Various single crystals are disclosed including sapphire. The single crystals have desirable geometric properties, including a width not less than about 15 cm and the thickness is not less than about 0.5 cm. The single crystal may also have other features, such as a maximum thickness variation, and as-formed crystals may have a generally symmetrical neck portion, particularly related to the transition from the neck to the main body of the crystal. Methods and for forming such crystals and an apparatus for carrying out the methods are disclosed as well.

Various single crystals are disclosed including sapphire. The single crystals have desirable geometric properties, including a width not less than about 15 cm and the thickness is not less than about 0.5 cm. The single crystal may also have other features, such as a maximum thickness variation, and as-formed crystals may have a generally symmetrical neck portion, particularly related to the transition from the neck to the main body of the crystal. Methods and for forming such crystals and an apparatus for carrying out the methods are disclosed as well.

Systems and methods for strengthening a sapphire part are described herein. One embodiment may take the form of a method including orienting a first surface of a sapphire member relative to an ion implantation device and performing a first implantation step. The implanting step may include directing ions at the first surface of the sapphire member to embed them under the first surface. The systems and methods may also include one or more of heating the sapphire member to diffuse the implanted ions into deeper layers of sapphire member, cooling the sapphire member, and performing at least a second implantation step directing ions at the first surface of the sapphire member to embed the ions under the first surface.

Systems and methods for strengthening a sapphire part are described herein. One embodiment may take the form of a method including orienting a first surface of a sapphire member relative to an ion implantation device and performing a first implantation step. The implanting step may include directing ions at the first surface of the sapphire member to embed them under the first surface. The systems and methods may also include one or more of heating the sapphire member to diffuse the implanted ions into deeper layers of sapphire member, cooling the sapphire member, and performing at least a second implantation step directing ions at the first surface of the sapphire member to embed the ions under the first surface.

Systems for and methods for improving mechanical properties of ceramic material are provided. The system comprises a heat source for heating the ceramic material to a temperature greater than a brittle-to-ductile transition temperature of the ceramic material; a probe for mounting the ceramic material and configured to extend the ceramic material into the heat source; a plasma-confining medium and a sacrificial layer disposed between the ceramic material and the plasma-confining medium; and an energy pulse generator such as a laser pulse generator. The sacrificial layer is utilized to form plasma between the ceramic material and the plasma-confining medium. The method comprises heating ceramic material to a temperature greater than a brittle-to-ductile transition temperature of the ceramic material and subjecting the ceramic material to energy pulses via a sacrificial layer and a plasma-confining medium whereby a plasma of the sacrificial coating forms between the ceramic material and a plasma-confining medium.

A self-supporting substrate includes a first nitride layer grown by hydride vapor deposition method or ammonothermal method and comprising a nitride of one or more element selected from the group consisting of gallium, aluminum and indium; and a second nitride layer grown by a sodium flux method on the first nitride layer and comprising a nitride of one or more element selected from the group consisting of gallium, aluminum and indium. The first nitride layer includes a plurality of single crystal grains arranged therein and being extended between a pair of main faces of the first nitride layer. The second nitride layer includes a plurality of single crystal grains arranged therein and being extended between a pair of main faces of the second nitride layer. The first nitride layer has a thickness larger than a thickness of the second nitride layer.

A self-supporting substrate includes a first nitride layer grown by hydride vapor deposition method or ammonothermal method and comprising a nitride of one or more element selected from the group consisting of gallium, aluminum and indium; and a second nitride layer grown by a sodium flux method on the first nitride layer and comprising a nitride of one or more element selected from the group consisting of gallium, aluminum and indium. The first nitride layer includes a plurality of single crystal grains arranged therein and being extended between a pair of main faces of the first nitride layer. The second nitride layer includes a plurality of single crystal grains arranged therein and being extended between a pair of main faces of the second nitride layer. The first nitride layer has a thickness larger than a thickness of the second nitride layer.

An object of this invention is to provide a crucible for growing a sapphire single crystal, which is optimized for providing a sapphire single crystal and is reusable. A crucible for growing a sapphire single crystal of this invention includes: a base material (3) containing molybdenum as a main component and having a crucible shape; and a coating layer (5) with which only an inner periphery of the base material (3) is coated and which is formed of tungsten and inevitable impurities, in which the coating layer (5) has a surface roughness Ra of 5 μm or more and 20 μm or less.

An object of this invention is to provide a crucible for growing a sapphire single crystal, which is optimized for providing a sapphire single crystal and is reusable. A crucible for growing a sapphire single crystal of this invention includes: a base material (3) containing molybdenum as a main component and having a crucible shape; and a coating layer (5) with which only an inner periphery of the base material (3) is coated and which is formed of tungsten and inevitable impurities, in which the coating layer (5) has a surface roughness Ra of 5 μm or more and 20 μm or less.

A heat-resistant synthetic jewelry material having a transparent, semitransparent or nontransparent composite nanocrystalline material on the basis of nanosized oxide and silicate crystalline phases. The material includes at least one of the following crystalline phases: spinel, quartz-like phases, sapphirine, enstatite, petalite-like phase, cordierite, willemite, zirconium, rutile, zirconium titanate, zirconium dioxide with a content of ions of transition elements, rare-earth elements and precious metals of from 0.001 to 4 mol %. One of the crystalline phases is additionally quartz-like solid solutions of lithium magnesium zinc aluminosilicates with a virgilite or keatite structure. The composition is selected from the following components,s SiO.sub.2, Al.sub.2O.sub.3, MgO, ZnO, Li.sub.2O, PbO, ZrO.sub.2, TiO.sub.2, NiO, CoO, CuO, Cr.sub.2O.sub.3, Bi.sub.2O.sub.3, Fe.sub.2O.sub.3, MnO.sub.2, CeO.sub.2, Nd.sub.2O.sub.3, Er.sub.2O.sub.3, Pr.sub.2O.sub.3 and Au.