Disclosed herein are glass-ceramic articles including a crystalline phase comprising a jeffbenite crystalline structure. The glass-ceramic articles may include a first surface, a second surface opposite the first surface, and a perimeter defining a shape of the glass-ceramic article. The glass-ceramic articles may further include a phase assemblage comprising one or more crystalline phases and a glass phase. The one or more crystalline phases may include a crystalline phase having the jeffbenite crystalline structure.

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.

Embodiments of a transparent glass-based material comprising a glass phase and a second phase that is different from and is dispersed in the glass phase are provided. The second phase may comprise a crystalline or a nanocrystalline phase, a fiber, and/or glass particles. In some embodiments, the second phase is crystalline. In one or more embodiments, the glass-based material has a transmittance of at least about 88% over a visible spectrum ranging from about 400 nm to about 700 nm and a fracture toughness of at least about 0.9 MPa.Math.m.sup.½, and wherein a surface of the glass-based material, when scratched with a Knoop diamond at a load of at least 5 N to form a scratch having a width w, is free of chips having a size of greater than 3w.

A glass-ceramic comprising, in weight percent on an oxide basis, of 50 to 70% SiO.sub.2, 0 to 20% Al.sub.2O.sub.3, 12 to 23% MgO, 0 to 4% Li.sub.2O, 0 to 10% Na.sub.2O, 0 to 10% K.sub.2O, 0 to 5% ZrO.sub.2, and 2 to 12% F, wherein the predominant crystalline phase of said glass-ceramic is a trisilicic mica, a tetrasilicic mica, or a mica solid solution between trisilicic and tetrasilicic, and wherein the total of Na.sub.2O+Li.sub.2O is at least 2 wt. %; wherein the glass-ceramic can be ion-exchanged.

An opaque gahnite-spinel glass ceramic is provided. The glass ceramic includes a first crystal phase including (Mg.sub.xZn.sub.1-x)Al.sub.2O.sub.4 where x is less than 1 and a second crystal phase includes at least one of tetragonal ZrO.sub.2, MgTa.sub.2O.sub.6, mullite, and cordierite. The glass ceramic has a Young's modulus greater than or equal to 90 GPa, and has a hardness greater than or equal to 7.5 GPa. The glass ceramic may be ion exchanged. Methods for producing the glass ceramic are also provided.

The invention relates to glass ceramics and glasses with cerium and tin content, which comprise the following components: TABLE-US-00001 Component wt.-% SiO.sub.2 42.0 to 80.0 Al.sub.2O.sub.3 0.1 to 42.0 Cerium, calculated as CeO.sub.2 0.5 to 10.0 Tin, calculated as SnO 0.1 to 4.0
and which are suitable in particular for the preparation of dental restorations, the fluorescence properties of which largely correspond to those of natural teeth.

A glass-ceramic includes SiO2 in a range of 40 mol. % to 80 mol. %; Al.sub.2O.sub.3 in a range of 5 mol. % to 20 mol. %; MgO in a range of 5 mol. % to 20 mol. %; and at least one of B.sub.2O.sub.3, ZnO, and TiO.sub.2, each in a range of 0 mol. % to 10 mol. %, such that the glass-ceramic further comprises a magnesium aluminosilicate crystalline phase at a concentration in a range of 5 wt. % to 80 wt. % of the glass-ceramic.

A tubular member for an exhaust gas treatment device according to at least one embodiment of the present invention includes: a tubular main body made of a metal; and an insulating layer formed at least on an inner peripheral surface of the tubular main body. The insulating layer contains glass containing a crystalline substance, and the glass contains silicon, boron, and magnesium.

Production of multilayered ceramic missile radomes with wide frequency band and high electromagnetic permeability through three-dimensional printing technology and the use of glass inter-layer materials to minimize defects caused by thermo-mechanical incompatibility of adjacent layers during sintering are provided. The three dimensional printing of the multilayered ceramic missile radomes provide an automated, operator-independent and repeatable manufacturing technique to produce wide band ceramic missile radomes.

Methods of forming a foldable substrate comprise providing a glass-based substrate comprising a first compressive stress region extending to an existing first depth of compression from an existing first major surface. Methods comprise contacting the existing first major surface with a solution to remove an outer compressive layer of the first compressive stress region to form a new first major surface. The outer compressive layer ranges from about 0.05 micrometers to about 5 micrometers. The solution can comprise a first temperature in a range from about 60° C. to about 120° C. The solution can comprise an alkaline solution comprising about 10 wt % or more of a hydroxide-containing base. In aspects, the method can comprise one or more of: attaching an adhesive layer to the new first major surface, attaching a display device to the new first major surface, or disposing a coating over the new first major surface.