Method for producing refractory filaments

Abstract

A process of producing at least one filament of refractory material comprising: (a) preparing a spin mix of a solution of cellulose and particles of refractory material; (b) wet spinning the spin mix to form at least one filament of regenerated cellulose having at least a portion of the particles dispersed therein; and (c) heating the filament of regenerated cellulose to remove substantially all of the regenerated cellulose and to sinter the portion of the particles dispersed therein to form a filament of the refractory material.

What is claimed is:  
     
         1 . A process of producing at least one filament of refractory material comprising: 
 preparing a spin mix of a solution of cellulose and particles of refractory material;    wet spinning said spin mix to form at least one filament of regenerated cellulose having at least a portion of said particles dispersed therein; and    heating said filament of regenerated cellulose to remove substantially all of said regenerated cellulose and to sinter said portion of said particles dispersed therein to form a filament of said refractory material.    
     
     
         2 . The process of  claim 1 , wherein said solution of cellulose is viscose.  
     
     
         3 . The process of  claim 1 , wherein said filament of regenerated cellulose is prepared using a lyocell process.  
     
     
         4 . The process of  claim 1 , wherein heating said filament to remove substantially all of said regenerated cellulose is conducted in an oxygen-containing environment at a temperature of about 200° C. to about 600° C.  
     
     
         5 . The process of  claim 1 , wherein heating said filament to sinter said portion of particles is conducted at a temperature of about 750° C. to about 2200° C.  
     
     
         6 . The process of  claim 1 , wherein wet spinning said spin mix comprises: 
 extruding said spin mix through a spinneret to form a stream; and    treating said stream with a solvent extraction medium to extract the solvent of the solution of cellulose from said stream to form said filament of regenerated cellulose.    
     
     
         7 . The process of  claim 6 , wherein said solvent extraction medium is an acid bath.  
     
     
         8 . The process of  claim 6 , wherein treating said stream reduces the diameter of said stream.  
     
     
         9 . The process of  claim 6 , further comprising pulling said filament of regenerated cellulose while treating said stream to stretch said stream as it forms said filament of regenerated cellulose.  
     
     
         10 . The process of  claim 9 , wherein said stream is stretched from about 32% to about 128% in forming said filament of regenerated cellulose.  
     
     
         11 . The process of  claim 9 , wherein diameter of said filament of regenerated cellulose is substantially less than said diameter of said spinneret.  
     
     
         12 . The process of  claim 1 , wherein the weight ratio of said particles to said cellulose in said spin mix is about 1:4.  
     
     
         13 . The process of  claim 12 , wherein the weight ratio of said particles to said cellulose in said spin mix is about 4:1.  
     
     
         14 . The process of  claim 1 , wherein said refractory material is a ceramic material.  
     
     
         15 . The process of  claim 14 , wherein said refractory mate rial is at least silicon carbide, aluminum nitride, silicon nitride, aluminum oxide, tin oxide, titanium carbide, hafnium oxide, zirconium oxide, titanium dioxide, molybdenum disilicide, lithium aluminate, ferrite, PZT (lead zirconium titanate), antimony oxide, a precursor for a superconductive ceramic, or a powdered, electrically conductive substoichiometric titanium dioxide having uniformly distributed within its molecular structure a chemically-combined metal of at least chromium, copper, nickel, platinum, tantalum, zinc, magnesium, ruthenium, iridium, niobium, vanadium, tin.  
     
     
         16 . The process of  claim 15 , wherein said refractory material is a piezoelectric material.  
     
     
         17 . The process of  claim 1 , wherein the filaments of refractory material have one or more defined properties selected from current carrying capacity, range of physical or mechanical properties, electrochemical properties, electrorestrictive properties or other properties which are substantially the same as the corresponding properties of said refractory material from which said filaments are prepared.  
     
     
         18 . A process of producing at least one filament of refractory material comprising: 
 preparing at least one filament of regenerated cellulose having particles of refractory material dispersed therein using a lyocell process; and    heat treating said filament of regenerated cellulose to remove substantially all of said regenerated cellulose and to sinter said particles dispersed therein to form said filament of said refractory material.    
     
     
         19 . The process of  claim 18 , wherein preparing said filament of regenerated cellulose comprises: 
 extruding a spin mix comprising a solution of cellulose and said particles of refractory material through a spinneret to form a stream; and    treating said stream with a solvent extraction medium to extract the solvent of the solution of cellulose to form said filament of regenerated cellulose.    
     
     
         20 . The process of  claim 18 , wherein the weight ratio of said particles to said cellulose in said spin mix is about 1:4.  
     
     
         21 . The process of  claim 20 , wherein the weight ratio of said particles to said cellulose in said spin mix is about 4:1.  
     
     
         22 . The process of  claim 20 , wherein said refractory material is at least silicon carbide, aluminum nitride, silicon nitride, aluminum oxide, tin oxide, titanium carbide, hafnium oxide, zirconium oxide, titanium dioxide, molybdenum disilicide, lithium aluminate, ferrite, PZT (lead zirconium titanate), antimony oxide, a precursor for a superconductive ceramic, or a powdered, electrically conductive substoichiometric titanium dioxide having uniformly distributed within its molecular structure a chemically-combined metal of at least chromium, copper, nickel, platinum, tantalum, zinc, magnesium, ruthenium, iridium, niobium, vanadium, tin.  
     
     
         23 . The process of  claim 22 , wherein said refractory material is a piezoelectric material.