Process for the manufacture of a ceramic foam part
AssigneeDeutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V.
InventorsHenri Bauer, Reiner Buck, Antje Seitz, Rainer Tamme
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Abstract
To provide a process for the manufacture of a ceramic part which is a ceramic part resistant to temperature changes and, in particular, suitable also for high temperatures, it is suggested that a formed body be produced by forming and sintering a ceramic material essentially comprising non-oxidic ceramic components and that the ceramic part be produced from the formed body by oxidizing the ceramic material starting from a surface of the formed body.
Claims13
Process for manufacturing a ceramic part, comprising the steps of:
- forming and sintering a ceramic material comprising non-oxidic ceramic components including at least one of a carbide and a nitride to obtain a formed body of an open cell porous ceramic foam material having pores surrounded by webs to provide a flow path for a transport medium, said formed body having a contour which is close to a final contour with a desired dimension of said ceramic part;
- said contour of said formed body being defined by an outer surface thereof;
- and
- oxidizing the at least one of a carbide and a nitride of said ceramic material of said formed body starting from said outer surface of said formed body by exposing said outer surface to an oxidizing agent in an oxidizing atmosphere, thereby converting the at least one of a carbide and a nitride to an oxide at said outer surface of said formed body and at least partially into a cross section thereof to cause at least a portion of said formed body to expand in a controlled manner to achieve said final contour with said desired dimension merely by said oxidation step;
- wherein the oxidation is carried out for such a time until substantially all exposed surfaces of the ceramic material including the pores thereof which provide flow paths for said transport medium have been passivated by said oxide.
A process for manufacturing a ceramic part with a desired final contour, comprising the steps of:
- obtaining a formed body with an initial contour which is close to said final contour by forming and sintering a ceramic material comprising non-oxidic ceramic components including at least one of a carbide and a nitride;
- said formed body comprising an open cell ceramic foam material having pores surrounded by webs to provide a flow path for a transport medium;
- said initial contour of said formed body being defined by an outer surface thereof;
- and
- oxidizing said formed body starting from said outer surface by exposing said outer surface to an oxidizing agent in an oxidizing atmosphere in a controlled manner to convert the at least one of a carbide and a nitride to an oxide at said outer surface and at least partially into a cross section thereof, thereby causing at least a portion of said formed body to expand in a correspondingly controlled manner to achieve said desired final contour merely by said oxidation step;
- wherein the oxidation is carried out for such a time until substantially all exposed surfaces of the ceramic material including the pores thereof which provide flow paths for said transport medium have been nassivated by said oxide.
Dependencies are inferred from the claim text.