The disclosure relates to tiles or slabs comprising a fired ceramic material which has a chemical composition with a particular combination of oxides; to a method for the manufacture of said tiles or slabs; and to the use thereof for construction or decoration applications.

To provide a crystallized glass substrate including a surface with a compressive stress layer, where a stress depth DOL.sub.zero of the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 μm, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and a central stress CT determined by using curve analysis is 55 to 300 MPa.

The present invention relates to a 3D printer printhead, a 3D printer using the same, a method for manufacturing a molded product by using the 3D printer, a method for manufacturing an artificial tooth by using the 3D printer, and a method for manufacturing a machinable glass ceramic molded product by using the 3D printer, the 3D printer printhead comprising: an inlet through which glass wire, which is a raw material, is introduced; a heating means for heating the glass wire introduced through the inlet; a melting furnace for providing a space in which the glass wire is fused; and a nozzle connected to the lower part of the melting furnace so as to temporarily store the fused glass or discharge a targeted amount of the fused glass, wherein the melting furnace includes an exterior frame made from a heat resistant material and an interior frame having a crucible shape, and the interior frame is made from platinum (Pt), a Pt alloy or graphite, which have a low contact angle, or a material having a surface coated with Pt or a diamond-like carbon (DLC) so as to prevent the fused glass from sticking thereto. According to the present invention, the molded product, the artificial tooth, and the machinable glass ceramic molded product can be manufactured with excellent mechanical properties, thermal durability, chemical durability and oxidation resistance and outstanding texture by using the glass wire as a raw material.

The invention relates to glass articles suitable for use as electronic device housing/cover glass which comprise a glass ceramic material. Particularly, a cover glass comprising an ion-exchanged glass ceramic exhibiting the following attributes (1) optical transparency, as defined by greater than 90% transmission at 400-750 nm; (2) a fracture toughness of greater than 0.6 MPa.Math.m.sup.1/2; (3) a 4-point bend strength of greater than 350 MPa; (4) a Vickers hardness of at least 450 kgf/mm.sup.2 and a Vickers median/radial crack initiation threshold of at least 5 kgf; (5) a Young's Modulus ranging between about 50 to 100 GPa; (6) a thermal conductivity of less than 2.0 W/m° C., and (7) and at least one of the following attributes: (i) a compressive surface layer having a depth of layer (DOL) greater and a compressive stress greater than 400 MPa, or, (ii) a central tension of more than 20 MPa.

A pore-free ceramic is provided that has a high modulus of elasticity and a low coefficient of thermal expansion. A process for producing a corresponding ceramic is also provided. The pore free ceramic is a dimensionally stable substrate material in applications subjected to temperature gradients including semiconductor manufacture.

The present invention relates to a crystallized glass including: at least one crystal of indialite and cordierite, in which the crystallized glass has a total amount of the crystal is 40 mass % or more of the crystallized glass, and the crystal comprises at least one of a vacancy and a different element at an Al site.

A glass-ceramic that includes a first crystal phase including (Mg.sub.xZn.sub.1-x)Al.sub.2O.sub.4, where x is ≤1, and a second crystal phase including tetragonal ZrO.sub.2. The glass-ceramic may be substantially free of arsenic, tin, antimony, and cesium, each of the arsenic, tin, antimony, and cesium present at less than 0.01% (by mole of oxide). Further, the glass-ceramic may include a transmittance of at least about 80% to light having a wavelength of 380 nm to 760 nm.

A glass ceramic for an optical filter and an optical filter are obtained that have both thermal expansion characteristics for preventing refractive index fluctuations at a usage temperature of a filter member and mechanical characteristics considering durability, and further have excellent workability.

An internal transmittance of the glass ceramic for an optical filter is 0.970 or more with respect to light having a wavelength of 1550 nm when a thickness of the glass ceramic is 1 mm. The glass ceramic includes, by mass % in terms of oxide, 40.0% to 70.0% of a SiO.sub.2 component, 11.0% to 25.0% of an Al.sub.2O.sub.3 component, 5.0% to 19.0% of a Na.sub.2O component, 0% to 9.0% of a K.sub.2O component, 1.0% to 18.0% of one or more components selected from a MgO component and a ZnO component, 0% to 3.0% of a CaO component, and 0.5% to 12.0% of a TiO.sub.2 component.

To provide a crystallized glass substrate including a surface with a compressive stress layer, in which a stress depth DOL.sub.zero of the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 μm, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and CS×DOL.sub.zero, which is a product of the compressive stress CS on the outermost surface and the stress depth DOL.sub.zero (μm), is 4.8×10.sup.4 or more.

A thermally tempered aluminosilicate glass-ceramic composition includes a crystalline phase and a residual glass phase, wherein the two phases form a system wherein the thermal expansion curve of the system has two distinct sections diverging from an inflection point temperature in the range of about 450° C. to about 600° C., and wherein the difference between coefficient of thermal expansion of the glass-ceramic below and above the inflection point is greater than about 4 ppm/° C.