Mullite-containing coatings for inorganic fibers and ceramic matrix composites
AssigneeE. I. Du Pont de Nemours and Company
InventorsEugene Michael McCarron, III, Mark Andrew Harmer, Sujata Jagota
Life of this patent
Estimating the term…
Abstract
A ceramic matrix composite article comprised of inorganic fibers having a mullite-containing coating disposed within a matrix phase. The invention also provides a method for mating such an article, as well as for preparing a fiber having a mullite-containing coating. The mullite-containing coating on inorganic fibers within a matrix acts as a debonding coating, and the ceramic matrix composite article exhibits high strength and fracture toughness, even at elevated temperatures.
Claims24
An improved ceramic matrix composite article comprising:
- (a) a matrix phase comprised of a ceramic material selected from the group consisting of crystalline ceramics, glass ceramics, glasses and combinations thereof;
- and
- (b) a fiber reinforcement phase comprised of a plurality of amorphous or crystalline inorganic fibers disposed within the matrix phase,
- wherein the improvement comprises the inorganic fibers having a mullite-containing coating on the surface of said inorganic fibers and wherein the inorganic fibers are not comprised of a mullite-precursor.
A process for making a ceramic matrix composite article comprising the steps of:
- (a) modifying a smectite clay by ion-exchange in solution to provide sufficient amounts of aluminum ions in the clay;
- (b) adding a pillared smectite clay to the solution to form a suspension;
- (c) drawing an inorganic fiber through the suspension of step (b) and drying the fiber thereafter;
- (d) repeating step (c) a plurality of times until the desired amount of coating is deposited on the surface of the fiber;
- and
- (e) combining a plurality of coated fibers with a matrix phase comprised of a ceramic material selected from the group consisting of crystalline ceramics, glass-ceramics, glasses and combinations thereof, to form a ceramic matrix composite such that the plurality of coated fibers are disposed within the matrix phase;
- and
- (f) heating the ceramic matrix composite to a temperature sufficient to convert the clay coating on the fibers to a coating containing mullite and wherein the inorganic fibers are not a mullite-precursor.
A method for coating a fiber with a mullite-containing coating, comprising the steps of:
- (a) modifying a smectite clay by ion-exchange in solution to provide sufficient amounts of aluminum ions in the clay;
- (b) adding a pillared smectite clay to the solution to form a suspension;
- (c) drawing an inorganic fiber through the suspension of step (b) and drying the fiber thereafter;
- (d) repeating step (c) a plurality of times until the desired amount of coating is deposited on the surface of the fiber;
- and
- (e) heating the coated fiber to a temperature sufficient to convert the clay coating to a coating containing mullite and wherein the inorganic fiber is not a mullite-precursor.
An amorphous or crystalline inorganic fiber having a mullite-containing coating wherein the inorganic fiber is not a mullite-precursor.
Dependencies are inferred from the claim text.