Abstract:
금속 함량이 0.2mug/g인, 발열 제조된 고순도 이산화 규소는 금속 함량이 30ppb 미만인 사염화규소를 화염 가수분해에 의해 반응시킴으로써 제조된다. 이산화규소는 높은 균일도를 나타내는 졸-겔 공정에 의해 고순도 유리를 제조하는 데 활용될 수 있다. 이는 광섬유 방사용 예비성형품으로서 사용될 수 있는 형태의 제품의 제조에 사용될 수 있다. 발열 제조, 이산화규소, 사염화규소, 고온 가수분해, 졸-겔 공정, 광섬유.
Abstract:
A quartz glass crucible for use in pulling up a silicon single crystal, wherein it has, at least in the curved portion thereof, a three-layer structure comprising a transparent inner layer being composed of a synthetic quartz glass and having a low Al concentration, a transparent or nontransparent intermediate layer being composed of a natural quartz glass or a mixture of natural and synthetic quartz glasses and having a high Al concentration, and a nontransparent outer layer being composed of a natural quartz glass and having an Al concentration higher than that of the intermediate layer. The quartz glass crucible is reduced in the deformation of the transparent inner layer, and allows the suppression of the change in the amount of dissolution of the quartz glass crucible associated with the pull-up of a single crystal and the achievement of the uniform oxygen concentration in the longitudinal direction of a single crystal.
Abstract:
PURPOSE: Provided is a method for manufacturing a silica glass shaped body which has open pores and correct final dimension and design, useful for filter materials, heat insulation materials, heat shields, catalyst supports and preforms. CONSTITUTION: The method for manufacturing a homogeneous silica glass shaped body having correct final dimension and design comprises a step for electrodepositing amorphous SiO2 particles formed of amorphous SiO2 particles having a relatively large size and SiO2 particles having a relatively small size from a water soluble dispersion(5) thereof onto a non-conductive membrane(3) by electrophoresis. The membrane(3) has a shape and geometry corresponding to those of SiO2 shaped body to be produced. Additionally, the membrane(3) has an average pore size greater than the average particle size of the above amorphous SiO2 particles having a relatively small size.
Abstract:
PURPOSE: Provided is a quartz glass crucible having high purity at the part of its inner circumference, suitable to be used in a method for pulling monocrystalline silicon for semiconductors from molten silicon. CONSTITUTION: The quartz glass crucible is manufactured by heating powder of quartz raw material present in the inside of a hollow rotational mold(10) with electric arc, wherein an electric voltage is applied between the mold(10) and an arc electrode(13) to cause metal impurities contained in the molten quartz glass disposed at the inner circumference of the crucible to be moved toward the outer circumference so that the purity of the molten quartz glass is increased. The arc-melting of the quartz material is performed until the thickness of the resultant glass layer becomes a thickness of 5 mm or more and that of the non-molten quartz glass layer becomes 2 mm or less. During the arc-melting, an earth arc electrode is maintained at a potential of +/- 500V. A voltage of -1,000 to -20,000 V is applied to the mold electrically insulated with the earth.
Abstract:
The present invention is directed to a silica container for pulling single crystal silicon, the silica container including a straight body portion, a curved portion, and a bottom portion, wherein the outside of the silica container is made of opaque silica glass containing gaseous bubbles, the inside of the silica container is made of transparent silica glass containing substantially no gaseous bubble, and, on the inner surface of the bottom portion, a silica glass layer containing the OH group in a concentration of more than 300 ppm by mass but 3000 ppm by mass or less, the silica glass layer having a thickness of 20 µm or more but 1000 µm or less, is formed. As a result, a low-cost silica container for pulling single crystal silicon, the silica container that can reduce cavity defects called voids and pinholes in pulled single crystal silicon, is provided.
Abstract:
First of all, there is provided a production process of a synthetic quartz glass which has less impurity, has a high-temperature viscosity characteristic equal to or more than that of a natural quartz glass, and hardly deforms even in a high-temperature environment, and especially a production process of a highly heat resistant synthetic quartz glass which is free from the generation of bubbles and is dense. Secondly, there is provided a highly heat resistant synthetic quartz glass body which is easily obtained by the production process of the present invention, and especially a transparent or black quartz glass body which is free from the generation of bubbles, is dense, has high infrared absorption rate and emission rate, and has an extremely high effect for preventing diffusion of alkali metal. The process is a process of producing a highly heat resistant quartz glass body having an absorption coefficient at 245 nm of 0.05 cm−1 or more, and the silica porous body was subjected to a reduction treatment, followed by baking, thereby forming a dense glass body.