Abstract: Tough ceramic products can be prepared without exotic pressure fabricating techniques by use of a matrix laminate comprising a continuous fiber ceramic reinforcement in tow or woven form for strength, stiffness, and toughness and a ceramic matrix generally comprising (a) a filler, such as mullite; (b) ceramic reinforcing whiskers, such as silicon nitride or silicon carbide, for fine-scale interlaminar shear resistance (c) a binder, such as colloidal silica; and (d) an activator, such as a trona-like material including sodium and carbonate. The matrix is brushed into the fiber reinforcement, which is then laid up, dried, and cured. Tandem ceramic composites can be fabricated.

Abstract: The composite comprises ceramic fiberformed insulation bonded to a fiber reinforced ceramic matrix laminate. Ceramic insulation has a mat of intersecting, discrete ceramic fibers bonded with a sol-gel glass binder. The insulation is prepared by forming a slurry of ceramic fibers, molding the slurry to form a soft felt mat, drying the mat, and incrementally introducing the binder into the mat with a multiple-impregnation technique, which controls shrinkage of the ceramic fiber mat. This process provides a layering technique that permits formation of a continuous fibrous structure having layers that impart distinct characteristics at desired regions within the structure. By using different ceramic fibers and fibers of differing physical dimension, or by including additives with the slurries, tailoring of the physical characteristics of the insulation is achieved.