Fiberformed ceramic insulation and method

A process for forming an insulation material, comprising the steps of:

• (a) placing a glass fiber cloth in a vacuum mold;
• (b) molding a slurry containing ceramic fibers over the cloth in the mold to form a soft felt mat having intersecting ceramic fibers;
• (c) drying the mat;
• (d) impregnating the soft felt mat with a portion of a sol-gel glass binder so that the mat is dimensionally stable;
• (e) gelling the binder to form bonds at the intersections of the ceramic fibers;
• (f) curing the gelled binder;
• (g) repeating each of steps d, e, and f at least once to form a rigid mat;
• (h) applying powdered glass to the glass fiber cloth on one side of the mat;
• (i) heating the mat to melt the powdered glass;
• (j) cooling the mat to solidify the glass and to bond the cloth to the mat to complete the insulation.

Insulation, comprising:

• (a) a mat of ceramic fibers, some of said fibers intersecting one another;
• (b) sol-gel glass bonds where the fibers intersect;
• and
• (c) a glass coating bonded to at least one surface of the mat.

A process for forming insulation, comprising the (a) forming a plurality of slurries containing

• (a) forming a plurality of slurries containing ceramic fibers;
• (b) molding each slurry in succession to form a soft felt mat having interlocking layers of ceramic fibers from the respective slurries, some ceramic fibers within each layer intersecting one another;
• (c) drying the mat;
• (d) impregnating the dry mat with a portion of a sol-gel glass binder so that the mat is dimensionally stable upon curing of the binder;
• (e) gelling the binder to form bonds at the intersection of ceramic fibers;
• (f) curing the gelled binder;
• and
• (g) repeating each of steps d, e, and f at least once to strengthen the mat into the desired insulation.

Insulation, comprising:

• (a) a mat of ceramic fibers, the fibers being disposed in a plurality of layers, some ceramic fibers within each layer intersecting other fibers within the same layer, some fibers within each layer intersecting fibers in an adjacent layer;
• (b) sol-gel glass bonds at the intersection of the ceramic fibers;
• and
• (c) a glass coating on at least one surface of

Insulation, resistant to high temperatures and large temperature gradients, comprising:

• (a) a mat of aluminosilicate fibers having a length between about 1/16-4.0 in and a diameter between about
• (b) an alumina sol-gel binder applied to and cured with the fibers in at least two steps, a first step, in air, to stabilize the mat dimensionally and a second step, in air or ammonia, to strengthen the mat;
• (c) a glass coating of borosilicate glass bonded to at least one surface of the mat;
• and
• (d) an aluminoborosilicate glass fiber cloth, having a boron nitride coating, within the glass layer as a reinforcement.

A process for forming a ceramic insulation having improved strength and density, comprising the steps of:

• (a) forming at least one slurry of ceramic fibers;
• (b) molding the slurry to form a soft felt mat having intersecting ceramic fibers;
• (c) drying the soft felt mat;
• (d) impregnating the mat with a portion of a sol-gel glass binder;
• (e) gelling the first portion of binder to form bonds at the intersections of the ceramic fibers so that the mat is dimensionally stabilized;
• (f) curing the gelled binder;
• (g) impregnating the stabilized mat at least once with another portion of a sol-gel glass binder;
• (h) gelling each added portion;
• and
• (i) curing the added binder, after the series of impregnating and gelling steps, in a nitrogen-containing atmosphere to exchange nitrogen for oxygen in the cured binder to form the ceramic insulation.

Insulation, resistant to high temperatures and large temperature gradients, comprising:

• (a) a honeycomb core having a perforated septum dividing honeycomb cells into inner and outer cavities;
• (b) ceramic insulation in the outer cavities of the core, the insulation including at least one layer of a mat of ceramic fibers having intersecting fibers bonded together with a sol-gel glass binder applied in an incremental process to improve the strength and density of the insulation while maintaining the dimensions of the mat;
• and
• (c) a glass coating on the outer surface of the mat, the coating including a glass fiber cloth reinforcement.