Patent EP-2192096-A2 (EP)
Inventor: SIEGEL DR STEFAN
IPC: C04B37/00
Filed: 2009-04-03
Abstract: The method for producing a ceramic component or carbon component with desired final geometries under using a cellulose-containing semi-finished molded part, which is pyrolysed in non-oxidizing gas atmosphere, comprises cohesively joining two semi-finished molded parts either in raw form or after partial carbonization, processing the joined molded parts for achieving the desired final geometries or one of the desired final geometries plus geometry corresponding to the over-measurement and then disposing as carbon component after the carbonization in the non-oxidizing gas atmosphere. The method for producing a ceramic component or carbon component with desired final geometries under using a cellulose-containing semi-finished molded part, which is pyrolysed in non-oxidizing gas atmosphere, comprises cohesively joining two semi-finished molded parts either in raw form or after partial carbonization, processing the joined molded parts for achieving the desired final geometries or one of the desired final geometries plus geometry corresponding to the over-measurement, disposing as carbon component after the carbonization in the non-oxidizing gas atmosphere and then converting into a ceramic matrix composite material by a metal infiltration process during simultaneous reactive joining of the two molded parts. The cohesive joining of the semifinished molded parts is carried out by an organic adhesive resin and wood glue in a raw state. Carbon carrier such as graphite, soot, pitch or pyrolysed fiber is added to the adhesive resin. The adhesive resin is used with optionally added carbon carrier for joining whose carbon yield is adapted to the requirements of the reactive ceramization during the pyrolysis and/or carbonization. The partially carbonized molded parts are joined by adhesive and/or water under using carbon-containing binder. A resin-based carbon-containing adhesive is used for cohesive joining of the two molded parts after partial carbonization. The adhesive used for joining the partially carbonized molded parts is sized by complementary additives such as graphite, soot, pitch and/or pyrolysed fiber with respect to its carbon supply for the reactive ceramization. Silicon and/or metallic carbide former that is single or in mixture is used for the metal infiltration process and/or the metal infiltration process is carried out over capillary-controlled liquid infiltration and/or metal vapor-containing gas atmosphere. The semifinished products are used in raw form and have a contour, which is coarsely adapted to the desired final geometries under the consideration of the shrinkage during the production of the ceramic component. The pyrolysis preceding the carbonization is carried out at a temperature (T(B)) of 250-800[deg] C and/or the carbonization is carried out at a temperature (T(V)) of 1100[deg] C. The joined semifinished molded parts are heated in steps of less than 0.1 K/minutes during the pyrolysis and/or the carbonization and/or the heating of the molded parts is carried out in steps of 5 K/minutes during the metal infiltration. After reaching a final temperature during the metal infiltration, the final temperature is kept over a time period (t) of 30 minutes. The modularly joined semifinished molded parts have maximum wall strength (D) of = 50 mm. The cellulose-containing hollow semifinished molded part consists of resin-containing binder and a raw material from plants and/or wood fibers. A medium density wood fiberboard with gross density and/or high density fiberboard are used as semifinished molded part, where surface areas are removed from the wood fiberboard and the density of the surface areas is larger than average density of the wood fiberboard. The structures and final product properties are requiremently controlled by impregnation the semifinished molded parts with resins and/or other ceramic precursors and/or component geometries and material structures are targetedly adjusted by joining process and/or impregnation process of the completely carbonized molded parts. Desired geometries, undercuts, recesses, subsections and/or threads are conformally or nearly conformally identified after the complete carbonization of the joined molded parts. A final processing of the ceramic component is restricted to required functional surfaces such as sealing surfaces by edging. The inorganic active components for the carbide formation and/or formation of later specific characteristic features of the ceramic component are introduced into the semi-finished molded part by metallic or organometallic additive for pressable offset. An independent claim is included for a method for producing ceramic composite materials and composite components made of the ceramic composite material.