Abstract:
The invention relates to a method for the production of opaque quartz glass wherein a blank is made from synthetic SiO2 crystals and heated to form a blank body made of opaque quartz glass at a given vitrification temperature. A method for the production of pure, opaque quartz glass is disclosed wherein said quartz glass has a homogeneous pore distribution and a high density, a high viscosity and a lower tendency to devitrify. According to the invention, the SiO2 crystals are formed from an at least partially porous agglomerate of SiO2 primary particles (21; 31) having a specific surface (according to BET) between 1.5 m2/g and 40 m2/g with a stamping density of at least 0.8 g/cm3. SiO2 granulate (21; 31) suitable for use in performing the procedure is characterized in that it is composed of an at least partially porous agglomerate of SiO2 primary particles and has a specific surface (according to BET) between 1.5 m2/g and 40 m2/g in addition to a stamping density of at least 0.6 g/cm3.
Abstract:
An opaque silica glass article comprising a transparent portion and an opaque portion, wherein the opaque portion has an apparent density of 1.70 - 2.15 g/cm 3 and contains 5 x 10 4 - 5 x 10 6 bubbles per cm 3 , said bubbles having an average diameter of 10 - 100 µm; and the transparent portion has an apparent density of 2.19 - 2.21 g/cm 3 and the amount of bubbles having a diameter of at least 100 µm in the transparent portion is not more than 1 x 10 3 per cm 3 . The opaque silica glass article is made by a process wherein a mold is charged with a raw material for forming the opaque portion, which is a mixture comprising a silica powder with a small amount of a silicon nitride powder, and a raw material for forming the transparent portion so that the two raw materials are located in the positions corresponding to the opaque and the transparent portions, respectively, of the silica glass article to be produced; and the raw materials are heated in vacuo to be thereby vitrified.
Abstract:
An object of the present invention is to provide silica glass having high purity, high heat resistance, large coefficient of thermal expansion, and low light transmittance and a method of producing the same. Another object of the present invention is to provide a silica glass jig with a vapor-deposited film thereon. Therefore cristobalite-contained silica glass wherein α-cristobalite in the shape of a small sphere or a small, round-edged or sharp-edged, three-dimensional region is dispersed in the silica glass matrix, the diameter of each α-cristobalite sphere or region is in the range of 0.1 νm to 1000 νm, and a content of the α-cristobalite is at least 10 wt.%. A method of producing the cristobalite-contained silica glass by heating a mixture of two kinds or more of crystalline silicon dioxide powder the melting points of which silicon dioxide are different from each other by 20 °C or more wherein the mixture contains the silicon dioxide having the highest melting point at a content in the range of 10 wt.% to 80 wt.% and is heated at temperatures in the range of the lowest melting point of the ingredients to a temperature lower than the highest melting point. The silica glass jig is made of the cristobalite-contained silica glass and the surface of the jig is covered with a vapor-deposited thin film which has a property of being resistant to plasma etching, and which is made of a material of almost the same coefficient of thermal expansion as that of the silica glass. The silica glass jig has no chance to generate particles therefrom and thereby to contaminate a silicon wafer.
Abstract:
The present invention is to provide a synthetic quartz glass body having a high light transmittance. The present invention provides a synthetic quartz glass body having pores in a surface part thereof, having been formed by physical or chemical etching.
Abstract:
Die Erfindung betrifft ein Verfahren zur Herstellung eines Bauteils aus opakem, synthetischen Quarzglas und ein nach dem Verfahren hergestelltes Quarzglasrohr. Um die kostengünstige Herstellung von Bauteilen, insbesondere von dünnwandigen Rohren oder Rohrteilen aus opakem Quarzglas hoher chemischer Reinheit und hoher Maßhaltigkeit zu ermöglichen wird erfindungsgemäß vorgeschlagen, ein Ausgangsmaterials bereitzustellen in Form eines Granulats aus synthetischem, hochreinem SiO 2 , das aus mindestens teilweise porösen Agglomeraten von SiO 2 -Primärteilchen gebildet ist und das eine Stampfdichte von mindestens 0,8 g/cm 3 aufweist, das Granulats in eine Form einzubringen und zu einer Vorform aus opakem Quarzglas zu erschmelzen und die Vorform in einem Heißumformprozess unter Bildung des Bauteils aus opakem Quarzglas umzuformen. Ein nach dem Verfahren hergestelltes Quarzglasrohr, das insbesondere zur Verwendung bei der Halbleiterfabrikation geeignet ist, zeichnet sich dadurch aus, dass es aus Quarzglas besteht, das aus einem Granulat aus synthetischem SiO 2 mit einem Lithium-Gehalt von maximal 100 Gew.-ppb hergestellt ist, und dass es eine Wandstärke im Bereich von 0,5 bis 15 mm aufweist.
Abstract:
Disclosed is a quartz glass product of enhanced opacity manufactured by fusion of silica particles, the opacity being enhanced by the reaction of an organosilicon additive in the course of the fusion process. A method of enhancing the opacity of a quartz glass product by fusing silica particles in the presence of an organosilicon additive is also disclosed.
Abstract:
Disclosed is a quartz glass product of enhanced opacity manufactured by fusion of silica particles, the opacity being enhanced by the reaction of an organosilicon additive in the course of the fusion process. A method of enhancing the opacity of a quartz glass product by fusing silica particles in the presence of an organosilicon additive is also disclosed.