to a heat treatment.

A three dimensional glass ceramic article with a thickness between 0.1 mm and 2 mm, having a dimensional precision control of less than or equal to ±0.1 mm. A method for forming a three dimensional glass ceramic article including placing a nucleated glass article into a mold, and heating the nucleated glass article to a crystallization temperature, where the nucleated glass article is in the mold during the heating. Then, holding the nucleated glass article at the crystallization temperature for a duration sufficient to crystallize the nucleated glass article and form a three dimensional glass ceramic article, where the nucleated glass article is in the mold during the holding, and removing the three dimensional glass ceramic article from the mold.

A method of manufacturing a lithium aluminosilicate glass product suitable for making a glass-ceramic product, includes melting a vitrifiable mixture of raw materials, which are free from arsenic oxides and antimony oxides, apart from unavoidable traces, refining the molten material, cooling the molten material so as to form a glass, forming of the glass, wherein the vitrifiable mixture of raw materials includes petalite having a fraction by weight of total iron, expressed as Fe.sub.2O.sub.3, less than or equal to 200 ppm.

The present invention relates to a glass ceramic for veneering a dental frame structure, wherein said glass ceramic is characterized by a high content of B.sub.2O.sub.3, to a process for the preparation thereof, and to the use thereof in the production of dental restorations.

Embodiments of a glass-based article including a first surface and a second surface opposing the first surface defining a thickness (t) of about 3 millimeters or less (e.g., about 1 millimeter or less), and a stress profile, wherein all points of the stress profile between a thickness range from about 0.Math.t up to 0.3.Math.t and from greater than about 0.7.Math.t up to t, comprise a tangent with a slope having an absolute value greater than about 0.1 MPa/micrometer, are disclosed. In some embodiments, the glass-based article includes a non-zero metal oxide concentration that varies along at least a portion of the thickness (e.g., 0.Math.t to about 0.3.Math.t) and a maximum central tension in the range from about 80 MPa to about 100 MPa. In some embodiments, the concentration of metal oxide or alkali metal oxide decreases from the first surface to a value at a point between the first surface and the second surface and increases from the value to the second surface. The concentration of the metal oxide may be about 0.05 mol % or greater or about 0.5 mol % or greater throughout the thickness. Methods for forming such glass-based articles are also disclosed.

A glass-ceramic article includes from 60 mol % to 72 mol % SiO2; from 2.5 mol % to 8 mol % Al.sub.2O.sub.3; from 17 mol % to 26 mol % Li.sub.2O; from 0.2 mol % to 4 mol % ZrO.sub.2; and from 0.5 mol % to 2 mol % P.sub.2O.sub.5. The sum of alkaline earth oxides and transitional metal oxides in the glass-ceramic article may be from 0.1 mol % to 6 mol %, wherein alkaline earth oxides is the sum of CaO, MgO, SrO, and BaO and transition metal oxides is the sum of La.sub.2O.sub.3, Y.sub.2O.sub.3, Ta.sub.2O.sub.5, and GeO.sub.2. The sum of P.sub.2O.sub.5 and ZrO.sub.2 in the glass-ceramic article may be from 1 mol % to 6 mol %. The glass-ceramic article may comprise a crystalline phase comprising lithium disilicate and petalite. The total amount of lithium disilicate and petalite in the crystalline phase of the glass-ceramic article may be greater than 50 wt %, based on a total weight of the crystalline phase.

Provided is a dental bulk block comprising a crystalline phase includes lithium disilicate as a main crystalline phase and eucryptite as a sub-crystalline phase in an amorphous glass matrix that is a functionally graded material having a main crystalline size gradient with respect to the depth thereof, and having no interface at the point of change in the main crystalline size gradient value, and is useful for manufacturing artificial teeth having structural characteristics similar to those of natural teeth, is facile to machine into an artificial tooth prosthesis due to the inclusion of eucryptite as the sub-crystalline phase compared to when only lithium disilicate exists, and can not only shorten the manufacturing time, but also increase the structural stability in terms of force distribution through functional grading of mechanical properties.