Planar porous composite structure and method for its manufacture

A method of manufacturing a planar porous composite structure, said method comprising the steps of:

• providing a plurality of regular textile planar layers selected from the group consisting of knitted, woven and braided layers, said layers being formed of continuous yarns, a reinforcing structure formed by reinforcing fibers included in said continuous yarns, and a matrix formed by a thermoplastic matrix material also included in said continuous yarns;
• said regular textile planar layers having each a plurality of openings extending through said layers, each of said openings being defined by portions of said continuous yarns and making the layers regular in structure;
• piling said regular textile planar layers on top of each other to form a structure having two dimensions at right angles to each other and a third dimension perpendicular to them and defining a plane having a direction along said two dimensions, said continuous yarns extending in the direction of said plane in said structure;
• forming a plurality of passages having walls and extending entirely through said structure in a direction substantially perpendicular to the plane of the structure by aligning said layers with respect to each other so that at least a portion of said openings in each of said layers are aligned with each other;
• joining said portions of said continuous yarns defining said openings and directly joining said layers by heating said matrix material to a melting temperature to allow the walls of the passages to be formed simultaneously by said continuous yarns extending in the direction of said plane and substantially perpendicularly to the passages, thereby simultaneously stiffening said structure;
• forming said matrix material into a desired shape;
• and
• cooling said structure.

A method of manufacturing a planar porous composite structure, said method comprising the steps of:

• providing a plurality of regular textile planar layers selected from the group consisting of knitted, woven and braided layers, said layers being formed of continuous yarns, a reinforcing structure formed by reinforcing fibers included in said continuous yarns, and a matrix formed by a matrix material carbonizable in a heat treatment into amorphous carbon, said matrix material also included in said continuous yarns;
• said regular textile planar layers having each a plurality of openings extending through said layers, each of said openings being defined by portions of said continuous yarns and making the layers regular in structure;
• piling said regular textile planar layers on top of each other to form a structure having two dimensions at right angles to each other and a third dimension perpendicular to them and defining a plane having a direction along said two dimensions, said continuous yarns extending in the direction of said plane in said structure;
• forming a plurality of passages having walls and extending entirely through said structure in a direction substantially perpendicular to the plane of the structure by aligning said layers with respect to each other so that at least a portion of said openings in each of said layers are aligned with each other;
• carbonizing said layers using heat in a protective atmosphere in an oven so that said carbonizable material is transformed into amorphous carbon to allow the walls of the passages to be formed simultaneously by said continuous yarns extending in the direction of said plane and substantially perpendicularly to the passages;
• and
• cooling said structure.