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.

Embodiments of this disclosure pertain to articles that exhibit scratch-resistance and improved optical properties. In some examples, the article exhibits a color shift of about 2 or less, when viewed at an incident illumination angle in the range from about 0 degrees to about 60 degrees from normal under an illuminant. In one or more embodiments, the articles include a substrate, and an optical film disposed on the substrate. The optical film includes a scratch-resistant layer and an optical interference layer. The optical interference layer may include one or more sub-layers that exhibit different refractive indices. In one example, the optical interference layer includes a first low refractive index sub-layer and a second a second high refractive index sub-layer. In some instances, the optical interference layer may include a third sub-layer.

A glass article including at least about 40 mol % SiO.sub.2 and, optionally, a colorant imparting a preselected color is disclosed. In general, the glass includes, in mol %, from about 40-70 SiO.sub.2, 0-25 Al.sub.2O.sub.3, 0-10 B.sub.2O.sub.3; 5-35 Na.sub.20, 0-2.5 K.sub.2O, 0-8.5 MgO, 0-2 ZnO, 0-10% P.sub.2O.sub.5 and 0-1.5 CaO. As a result of ion exchange, the glass includes a compressive stress (as) at at least one surface and, optionally, a color. In one method, communicating a colored glass with an ion exchange bath imparts as while in another; communicating imparts as and a preselected color. In the former, a colorant is part of the glass batch while in the latter; it is part of the bath. In each, the colorant includes one or more metal containing dopants formulated to impart to a preselected color. Examples of one or more metal containing dopants include one or more transition and/or rare earth metals.

Glasses with compressive stress profiles that allow higher surface compression and deeper depth of layer (DOL) than is allowable in glasses with stress profiles that follow the complementary error function at a given level of stored tension. In some instances, a buried layer or local maximum of increased compression, which can alter the direction of cracking systems, is present within the depth of layer. Theses compressive stress profiles are achieved by a three step process that includes a first ion exchange step to create compressive stress and depth of layer that follows the complimentary error function, a heat treatment at a temperature below the strain point of the glass to partially relax the stresses in the glass and diffuse larger alkali ions to a greater depth, and a re-ion-exchange at short times to re-establish high compressive stress at the surface.

Chemically strengthened glass articles having at least one deep compressive layer extending from a surface of the article to a depth of at least about 45 μm within the article are provided. In one embodiment, the compressive stress profile includes a single linear segment extending from the surface to the depth of compression DOC. Alternatively, the compressive stress profile includes two linear portions: the first portion extending from the surface to a relatively shallow depth and having a steep slope; and a second portion extending from the shallow depth to the depth of compression. The strengthened glass has a 60% survival rate when dropped from a height of 80 cm in an inverted ball drop test and a peak load at failure of at least 10 kgf as determined by abraded ring-on-ring testing. Methods of achieving such stress profiles are also described.

Glass-based articles having sections of different thicknesses where a maximum central tension in a thinner section is less than that of a thicker section. The articles comprise an alkali metal oxide having a independent nonzero concentrations that vary along at least a portion of the thickness of each section. Consumer electronic products may comprise the glass-based articles having sections of different thicknesses.

A glass and an enclosure, including windows, cover plates, and substrates for mobile electronic devices comprising the glass. The glass has a crack initiation threshold that is sufficient to withstand direct impact, has a retained strength following abrasion that is greater than soda lime and alkali aluminosilicate glasses, and is resistant to damage when scratched. The enclosure includes cover plates, windows, screens, and casings for mobile electronic devices and information terminal devices.

The present disclosure relates to fusion formable highly crystalline glass-ceramic articles whose composition lies within the SiO.sub.2—R.sub.2O.sub.3—Li.sub.2O/Na.sub.2O—TiO.sub.2 system and which contain a silicate crystalline phase comprised of lithium aluminosilicate (β-spodumene and/or β-quartz solid solution) lithium metasilicate and/or lithium disilicate. Additionally, these silicate-crystal containing glass-ceramics can exhibit varying Na.sub.2O to Li.sub.2O molar ratio extending from the surface to the bulk of the glass article, particularly a decreasing Li.sub.2O concentration and an increasing Na.sub.2O concentration from surface to bulk. According to a second embodiment, disclosed herein is a method for forming a silicate crystalline phase-containing glass ceramic.

A strengthened glass container or vessel such as, but not limited to, vials for holding pharmaceutical products or vaccines in a hermetic and/or sterile state. The strengthened glass container undergoes a strengthening process that produces compression at the surface and tension within the container wall. The strengthening process is designed such that the tension within the wall is great enough to ensure catastrophic failure of the container, thus rendering the product unusable, should sterility be compromised by a through-wall crack. The tension is greater than a threshold central tension, above which catastrophic failure of the container is guaranteed, thus eliminating any potential for violation of pharmaceutical integrity.

A glass, glass-ceramic, or ceramic bead is described, with an internal porous scaffold microstructure that is surrounded by an amorphous shield. The shield serves to protect the internal porous microstructure of the shield while increasing the overall strength of the porous microstructure and improve the flowability of the beads either by themselves or in devices such as biologically degradable putty that would be used in bone or soft tissue augmentation or regeneration. The open porosity present inside the bead will allow for enhanced degradability in-vivo as compared to solid particles or spheres and also promote the growth of tissues including but not limited to all types of bone, soft tissue, blood vessels, and nerves.