University of Michigan

Gregory E Hilmas

John William Halloran

Scott R Somers

Gregory Zywicki

Andrew Barda

Guy Allen Brady

Tseng-Ying Tein

Dragan Popovic'

A method for the preparation of a fibrous monolithic ceramic which exhibits non-brittle fracture characteristics from green monofilament ceramic fibers having a controlled texture. This method includes the steps of: (a) forming a first ceramic-laden composition includes a thermoplastic polymer and at least about 40 vol. % of a ceramic particulate into a substantially cylindrical core, (b) applying a layer of a second ceramic-laden composition includes a thermoplastic polymer and at least about 40 vol. % of a ceramic particulate which differs from the particulate contained in the first composition onto the core to form a substantially cylindrical feed rod having an average initial diameter, (c) extruding the feed rod to form a green ceramic monofilament fiber which has an average diameter that is less than the average diameter of the feed rod, and (e) arranging the green ceramic monofilament fibers into a desired configuration to provide a green fibrous monolith, wherein, during the extrusion step, each ceramic-laden composition has a viscosity which is approximately equivalent to that of each other ceramic-laden composition, and, if the ceramics present in the extruded ceramic monofilament fiber are sintered, a plane of weakness defined by the interface of the core and the layer is provided, the interface being relatively weaker than the core. The green fibrous monolith may be sintered to provide a fibrous monolith.

Process for preparing textured ceramic composites

Method of improving the toughness of SiC-based ceramics. SiC, , AlN, Al.sub.2 O.sub.3 and optionally .alpha.-Si.sub.3 N.sub.4 are hot pressed to form a material which includes AlN polytypoids within its structure.

Method for improving the toughness of silicon carbide-based ceramics

Growing community of inventors

Dexter, MI, United States of America

Gregory E Hilmas