Provided is a method that can manufacture a glass material having excellent homogeneity by containerless levitation. With a block (12) of glass raw material held levitated above a forming surface (10a) of a forming die (10) by jetting gas through a gas jet hole (10b) opening on the forming surface (10a), the block (12) of glass raw material is heated and melted by irradiation with laser beam, thus obtaining a molten glass, and the molten glass is then cooled to obtain a glass material. Control gas is jetted to the block (12) of glass raw material along a direction different from a direction of jetting of the levitation gas for use in levitating the block (12) of glass raw material or the molten glass.

Methods for making articles comprising crystalline material. Exemplary articles made by a method described herein include electronics enclosure (e.g., a watch case, cellular phone case, or a tablet case).

The present invention relates to a black quartz glass comprising Si of 0.5 to 10 mass %, SiO of 0.1 to 5 mass % and SiO.sub.2 of the residue, wherein the SCE reflectance at a wavelength of 350 nm to 750 nm is 10% or less; a method for producing the black quartz glass, comprising: pressure-molding a powder obtained by mixing and consolidating (1) fumed silica, or (2) a mixture powder of fumed silica and a synthetic silica powder, or (3) a mixture powder of fumed silica, spherical silica and a synthetic silica powder, with a Si powder of 0.5 to 10 mass % and a SiO powder of 0.1 to 5 mass %, and heating and sintering the pressure-molded product in the atmosphere; and a product comprising a black quartz glass member made of the black quartz glass. The present invention allows to provide a black quartz glass which has an excellent light-shielding property, has no risk of causing contamination in a step of using it, has sufficient color uniformity when the size is enlarged, and is capable of producing a large ingot, and to provide a method for producing the black quartz glass with excellent productivity even in the large ingot, and to provide a black quartz glass product made of the black quartz glass.

A process for the preparation of multi-coloured glass ceramic blanks for dental purposes is described, in which lithium silicate glasses with different compositions are introduced into a mould in order to form a glass blank, the glass blank is optionally compacted by pressing, the glass blank is heat-treated in order to obtain a glass ceramic blank with lithium silicate as main crystal phase, and the glass ceramic blank is compacted by hot pressing.

Provided is a method that can manufacture a glass material having excellent homogeneity by containerless levitation. With a block (12) of glass raw material held levitated above a forming surface (10a) of a forming die (10) by jetting gas through a gas jet hole (10b) opening on the forming surface (10a), the block (12) of glass raw material is heated and melted by irradiation with laser beam, thus obtaining a molten glass, and the molten glass is then cooled to obtain a glass material. Control gas is jetted to the block (12) of glass raw material along a direction different from a direction of jetting of the levitation gas for use in levitating the block (12) of glass raw material or the molten glass.

Provided is a glass material that can satisfy both high Faraday effect and high light transmittance at wavelengths used. A glass material containing, in terms of % by mole of oxide, more than 40% Tb.sub.2O.sub.3 and having a percentage of Tb.sup.3+ of 55% by mole or more relative to a total content of Tb.

Composite materials are provided which include a glass-ceramic matrix composition that is lightly crystallized, a fiber reinforcement within the glass-ceramic matrix composition which remains stable at temperatures greater than 1400 C., and an interphase coating formed on the fiber reinforcement. A method of making a composite material is also provided, which includes applying heat and pressure to a shape including fiber reinforcements and glass particles. The heat and pressure lightly crystallize a matrix material formed by the heat and pressure on the glass particles, forming a thermally stable composite material.

Provided is a method that enables a crystal-free glass material to be stably produced by a containerless levitation technique. A glass material 30 has a first surface 31 facing a forming surface 10a and a second surface 32 located on a side opposite to the forming surface 10a. The first surface 31 includes a central portion 31a and a peripheral portion 31b located outside of the central portion 31a. Gas is jetted through a gas jet hole at a flow velocity and a flow volume at which a glass material satisfying R.sub.2<R.sub.3<R.sub.1 is formed where R.sub.1 represents a radius of curvature of the central portion 31a, R.sub.2 represents a radius of curvature of the peripheral portion 31b, and R.sub.3 represents a radius of curvature of the second surface 32.

A quartz glass provides an opaque quartz glass having high light-shielding property, excellent mechanical strength and excellent cleaning resistance against hydrofluoric acid. By setting the maximum width of the amorphous bubbles existing in the opaque quartz glass to an average of 3 to 15 m and the density to 2.15 g/cm.sup.3 or more, the mechanical strength after baking and the cleaning resistance by hydrofluoric acid are improved. The opaque quartz glass has a whiteness at a thickness of 10 mm of 75 to 90%, the reflectance of light with a wavelength of 0.24 to 2.6 m at a thickness of 4 mm is 60 to 85%, and the bending strength after baking is 95 MPa. In addition, a foaming agent may be mixed in the opaque quartz glass. An opaque quartz glass having cleaning resistance against acid can be obtained.

The invention discloses a method for preparing lead smelting slag glass-ceramics based on the oxidation of silicon-rich silicon smelting slag and composition adjustment, and belongs to the technical field of resource utilization of smelting slag rich in monatomic silicon. The method comprises the steps: mixing the silicon slag rich in monatomic silicon with an oxidant, a fluxing agent and a clarifying agent according to a formula ratio, ball-milling and screening to obtain a tempering raw material with uniform size, and performing high-temperature oxidation melting on the tempering raw material to form an oxidation-state molten tempering material; and carrying out further mixed melting on the molten tempering material and hot lead slag, carrying out water quenching to obtain basic glass, and carrying out heat treatment system on the obtained basic glass to form the glass ceramics. According to the method, the smelting slag rich in monatomic silicon is subjected to oxidation tempering and mixed melting with the hot lead slag to prepare the basic glass, and the glass ceramics are obtained by regulating and controlling the heat treatment system of the basic glass. The method is simple in technological process, high in production efficiency and low in cost, achieves the collaborative high-value conversion target of the silicon-rich silicon slag and the lead slag, and is easy to industrially popularize and apply.