Manufacture and use of engineered carbide and nitride composites

Abstract

Carbides and nitrides are provided containing a controlled amount of pre-determined diluents and methods for their manufacture and use are disclosed. The pre-determined diluents include at least one of the silica, silicon metal, carbon, alumina, boron oxide, alkaline earth oxides such as calcium oxide, magnesium oxide, alkali oxides such as sodium oxide, potassium oxide, iron oxide, titanium oxide, and other components typically present in glass, ceramics, or metals. The carbides and nitrides with pre-determined diluents are formed by optionally pyrolyzing a precursor material to form a carboneous mixture and heat treating the carboneous mixture for a pre-determined time and at an elevated temperature during which carbon and / or nitrogen reacts with silica in the mixture to form carbides and / or nitrides and controlled amounts of pre-determined diluents. The carbides and nitrides disclosed herein may be used as blowing agents in a glass, ceramic, or metal forming processes or for promoting dispersion of the carbides and nitrides throughout a glass, ceramic, or metal composite.

Description

RELATED APPLICATIONS[0001]This application claims priority to U.S. Provisional Patent Application having Ser. No. 60 / 515,863, filed on Oct. 29, 2003 entitled “MANUFACTURE AND USE OF CARBIDES AND NITRIDES CONTAINING IMPURITIES,” the entire contents of which is expressly incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates generally to carbide and nitride composite materials, the manufacture of such composites, and their use in the glass making process.[0004]2. Description of the Related Art[0005]Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.[0006]Carbides and nitrides are commonly used to form various articles that can withstand high temperature and stress without substantial deterioration. They are particularly suitable for applications in which oxidation at h...

AI Technical Summary

Benefits of technology

[0013]According to another embodiment of the invention a blowing agent comprises carbide and/or nitride composite containing a diluent, wherein the diluent is a functional component of a glass, ceramic, or metal composite. The diluent may comprise, by weight percent, at least about 5, 10, 20, 40, 50, 80, or more of the blowing agent even up to about 99%. The diluent is preferably silica, carbon, alumina, boron oxide, calcium oxide, magnesium oxide, alkali metal oxides, iron oxide, titanium oxide, zirconium oxide, phosphorous oxide, or combinations thereof The blowing agent may further comprise a binder, which may be an alkali metal containing binder comprising greater than about 3 wt. % of the blowing agent. According to some embodiments, the binder may be alkali metal silicates, alkali metal borates, alkali metal phosphates, polymer emulsions, polyvinyl alcohol emulsions, cellulose ethers, methylcellulose, or sugar.

[0014]Another embodiment of the present invention teaches a method of forming a silicon carbide composite material, wherein the method comprises forming a precursor material comprising at least one silicate material and at least one carbon bearing material; pyrolyzing said precursor to form a carboneous mixture; and reacting carbons in said carboneous mixture with silicon from said silicate material in the presence of nitrogen or hydrogen, inert gases, or vacuum, to form silicon carbide and a controlled amount of at least one diluent, wherein said diluent makes up at least about 10% by weight of the silicon carbide composite material. The method may further include the step of drying sai

Problems solved by technology

Despite the known utility of carbides and nitrides, their widespread use in glass and ceramic manufacturing has been limited to a large extent by their production cost.

Even the technical grade products, which are generally less expensive than commercial grade products, are still costly when compared to conventional oxides such as silica and alumina used in the glass and ceramic industries.

The high cost is attributable in part to the high cost of manufacturing.

Homogeneous dispersion of silicon carbide in these composites is often problematic, requiring one or more processing steps to increase dispersion, yet still requires subsequent quality control checks.

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