摘要:
A composite hollow ceramic fiber includes a porous hollow core supporting a thin, dense sheath. The non-gas-tight core comprises a first ceramic compound and an interconnecting network of pores. The gas-tight sheath comprises a second ceramic compound. The fiber is made by extruding first and second suspensions of the first and second ceramic compounds in polymeric binders and solvent from a spinnerette and coagulating the nascent hollow fiber to effect phase inversion of the polymeric binders. The resultant green fiber is sintered in a two step process. First, the binder is burned off. Second, the sheath is densified and the second ceramic compound is sinter without fully sintering the first ceramic compound. The first ceramic compound has a melting point higher than that of the second ceramic compound.
摘要:
A composite hollow ceramic fiber includes a porous hollow core supporting a thin, dense sheath. The non-gas-tight core comprises a first ceramic material and an interconnecting network of pores. The gas-tight sheath comprises a second ceramic material. The fiber is made by extruding core and sheath suspensions from a spinnerette. The core suspension includes particles of the first ceramic material, a polymeric binder, a solvent, and a pore former material insoluble in the solvent. The sheath suspension includes particles of the second ceramic material, a polymeric binder and a solvent. The nascent hollow fiber is coagulated in a coagulant bath to effect phase inversion of the polymeric binders. The resultant green fiber is sintered in a two step process. First, the binders and pore former material are burned off. Second, the sheath is densified and the second ceramic material is sintered without fully sintering the core.