Method for fabricating ceramic matrix composite components
A method for fabricating a component according to an example of the present disclosure includes the steps of depositing a stoichiometric precursor layer onto a preform, and densifying the preform by depositing a matrix material onto the stoichiometric precursor layer. An alternate method and a component are also disclosed.
1. A method of fabricating a component, the method comprising:
arranging one or more preforms in a reactor;
providing a silicon-containing precursor to the reactor such that the silicon-containing precursor adsorbs onto the one or more preforms;
providing a carbon-containing precursor to the reactor such that the carbon-containing precursor reacts with the silicon-containing precursor to form a stoichiometric precursor layer, wherein the ratio of silicon atoms to carbon atoms in the stoichiometric precursor layer is approximately one; and
providing at least one silicon carbide precursor to the reactor to densify the one or more preforms by depositing a silicon carbide matrix onto the stoichiometric precursor layer.
2. The method of claim 1 , wherein the silicon carbide matrix has a ratio of silicon atoms to carbon atoms, and the ratio is approximately one.
3. The method of claim 1 , wherein the silicon-containing precursor includes one of Cl 2 SiH 2 , SiH 4 , ClSiH 3 , and Si 2 H 6 and the carbon-containing precursor includes one of CH 4 (methane), C 2 H 6 (ethane), C 3 H 8 (propane), C 2 H 2 (acetylene), and C 2 H 4 (ethylene).
4. The method of claim 1 , wherein the at least one silicon carbide precursor includes a first precursor and a second precursor, and the first precursor is methyltrichlorosilane (MTS) and the second precursor is hydrogen (H 2 ).
5. The method of claim 1 , further comprising the step of vacuuming the reactor after the step of providing the silicon-containing precursor to the reactor to remove excess silicon-containing precursor from the reactor.
6. The method of claim 1 , further comprising the step of vacuuming the reactor after the step of providing the carbon-containing precursor to the reactor to remove excess carbon-containing precursor from the reactor.
7. The method of claim 1 , wherein the reactor includes an exhaust valve, and wherein the exhaust valve is closed during the step of providing the silicon-containing precursor to the reactor and the step of providing the carbon-containing precursor to the reactor, and the exhaust valve is open during the step of providing at least one silicon-carbide precursor to the reactor.
8. The method of claim 1 , wherein the one or more preforms comprise silicon carbide fibers.
9. The method of claim 8 , wherein the silicon carbide fibers are coated with a boron nitride interfacial coating.
10. The method of claim 8 , wherein the silicon carbon fibers have a unidirectional orientation with respect to one another.
11. The method of claim 8 , further comprising determining the ratio of silicon atoms to carbon atoms in the silicon carbide matrix, and comparing the ratio to one.