DENSE SKIN CERAMIC STRUCTURE AND METHOD OF MAKING THE SAME

    公开(公告)号:ZA875716B

    公开(公告)日:1988-02-11

    申请号:ZA875716

    申请日:1987-08-03

    Abstract: The disclosure concerns self-supporting ceramic structures, including ceramic composite structures embedding a filler, and methods of making them. The ceramic structures comprise a polycrystlline material made by oxidation of a body of molten parent metal with an oxidant. The polycrystalline material has a first region substrate surmounted by a terminal region stratum which is integral with the first region. The terminal region stratum which is harder and of denser, finer crystalline structure than the first region substrate and is formed in a reaction stage subsequent to the reaction stage in which the first region of polycrystalline material is formed. Growth of the first stage is attained by by attenuating or interrupting the transport of molten parent metal to the first region under conditions which nonetheless leave or maintain therein enough oxidizable molten parent metal to form the polycrystalline material of the terminal region.

    55.
    发明专利
    未知

    公开(公告)号:ES2036595T3

    公开(公告)日:1993-06-01

    申请号:ES87630183

    申请日:1987-09-10

    Abstract: A method is disclosed for producing a ceramic body by oxidation of a parent metal, the ceramic body having a graded microstructure characterized by a plurality of zones differing from each other in one or more properties. The zones in the ceramic body are attained by altering the process conditions during formation of said ceramic body such that a zone of the oxidation reaction product formed posterior to said altering has one or more properties different from a zone of the oxidation reaction product formed anterior to said altering.

    58.
    发明专利
    未知

    公开(公告)号:ES2032855T3

    公开(公告)日:1993-03-01

    申请号:ES87630182

    申请日:1987-09-10

    Abstract: A method of producing self-supporting ceramic structures (12) comprising (i) a polycrystalline oxidation reaction product formed upon oxidation of a molten parent metal (14) with an oxidant, and (ii) interconnected porosity (13) at least partially accessible from one or more surfaces (15) of said ceramic body. A second polycrystalline ceramic material is incorporated into the porosity of said ceramic body to modify or contribute to its properties.

    59.
    发明专利
    未知

    公开(公告)号:ES2032854T3

    公开(公告)日:1993-03-01

    申请号:ES87630178

    申请日:1987-09-03

    Abstract: A method of producing self-supporting ceramic structures includes providing a first self-supporting ceramic body (10) comprising (i) a polycrystalline oxidation reaction product (12) formed upon oxidation of a first molten parent metal with a first oxidant, and (ii) interconnected porosity (13) at least partially accessible from one or more surfaces (15) of said first ceramic body (10). A second ceramic body is used to form, by reaction with a vapor-phase oxidant, a second polycrystalline material which is infiltrated into the porosity of at least a zone of said first ceramic body (10).

    60.
    发明专利
    未知

    公开(公告)号:ES2028061T3

    公开(公告)日:1992-07-01

    申请号:ES87300409

    申请日:1987-01-19

    Abstract: A method of producing a self-supporting ceramic composite body having therein at least one cavity which inversely replicates the geometry of a positive mold of parent metal, includes embedding the mold of parent metal within a conformable bed of filler to provide therein a cavity shaped and filled by the mold. The assembly is heated to melt the parent metal mold, e.g., an aluminum parent metal mold, and contacted with an oxidant to oxidize the molten parent metal to form a polycrystalline material which grows through the surroundings of filler, the molten metal being drawn through the growing polycrystalline material to be oxidized at the interface between the oxidant and previously formed oxidation reaction product whereby the cavity formerly filled by the mold of parent metal is eventually evacuated by the metal. There remains behind a cavity whose shape inversely replicates the original shape of the mold. The method provides ceramic composite articles having therein at least one cavity inversely replicating the shape of the mold which supplied the parent metal for oxidation.

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