Cellular structures with interconnected microchannels
A method for fabricating a cellular tritium breeder component includes obtaining a reticulated carbon foam skeleton comprising a network of interconnected ligaments. The foam skeleton is then melt-infiltrated with a tritium breeder material, for example, lithium zirconate or lithium titanate. The foam skeleton is then removed to define a cellular breeder component having a network of interconnected tritium purge channels. In an embodiment the ligaments of the foam skeleton are enlarged by adding carbon using chemical vapor infiltration (CVI) prior to melt-infiltration. In an embodiment the foam skeleton is coated with a refractory material, for example, tungsten, prior to melt infiltration.
1. A method for fabricating a cellular tritium breeder component comprising:
obtaining a reticulated carbon foam skeleton, wherein the carbon foam skeleton comprises a network of interconnected ligaments;
melt-infiltrating the carbon foam skeleton with a tritium breeder material to fill void space in the network of interconnecting ligaments;
allowing the breeder material to solidify; and
removing the carbon foam skeleton such that the breeder material defines a three-dimensional component containing a network of interconnected channels therethrough,
wherein the tritium breeder material volumetric density in the breeder component is between 70 percent and 95 percent.
2. The method of claim 1 , wherein the breeder material comprises one or more of lithium zirconate, lithium titanate, lithium orthosilicate, and lithium oxide.
3. The method of claim 1 , wherein the carbon foam skeleton network of interconnected ligaments comprises a reticulated vitreous carbon foam.
4. The method of claim 1 , wherein the carbon foam skeleton comprises a foam skeleton having an open porosity between 96 vol. % and 98 vol. %.
5. The method of claim 1 , further comprising enlarging the transverse dimension of the interconnected ligaments before melt-infiltrating the carbon foam skeleton by adding carbon to the carbon foam skeleton.
6. The method of claim 5 , wherein the carbon is added to the carbon foam skeleton by chemical vapor infiltration.
7. The method of claim 5 , wherein the carbon foam skeleton has a volume density between 10 vol. % and 20 vol. % after adding the carbon to the carbon foam skeleton.
8. The method of claim 1 , further comprising coating the carbon foam skeleton with a refractory material prior to melt-infiltrating the carbon foam skeleton.
9. The method of claim 8 , wherein the refractory material comprises a refractory metal.
10. The method of claim 9 , wherein the refractory material comprises tungsten.
11. The method of claim 8 , wherein coating the carbon foam skeleton is accomplished by chemical vapor infiltration.
12. The method of claim 4 , further comprising coating the carbon foam skeleton with a refractory metal prior to melt-infiltrating the carbon foam skeleton.
13. The method of claim 12 , wherein the refractory metal comprises tungsten.
14. The method of claim 1 , wherein the foam skeleton defines a plurality of open cells, and further wherein the open cells define at least 50 pores per inch.
15. The method of claim 1 , wherein the foam skeleton defines a plurality of open cells, and further wherein the open cells define 65 to 100 pores per inch.
16. The method of claim 1 , wherein the step of melt-infiltrating the carbon foam skeleton is performed in an inert atmosphere.
17. The method of claim 16 , wherein the inert atmosphere comprises argon.
18. The method of claim 1 , further comprising the step of forming the foam skeleton into a desired shape before melt-infiltrating the carbon foam skeleton.
19. The method of claim 1 , wherein the step of melt-infiltrating the carbon foam skeleton is performed at a pressure less than 0.9 atmospheres.