Abstract Fibers incorporating a boron and nitrogen containing composition are produced by reacting, with a nitrogen and hydrogen containing composition, fibers having a maximum diameter of about 20-30 microns and incorporating substantially throughout their thickness a boron and oxygen containing composition. Preferably, boric oxide fibers having a maximum diameter of about 10 microns are heated in an ammonia atmosphere according to a suitable temperature program to produce fibers consisting essentially of a boron nitride composition. Fibers may also be produced consisting of boron nitride and other constituents such as silica. Fibers produced according to the invention are useful for a wide variety of purposes including thermal and electrical insulation, fabrication of textiles and reinforcement of plastics, ceramics and metals.
An inorganic fiber as set forth in claim 1 having a maximum diameter of about 10 microns.
Claim 2
Dependent Claim
116 words
A process for the production of an inorganic fiber consisting essentially of from about 1 percent to about 99 percent by weight boron nitride and from about 99 percent to about 1 percent by weight silica which comprises heating a precursor fiber having a maximum diameter of about 30 microns and consisting essentially of boric oxide and silica at a temperature rise between 25* C. per hour and 5000* C. per hour up to a final temperature between 300* C. and 1500* C. in a current of ammonia having a flow rate between 0.025 liter and 6 liters/min./gram of fiber and continuing heating at said final temperature until said borIc oxide is converted to boron nitride.
Claim 3
Dependent Claim
20 words
A process as set forth in claim 3 wherein said precursor fiber has a maximum diameter of about 10 microns.