CERAMIC FIBERS AND METHODS, MACHINES AND COMPOSITIONS OF MATTER FOR MAKING THE SAME

摘要

This invention relates to very fine, comparatively long, uniform surfaced and substantially round ceramic fibers and filaments, and apparatus, methods and compositions of matter for making same. Ceramic material of desired characteristics is rendered into a meniscus or convex molten apex of small horizontal diameter by such means as forming the ceramic feed-stock into a small diameter, solid rod (14) that is oriented vertically with its top end melted by a laser beam (22) or other nondisrupting, localized heat source, or using a synchronized vibrator or other physical energy means to produce a standing tip on the surface of molten ceramic contained in a crucible or other container. A narrow moving surface of adequate thermal, chemical and mechanical tolerance and heat transmission capability, such as the peripheral edge of a revolving molybdenum wheel (10) of small circumferential edge (12) width or a narrow endless belt, and the top surface of the molten apex (18) are brought into contact without the moving surface penetrating into the molten ceramic, and then backed away from each other. The ceramic, characterized, when molten, by its ability to wet the moving surface and by exhibiting melt viscosities that are conducive to free flowing as well as inherent cohesiveness, adheres to the moving surface, causing a strand (24) of ceramic to be formed, string-like, and pulled away from the molten apex, and then to be cooled while adhering to the moving surface. As it does so, it 'free-forms' into a smooth surfaced filament (26) of substantially uniform roundness because the surface tension of the outer surface layer of the strand then contracts, creating 'hoop' compression forces on the mass of the still fluid ceramic which it surrounds, thus forming the desired filament, which is then stripped off and recovered from the moving surface.