A cover glass made of a glass ceramic that is silica based and has a main crystal phase of high quartz solid solution or keatite solid solution is provided. The cover glass has a stress profile with at least one inflection point at a depth of the cover glass of more than 10 μm, a thickness from 0.1 mm to 2 mm, and a chemical tempering structure with a surface compressive stress of at least 250 MPa and at most 1500 MPa. A process for producing the cover glass is provided that includes producing a silica based green glass, hot shaping the silica based green glass, thermally treating the silica based green glass with a nucleation step and a ceramization step, and performing an ion exchange at an exchange bath temperature for a duration of time in an exchange bath.

The present invention provides a microcrystalline glass product. The microcrystalline glass product includes the following components in percentage by weight: SiO.sub.2: 45-70%; Al.sub.2O.sub.3: 8-18%; Li.sub.2O: 10-25%; ZrO.sub.2: 5-15%; P.sub.2O.sub.5: 2-10%; and Y.sub.2O.sub.3: greater than 0 but less than or equal to 8%. Through reasonable component design, the microcrystalline glass and the microcrystalline glass product obtained in the present invention have excellent mechanical and optical properties and are suitable for electronic devices or display devices.

The present invention relates to a glass ceramic including crystals, and including, in mol % in terms of oxides: 65-75% of SiO.sub.2; 3-6% of Al.sub.2O.sub.3; 15-25% of Li.sub.2O; 0.2-4% of P.sub.2O.sub.5; 0.5-5% of ZrO.sub.2; and 0.01-0.5% of HfO.sub.2, in which the crystals include one or more kinds of crystals selected from the group consisting of β-spodumene crystals, petalite crystals, and eucryptite crystals.

A glass-based article may include from about 45 mol. % to about 80 mol. % SiO.sub.2; from about 0 mol. % to about 10 mol. % Na.sub.2O; less than about 5 mol. % K.sub.2O; a non-zero amount of Al.sub.2O; and an amorphous phase and a crystalline phase. The article may further in include a stress profile comprising a surface compressive stress (CS) and a maximum central tension (CT). A ratio of Li.sub.2O (mol. %) to R.sub.2O (mol. %) in the article is from about 0.5 to about 1, where R.sub.2O is the sum of Li.sub.2O, Na.sub.2O, and K.sub.2O in the article. CT may be greater than or equal to about 50 MPa and less than about 100 MPa. CS may be greater than 2.0.Math.CT. A depth of compression (DOC) of the stress profile may be greater than or equal to 0.14.Math.t and less than or equal to 0.25.Math.t, where t is the thickness of the article.

Lithium silicate materials are described which can be easily processed by machining to dental products without undue wear of the tools.

The invention relates to a medical form body of lithium silicate glass ceramic. To increase its strength it is proposed that in the form body comprising lithium silicate glass or containing lithium silicate glass the lithium ions are replaced by alkali ions of greater diameter to generate a surface compressive stress. To this end the form body is covered with a melt containing an alkali metal for which an aliquoted quantity of salt containing the alkali metal is used.

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 0.7.Math.t, comprise a tangent that is less than about −0.1 MPa/micrometers or greater than about 0.1 MPa/micrometers, 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). In some embodiments, the concentration of metal oxide or alkali metal oxide decreases from the first surface to a point between the first surface and the second surface and increases from the point 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 solid electrolyte material comprises Li, T, X and A wherein T is at least one of P, As, Si, Ge, Al, and B; X is one or more halogens or N; A is one or more of S and Se. The solid electrolyte material has peaks at 17.8°±0.75° and 19.2°±0.75° in X-ray diffraction measurement with Cu-Kα(1,2)=1.5418 Å and may include glass ceramic and/or mixed crystalline phases.

A chemically strengthened bioactive glass-ceramic composition as defined herein. Also disclosed are methods of making and using the disclosed compositions.

Coated glass or glass ceramic substrates having high temperature resistance, high strength, and a low coefficient of thermal expansion. The coating includes pores, is fluid-tight and suitable for coating a temperature-resistant, high-strength glass or glass ceramic substrate with a low coefficient of thermal expansion, and to a method for producing such a coated substrate.