Abstract:
The invention relates to a crucible for the crystallization of silicon and to the preparation and application of release coatings for crucibles used in the handling of molten materials that are solidified in the crucible and then removed as ingots, and more particularly to release coatings, for crucibles used in the solidification of polycrystalline silicone. The objective of the inventor was to provide a crucible which does not require the preparation of a very thick coating at the end user facilities, which is faster and cheaper to produce and which presents a stronger coating with an improved adherence to the walls. It has now been found that these problems can be solved with a crucible for the crystallization of silicon comprising a) a base body comprising a bottom surface and side walls defining an inner volume; b) an intermediate layer comprising 50 to 100 wt% of silica at the surface of the side walls facing the inner volume; and c) a surface layer comprising 50 to 100wt% silicon nitride, up to 50wt% of silicon dioxide and up to 20wt% of silicon on the top of the intermediate layer.
Abstract:
The present invention relates to refractory articles in general having improved surface properties. The objective of the invention is to propose an improvement of the refractory articles comprised of a fused silica matrix which will overcome the some of the defects while keeping the excellent known properties of the fused silica matrix. This objective is reached when a sintered ceramic phase is present in the porosity of at least a portion of at least a surface of the matrix. The present invention also relates to a process for producing such an article.
Abstract:
L'invention concerne un creuset monobloc (10) pour la fusion d'un produit non ferreux, du type comportant un fond (12) délimité par une surface interne sensiblement plane (16) du creuset entourée par une surface interne courbe (18) muni de moyens de marquage (20) matérialisant la base d'une zone imaginaire de remplissage (22) du produit à l'état solide dans le creuset, dans lequel les moyens de marquage (20, 20') séparent la surface plane (16) en une première partie (24) centrale et une seconde partie (26) périphérique. L'invention concerne également un procédé de remplissage d'un creuset pour la fusion d'un produit non ferreux, au cours duquel on dispose le produit à l'état solide dans une zone imaginaire (22) de remplissage du creuset. On utilise des moyens de marquage (20) pour matérialiser une base de la zone imaginaire de remplissage du produit à l'état solide dans le creuset, et l'on dispose le produit en fonction de ces moyens de marquage de telle sorte que le produit puisse se dilater lors de la fusion du produit non ferreux sans entrer en contact avec la surface interne courbe du creuset.
Abstract:
The invention relates to a crucible for the treatment of molten silicon comprising a basic body with a bottom surface and lateral walls defining an inner volume. According to the invention, the basic body comprises at least 65% by weight of silicon carbide, from 12 to 30 % by weight of a constituent selected from silicon oxide or nitride. Moreover, the basic body comprises at least one silicon oxide and/or nitride coating, at least on the surfaces defining the inner volume of the crucible contrarily to the state of the art crucibles, such a crucible can be used several times without any visible degradation of its physical integrity.
Abstract:
The invention relates to a crucible for the crystallization of silicon and to the preparation and application of release coatings for crucibles used in the handling of molten materials that are solidified in the crucible and then removed as ingots, and more particularly to release coatings for crucibles used in the solidification of polycrystalline silicon. The objective of the inventor was to provide a crucible comprising a silicon nitride coating which is faster and cheaper to produce and which is stronger with an improved adherence to the walls. It has now been found that these problems can be solved with a crucible for the crystallization of silicon comprising a) a base body comprising a bottom surface and side walls defining an inner volume; b) a protective coating comprises 80 to 95 wt. % of silicon nitride and 5 to 20 wt. of a low temperature mineral binder, the total oxygen content ranging from 5 to 15 % by weight.
Abstract:
The invention relates to a roller (21) from a refractory material, for example in vitreous silica, for transporting a flat article provided at its end with a new arrangement for rotationally driving it as well as to an assembly of such a roller and its driving device. This roller (21) comprises an external surface (2), an inner surface (5) and two side surfaces (12), at least one side surface having indentations (22) parallel to the roller axis (3) and spaced apart from the external (2) and inner surface (5) for receiving rotationally driving pins (8), it is characterized in that at least one of the indentations (22) of the roller is provided with a metal jacket (24). The invention permits to avoid the breakage of the roller around the driving indentations.
Abstract:
The present invention relates to refractory articles for guiding or conveying a solidified material comprising a vitreous silica basis, in particular rollers or guiding elements and to a process for the manufacture of said articles which do not show the pickup problems normally observed with the articles of the art. The refractory articles of the invention comprise a vitreous bases and, homogeneously distributed therein, a carbonaceous material.
Abstract:
A thermal insulation panel is constructed from a hot face layer, an intermediate layer and an ambient face layer. Features providing insulating capability include the incorporation of an IR opacifier into the hot face layer, the provision of a low conduction volume such as an air gap between the hot face layer and the intermediate layer, and between the intermediate layer and the ambient face layer, and the use of infrared reflective foil on the back surface of the hot face layer and/or on the front surface of the intermediate layer. Base materials that may be used in the hot face layer include silica, alumina, and alumina-silica based ceramic materials. IR opacifiers in the hot face layer may contain ZrO 2 , SiC, rutile, TiO 2 , MnO, iron oxides, CrO 2 , ZrSiO 2 , Al 2 O 3 and mixtures thereof.
Abstract:
The invention encompasses a method for manufacturing a high density indium oxide/tin oxide (ITO) sintered body, as well as the ITO sintered body itself. The method produces an ITO sintered body of high homogeneity for use as a sputtering target in manufacturing processes where thin, transparent and electrically conductive ITO layers are deposited over transparent substrates. The method comprises the steps of preparing a slurry whose solid constituents consist of a finely divided mixture of between 99 and 50 weight percent of In2O3 and 1 to 50 weight percent of SnO2, and between about 0.05 through 0.25 percent of a sintering agent formed from an oxide of only one of the group consisting of aluminum, magnesium, yttrium, and silicon; forming the resulting slurry into a green body having a density of between about 4.0 and 4.8 gm/c and heating the green body to a sintering temperature of between about 1500 and 1600 DEG C while maintaining a flow of oxygen over the green body sufficient avoid the creation of a reducing atmosphere around the body, but insufficient to cause substantial disassociation of the In2O3 and SnO2. The green body may be formed by casting the resulting slurry or by adding a powdered binder to the slurry, spray drying it, and cold pressing the resulting powder.
Abstract:
The invention concerns a fired magnesia-carbon shape (12) having a combination of properties making it especially suitable for slide gate plates, inserts for such plates and for pouring nozzles (2) useful in casting aggressive steels. The fired refractory shape (12) is formed from a batch consisting essentially of, by weight percent: 2 to 8 finely divided graphite (natural or synthetic); 3 to 8 aluminum metal powder; 1 to 5 of finely divided silica and/or a silicon yielding powder; an effective amount of carbon bond forming resins; and the balance coarse and fine magnesia grains. The magnesia grains should contain less than about 0.02 weight percent boron oxide. After firing, the shape is characterized by a carbon bonding system including a spinel (magnesia-alumina) phase plus aluminum carbide bonding the magnesia-carbon matrix. The refractory shape is preferably carbon impregnated after firing to further enhance its properties.