SHAPED CERAMIC COMPOSITES AND METHODS OF MAKING THE SAME

    公开(公告)号:ZA872584B

    公开(公告)日:1987-09-30

    申请号:ZA872584

    申请日:1987-04-10

    Abstract: A method of producing self-supporting ceramic composite bodies of desired shaped by infiltrating a permeable preform with polycrystalline matrix material consisting essentially of an oxidation reaction product obtained by oxidation of a parent metal precursor, such as aluminum, and optionally containing therein metallic constituents. The composite body is formed by contacting a zone of a permeable preform, having at least one defined surface boundary spaced from said contacting zone, with a body of molten metal which is reacted with a suitable vapor-phase oxidant to form an oxidation reaction product. Within a certain temperature region, and optionally with one or more dopants in or on the parent metal or said permeable preform, molten parent metal migrates through previously formed oxidation reaction product into contact with the oxidant, causing the oxidation reaction product to grow into the preform toward said defined surface boundary so as to infiltrate the preform up to said defined surface boundary, and provide the composite structure of desired geometry.

    74.
    发明专利
    未知

    公开(公告)号:ES2032469T3

    公开(公告)日:1993-02-16

    申请号:ES87630135

    申请日:1987-07-28

    Abstract: There is disclosed a method for making a self-supporting ceramic composite article having a porous core bearing a dense surface layer formed integrally with said core. A preform comprises a filler material and parent metal distributed therethrough, wherein the volume percent of parent metal is sufficient to form a volume of oxidation reaction product exceeding the total volume available within said preform. The parent metal is molted and reacted with an oxidant to form an oxidation reaction product filling the spatial volume and leaving voids. The reaction is continued to further transport molten parent metal through the oxidation reaction product to at least one surface of the preform to form oxidation reaction product on said surface substantially free of voids thereby forming a relatively dense surface layer.

    75.
    发明专利
    未知

    公开(公告)号:ES2000418T3

    公开(公告)日:1993-02-16

    申请号:ES87630075

    申请日:1987-04-30

    Abstract: A method of producing self-supporting ceramic composite bodies of desired shaped by infiltrating a permeable preform with polycrystalline matrix material consisting essentially of an oxidation reaction product obtained by oxidation of a parent metal precursor, such as aluminum, and optionally containing therein metallic constituents. The composite body is formed by contacting a zone of a permeable preform, having at least one defined surface boundary spaced from said contacting zone, with a body of molten metal which is reacted with a suitable vapor-phase oxidant to form an oxidation reaction product. Within a certain temperature region, and optionally with one or more dopants in or on the parent metal or said permeable preform, molten parent metal migrates through previously formed oxidation reaction product into contact with the oxidant, causing the oxidation reaction product to grow into the preform toward said defined surface boundary so as to infiltrate the preform up to said defined surface boundary, and provide the composite structure of desired geometry.

    76.
    发明专利
    未知

    公开(公告)号:ES2031923T3

    公开(公告)日:1993-01-01

    申请号:ES87630179

    申请日:1987-09-03

    Abstract: Ceramic bodies are bonded by providing a first body formed of polycrystalline material and interconnected residual metal formed by the oxidn. reaction of molten metal and a vapour phase oxidant and grown as molten metal is transported through and then oxidised on the surface of its own oxidn. reaction prod.; holding a second ceramic body against a surface of the first; and heating so that the residual metal content of the first body is transported to the interface where an oxidn. reaction prod. continues to grown as above and forms a bond. - Specifically the metal is Al, oxidant is air and oxidn. reaction prod. is Al2O3. The first body may be formed by infiltrating a filler with oxidn. reaction prod. A barrier material, pref. Ca sulphate, silicate or phosphate or Portland cement, is used to embed and surround all surfaces of the first body except the contacting surface. A body of metal may be placed in contact with another surface of the first body embedded in the barrier material, so that the metal melts and is transported to the bonding interface during the heating step. The second body may have the same ceramic compsn. as the first; it may be made by a different method; or may be of a different compsn. but made by the same method. Pref. the reaction prod. is an oxide, nitride or carbide and the metal is Ti, Si, Zr, Hf or Sn.

    ASSEMBLY FOR MAKING CERAMIC COMPOSITE STRUCTURES AND METHOD OF USING THE SAME

    公开(公告)号:ZA88202B

    公开(公告)日:1988-06-30

    申请号:ZA88202

    申请日:1988-01-13

    Abstract: An assembly for the preparation of ceramic composite structures includes a segmented container (12) within which a permeable filler is retained and a parent metal body (20) is contacted with the bed (18) of permeable filler. The segmented container (12) is comprised of one or more segments made of a material, such as an Inconel alloy, which has a coefficient of thermal expansion which is significantly greater than that of the filler. The segments are arranged to define between or among them one or more expansion joints which are effective to accommodate circumferential thermal expansion of the segments to thereby inhibit or prevent volumetric expansion of the container (12). A method of forming ceramic composite structures includes heating the resulting assembly to melt and oxidize the parent metal, (20), e.g., aluminum, to form a polycrystalline material comprising an oxidation reaction product which grows through the mass of filler to embed it and thus form the composite structure.

    METHOD OF MAKING SHAPED CERAMIC ARTICLES BY SHAPE REPLICATION OF AN EXPENDABLE PATTERN

    公开(公告)号:ZA8859B

    公开(公告)日:1988-06-27

    申请号:ZA8859

    申请日:1988-01-06

    Abstract: A method of producing shaped, self-supporting ceramic bodies includes preparing a mold by applying a permeable, conformable material (5) to a shape-defining surface (3) of an expendable pattern (2). The permeable, conformable material, when set or stable, provides a mold with a shaped surface which is defined by, and is therefore substantially congruent to, the shape-defining surface. Upon heating, the material of the expendable pattern (2) combusts or volatilizes and thus establishes the shaped cavity mold. A molten parent metal (1) is then vaporized with a vapor-phase oxidant in such a manner as to form a ceramic body which grows into the mold cavity, and is shaped by it. The ceramic body is recovered from the mold having a shaped surface replicating the shape-defining surface (3) of the expendable pattern (2).

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