Engineered SiC-SiC composite and monolithic SiC layered structures
Systems, structures, devices, and fabrication processes for ceramic matrix composites suitable for use in a nuclear reactor environment and other applications requiring materials that can withstand high temperatures and/or highly corrosive environments are disclosed. In one aspect, a ceramic composite structure is provided. The structure comprises a chamber including an external shell and a hollow space inside the external shell. The external shell includes an inner composite layer including a first composite structure, a middle composite layer placed outside of the inner composite layer, the middle composite layer including a second composite structure that is different from the first composite structure, and an outer monolithic layer that has a spatially uniform material property and placed outside of the middle composite layer.
1. A multilayer ceramic structure formed by a chemical vapor deposition process or a chemical vapor infiltration process, comprising a chamber including an external shell and a hollow space inside the external shell, wherein the external shell includes:
an inner composite layer including a first composite structure, wherein the first composite structure comprises a first ceramic matrix reinforced by a first composite reinforcement comprising at least one of (1) ceramic additives at a first loading amount or (2) ceramic fibers arranged at a first reinforcement orientation,
a middle composite layer placed outside of the inner composite layer, the middle composite layer including a second composite structure that is different from the first composite structure, and wherein the second composite structure comprises a second ceramic matrix reinforced by a second composite reinforcement comprising at least one of (1) ceramic whiskers at a second loading amount or (2) ceramic fibers arranged at a second reinforcement orientation, and
an outer ceramic impermeable monolithic layer that is placed outside of the middle composite layer.
2. The multilayer ceramic structure of claim 1 , further comprising:
one or more composite layers placed between the inner composite layer and the middle composite layer, each of the one or more composite layers having a different composite structure.
3. The multilayer ceramic structure of claim 1 , further comprising:
one or more ceramic monolithic layers placed between the middle composite layer and the outer ceramic impermeable monolithic layer.
4. The multilayer ceramic structure of claim 3 , further comprising:
a plurality of thin layers deposited outside the outer ceramic impermeable monolithic layer or between the outer ceramic impermeable monolithic layer and one of the one or more ceramic monolithic layers, and between each of remaining layers of the one or more ceramic monolithic layers, to inhibit crack propagation, wherein the plurality of thin layers comprises a metal.
5. The multilayer ceramic structure of claim 4 , wherein the plurality of thin layers comprise a ductile material.
6. The multilayer ceramic structure of claim 4 , wherein the plurality of thin layers include pyrolytic carbon or metal.
7. The multilayer ceramic structure of claim 1 , wherein the first composite structure comprises a first reinforced silicon carbide (SIC) composite, and wherein the second composite structure comprises a second reinforced silicon carbide (SIC) composite.
8. The multilayer ceramic structure of claim 7 , wherein the first reinforced SiC composite or the second reinforced SiC composite includes a braided SiC fiber composite, a wound SiC fiber composite, or a small-scale additive composite with additives having a dimension in a nanometer or micrometer range.
9. The multilayer ceramic structure of claim 1 , wherein the outer ceramic impermeable monolithic layer includes a β-SiC material.
10. The multilayer ceramic structure of claim 1 , further comprising a barrier coating layer placed outside of the outer ceramic impermeable monolithic layer, wherein the barrier coating layer comprises a metal or a ceramic.
11. The multilayer ceramic structure of claim 1 , wherein thickness of the inner composite layer and the middle composite layer comprises greater than 70% of an overall thickness of the external shell.
12. The multilayer ceramic structure of claim 1 , wherein the external shell is structured for fabrication of a nuclear fuel cladding for holding a nuclear fuel material, a part of a heat exchanger, a part of a nozzle, a nosecone, a shroud, a combustor liner, or a flow channel insert.
13. The multilayer ceramic structure of claim 1 , wherein the first composite structure of the inner composite layer comprises ceramic additives and the ceramic additives comprise micro- and nano-scale additives, wherein micro-scale refers to a sub-millimeter range and nano-scale refers to a sub-micron range, and wherein the second composite structure of the middle composite layer comprises ceramic fibers which are structured to exhibit different ratios in fiber strength in a hoop direction and an axial direction of the external shell, respectively, and wherein the nano-and micro-scale additives of the inner composite layer comprises a smoother surface than ceramic fiber reinforcement of the middle composite layer.
14. The multilayer ceramic structure of claim 13 , wherein the ceramic fibers are structured to be hoop-biased, having a ratio above 1:1 and up to 1.3:1 in the hoop direction and the axial direction of the external shell.
15. The multilayer ceramic structure of claim 13 , wherein the ceramic fibers are structured to be axial biased, having a ratio above 1:1 and up to 1:1.5 in the hoop direction and the axial direction of the external shell.
16. The multilayer ceramic structure of claim 1 , wherein the outer ceramic impermeable monolithic layer is structured with respect to the inner and middle composite layers to remain in compression when subjected to an operating stress.
17. The multilayer ceramic structure of claim 1 , wherein the outer ceramic impermeable monolithic layer is further configured to provide corrosion resistance.
18. The multilayer ceramic structure of claim 1 , wherein a thickness of the outer ceramic impermeable monolithic layer is at least 100 μm.
19. The multilayer ceramic structure of claim 1 , wherein a roughness measurement of the inner composite layer is within a range of 4 to 50 μm.