Controlled particle injection in fabric for improved microstructre homogeneity in CMCs
A method for manufacturing ceramic matrix composites (CMC) and CMCs made by the method are disclosed. The method can be a manual process or an automated process, such as using a robotic system, that is used for controlled delivery of ceramic particles in a CMC fabric. The method includes identifying voids present between adjacent tows of the CMC fabric and dispensing ceramic particles into the voids. Applying the ceramic particles in the center of the voids reduces the size and volume fraction of the voids/defects, improving the homogeneity of surface texture of the preform, homogeneity of microstructure, and part model shape conformity. The method for manufacturing CMCs creates CMCs having a homogenous distribution of small pores after matrix formation that improves the interlaminar mechanical and thermal properties of the CMCs.
1 . A method of manufacturing a ceramic matrix composite (CMC) component, the method comprising:
at least one ply formed from a plurality of interconnected tows;
measuring a distance, area, and/or volume between adjacent tows of the at least one ply to collect distance, area, and/or volume data;
comparing the distance, area, and/or volume measurement data to a spacing, area, and/or volume threshold;
identifying a void between adjacent tows of the at least one ply based on the distance, area, and/or volume measurement data exceeding the spacing, area, and/or volume threshold, wherein the spacing, area, and/or volume threshold is indicative of a void that is larger than desired;
selectively applying ceramic particles into the identified void of the at least one ply stacking one or more of the at least one ply in a desired manner to form a stack of plies;
debulking the stack of plies; and
densifying the stack of plies to form the CMC component through one or more of a chemical vapor infiltration, chemical vapor deposition, melt infiltration, and polymer infiltration and pyrolysis process.
2 . The method of claim 1 , wherein the ceramic particles are selectively applied into the identified void of the at least one ply using one or more of a pipette, a syringe, and a nozzle.
3 . The method of claim 2 , wherein the nozzle is one or more of an ultrasonic nozzle, air spray nozzle, or other spray nozzle.
4 . The method of claim 1 , wherein the spacing threshold for a distance between adjacent tows of the CMC component ranges from 100 micrometers to 1500 micrometers.
5 . The method of claim 1 , wherein the area threshold for an area between adjacent tows of the CMC component ranges from 23,000 square micrometers to 2,400,000 square micrometers.
6 . The method of claim 1 , wherein the volume threshold for a volume between adjacent tows of the CMC component ranges from 2,700,000 cubic micrometers to 550,000,000 cubic micrometers.
7 . The method of claim 1 , wherein:
the ceramic particles can be one or more of silicon carbide, boron carbide, silicon nitride, pure silicon, pure carbon, aluminum oxide, and hafnia.
8 . The method of claim 1 , wherein the distance measurement data is gathered using one or more of a caliper, a gauge, and a vision system.
9 . The method of claim 8 , wherein the vision system is one or more of a laser scanner, a white light scanner, and a confocal microscope.
10 . The method of claim 1 , wherein the ceramic particles are applied into the identified void concurrently with a binder.