Silicon carbide-silicon composite having improved oxidation resistance and method of making
AssigneeGeneral Electric Company
InventorsKrishan Lal Luthra, Hongyu Wang
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Abstract
A Silicon carbide-silicon matrix composite having improved oxidation resistance at high temperatures in dry or water-containing environments is provided. A method is given for sealing matrix cracks in situ in melt infiltrated silicon carbide-silicon matrix composites. The composite cracks are sealed by the addition of various additives, such as boron compounds, into the melt infiltrated silicon carbide-silicon matrix.
Claims13
A ceramic composite capable of self-healing cracks, comprising coated fibers in a silicon-silicon carbide matrix containing a boron-containing material having a ratio of boron atoms to silicon atoms in said matrix is between about 0.05 to about 0.40, where said boron-containing material is selected from the group consisting of boron, boron carbide, titanium borides, zirconium borides, aluminum borides, calcium borides, boron silicides, and mixtures thereof, and where said silicon-silicon carbide matrix comprises a phase mixture of silicon carbide and silicon.
A ceramic composite with a porosity of less than about 20% by volume, with a capacity to heal matrix cracks on oxidation in situ in a silicon carbide-silicon matrix composite, comprising a fibrous material of which the fibrous material component comprises at least about 5% by volume of the composite;
- at least about 1% by volume of a phase of elemental silicon;
- and boron-containing material dispersed throughout the matrix where an atomic ratio of boron to silicon atoms in the composite matrix is between about 0.05 to about 0.40, and boron is present in the form of elemental boron or at least one boron-containing compound or mixtures thereof.
A method of making a silicon carbide-silicon composite capable of healing cracks in situ from oxidation in the composite matrix, comprising the steps of:
- depositing at least a first coating on a silicon carbide-containing fibrous material which substantially covers an outer surface of said fibrous material;
- admixing a carbon particulate or a silicon carbide particulate or carbon particulate and silicon carbide particulate, and at least one boron-containing material with said fibrous material;
- forming said admixture into a preform;
- infiltrating said preform with an infiltrant comprising substantially molten silicon;
- and cooling said infiltrated preform to produce the silicon carbide-silicon matrix composite, where a ratio of boron atoms to silicon atoms in said matrix is between about 0.05 to about 0.40.
An article of manufacture for use in an engine, said article comprising a ceramic composite containing an elemental silicon phase with dissolved boron, a silicon carbide phase, fibrous material, and boron-containing materials dispersed throughout a silicon-silicon carbide composite matrix, where said boron-containing material is selected from the group consisting of boron, boron carbide, titanium borides, zirconium borides, aluminum borides, calcium borides, boron silicides, and mixtures thereof, and a ratio of boron atoms to silicon atoms in said matrix is between about 0.05 to about 0.40.
Dependencies are inferred from the claim text.