Duennwandige,kohlenstoffhaltige Wabe und Verfahren zu ihrer Herstellung

1387143 Honeycomb structures of carbon NIPPON TOKI KK 25 Jan 1972 [18 May 1971] 3376/72 Heading ClA A honeycomb structure, i.e. a series of linked juxtaposed hollow bodies of substantially the same shape, made of carbon is formed by coating mandrels which are tubes or rods having the desired cross-sectional shape with a material which is carbonizable when heated at a sufficient temperature in a non-oxidizing environment, said tubes being carbonizable under the same conditions or said tubes or rods being removable from the product obtained by drying the coated mandrels without damage to the shaped body formed, either by sample withdrawal or dissolution, arranging the coated mandrels so they are in contact with one another and together form the desired honeycomb block, drying the coated mandrels and if appropriate removing the initial mandrel tube or rod by withdrawal or dissolution, and finally heating the dried product to carbonize it and form the desired honeycomb. The removable mandrel may be metallic or made of a thermoplastics material which latter is conveniently removed by dissolution. The honeycomb formed may be strengthened by impregnating the honeycomb with thermosetting resin. If desired, the resin impregnated body may be subsequently carbonized. The non-oxidizing environment used during the carbonizing step may be powdered carbon. The cells of the honeycomb may be of different sizes, and they may be made of amorphous carbon, active carbon, graphite or glassy carbon. The walls of the cells may be composed of two different types of carbon, one of which carbons may be formed by deposition on the other. The cells of the honeycomb may be circular, elliptical, triangular or polygonal. The carbonizable mandrels may be of paper or thermosetting resin and the materials used for coating the mandrels may contain carbon black, graphite powder, coke powder coal powder, and organic materials for example sugar, phenol-formaldehyde resin, powdered nut shells and staple artificial or natural fibres. All these coating materials have to be mixed with binders to provide green mouldings of sufficient strength. Suitable binders and solvents are listed. The carbon honeycombs may be subsequently activated to give an active carbon of stated surface area.